Thursday, November 30, 2017

Nilotinib and Parkinson's Disease


Parkinson’s disease: a diagnosis that marks the beginning of end of a patient’s motor functions. It is the most common of the neurodegenerative diseases, and in terms of treatment, also happens to be the most elusive. The disease is characterized by the unexplained death of dopaminergic neurons in the substantia nigra (SN) portion of the brain. Dopamine is vital for control of motor function, thus the death of these neurons begins the start of the disease. Thus far, we have only learned how to treat the symptoms of the disease. Patients are treated with Levodopa, a precursor to dopamine, coupled with carbidopa to ensure its safe delivery to the brain and even distribution to the central nervous system.
Patients diagnosed with Parkinson’s disease will experience resting tremors (especially in the hands), bradykinsesia (slowness of movements), limb rigidity, and gait and balance issues. In addition to motor function loss, there are non-motor symptoms as well. These include, but are not limited to: depression, loss of sense of smell, and cognitive impairment.
Molecular causes of the disease are largely unknown. Only 10-15% of cases can be attributed to genetics, while the remaining are sporadic with no known cause. There are currently one million people in the United States living with PD. Because of the late onset of symptoms, the majority of cases are only caught when the symptoms have begun and the patient’s motor function is already degenerating, they are already late stage patients. This gives doctors and PD researchers no time to focus on prevention or see what exactly is causing it.      
Nilotinib, advertised as Tasigna, is currently approved for treating newly diagnosed adult patients with Philadelphia chromosome–positive chronic myeloid leukemia (Ph+ CML) in chronic phase (CP). Studies have shown that Nilotinib decreases levels of alpha-synuclein in the brain as well as the blood. The primary component of the Lewy Bodies found in the substantia nigra, the site of this neuron death, is alpha-synuclein. Alpha-synuclein activates Abl, a tyrosine kinase that has many functions, including apoptosis. In trials with mice, the drug was found to not only increase dopaminergic levels and improve motor function, but also to clear cytosolic debris in SN neurons.
Is Nilotinib scraping the surface of new treatment options for Parkinson’s? Are we finally understanding the molecular events that lead up to this devastating neurodegenerative disease?
Resources
Dauer, W., & Przedborski, S. (2003). Parkinson’s Disease: Mechanisms and Models. Neuron,
39, 889-909. Retrieved November 16, 2017.
Hebron, M. L., Lonskaya, I., & Moussa, C. E. (2013). Nilotinib reverses loss of dopamine
neurons and improves motor behavior via autophagic degradation of  -synuclein in           
Parkinsons disease models. Human Molecular Genetics, 22(16), 3315-3328.
doi:10.1093/hmg/ddt192
Karuppagounder, S. S., Brahmachari, S., Lee, Y., Dawson, V. L., Dawson, T. M., & Ko, H. S.
(2014). The c-Abl inhibitor, Nilotinib, protects dopaminergic neurons in a preclinical
animal model of Parkinsons disease. Scientific Reports, 4(1). doi:10.1038/srep04874
Pagan, F., Hebron, M., Valadez, E. H., Torres-Yaghi, Y., Huang, X., Mills, R. R., . . . Moussa, C.
(2016). Nilotinib Effects in Parkinson’s Disease and Dementia with Lewy Bodies.
Journal of Parkinson's Disease,6, 503-517. Retrieved November 15, 2017.
Parkinson Disease Treatment & Management. (2017, November 15). Retrieved November 16,
Tasigna. (n.d.). Retrieved November 16, 2017, from https://www.hcp.novartis.com/products/ta
What Is Parkinson's? (2017, October 18). Retrieved November 16, 2017, from http://www.parkinson.org/understanding-parkinsons/what-is-parkinsons
By Savannah Tucker, Bachelor of Public Health Student, University of Kentucky

Crohn's Disease

     The feeling one just cannot shake. That sudden urge to go to the restroom. It is monstrous and undeniable. But, what if that urge is more often than the norm? And, it is followed with abdominal pain, diarrhea and a fever? It may be something to look in to. A disease known as Crohn’s disease.  Crohn’s disease is increasing among all ethnicities; but, it is not something that cannot be treated. With extensive research and years of testing, adalimumab (Humira) has provided a treatment for those who suffer from this irritable disease. Because Crohn’s disease is growing in incidence and prevalence, adalimumab has been created to assist those who are battling with this disease.

      Crohn’s disease is a relapsing systematic inflammatory disease effecting the gastrointestinal tract that is associated with immune disorders. The exact cause of Crohn’s disease is unclear (1). However, it can be linked to environmental factors, aberrant immune function and bacterial factors (1). Those who suffer from the disease experience an array of symptoms such as consistent abdominal pain, high fever, unintended weight loss and frequent diarrhea with passage of blood or mucus (1). Crohn’s disease and Ulcerative colitis are the two main components of inflammatory bowel disease.


     There are five known types of Crohn’s disease that affect different location of the gastrointestinal tract (2). The severity of each depends on the progression of the disease and the genetic and environmental build-up of a person. The five types of Crohn’s disease are gastroduodenal which affects the stomach and duodenum. Those who suffer from this form of Crohn’s disease experience symptoms such as loss of appetite, weight loss, nausea and vomiting. Crohn’s colitis is also a form of Crohn’s disease but only affects the colon. Those who suffer from Crohn's colitis experience diarrhea, rectal bleeding and complications around the anus. Another type is ileocolitis. It is the most common form of Crohn’s disease and affects the ileum and colon. Those who suffer from ileocolitis experience symptoms such as diarrhea, cramping or pain in the right lower part or middle of the abdomen, and weight loss. Jejunoileitis is also a form of Crohn’s disease. Jejunoileitis creates patchy areas of inflammation in the jejunum and ileum. Those who suffer from jejunoileitis experience abdominal pain, cramps following meals and diarrhea. The fifth form of Crohn's disease is ileitis. It affects only the ileum and its symptoms are similar to those of ileocolitis (2).

     Large concordance studies in twins in northern Europe were early indicators of a genetic component in Crohn’s disease. The study showed that thirty five percent of monozygotic pairs and only three percent of dizygotic pairs were concordant for the disorder. In seventy percent of discordant monozygotic pairs, the first-born had inflammatory bowel disease. Substantial   phenotypic (such as the location, behavior, and age at diagnosis) concordance exists, both at diagnosis and longitudinally, in monozygotic twins. As stated above there has been a prevalence in all ethnicities. For example, prevalence in Ashkenazi Jews is higher than any other ethnic group. Genome wide association studies and computerized (in silico) meta-analyses have identified and confirmed seventy-one susceptibility loci for Crohn’s disease on seventeen chromosomes (3).
Environmental factors also affect the rate of Crohn’s disease. Rates of the disease in the northern and southern are equal. Because of industrialization, most people focus on their career and higher education. This led to a change in life events like breast feeding and there are smaller families with larger less crowded living conditions. The improved domestic hygiene and sanitation, consumption of diet and less active lifestyle are all factors that contribute to the gain (3) of Crohn’s disease. One of the most prominent risk factors is the use of tobacco products. Also, use of tobacco significantly increases the risk of developing the disease. An estimated three million U.S. adults have been diagnosed with either Crohn’s disease or ulcerative colitis. This is a one million person increase since the year 1999.

