Steven Aibor Dkhar

Emerging trends of nanomedicine - an overview

Nanotechnology is an emerging branch of science for designing tools and devices of size 1 to 100 nm with unique function at the cellular, atomic and molecular levels. The concept of using nanotechnology in medical research and clinical practice is known as nanomedicine. Nanoparticles possess some novel properties not seen with the macro molecules and they can be manipulated by attaching therapeutic components to help in diagnosis and treatment. They can also be used to probe cellular movements and molecular changes associated with pathological states. Nanodevices like carbon nanotubes to locate and deliver anticancer drugs at the specific tumour site are under research. Nanotechnology promises construction of artificial cells, enzymes and genes. This will help in the replacement therapy of many disorders which are due to deficiency of enzymes, mutation of genes or any repair in the synthesis of proteins. Currently nanodevices like respirocytes, microbivores and probes encapsulated by biologically localized embedding have a greater application in treatment of anaemia and infections. Thus in the present scenario, nanotechnology is spreading its wings to address the key problems in the field of medicine. Hence this review discusses in detail the applications of nanotechnology in medicine with more emphasis on drug delivery and therapy.

The dawn of hedgehog inhibitors: Vismodegib

Cancer, one of the leading causes of death worldwide is estimated to increase to approximately 13.1 million by 2030. This has amplified the research in oncology towards the exploration of novel targets. Recently there has been lots of interest regarding the hedgehog (Hh) pathway, which plays a significant role in the development of organs and tissues during embryonic and postnatal periods. In a normal person, the Hh signaling pathway is under inhibition and gets activated upon the binding of Hh ligand to a transmembrane receptor called Patched (PTCH1) thus allowing the transmembrane protein, smoothened (SMO) to transfer signals through various proteins. One of the newer drugs namely vismodegib involves the inhibition of Hh pathway and has shown promising results in the treatment of advanced basal-cell carcinoma as well as medulloblastoma. It has been granted approval by US Food and Drug Administrations (US FDA) priority review program on January 30, 2012 for the treatment of advanced basal-cell carcinoma. The drug is also being evaluated in malignancies like medulloblastoma, pancreatic cancer, multiple myeloma, chondrosarcoma and prostate cancer. Moreover various Hh inhibitors namely LDE 225, saridegib, BMS 833923, LEQ 506, PF- 04449913 and TAK-441 are also undergoing phase I and II trials for different neoplasms. Hence this review will describe briefly the Hh pathway and the novel drug vismodegib.

Newer antipsychotics and upcoming molecules for schizophrenia.

BackgroundThe management of schizophrenia has seen significant strides over the last few decades, due to the increasing availability of a number of antipsychotics. Yet, the diminished efficacy in relation to the negative and cognitive symptoms of schizophrenia, and the disturbing adverse reactions associated with the current antipsychotics, reflect the need for better molecules targeting unexplored pathways.PurposeTo review the salient features of the recently approved antipsychotics; namely, iloperidone, asenapine, lurasidone and blonanserin.MethodsWe discuss the advantages, limitations and place in modern pharmacotherapy of each of these drugs. In addition, we briefly highlight the new targets that are being explored.ResultsPromising strategies include modulation of the glutamatergic and GABAergic pathways, as well as cholinergic systems.ConclusionsAlthough regulatory bodies have approved only a handful of antipsychotics in recent years, the wide spectrum of targets that are being explored could eventually bring out antipsychotics with improved efficacy and acceptability, as well as the potential to revolutionize psychiatric practice.

Inter and intra-ethnic differences in the distribution of the molecular variants of TPMT, UGT1A1 and MDR1 genes in the South Indian population

Molecular variants of polymorphic drug metabolizing enzymes and drug transporters are attributed to differences in individual’s therapeutic response and drug toxicity in different populations. We sought to determine the genotype and allele frequencies of polymorphisms for major phase II drug-metabolizing enzymes (TPMT, UGT1A1) and drug transporter (MDR1) in South Indians. Allelic variants of TPMT (*2,*3A,*3B,*3C & *8), UGT1A1 (TA)6>7 and MDR1 (2677G>T/A & 3435C>T) were evaluated in 450–608 healthy South Indian subjects. Genomic DNA was extracted by phenol–chloroform method and genotype was determined by PCR–RFLP, qRT-PCR, allele specific PCR, direct sequencing and SNaPshot techniques. The frequency distributions of TPMT, UGT1A1 and MDR1 gene polymorphisms were compared between the individual 4 South Indian populations viz., Tamilian, Kannadiga, Andhrite and Keralite. The combined frequency distribution of the South Indian populations together, was also compared with that of other major populations. The allele frequencies of TPMT*3C, UGT1A1 (TA)7, MDR1 2677T, 2677A and 3435T were 1.2, 39.8, 60.3, 3.7, and 61.6% respectively. The other variant alleles such as TPMT*2, *3A, *3B and *8 were not identified in the South Indian population. Sub-population analysis showed that the distribution of UGT1A1 (TA)6>7 and MDR1 allelic variants differed between the four ethnic groups. However, the frequencies of TPMT*3C allele were similar in the four South Indian populations. The distribution of TPMT, UGT1A1 and MDR1 gene polymorphisms of the South Indian population was significantly different from other populations.

