Displaying publications 1 - 20 of 28 in total

  1. Das AK
    Indian J Surg, 2011 Aug;73(4):245-50.
    PMID: 22851835 DOI: 10.1007/s12262-011-0307-5
    An ethically conducted randomised controlled trial (RCT) is the backbone of evidence based medicine. In surgical practice however, RCTs have taken a backseat, drawing much adverse comment. There are several reasons to explain surgeons' disinclination to conduct RCTs. These include many practical difficulties such as the problem of blinding surgical procedures, design and funding issues. There are also many ethical issues which need to be considered including the concept of equipoise as well as the ethical issues associated with sham surgery as a control. While there is no doubt that RCTs are essential and in fact have helped to weed out several unnecessary surgical procedures, it is important not to lose sight of the fact that they may not be always necessary in order to obtain evidence in favour of a procedure. Possible solutions could be to follow guidelines that have been issued by learned bodies and a strict adherence to all ethical norms that have been recommended in the conduct of trials.
  2. Das AK
    Indian J Surg, 2009 Aug;71(4):177-81.
    PMID: 23133150 DOI: 10.1007/s12262-009-0059-7
    Critical limb ischaemia is an intractable condition associated with high levels of amputation, leading to a low quality of life and increased morbidity and mortality. It is often not treatable by standard therapeutic modalities. Neoangiogenesis has been proposed as a novel method of treatment of such patients. Vascular endothelial growth factor (VEGF) and cytokine fibroblast growth factor (FGF-1) have been shown to elicit neoangiogenesis. Stem cells are progenitor cells which can differentiate in vivo into different types of cells. Mesenchymal stem cells (MSCs) are a type of adult stem cells which have an immunomodulatory effect. Stem cell therapy has been used in animal studies to improve limb vascularity in rat and rabbit models. Several clinical studies have also validated their use for critical limb ischaemia. However many issues are still unresolved. These include the dosage, delivery and safety issues in relation to stem cell therapy. However stem cells are likely to be an important therapeutic modality to treat critical limb ischaemia in the near future.
  3. Das AK
    Indian J Med Ethics, 2020 5 13;V(2):143-148.
    PMID: 32393455 DOI: 10.20529/IJME.2020.032
    Malaysia is a South East Asian country with a racially diverse population. Islam is the state religion and about 60% of the population is Muslim, but the rights of other religious groups are protected by law. The Parti Islam se Malaysia, which has ruled the state of Kelantan since 1999, and believes that Malaysia should be ruled by Sharia law, recently proposed the implementation of Hudud laws in Kelantan. However, the federal government has ruled out its implementation. The suggestion stirred up a controversy among the physician community and the Malaysian Medical Association rejected a proposal by the state's political leadership to utilise the services of qualified surgeons to carry out punitive limb amputations. Several Islamic states such as Sudan, Saudi Arabia, and Iran practice Islamic penal justice, including amputations. The question therefore arises: how should a modern medical practitioner approach this ethical question? This study focuses mainly on Malaysia, but draws upon practices in other Islamic countries also.
  4. Das AK
    Indian J Med Ethics, 2020 5 13;V(2):151.
    PMID: 32393445 DOI: 10.20529/IJME.2020.043
    I would like to thank Dr Adriaan Van Es for his commentary (1) on my article (2). To start with, let me make one thing clear: I am not sure why he thinks that I am condoning the practice of penal amputation. As I clearly state in my conclusion, the arguments that may (or may not) justify penal amputation are abhorrent in liberal societies. We are on the same side here. But what of those who live in less secular societies where religious faith may be unquestioned? In my opinion, van Es has resorted to a typical example of a tortured form of ethical logic (3), which researchers from countries that have different value systems and different problems have deplored, albeit in a different context.
  5. Das AK, Pal R
    J Tissue Eng Regen Med, 2010 Aug;4(6):413-21.