     But, let’s get down to the nitty gritty. How is it treated… with adalimumab of course? Adalimumab was approved by the FDA December 2002. It was initially launched for the treatment of rheumatoid arthritis but was later found to assist in the treatment of irritable bowel diseases such as Crohn’s disease. In two clinical studies, adalimumab showed fifty-eight and fifty-two percentage approval compared to the thirty-four percent who consumed the placebo. Thirty-six and twenty-one percent also achieved remission in comparison to the twelve and seven percent who consumed the placebo (4). This is how it works. Adalimumab binds to TNF-alpha and blocks its interaction with the p55 and p75 cell surface TNF receptors. Adalimumab also lyses surface TNF expressing cells in vitro in the presence of complement. This mechanism blocks cytokine effects, thereby reducing TNF-induced inflammation and halting tissue destruction (5).

     With extensive research and years of testing, Humira has provided a treatment for those who suffer from this irritable disease. Because Crohn’s disease is growing in incidence and prevalence, adalimumab has been created to assist those who are battling with this disease. A total of sixty genes have been studied and evaluated to determine whether genetic variants are associated with irritable bowel syndrome. Also, there are five main pathways effected by Crohn’s: serotonin, adrenergic, inflammation, intestinal barrier, and psychiatric that have been found. As technology improves hopefully there will be further research for a cure for irritable bowel syndrome/disease.

Work Cited

1. Baumgart, Daniel C, and William J Sandborn. “Crohn's Disease .” Lancet, vol. 2012, no. 380, ser. 1590-1605, 20 Aug. 2012, pp. 1–16. 1590-1605, doi:http://dx.doi.org/10.1016/ S0140-6736(12)60026-9.
2. “HUMIRA (Adalimumab) Clinical Data | Ulcerative Colitis.” HUMIRA (Adalimumab) | Official Healthcare Professional Site, www.humirapro.com/gastroenterology/ulcerative-colitis-clinical-data.
3. Saito, Yuri A. “The Role of Genetics in IBS.” Gastroenterology clinics of North America 40.1 (2011): 45–67. PMC. Web. 28 Nov. 2017
4. HUMIRA (Adalimumab), Abbott Laboratories - Package Insert, www.accessdata.fda.gov/drugsatfda_docs/label/2002/adalabb123102lb.htm

5. “Adalimumab.” DrugBank, www.drugbank.ca/drugs/DB00051.

By Lexus Cabiness, Post Baccalaureate Student, University of Kentucky

Preventing Noncompliance in Psychotic Patients

Image from:  Youthvillage.co.za
Non-adherence to medication and medical recommendations in patients is very common across all branches of the healthcare field. In fact, it is one of the challenges healthcare providers face on a daily basis with their patients. We all know or have heard of the patient with diabetes type 2 consuming carbohydrates in excessive amount regularly or the elderly man who recently suffered from a heart attack eating food high in cholesterol regularly or even the patient with a microbial infection rejecting the full course of the antibiotic treatment prescribed by the physician. I have to admit that I have been guilty of the latter. So, when patients become noncompliant to their medications, it makes it very difficult to provide effective medical care. Unfortunately, for psychotic patients, these noncompliant behaviors can pose greater risks, as studies show a higher frequency of noncompliance in psychotic patients.

Many psychotic patients rely on their medications alone to control and regulate their mental disorders. Neuroleptic drugs are essential in treating psychotic disorders such as bipolar disorder, schizophrenia, clinical depression and many more. Some patients require several months or years of medication or even lifelong medication is necessary.  However, up to 80% of psychotic patients fail to comply with their treatment (1). This is a major problem! I think the first question we need to ask ourselves is why so many patients with mental disorders are either rejecting treatment, self-medicating with illegal drugs, or discontinuing a prescribed medication? Is it due to the patient’s negligence? Carelessness? In the case of an acquaintance with schizophrenia that is not the case. He informed me that his medication was making him gain an excessive amount of weight, something he despises. He proceeded to tell me he felt like a “zombie”. I asked him if he was still taking his medication but he informed me that he was self-medicating with marijuana. A few months later, I found out he relapsed and got hospitalized. Sadly, this has been an ongoing battle with many patients. For many the side effects are just too much to bear.  You see, one of the major reasons these patients are noncompliant to their treatment is due to the side effects of these drugs. Although these medications can cause great relief to a mental condition that has been affecting the lives of these individuals, they are not of small risks.

Almost all psychotropic medications cause some serious side effects which can be life-threatening and irreversible. In many cases, these psychotropic medications fail to help patients. So, it really makes me wonder if these patients are being treated in the most effective way. Healthcare providers can only hope that their patients are actually following the course of treatment. Unfortunately, it is difficult to ensure compliance. According to the National Institute of Neurological Disorders and Strokes of the National institutes of Health, antipsychotic drugs can cause neuroleptic malignant syndrome (NMS)(3). NMS is characterized by fever, muscular rigidity, altered mental status and autonomic dysfunctions. One of the most common side effects of antipsychotic drugs is a condition known as akathisia. Between 20 to 75 percent of patients develop this condition.(4) Akathisia is a movement disorder characterized by uncontrollable physical restlessness, agitation, shaking of arms and legs, anxiety and panic. The condition can develop as soon as the patient start taking the drug. Many of these side effects are associated with older neuroleptic drugs. There have been major advancement of modern psychopharmacology with the development of newer drugs. But even with these new drugs, weight gain and sexual dysfunction can be two of the most common side effects associated. Some other common side effect associated with these drugs are nausea, dizziness, sleepiness, Diarrhea, suicidal behaviors etc.