Globalization of Clinical Trials – Where are We Heading?

The last decade has witnessed a greater transparency in clinical research with the advent of clinical trial registries. The aim of the study was to describe the trends in the globalization of clinical trials in the last five years. We performed an internet search using the WHO International clinical trials registry platform (WHO ICTRP) to identify the clinical trials conducted from January 2007 to December 31, 2011 among 25 countries. Among the 25 countries, the United States, Japan and Germany occupy the top positions in the total number of clinical trials conducted. Clinical trials in the US (36312) constituted 31.5% of the total number of trials performed during this period. However over a period of five years both US and Western Europe appear to show a decline, while the emerging countries show a rise in clinical trials registered. Among the emerging countries China, India and Republic of Korea are most active regions involved in clinical trials. Cancer, diabetes and respiratory diseases were most widely researched areas overall. Although the study confirms the transition in the clinical trials research towards emerging countries, the developed regions of the world still contribute to more than 70% of the trials registered worldwide.

Effect of insulin on small intestinal transit in normal mice is independent of blood glucose level

BackgroundInsulin is the drug of choice in the management of diabetes mellitus (DM). About 76 % of diabetic patients suffer from gastrointestinal (GI) disorders. Therapy of DM with insulin primarily involves lowering of elevated blood glucose levels. Hence, on any organ in addition to insulins effect, hypoglycaemic effect also prevails. A systematic study exploring the effect of insulin on small intestinal transit in normal laboratory animals is lacking. Hence, in the present study, the possible effect of insulin with or without associated hypoglycaemia on small intestinal transit in normal mice was examined.ResultsInsulin in all the doses tested (2 μ, 2 m and 2 U/kg) elicited a significant acceleration of SIT. The lower doses of insulin (2 μ and 2 m U/kg) produced significant acceleration of SIT and were associated with normal blood glucose levels. However, the highest dose of insulin (2 U/kg) produced an acceleration of SIT that was associated with significant fall in blood glucose levels. Further, the 2 m and 2 U doses of insulin significantly elevated serum insulin and C-peptide levels.ConclusionInsulin at the lowest dose produced an acceleratory effect on SIT that was independent of blood glucose and serum insulin levels in normal mice.

Clinical trials in India: Where do we stand globally?

Aims: To evaluate the trend of clinical trials in India over the last 4 years compared to the well-established countries using clinical trial registries since the advent of clinical trial registry of India (CTRI). Materials and Methods: The data of clinical trials registered in India, United States (US), and European Union (EU) were obtained from websites of CTRI, clinicaltrial.gov and EU clinical trial registry, respectively from July 20, 2007 to August 29, 2011 for a period of 4 years. Trials registered in Australia, Canada, China, and Japan were obtained from WHOs international clinical trial registry platform for the same period. We used search words for the common diseases such as diabetes, hypertension, etc., Results: The total number of clinical trials registered during the study period was 67,448 across seven study nations. Clinical trials from India constituted only 2.7% of the total number of trials carried out, compared to US constituting 47% of the total number of trials registered, followed by 18% from EU and 11% from Japan. However, India, China, and Japan have been found to show an increase of 3.7%, 5.1%, and 13.1% increase in the number of trials registered in 2011 compared to 2007. In contrast, US and EU showed a decline of 11.3% and 11.95% respectively in the total number of trials registered in 2011 compared to 2007. Conclusions: Although India shows gradual increase in trials registered since the advent of CTRI, still it continues to lag behind established countries in clinical research.

Effect of Vitamin D supplementation on vascular functions and oxidative stress in type 2 diabetic patients with Vitamin D deficiency