    PMID: 20084623 DOI: 10.1002/term.258
    Pluripotent stem cells possess the unique property of differentiating into all other cell types of the human body. Further, the discovery of induced pluripotent stem cells (iPSCs) in 2006 has opened up new avenues in clinical medicine. In simple language, iPSCs are nothing but somatic cells reprogrammed genetically to exhibit pluripotent characteristics. This process utilizes retroviruses/lentiviruses/adenovirus/plasmids to incorporate candidate genes into somatic cells isolated from any part of the human body. It is also possible to develop disease-specific iPSCs which are most likely to revolutionize research in respect to the pathophysiology of most debilitating diseases, as these can be mimicked ex vivo in the laboratory. These models can also be used to study the safety and efficacy of known drugs or potential drug candidates for a particular diseased condition, limiting the need for animal studies and considerably reducing the time and money required to develop new drugs. Recently, functional neurons, cardiomyocytes, pancreatic islet cells, hepatocytes and retinal cells have been derived from human iPSCs, thus re-confirming the pluripotency and differentiation capacity of these cells. These findings further open up the possibility of using iPSCs in cell replacement therapy for various degenerative disorders. In this review we highlight the development of iPSCs by different methods, their biological characteristics and their prospective applications in regenerative medicine and drug screening. We further discuss some practical limitations pertaining to this technology and how they can be averted for the betterment of human life.
  6. Das AK, Gopurappilly R, Parhar I
    Curr Stem Cell Res Ther, 2011 Jun;6(2):93-104.
    PMID: 21190537
    Spinal cord injuries (SCIs) are a common form of trauma that leaves a huge trail of morbidity and human suffering in its wake. They occur mostly among the young, causing severe physical, psychological, social and economic burdens. The treatment of this condition has rather been disappointing; most of the management strategies being mainly supportive and prophylactic. In recent years there has been an emerging interest in the use of stem cells to regenerate the nervous tissue that has been damaged or lost. Although there has been much hype and unfounded hope, modest successes have been witnessed, and it is possible that these therapeutic strategies may have much more to offer in the future. This paper will review the current strategies of exploring cell-based therapies, mainly different types of stem cells to treat SCI along with the evidence that has been accumulated over the past decade in a rational bench-to-bedside approach. Furthermore, critical aspects such as the mode of delivery and ethical considerations are also discussed along with feasible suggestions for future translational research to provide a contextual picture of the current state of advancements in this field. The impediments to regeneration in the site of injury are briefly explained along with the benefits and drawbacks of different cell types used in the treatment of this condition. We hope that this review will offer a significant insight into this challenging clinical condition.
  7. Mamidi MK, Das AK, Zakaria Z, Bhonde R
    Osteoarthritis Cartilage, 2016 Aug;24(8):1307-16.
    PMID: 26973328 DOI: 10.1016/j.joca.2016.03.003
    Treatment for articular cartilage damage is quite challenging as it shows limited repair and regeneration following injury. Non-operative and classical surgical techniques are inefficient in restoring normal anatomy and function of cartilage in osteoarthritis (OA). Thus, investigating new and effective strategies for OA are necessary to establish feasible therapeutic solutions. The emergence of the new discipline of regenerative medicine, having cell-based therapy as its primary focus, may enable us to achieve repair and restore the damaged articular cartilage. This review describes progress and development of employing mesenchymal stromal cell (MSC)-based therapy as a promising alternative for OA treatment. The objective of this review is to first, discuss how in vitro MSC chondrogenic differentiation mimics in vivo embryonic cartilage development, secondly, to describe various chondrogenic differentiation strategies followed by pre-clinical and clinical studies demonstrating their feasibility and efficacy. However, several challenges need to be tackled before this research can be translated to the clinics. In particular, better understanding of the post-transplanted cell behaviour and learning to enhance their potency in the disease microenvironment is essential. Final objective is to underscore the importance of isolation, storage, cell shipment, route of administration, optimum dosage and control batch to batch variations to realise the full potential of MSCs in OA clinical trials.
  8. Mamidi MK, Dutta S, Bhonde R, Das AK, Pal R
    Med Hypotheses, 2014 Dec;83(6):787-91.
    PMID: 25456787 DOI: 10.1016/j.mehy.2014.10.010
    Stem cell transplantation is a generic term covering different techniques. However there is argument over the pros and cons of autologous and allogeneic transplants of mesenchymal stem cells (MSCs) for regenerative therapy. Given that the MSCs have already been proven to be safe in patients, we hypothesize that allogeneic transplantation could be more effective and cost-effective as compared to autologous transplantation specifically in older subjects who are the likely victims of degenerative diseases. This analysis is based on the scientific logic that allogeneic stem cells extracted in large numbers from young and healthy donors could be physiologically, metabolically and genetically more stable. Therefore stem cells from young donors may be expected to exhibit higher vigor in secreting trophic factors leading to activation of host tissue-specific stem cells and also be more efficient in remodeling the micro-environmental niche of damaged tissue.