There are many factors associated with noncompliance in psychotic patients. The lack of insight and lack of awareness of the illness itself pose a challenge especially in schizophrenia.(2) However, we cannot deny that adverse effects of these psychiatric drugs contribute greatly to this critical issue. So, what is the solution? How do we reduce the lack of compliance due to psychotic drugs’ adverse effects? Firstly, it is the responsibility of clinicians to educate their patients on the illness and the different side effects of the drugs prescribed. In addition, patients need to be part of the decision-making process. Pharmacological strategies such as dose adjustment and the use of long-acting injections would be a great way to ensure patients comply with treatment. Dose adjustment is especially important because prescribing medication is not a “one size fits all” process. Reducing medication dose can reduce the side effects in patients. Of course, I understand that some patients require higher dose and in that case, clinicians could add another class of medication, such as anticholinergic for extrapyramidal side effects.(2) Another interesting approach would be the use of psychotherapy in addition to drug therapy. Psychotherapy provides a holistic approach to treating a psychotic patient, something that drugs cannot do on their own. There are different types of psychotherapy and research has shown that Cognitive Behavioral Therapy can change thinking and behavior patterns that are harmful or ineffective and replace them with functional behaviors.(4)

There is not just one strategy to use to improve compliance. Every patient is different and has different requirements.  Some clinicians use a combination of strategies and approaches to improve compliance in their patients. The ultimate goal is to ensure that psychotic patients are being treated efficiently and thoroughly to avoid relapse and psychiatric hospitalization. In the end, we need to put more emphasis on new drugs development, the use of psychotherapies and drugs adjustments to reduce noncompliance in patients with psychotic disorders and improve the quality of life of these patients.

References:
1.Gray, R. “Compliance Therapy in Psychotic Patients. Many Ethical Questions Arise from Study.” BMJ (Clinical Research Ed.)., U.S. National Library of Medicine, 18 May 1996,
2.Kane, John M, Taishiro Kishimoto, and Christoph U Correll. “Non-Adherence to Medication in Patients with Psychotic Disorders: Epidemiology, Contributing Factors and Management Strategies.” World Psychiatry 12.3 (2013): 216–226. PMC. Web. 30 Nov. 2017.
3.Medical Whistleblower Advocacy Network.” Psychiatric Drugs Side Effects | Medical Whistleblower, medicalwhistlebloweradvocacynetwork.com/psychiatric-drugs-side-effects-.
4.Pareck, Ranna. “What Is Psychotherapy.” Psychiatry.org, July 2016, www.psychiatry.org/patients-families/psychotherapy.
5.Balon, Richard. “Managing Compliance.” Managing Compliance | Psychiatric Times, 1 May 2002, www.psychiatrictimes.com/articles/managing-compliance/page/0/1.

By Tressie Charles, Master of Science in Medical Sciences, University of Kentucky


Tuesday, November 21, 2017

Autism Spectrum Disorder


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A blue puzzle piece. This has become the renowned symbol for autism awareness. We all know someone who has been diagnosed with autism or is close to someone who was. Autism has actually been absorbed into a group of conditions called Autism Spectrum Disorder or ASD. Autism, Childhood Disintegrative Disorder, Rett disorder, Asperger’s syndrome, and a broad category, Pervasive Development Disorders Not Otherwise Specified (PDDNOS), are all diagnosed as a form of Autism Spectrum Disorder.  Autism Spectrum Disorder is a neurodevelopmental disorder. Its origins are unknown but it is thought to stem from a multifaceted genetic complication.  No, vaccinations do not cause autism! However, researchers have not ruled out environmental factors that may contribute to the onset of Autism. ASD covers a broad range of individuals that are affected by a variety of symptoms. The most commonly recognized symptoms are severely impaired social skills, challenges with speech and non-verbal communication, and exhibit repetitive behaviors. Commonly individuals will avoid eye contact, resist making social relationships, and will fail to show interest in the feelings of others. Autism Spectrum Disorder also has become known to be a full body disorder It is often accompanied by other serious conditions like epilepsy, gastro Intestinal disorders, sleep disruption, feeding issues, and mental health problem such as anxiety, depression, schizophrenia, ADHD, and bipolar disorder.

ASD is an unusual disorder because those affected may also have unique strengths when it comes to learning, thinking, and problem solving. Each person with ASD is likely to experience different levels of strengths and challenges. Some are high-functioning and are able to become accustomed to living day to day with autism. Others struggle to recognize emotions and social cues that make it difficult for them to interact with family and their peers on a daily basis. The signs if autism are likely to emerge and be recognized by the age of 3.  The CDC reports about 1 in every 68 children in the United States are afflicted with some sort of disorder on the Autism spectrum, a majority of which are male. The prevalence of this disorder and our lack of knowledge about it makes autism a relevant area for pharmacologic research. Behavioral therapy is usually the first treatment for ASD. Medications are currently just administered to assist patients with functioning in daily activities.

Currently the FDA has approved only two drugs, risperidone and aripiprazole, for ASD patients. These drugs are used only to manage irritability and aggression. Risperidone is an antipsychotic drug used in Autistic patients aged 5 and older. Studies of the use of this drug in children between the ages of 5 and 17 produced results that indicated risperidone was effective in reducing the number of tantrums and aggressive episodes in autistic children. While this drug has its benefits, there are also some concerning side effects like dizziness, drooling fatigue, hepatotoxicity, and weight gain.

Aripiprazole is also an antipsychotic drug used in autistic children aged 6 and older. It’s mechanism of action is not completely understood but it is suspected to involve agonist activity at dopamine type 2 and serotonin 1A receptors and antagonist activity at serotonin 2A receptors. This therapy was shown to increase the quality of life inventory scores in autistic children as well as significantly reduce irritability, hyperactivity, and repetitive actions. Aripiprazole also has some discouraging side effects that include dizziness, vomiting, fatigue, sedation, and weight gain. Many parents are most concerned with the weight gain that is associated with these drugs because of the chronic illnesses that accompany obesity such as heart disease and diabetes.

While there are only two FDA approved drugs for use in ASD cases, there are a variety of other pharmacotherapeutic options being studied for use in individuals with ASD to manage other symptoms. Anti-psychotics Clozapine and Haloperidol which are dopamine receptor antagonists also have been looked at to treat irritability is ASD patients but have harsher adverse effects like seizures and dyskinesia. Methylphenidate, which is a CNS stimulant used to treat ADD/ADHD has been studied to reduce inattention and hyperactivity in ASD patients. It is effective for those purposes at medium and high doses but alternatively increases irritability. Anxiety, repetitive behavior, and some social withdrawal symptoms seem to respond well to selective serotonin reuptake inhibitors which are intended for use as antidepressants. Melatonin, the sleep hormone has been used to reduce insomnia. A few other treatments such as Naltrexone and Oxytocin have been discussed as treatments for ASD but until the mechanism of the disorder is better understood, it will be very difficult to prove these treatments are effective against ASD not just the symptoms.

References:

“Autism Spectrum Disorder (ASD).” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 26 Feb. 2015, www.cdc.gov/ncbddd/autism/signs.html.
“How Is Autism Treated?” Autism Speaks, 24 July 2012, www.autismspeaks.org/what-autism/treatment.
King, Bryan H, and Jeff Q Bostic. “An Update on Pharmacologic Treatments for Autism Spectrum Disorders.” Child & Adolescent Psychiatric Clinics of North America, vol. 15, no. 1, pp. 161–175.
LeClerc, Sheena, and Deidra Easley. “Pharmacological Therapies for Autism Spectrum Disorder: A Review.” Pharmacy and Therapeutics 40.6 (2015): 389–397. Print.
Lee, Seung Yup et al. “Is Oxytocin Application for Autism Spectrum Disorder Evidence-Based?” Experimental Neurobiology 24.4 (2015): 312–324. PMC. Web. 11 Nov. 2017.