Background: Vitamin D levels are reported to have an inverse liaison with the risk of cardiovascular diseases. Hence, we aimed to evaluate the effect of Vitamin D supplementation on changes in vascular functions and oxidative stress in type 2 diabetic patients with Vitamin D deficiency. Subjects and Methods: One hundred and three patients with type 2 diabetes attending endocrinology outpatients department in a tertiary care hospital were screened for Vitamin D deficiency. Patients with serum 25-hydroxy Vitamin D levels <20 ng/ml were considered as deficient and were administered 60,000 IU of oral Vitamin D3 weekly for 8 weeks. In these patients, parameters of vascular functions (carotid-femoral pulse wave velocity, brachial-ankle pulse wave velocity, and arterial stiffness index) and oxidative stress (serum malondialdehyde levels and total antioxidant status) were measured at baseline and after 8 weeks of oral Vitamin D supplementation. Results: Among 103 patients with type 2 diabetes, 75 (72.82%) were found to have Vitamin D deficiency. Amidst these patients, carotid-femoral pulse wave velocity (991.6 ± 161.82 vs. 899.29 ± 151.86, P< 0.001), right brachial-ankle pulse wave velocity (1446.16 ± 204.33 vs. 1350.8 ± 178.39, P< 0.001), and left brachial-ankle pulse wave velocity (1493.81 ± 219.65 vs. 1367.61 ± 220.64, P< 0.001) showed a significant reduction following Vitamin D supplementation. Further, these patients were found to have significant fall in serum malondialdehyde levels with rise in total antioxidant status ensuing Vitamin D supplementation. Conclusion: The present study shows that oral Vitamin D supplementation of 60,000 IU/week for 8 weeks significantly improves vascular functions and reduces oxidative stress in type 2 diabetic patients with Vitamin D deficiency.

Effect of metformin on exercise capacity in metabolic syndrome

OBJECTIVE Metabolic syndrome is a constellation of risk factors with increased predilection towards occurrence of cardiovascular diseases. Currently physical exercise and management with metformin are the prevailing treatment modalities for metabolic syndrome. Patients with metabolic syndrome have been found to have reduced exercise capacity over a period of time. Likewise metformin has been shown to decrease exercise capacity among healthy volunteers. Hence this study aims to evaluate the effect of metformin on the exercise capacity of patients with metabolic syndrome. DESIGN Prospective study with 6 weeks follow up. METHODS Newly diagnosed patients with metabolic syndrome and to be started on Table Metformin 500mg twice a day were recruited for the study after obtaining written informed consent. Cardiopulmonary Exercise Testing (CPET) was done at baseline before the subjects were started on metformin and after 6 weeks of treatment using cardiopulmonary exercise testing apparatus (ZAN600). RESULTS Fifteen treatment naïve patients with metabolic syndrome completed six weeks of therapy with metformin. In these patients oxygen uptake [VO2] showed statistically significant decrease from 1.10±0.44 at baseline to 0.9±0.39 (l/min) after six weeks of treatment with metformin [mean difference of -0.20 (-0.31 to -0.09); P=0.001]. Similarly oxygen uptake/kg body weight [VO2/Kg] showed a significant decrease from 14.10±4.73 to 11.44±3.81 (mlkg-1min-1) at the end of six weeks of treatment [mean difference of -2.66 (-4.06 to -1.26); P=0.001]. CONCLUSION Six weeks of treatment with metformin significantly decreases exercise capacity in newly diagnosed patients with metabolic syndrome.

Comparison of ranolazine and trimetazidine on glycemic status in diabetic patients with coronary artery disease - a randomized controlled trial.

INTRODUCTION Cardiovascular diseases have become the leading cause of death around the globe and diabetes mellitus (DM) is considered to be a coronary artery disease (CAD) risk equivalent. Ranolazine, an anti anginal drug has been found to reduce Glycated haemoglobin (HbA1c) in diabetes patients with chronic angina. However the effect of another antianginal drug trimetazidine, on glycemic status is not clear. AIM To compare the effect of ranolazine and trimetazidine on glycemic status in diabetic patients with CAD. SETTINGS AND DESIGN Patients diagnosed with CAD and diabetes mellitus attending Cardiology Out Patient Department (OPD), Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry, India were recruited for this randomized open label parallel arm trial. MATERIALS AND METHODS The study conducted from January-2012 to April-2013 had 47 eligible patients diagnosed with CAD and diabetes mellitus. They were randomized to receive either ranolazine 500 mg BD or trimetazidine 35 mg BD for 12 weeks. HbA1c levels, fasting blood glucose (FBG), lipid profile, QT and QTc intervals were measured at baseline and after 12 weeks. STATISTICAL ANALYSIS Unpaired t-test was used to compare the baseline characteristics of between the groups while comparison within the groups were done using Paired t-test. Wilcoxon and Mann Whitney U-tests were used for non parametric data. Graph pad instat version-3 was used for statistical analysis. Values were expressed as mean ± SD. A p < 0.05 was considered statistically significant. RESULTS The study could not find any change in HbA1c levels in both ranolazine and trimetazidine groups. The adverse effects reported from patients on ranolazine include angina, constipation, postural hypotension, headache, dizziness, nausea and weakness while patients on trimetazidine complained of constipation, weakness, palpitations, angina, dizziness, nausea, dyspepsia, headache, gastric discomfort, joint pain, etc. CONCLUSION In patients with chronic angina and diabetes mellitus Ranolazine 500mg BD and Trimetazidine 35mg BD did not show any effect on HbA1c and fasting blood glucose lebel.