  9. Das AK, Okita T, Enzo A, Asai A
    Asian Bioeth Rev, 2020 Jun;12(2):103-116.
    PMID: 33717332 DOI: 10.1007/s41649-020-00114-6
    The use of single-use items (SUDs) is now ubiquitous in medical practice. Because of the high costs of these items, the practice of reusing them after sterilisation is also widespread especially in resource-poor economies. However, the ethics of reusing disposable items remain unclear. There are several analogous conditions, which could shed light on the ethics of reuse of disposables. These include the use of restored kidney transplantation and the use of generic drugs etc. The ethical issues include the question of patient safety and the possibility of infection. It is also important to understand the role (or otherwise) of informed consent before reuse of disposables. The widespread practice of reuse may bring down high healthcare costs and also reduce the huge amount of hospital waste that is generated. The reuse of disposables can be justified on various grounds including the safety and the cost effectiveness of this practice.
  10. Konala VB, Mamidi MK, Bhonde R, Das AK, Pochampally R, Pal R
    Cytotherapy, 2016 Jan;18(1):13-24.
    PMID: 26631828 DOI: 10.1016/j.jcyt.2015.10.008
    The unique properties of mesenchymal stromal/stem cells (MSCs) to self-renew and their multipotentiality have rendered them attractive to researchers and clinicians. In addition to the differentiation potential, the broad repertoire of secreted trophic factors (cytokines) exhibiting diverse functions such as immunomodulation, anti-inflammatory activity, angiogenesis and anti-apoptotic, commonly referred to as the MSC secretome, has gained immense attention in the past few years. There is enough evidence to show that the one important pathway by which MSCs participate in tissue repair and regeneration is through its secretome. Concurrently, a large body of MSC research has focused on characterization of the MSC secretome; this includes both soluble factors and factors released in extracellular vesicles, for example, exosomes and microvesicles. This review provides an overview of our current understanding of the MSC secretome with respect to their potential clinical applications.
  11. Mamidi MK, Pal R, Dey S, Bin Abdullah BJ, Zakaria Z, Rao MS, et al.
    Cytotherapy, 2012 Sep;14(8):902-16.
    PMID: 22731756 DOI: 10.3109/14653249.2012.693156
    Critical limb ischemia (CLI) is a syndrome manifested by ischemic rest pain, non-healing ulcers and tissue loss. CLI patients are at very high risk of amputation and experience poor physical function, leading to severe morbidity and mortality. The fundamental goal for CLI treatment is to relieve ischemic rest pain, heal ulcers, prevent limb loss and improve the quality of life, thereby extending the survival of the patient. Surgical or endovascular revascularization aimed at increasing blood flow is currently available for limb salvage in CLI. However, up to 30% of CLI patients are not suitable for such interventions because of high operative risk or unfavorable vascular anatomy. Therefore exploring new and more effective strategies for revascularization of ischemic limbs is imperative for the establishment of a viable therapeutic alternative. With the emergence of new approaches, this review describes up-to-date progress and developments in cell-based therapy as a novel and promising alternative for CLI treatment. Preliminary clinical data have established the safety, feasibility and efficacy of stem cells, and numerous studies are underway to consolidate this evidence further. However, significant hurdles remain to be addressed before this research can be responsibly translated to the bedside. In particular, we need better understanding of the behavior of cells post-transplantation and to learn how to control their survival and migration proliferation/differentiation in the hostile pathologic environment. Future research should focus on methods of isolation, optimal dosage, appropriate cell type, route of administration, role of tissue-derived factors and supportive endogenous stimulation.
  12. Gopurappilly R, Pal R, Mamidi MK, Dey S, Bhonde R, Das AK
    CNS Neurol Disord Drug Targets, 2011 Sep 1;10(6):741-56.