By Jordan Wells, Master of Medical Science Student, University of Kentucky

Wednesday, November 8, 2017

Energy Drinks

Caffeine, taurine, glucoronolactone, thiamine, pantothenic acid, pyridoxine hydrochloride, biotin, cyanocobalamin, guarana, ginseng, Ginkgo biloba, I-Carnitine, and sugars: a long and intimidating list of common ingredients. Common ingredients for what? Energy drinks.
Image from:  Caffeineformer.com
 Energy drinks first came on the market in 1997 in the United States. Since their introduction, they have gained mass popularity throughout the country, resulting in an average of 290 million gallons of energy drinks consumed in 2007. Energy drinks can be spotted everywhere, in the hand’s of students, soldiers, healthcare professionals, or anyone who ever really finds themselves in need of a boost. While the average US citizen may resort to a cup of coffee, an energy drink contains a close amount of caffeine, hovering around 90mg. Energy drinks contain many more chemicals and sugar than coffee though, including the list of aforementioned names. So what do all of the ingredients in energy drinks do to the body, and could they be potentially harmful over time?
               Caffeine, the most commonly known ingredient in energy drinks, is a psychoactive drug that is available to anyone across the world that seeks it. The drug is an adenosine and benzodiazepine receptor antagonist and a nervous system stimulant. Ingesting caffeine, something most children and adults do on a regular basis, can cause a wide range of physiological effects. Caffeine can cause the stimulation of smooth muscle, cardiac stimulation and antagonism, cerebral vasoconstriction, reduces insulin sensitivity, and causes increased urine flow. While caffeine is known to increase focus, cognitive ability, and exercise endurance, the amount of caffeine consumed can greatly influence the side effects on the body. Adults and children who consume too much caffeine can experience more extreme symptoms such as irritability, anxiety, insomnia, vomiting, abdominal pain, hallucinations, cerebral edema, arrhythmias, stroke, and in severe cases of caffeine intoxication, death. Guarana, a second form of caffeine found in energy drinks, adds to the overall “energizing” effects on the body found in caffeine drinks. A study in Australia found that the added caffeine contained in guarana may not be added into the official label, meaning a drink could potentially contain more caffeine than advertised. Throughout the years, caffeine intoxication has been widely reported as a result of energy drink consumption and has lead to death in several cases.

Another common ingredient found in energy drinks is taurine. Taurine is an amino acid that naturally occurs in the body that is a normal ingredient of the human body. The amino acid helps aid in skeletal muscle contraction and plays different roles in both the cardiac and nervous system. The amount of taurine in a single energy drink is low, and no official studies in humans have shown adverse reactions. In Norway, France, and Denmark, Red Bull was banned after a study performed on rats showed that the rats were prone to anxiety and self-mutilation after exposure to taurine.
               Energy drinks also contain a wide array of Vitamin B subclasses that can help convert the sugar available in energy drinks to energy. On average, an energy drink contains around 54 mg of sugar. Ingesting 54 mg of sugar is equivalent to eating ¼ cup of sugar, for each energy drink consumed. High levels of sugar in the diet can lead to extreme health problems such as heart disease that can cause fatal side effects or even death.
               Another factor to consider when examining the potential effects of energy drinks is to review the potentially hazardous effects when energy drinks are mixed with other substances such as alcohol. Many common drinks and shots now contain alcohol mixed with energy drinks that can have negative side effects. Energy drinks can decrease the overall feeling of intoxication, leading a person to believe there are less drunk than they are.
               Many people use energy drinks commonly, and the side effects and long-term problems should be seriously examined since they play such a large role in the American beverage industry. Children and adolescents should be made aware of the potentially negative effects of the ingredients listed on the back of an energy drink that the average consumer may not understand.  

Sources:

Higgins, John P., et al. “Energy Beverages: Content and Safety.” NCBI, Mayo Clinic Proceedings, 11 Nov. 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC2966367/.

Seifert, Sara, et al. “Health Effects of Energy Drinks on Children, Adolescents and Young Adults.” Pediatrics, pediatrics.aappublications.org/content/pediatrics/early/2011/02/14/peds.2009-3592.full.pdf.

Strain, Eric C, and Roland R. Griffiths. “Caffeinated Energy Drinks-A Growing Problem.”Drug and Alcohol Dependence, Elsevier, 21 Sept. 2008, www.sciencedirect.com/science/article/pii/S0376871608002858.

Article by: Olivia Murphy, Master of Science in Medical Sciences, University of Kentucky

Wednesday, October 25, 2017

Antibiotic Resistance



Did you know that each year there are over 154 million antibiotics prescribed by doctor’s offices and emergency rooms in America? While some of these prescriptions are needed, it is estimated that 47 million of these are unnecessary and could be contributing to the growing problem of antibiotic resistance throughout the world. Each year in the U.S. at least 2 million people are infected with resistant bacteria and at least 23,000 die because of the infection. Bacteria that cause pneumonia, tuberculosis, blood poisoning and gonorrhea are becoming more difficult to treat and the list is continuing to grow. Antibiotic resistance occurs when an antibiotic has lost its ability to effectively eliminate a bacterium. These resistant bacteria will continue to not only thrive, but multiply even in the presence of the therapeutic levels of an antibiotic. This is a major concern in the health field because infections that were once easily treatable are now becoming incurable, resulting in serious complications and sometimes even death. 

              In bacterial colonies, antibiotic resistance can occur when bacteria change in ways that cause a decline in the effectiveness of an antibiotic. Once this small number of bacterial cells become resistant to the antibiotic they will survive and reproduce to create more bacterial cells that are resistant to the bacteria. Another major concern, is the ability of bacteria to obtain bacterial resistance from other bacteria. In some cases, the bacteria transfer their genetic material, including genes encoding for resistance to antibiotics, via a
mating process called conjugation from one bacteria to another. The emergence of antibiotic resistance has occurred in part due to the misuse and overuse of antibiotics in the healthcare field. Each time a person uses antibiotics resistant bacteria is left behind, if these bacteria are left alone they will continue multiply, and repopulate the environment. Once these bacteria repopulate, another antibiotic will be prescribed which can cause the process to repeat itself leading to multi-resistant bacteria or “super bugs.” 
                 
Colonies of bacteria that are resistant to antibiotics (Right) compared to bacteria treated with bacteria in which they are killers (Left).















    Bacteria can become resistant to antibiotics in many ways. Some bacteria can destroy the antibiotic by simply neutralizing them which can make it harmful to the individual. Another method bacteria can use is to prevent the antibiotic from getting to its target. This is done by the bacteria pumping the antibiotic back outside of the cell before it takes it effect on the bacteria. Bacteria can also change their targets by changing their outside appearance so the antibiotic cannot bind to the target rendering the antibiotic ineffective.

                So, what is being done to prevent a world where antibiotic resistance bacteria are dominant? The Centers for Disease Control and Prevention (CDC) and The World Health Organization (WHO) are working to improve awareness about antibiotic resistance and how healthcare professional can prevent antibiotic resistance. This awareness includes ways in to prevent different infection in the first place, and if an infection is established to create guidelines on how antibiotics should be prescribed and dispensed. The consequences of a continuing growth in antibiotic resistance will lead to the need for more expensive drugs, increase cost in health care, and possibly an increase in infections and death due to antibiotic resistance.

Bibliography
Center For Disease Control . Antibiotic Resistance Questions and Answers. 25 September 2017. 22 October 2017. <https://www.cdc.gov/antibiotic-use/community/about/antibiotic-resistance-faqs.html>.

Kuiper, Randy L. "Overuse of antibiotics leads to bacterial resistance." Great Falls Tribune May 19 2014: 1-3.

Ventol, C. Lee. "The Antibiotic Resistance Crisis." Pharmacy and Therapeutics (2015): 227-283.


World Health Organization . Antibiotic resistance. October 2017. 22 October 2017. <http://www.who.int/mediacentre/factsheets/antibiotic-resistance/en/>.

 By:  Maya Hines, MSMS Graduate Student 

Thursday, October 12, 2017

Innovative approaches in drug development



We all know that it takes great amount of resources and time to develop an effective drug. Pharmaceutical companies must go through very costly trials to refine a drug with best effectiveness. According to ‘Tufts Center for the Study of Drug Development’, the cost of developing new drugs and bringing it to market has significantly increased since 1970 from few hundred million to 3 billion over the course of 40 years. This increasing cost of research also increases the cost of treatment on public. [1]

According to Food and Drug Administration, there are multiple stages involved in drug development process such as drug discovery, studying its chemical property, preclinical research, clinical trials on human with small scale Phase 1 to large scale Phase 3. The goal of preclinical research is to find outs drug’s toxicity by testing it in vivo and in vitro; then drug is tested on human during clinical trial stage. In other word, human cells don’t usually see a drug until it reaches phase-1 of clinical trial and until now, we were relying on data using animal models. Researchers has come to notice that every patient is different and understands that there may not be one drug for all patients. These ideas lead to concept of precision medicine which involves personalized therapies based on patient’s individual needs. The new technique developed by Stanford university called “clinical trials in a dish” uses patient-specific induced pluripotent stem (iPS) cells to predicts if specific patients will benefit from a drug or not. [2]

The current in vitro research involves genetic modifications (mutations) of a human embryonic kidney cells or Chinese hamster ovarian cells to generate a tissue that resemble a tissue with disease. However, the new technique allows researchers to test drugs directly on human cells which includes hereditary mutation instead of kidney or hamster cells with induced mutations. The iPS cells are generated by reprogramming skin cells into stem cell state and then these stem cells are induced to differentiate into variety of cells such as neuron, liver cell or cardiac cell. This non-invasive technique provides researcher unlimited supply of patient derived specific tissue cells and since iPS cells retains DNA of a patient it can be used to evaluate personalized drug responses. One of the study by Stanford University used iPS cell derived cardiomyocytes (heart cells) and successfully predicted if Doxorubicin, chemotherapy drug will cause any toxicity to a cardiac tissue. [3]

I attended the seminar by Dr. Donald Ingber, who was the guest speaker at University
 Source:  Wyss Institute at Harvard University
Organ on a chip

of Kentucky during 2014 Naff Symposium. He provided the earlier insights on biologically inspired engineering to build an ‘organ-on-a-chip’. The chip is a size of AA battery with living cells with its microenvironment to mimic the physiological environment. Dr Ingber showed that their lab currently has bone marrow, liver, intestine, lung, heart and kidney on a chip. These chips can even be combined with another organ chip to study the inter-organ interactions. These chips can also be personalized using patient derived iPS cells which will reduce the need for lengthy and costly clinical trials. The chip is programmed and run by a computer simulation and this technique will easily replaces in vitro method to in silico. [4]


Something that was merely a dream few years back is now taking its shape and it’s going to revolutionize drug development industry. Recently, on April 11th, 2017 FDA has made agreement to work with researchers to test the potentials of this organ-on-chips in drug development. Although only liver-chip is currently being evaluating by FDA, they are hoping to expand it to other organs including kidney, intestine and lung model. [5]

The benefits of these new techniques will provide researchers better tools to develop drug toxicity model and drug efficacy model. Since these tools will eliminate the need of animal model, it won’t raise any ethical issues and it will also keep PETA happy since there won’t be any animal cruelty. These techniques will predict how patient will react to a specific drug, thus increasing their chance of survival and decreasing the lethal side effects before patients are given such treatments. Although this new tool comes with great advantage, it is not without its limitation. These tools cannot predict if patients will have some side effects such as mood swing or insomnia.


References

[1] Commissioner, Office of the. “The Drug Development Process.” US FDA Home Page, Office of the Commissioner, 24 June 2015, www.fda.gov/ForPatients/Approvals/Drugs/default.htm.

[2]  Strauss, D.G. and K. Blinova, Clinical Trials in a Dish. Trends Pharmacol Sci, 2017. 38(1): p. 4-7

[3] Burridge, P. W., Li, Y. F., Matsa, E., Wu, H., Ong, S. G., Sharma, A., . . . Wu, J. C. (2016). Human induced pluripotent stem cell-derived cardiomyocytes recapitulate the predilection of breast cancer patients to doxorubicin-induced cardiotoxicity. Nat Med, 22(5), 547-556. doi:10.1038/nm.4087

[4] Bhatia, S. N., & Ingber, D. E. (2014). Microfluidic organs-on-chips. Nat Biotech, 32(8), 760-772. doi:10.1038/nbt.2989

 [5] Center for Food Safety and Applied Nutrition. “Constituent Updates - FDA Researchers to Evaluate 'Organs-on-Chips' Technology.” US FDA, Center for Food Safety and Applied Nutrition, 11 Apr. 2017, www.fda.gov/food/newsevents/constituentupdates/ucm551503.htm.