    PMID: 21838668
    Stroke causes a devastating insult to the brain resulting in severe neurological deficits because of a massive loss of different neurons and glia. In the United States, stroke is the third leading cause of death. Stroke remains a significant clinical unmet condition, with only 3% of the ischemic patient population benefiting from current treatment modalities, such as the use of thrombolytic agents, which are often limited by a narrow therapeutic time window. However, regeneration of the brain after ischemic damage is still active days and even weeks after stroke occurs, which might provide a second window for treatment. Neurorestorative processes like neurogenesis, angiogenesis and synaptic plasticity lead to functional improvement after stroke. Stem cells derived from various tissues have the potential to perform all of the aforementioned processes, thus facilitating functional recovery. Indeed, transplantation of stem cells or their derivatives in animal models of cerebral ischemia can improve function by replacing the lost neurons and glial cells and by mediating remyelination, and modulation of inflammation as confirmed by various studies worldwide. While initially stem cells seemed to work by a 'cell replacement' mechanism, recent research suggests that cell therapy works mostly by providing trophic support to the injured tissue and brain, fostering both neurogenesis and angiogenesis. Moreover, ongoing human trials have encouraged hopes for this new method of restorative therapy after stroke. This review describes up-to-date progress in cell-based therapy for the treatment of stroke. Further, as we discuss here, significant hurdles remain to be addressed before these findings can be responsibly translated to novel therapies. In particular, we need a better understanding of the mechanisms of action of stem cells after transplantation, the therapeutic time window for cell transplantation, the optimal route of cell delivery to the ischemic brain, the most suitable cell types and sources and learn how to control stem cell proliferation, survival, migration, and differentiation in the pathological environment. An integrated approach of cell-based therapy with early-phase clinical trials and continued preclinical work with focus on mechanisms of action is needed.
  13. Dutta S, Singh G, Sreejith S, Mamidi MK, Husin JM, Datta I, et al.
    CNS Neurosci Ther, 2013 Jan;19(1):5-11.
    PMID: 23253099 DOI: 10.1111/cns.12027
    Neurodegenerative diseases are devastating because they cause increasing loss of cognitive and physical functions and affect an estimated 1 billion individuals worldwide. Unfortunately, no drugs are currently available to halt their progression, except a few that are largely inadequate. This mandates the search of new treatments for these progressively degenerative diseases. Neural stem cells (NSCs) have been successfully isolated, propagated, and characterized from the adult brains of mammals, including humans. The confirmation that neurogenesis occurs in the adult brain via NSCs opens up fresh avenues for treating neurological problems. The proof-of-concept studies demonstrating the neural differentiation capacity of stem cells both in vitro and in vivo have raised widespread enthusiasm toward cell-based interventions. It is anticipated that cell-based neurogenic drugs may reverse or compensate for deficits associated with neurological diseases. The increasing interest of the private sector in using human stem cells in therapeutics is evidenced by launching of several collaborative clinical research activities between Pharma giants and research institutions or small start-up companies. In this review, we discuss the major developments that have taken place in this field to position stem cells as a prospective candidate drug for the treatment of neurological disorders.
  14. Warrier S, Marimuthu R, Sekhar S, Bhuvanalakshmi G, Arfuso F, Das AK, et al.
    Int J Biochem Cell Biol, 2016 06;75:104-11.
    PMID: 27063405 DOI: 10.1016/j.biocel.2016.04.002
    The extracellular ligand, Wnt, and its receptors are involved in sign al transduction and play an important role in axis formation and neural development. In neurodegenerative disorders such as Alzheimer's disease (AD), a decrease of the intracellular Wnt effector, β-catenin, has been linked to amyloid-β-peptide-induced neurotoxicity. Despite this knowledge, targeting Wnt inhibitors as potential biomarkers has not been explored, and harnessing Wnt activators as therapeutic candidates remains largely not investigated. A wide acting family of Wnt mediators, secreted frizzled-related proteins (sFRPs), has not been probed so far as molecular indicators of disease occurrence and progression of Alzheimer's. Unlike the effect of the Dickkopf (DKK) family of Wnt antagonists on AD, the sFRP molecules have a more pleiotropic impact on the Wnt signaling cascade and probably have a far-reaching involvement in neurodegeneration. The role of sFRPs has been poorly described in AD, and in this review, we analyze the present status of the role of sFRPs on neurodegeneration, their likely involvement, and potential implications in treatment modalities of AD. This information would provide valuable clues for the development of potential therapeutic targets for aberrant neurodegenerative disorders.
  15. Das AK, Bin Abdullah BJ, Dhillon SS, Vijanari A, Anoop CH, Gupta PK
    World J Surg, 2013 Apr;37(4):915-22.