By Falak Patel, Master's of Medical Science Student, University of Kentucky

Friday, September 29, 2017

CRISPR: a case for revision



            It started out as kids; along for the ride as our patents watched science fiction thrillers. The writers and directors would look into the future and ‘wow’ audiences with what they thought it would hold. Star Trek gave us teleportation, Back to the Future gave us time travel, Blade Runner let us look into a world of replicants (artificial intelligence), and many more. What all of these movies had in common though are dreams. As adults now, we have watched some of those dreams materialize, and we’ve watched others merely fade away.

            Accurate and precise gene editing was once one of those dreams. CRISPR was once one of those dreams! Now it is anything but that, and as with every great discovery there is excitement, but there are also many ethical questions that accompany the use of such a tool.

            Clustered Regularly Interspaced Short Palindromic Repeats, more commonly known as CRISPR or CRISPR-Cas9, (once part of a E. Coli defense system) are RNA-guided engineered nucleases. That’s a lot to take in from one definition so I will try to explain it a little better. CRISPR is composed of two subunits: the first subunit is the Cas9 nuclease, which acts like scissors to cut the DNA, and second subunit is a small RNA molecule that can precisely and accurately direct Cas9 to where it is supposed to cut the DNA. Once cut, the new DNA or gene can be incorporated by the repair enzymes. Scientist were able to take advantage of what was originally a defensive mechanism and turn it into an offensive mechanism. (1)

            Wait! Haven’t scientist been able to edit genes for quite some time? The answer is yes, but to a large extent we’ve used applications that are inferior to CRISPR (since its discovery). Targeting the genome before CRISPR was mainly done through engineering DNA nucleases. Two examples of this would be (the oldest and most studied) Zinc Finger Nucleases (ZFNs), and Transcription Activation-Like Effector Nucleases (TALENs). Although both ZFNs and TALENs have been essential for research, their shortcomings for gene therapeutics are made aware by the advantages of CRISPR. ZFNs and TALENs can be expensive, they can be very hard to make, they can be toxic, and they often times (ZFN more so that TALEN) have poor targeting. (2)

            Ben Parker once said, “With great power comes great responsibility” and that is very true in the world of science whenever a new tool like CRISPR is discovered.

            The ability to edit a genome is amazing! It’s exciting, and above all else it has the real power to effect lives. Diseases like malaria, that shake entire continents could be eradicated. HIV, Huntington’s Disease, and any other genetic disease could be a thing of the past. Isn’t that everyone’s goal when choosing a career in healthcare? To help patients, or develop ways to help patients?

            The power to effect change at all is intoxicating, but can sometimes be detrimental. When looking at CRISPR, the ethical questions raised by it are not different from the same ones raised about gene editing/therapy. Most of the ethical problems associated with CRISPR are from a misuse of the tool, but some are purely associated to using the tool at all.
            The first question that comes to mind is for me is the regulation of CRISPR not only in terms of when to use it, but also how it is consumed. I hate to bring up the past, but in a way CRISPR can be seen as a form of positive eugenics. Especially if strict regulations are not placed on it. Theoretically parents in the future could pick and choose how their babies would be edited, leading to “designer” babies. If CRISPR isn’t available to all, or can only be used by those with the resources then that could lead to selective advantages for some (this is all highly hypothetical though). It will take a lot of work from organizations around the world to not only work together for uniform regulation, but to also enforce these regulations across borders. (3)

Also, are the benefits of CRISPR worth the risk? Anytime you work with editing the genome there is a chance that you don’t get your desired effect. There are off-target effects that can be deleterious too if CRISPR is used. If you can cure one disease, but that cure leads to other problems is it worth it? (4)

All of that aside, CRISPR was, is, and will continue to be a discovery for the ages. The very fact that we can have these conversations now is amazing. Elon Musk recently said in an interview with Neil deGrasse Tyson on StarTalk Radio that there were five things he thought would change the future of humanity. They are the internet, sustainable energy, space exploration, artificial intelligence, and rewriting human genetics. All of those are honorable quest, but as future healthcare professionals rewriting the human genome is right up our alley and CRISPR just might be the tool that helps us reach that goal. (5)

             
          


Citations:
1.     Ledford H. CRISPR: gene editing is just the beginning. Nature. 531, 156-159. 10 March 2016.
2.     Mestrovic T. How Does CRISPR Compare to Other Gene-Editing Techniques? News Medical Life Sciences. 13 January 2016.
3.     Mulvilhill J. et al. Ethical issues of CRISPR technology and gene editing through the lens of solidarity. British Medical Bulletin, Volume 122, Issue 1, 1 June 2017, Pages 17-29.
4.     Rodriguez E (2016). Ethical Issues in Genome Editing using Crispr/Cas9 System. J Clin Res Bioeth 7:266. doi:10.4172/2155-9627.1000266
5.     Zimmer C. Breakthrough DNA editing born of bacteria. Quanta Magazine 2015. https://www.quantamagazine.org/20150206-crispr-dna-editor-bacteria/
6.     Welsh J. 5 things Elon Musk believed would change the future of humanity in 1995. Science. Business Insider. 6 April 2015.

 By Christopher Adams, Master's of Medical Science Student, University of Kentucky
           


A class blog on opioids and the treatment of pain


   
Image result for opioid epidemic 2017

The opioid epidemic is thought to be due in part to the over-prescription of drugs like OxyContin to treat patients with symptoms of chronic pain.  These drugs are known as a class as "opioids" that all act via their interactions with the opioid receptors.  By understanding how these drugs work, we can develop new drugs that can still be effective in treating pain, but lack the addictive properties of our currently used drugs. We can also learn more about pain and chronic pain to develop drug-free strategies that lessen the symptoms of pain. 
                How do Opioids cause their effects?   Opioids target opioid receptors within the body in a variety of locations, the central nervous system, peripheral nervous system as well as the gastrointestinal tract. The three original major subtypes of opioid receptors are mu, kappa, and delta opioid receptors within the body. The mu opioid receptor has three subtypes, µ1, µ2, µ3 and is expressed in the brain spinal cord, intestinal tract, and sensory neurons. The kappa opioid receptor also has three receptor subtypes, κ1 κ2 κ3, and is expressed in the brain and the spinal cord. The delta opioid δ1 δ2 receptor is expressed in the brain and sensory neurons. Opioid receptors are G protein coupled receptors that use opioids as their ligands and form hetero and homotrimeric complexes that signal to kinase cascades and aid in the integrity of a variety of proteins. Once the opioid is bound to the active site the receptor undergoes a conformational change, which activates the intracellular G proteins. The α subunit of the G-protein exchanges its bound GDP molecule for an intracellular GTP molecule. This allows the α-GTP complex to dissociate from the βγ complex. These complexes are now able to interact with target proteins. Typically the opioid agonist binds to its G-protein receptor, which results in the inhibition of adenylyl cyclase. This causes a reduction in intracellular cyclic adenosine monophosphate (cAMP) levels. These complexes also interact with a number of ion channels, producing activation of potassium and inhibition of calcium. The net effect of these occurrences cause a reduction of neurotransmitter release, which decreases the generation of the postsynaptic impulse which inhibits tonic neuronal activity. Opioid receptors can also be activated by endogenous peptides that are released by neurons in the brain. There are three pro-hormone precursors that provide the parent compounds these endogenous ligands. Proenkephalin, is cleaved to form met-enkephalin and leu-enkephalin, and bind to the DOP (delta opioid receptor). Prodynorphin which is cleaved to form Dynorphin A and B, these are agonists at the KOP (kappa opioid receptor). β- endorphin is cleaved to form Pro-opiomelancortin (POMC), which is an agonist at the MOP (mu opioid receptor). However, POMC is capable of displaying agonist activity at all three classical opioid receptors.
Schumacher MA, Basbaum AI, Naidu RK. Opioid Agonists & Antagonists. In: Katzung BG, Trevor AJ. eds. Basic & Clinical Pharmacology, 13e New York, NY: McGraw-Hill; 2015.
Sobczak, Marta, et al. “Physiology, Signaling, and Pharmacology of Opioid Receptors and Their Ligands in the Gastrointestinal Tract: Current Concepts and Future Perspectives.”NCBI, US National Library of Medicine, Feb. 2013, www.ncbi.nlm.nih.gov/pmc/articles/PMC3895212/.
               Biased agonism and tolerance.  Opiods exert other actions that proceed via events known as "biased agonism" and "tolerance".  These two events are related.  Biased agonism occurs when a receptor has affinity for multiple ligands. Depending on the ligand, a different signal transduction pathway can be activated, but the ligand specifies which will be activated. Tolerance is a reduced reaction to a drug after repeated use. When a patient is prescribed continuous use of an opiate, tolerance can become a problem in a clinical setting. Since opioids cause analgesic side effects, the dose may be increased at times when the analgesic side effects are no longer as strong. Opioid tolerance associated with biased agonism is currently not a completely understood process, but ongoing research aims to understand the effects. Some scientists argue that an opioid such as morphine may bind a receptor, and even though the morphine is never internalized, the cell is still signaling and causes a tolerance buildup to occur. Other ligands in the body have the ability to become phosphorylated, which changes their structure, and then are internalized and desensitized in the cell, which leads to tolerance. Structurally different agonists for a receptor such as mu can produce different binding efficiencies, which can influence the rate of arrestin recruitment or G protein activation. Research is still being conducted in order to obtain more clear results. Many researchers also hypothesize that because mu receptors are recycled, tolerance is increased.
 Williams, John T. et al. “Regulation of µ-Opioid Receptors: Desensitization, Phosphorylation, Internalization, and Tolerance.” Ed. Annette C. Dolphin. Pharmacological Reviews 65.1 (2013): 223–254. PMC. Web. 18 Sept. 2017.
Al-Hasani, Ream, and Michael R. Bruchas. “Molecular Mechanisms of Opioid Receptor-Dependent Signaling and Behavior.” Anesthesiology 115.6 (2011): 1363–1381. PMC. Web. 18 Sept. 2017.
Anderson, B. (2011). A Pharmacological Primer of Biased Agonism. Endocrine, Metabolic and Immune Disorders: Drug Targets. doi:10.2174/187153011795564179
               Other approaches that can be used to treat pain.  Drugs that can be administered include non steroidal anti-inflammatories, such as acetaminophen, antidepressants, anticonvulsants, muscle relaxants, the use of nerve block procedures (epidural steroid injections; facet joint injections; lumbar sympathetic block) and natural alternatives (arnica gel; aromatherapy; vitamin C).  These drugs and approaches vary with respect to their effectiveness and limitations.  Nonsteroidal anti-inflammatory drugs, like ibuprofen, can be a convenient and effective method of treating pain. They can be bought over-the-counter and are unlikely to cause addiction. They often work well in treating acute pain, such as headaches and muscle aches.  They do, however, have some potentially dangerous side effects when taken for a prolonged period of time. Their metabolism can lead to damage of the liver and/or kidneys. They may also negatively impact the heart, blood clotting, the GI tract, and increase the patient's risk of ulcers. Taking an excessive amount of acetaminophen in 24 hours can cause liver failure; some opioids contain acetaminophen.
               Muscle relaxants can also be used to treat some kinds of muscle pains, however these medications often cause drowsiness. Nerve block procedures are very effective in treating pain, but they must be administered  via injection and must be given by a physician. Tricyclic antidepressants can also be effective in treating chronic pain. The dose of medication needed to treat pain is typically lower than of that required to treat depression. One limitation of these drugs is that the medication must be taken every day, even you aren't experiencing pain a given day. Generally, they should be taken at night because sedation is a side effect. Anti-seizure medications can be taken to treat some nerve pain. This is another medication that is not intended to be taken on an "as needed" basis- and therefore must be taken every day, regardless of the patient's pain level on a given day. Older anticonvulsant drugs required that users have liver activity monitor while taking the medication; the newer drugs do not require liver monitoring, but can still pose a threat to the kidneys. Another limitation would be the type of pain anti-seizure medications can treat- they are suitable for burning and shooting pains.
               Natural alternative are certainly an option and should be considered (the less medication we have to take, the better). They may work surprisingly well for mild pain, but these alternatives are likely to be limited in their effectiveness in treating severe pain. Arnica gel can be used for bruising and muscle soreness. Some users have said the arnica gel helped control their arthritis on a level comparable to ibuprofen. Sufferers of chronic pain like fibromyalgia could consider aromatherapy- for example, massaging essential oils into areas of discomfort. Lastly, it is thought that taking vitamin C supplements may sooth sufferers of some chronic pain, like osteoarthritis.
Wolkerstorfer, A., Handler, N., & Buschmann, H. (2016). New approaches to treating pain. Bioorganic & Medicinal Chemistry Letters,26(4), 1103-1119. Retrieved September 18, 2017, from http://www.sciencedirect.com/science/article/pii/S0960894X15304169
Pain, R. (2000). Limitations of NSAIDs for pain management: Toxicity or lack of efficacy? The Journal of Pain,1(3), 14-18. Retrieved September 18, 2017, from http://www.jpain.org/article/S1526-5900(00)09397-4/fulltext
Dean, L. (2011). Comparing NSAIDs. Pubmed: Clinical Q&A. Retrieved September 18, 2017, from https://www.ncbi.nlm.nih.gov/books/NBK45590/.
Munir, M., MD, Enany, N., MD, & Zhang, J., MD. (2007). Nonopioid Analgesics. Medical Clinics of North America,91(1), 97-111. Retrieved September 18, 2017, from http://www.sciencedirect.com/science/article/pii/S0025712506001179?via%3Dihub
Lukatz, T. (2000). Anticonvulsants for neuropathic pain syndromes: mechanisms of action and place in therapy. Drugs,60(5). Retrieved September 18, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/11129121.
Wiffen, P. (2013). Antiepileptic drugs to treat neuropathic pain or fibromyalgia an overview of Cochrane reviews. Cochrane. doi:10.1002/14651858.CD010567.pub2
Development of new drugs that target the opioid receptor.  Researchers at Tulane University have developed a new painkiller drug that has a comparable strength to morphine but has fewer side effects and likelihood of addiction.  Here, several different endomorphin analogs, referred to as EM analogs, were developed using an endogenous cyclized δ–amino acid-containing endomorphin analog.  Of the four different synthesized EM analogs, the study found EM analog 4 to be the most effective. The engineered EM analogs are highly selective for µ receptors (MOPs), which are the most effective opioid analgesic targets.  The EM analogs acted through binding to the µ receptor, and further decreasing glial P38/CGRP/P2X7 receptor signaling. Activation of this receptor signaling pathway has implications in causing chronic pain.
The study was performed as follows.  First four different EM analogs were synthesized.  Then,  the activation of MOP, DOP, KOP was ensured through completing receptor binding assays that utilized cloned CHO-K1 membranes as the membrane for the respective receptors to function within. To ensure the activation of these receptors by the EM analogs, activation of the receptors was measured through completion of GTPgS assays, which demonstrated over a 95% efficacy for successful MOP activation. Once it was established that the opioid receptors were activated with the EM analogs, trials progressed to an in vivo setting.
               This study used both male CD-1 mice and Sprague-Dawley rats that were exposed to a 12-hour light photoperiod/12-hour dark photoperiod. Drug administration for the Sprague-Dawley rats used an indwelling jugular vein catheter, whereas drug administration for the CD-1 mice was done either through SQ injections in the neck region or through oral routes using a gavage. The same measures were completed for both rats/mice injected with morphine as well as mice/rats injected with EM analogs.
Antinociception was tested through the “tail-flick” test, where rodents were exposed to a heat source at their tail. Reaction latency was recorded with a nine second cutoff time to prevent possible tissue damage. The duration of antinociception for IV, SQ, and oral administration of EM analog 4 were all higher than the respective durations of antinociception for morphine administration.
Respiratory depression was measured in non-anesthetized rats that were allowed free movement within a plethysmography system. Minute ventilation was monitored over a 20-minute time span before drug administration, then again ever 20 minutes after drug administration until antinociception levels had decreased to >50%. Compared to morphine, rodents who were exposed to EM analogs had a decreased level of respiratory depression, and even complete absence of respiratory depression in some rodents.
Motor coordination was examined using a rotorod system, which is a system that measures the ability of an animal to remain upright while on a moving rod. Rodents were given their respective drugs every twenty minutes until a %MPE of greater than 90% was achieved. From there the rats were left on the rotorods for 3 minutes until being removed. Motor coordination was calculated using the Rotomex-5 instrument. Compared to rodents exposed to morphine, rodents who were exposed to EM analogs did not have statistically significant motor coordination impairment whereas their morphine rodent counterparts did. 
Both hyperalgesia and tolerance were tested over a seven-day period, and ED50s values (effective dose values) were compared before and after the seven-day period. Rodents exposed to EM analogs demonstrated less tolerance than the morphine exposed rodents after a seven-day period. EM analog 4, when compared with morphine, demonstrated no induced hyperalgesia whereas the rodents given morphine showed induced hyperalgesia after the seven-day period.
The activation of glial P38/CGRP/P2X7 receptor signaling was measured through using markers for astrocytes, microglia, and MAP kinase and then examined for the expression of the different markers within post-mortem rodents. The rodents injected with morphine demonstrated a greater activation of cell receptor signaling than the rodents injected with EM analogs, which indicates a reduced expression of chronic pain within the EM analog rodents than the morphine rodents.
The risk of dependency and abuse were measured in two different formats, both in conditioned place preference settings and in self-administration settings. For the conditioned place preference setting, rodents could freely roam in a two-compartment box for two days. After two days, the rodents were given their respective opioid drug and confined to only one of the compartments for a 30-minute duration. This cycle of drug administration and 30-minute confinement was repeated for three consecutive days. On the fourth day, the rodents were placed back in the two-compartment box without being given their opioid drug and were allowed free roaming between either compartment. The amount of time spent in each compartment was recorded over a twenty-minute time span. The rodents that had been injected with morphine spent a significantly greater amount of time in the compartment in which they had been administered morphine in rather than the other compartment. The rodents that had been injected with EM analog, however, and demonstrated no preference between the two compartments. For the self-administration setting, rodents were placed in a compartment that had an “active” bar that when pushed on administered their respective drug intravenously, and an “inactive” bar that when pressed did not cause drug release. Infusion release was regulated to only allow a fixed ratio of drug administration over a seven-day period with exposure to the different bars for 12 hours per day. The rodents that received morphine exhibited an increase “active” bar pressing by a five-fold increase. The rodents that received EM analog after pressing their “active” bar did not demonstrate a more frequent bar pressing over the seven-day period.
               One of the limitations of this study was the limited comparison to morphine exposure and not any of the other available opioid drugs. While morphine is a commonly used opioid both in the medical profession and in illegal-use, morphine is not the only drug used in both settings. This study also only compared the effects of morphine and the EM analogs in two rodent species. Another limitation of this study is the duration of time that these measurements were taken over, which fail to demonstrate the same side effects of their drug usage over a longer time interval. Many opioid drugs demonstrate greater side effects and complications during prolonged use for chronic pain, and an experimental setting that only examined these parameters concerning opioid drug side effects during a seven-day period cannot be used to predict possible implications on the same drug usage over a longer interval.
               While the EM analogs described in this study, particularly EM analog 4, demonstrated an improved analgesic-to-side-effect ratio, several steps need to be taken to determine the possible applications of EM analog 4 in the medical field. Similar studies need to be done that compare other opioid drugs, such as fentanyl and codeine. Similar studies also need to be completed over a larger time span to determine the applications of EM analog 4 in the treatment of chronic pain, seeing that many of the instances that use opioid drugs for the management of chronic pain. Once studies such as these have been completed within the rodent species, comparable experiments need to be conducted using primate species before any human implications can be derived through the substitution of EM analogs for pain management in the medical field.
Zadina, J., Nilges, M., Morgenweck, J., Zhang, X., Hacker, L., & Fasold, M. (2015). Endomorphin analog analgesics with reduced abuse liability, respiratory depression, motor impairment, tolerance, and glial activation relative to morphine. Neuropharmacology,105, 215-227. Retrieved September 18, 2017, from http://www.sciencedirect.com/science/article/pii/S0028390815302203