    PMID: 23307180 DOI: 10.1007/s00268-012-1892-6
    BACKGROUND: Critical limb ischemia (CLI) caused by peripheral arterial disease is associated with significant morbidity and mortality. This condition is associated with a 30 % amputation rate as well as mortality levels which might be as high as 25 %. There is no pharmacological therapy available, but several reports have suggested that mesenchymal stem cells (MSCs) may be a useful therapeutic option.
    METHODS: This study, done at a university hospital, evaluated 13 patients for a phase I trial to investigate the safety and efficacy of intra-arterial MSCs in CLI patients. Eight patients with ten affected limbs were recruited for the study. As two patients (three limbs) died of ischemic cardiac events during the 6-month follow-up period, seven limbs were finally evaluated for the study.
    RESULTS: There was significant pain relief. Visual analog scale (VAS) scores decreased from 2.29 ± 0.29 to 0.5 ± 0.34 (p < 0.05), ankle brachial pressure index (ABPI) increased significantly from 0.56 ± 0.02 to 0.67 ± 0.021 (p < 0.01), and transcutaneous oxygen pressure (TcPO2) also increased significantly in the foot from 13.57 ± 3.63 to 38 ± 3.47. Similar improvement was seen in the leg as well as the thigh. There was 86 % limb salvage and six of seven ulcers showed complete or partial healing.
    CONCLUSION: It was concluded that intra-arterial MSCs could be safely administered to patients with CLI and was associated with significant therapeutic benefits.
  16. Islam MN, Liza AA, Khatun ML, Faruk MO, Das AK, Dey M, et al.
    Glob Chall, 2021 Sep;5(9):2100002.
    PMID: 34504715 DOI: 10.1002/gch2.202100002
    This study investigates the efficacy of chemically modified bone adhesive as a formaldehyde-free binder for wood-based industries. Two different types of adhesive are formulated after chemical modification of bone powder using sulfuric acid (0.5 m) and polyvinyl acetate (PVA). Gel time, solid content, Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), viscosity, and single lap joint test for shear strength are analyzed in order to assess the adhesive properties. To analyze the efficacy of the formulated adhesive, particleboards are fabricated using boiled and unboiled sugarcane bagasse. The physical and mechanical properties of the fabricated panels are measured following ASTM standards. It is found that adhesive Type C (T-C) has the shortest gel time of 4.2 min for the highest shear strength, i.e., 5.31 MPa. The particleboard (BTC-2) fabricated using T-C adhesive shows a highest density of 0.73 g cm-3, a modulus of elasticity (MOE) of 1975 N mm-2, and a modulus of rupture (MOR) of 11.80 N mm-2. The dimensional stability of the fabricated particleboards does not follow the standard requirements; however, further study might be helpful for using the chemically modified bone adhesive as a biobased adhesive.
  17. Fui LW, Lok MPW, Govindasamy V, Yong TK, Lek TK, Das AK
    J Tissue Eng Regen Med, 2019 12;13(12):2218-2233.
    PMID: 31648415 DOI: 10.1002/term.2966
    Mesenchymal stem cells (MSCs) transplantation seems to be a promising new therapy for diabetic wound healing (DWH), and currently, arrays of MSCs from various sources ranging from umbilical, adipose to dental sources are available as a treatment modality for this disease. However, it now appears that only a fraction of transplanted cells actually assimilate and survive in host tissues suggesting that the major mechanism by which stem cells participate in tissue repair are most likely related to their secretome level. These include a wide range of growth factors, cytokines, and chemokines, which can be found from the conditioned medium (CM) used to culture the cells. Basic studies and preclinical work confirm that the therapeutic effect of CMs are comparable with the application of stem cells. This review describes in detail the wound healing process in diabetes and the cellular and biological factors that influence the process. Subsequently, through a comprehensive literature search of studies related to wound healing in diabetics, we aim to provide an overview of scientific merits of using MSCs-CM in the treatment of diabetic wound as well as the significant caveats, which restricts its potential use in clinical set-ups. To our best knowledge, this is one of the first review papers that collect the importance of stem cells as an alternative treatment to the DWH. We anticipate that the success of this treatment will have a significant clinical impact on diabetic wounds.
  18. Islam MJ, Saha SK, Das AK, Jahan MS, Pervin S, Karim CF, et al.
    Mymensingh Med J, 2019 Oct;28(4):935-939.
    PMID: 31599264
    Hepatocellular carcinoma (HCC) is an important reason of liver-related death globally. HCC is the fifth most common cancer, the third most common cause for cancer related death in the world and responsible for approximately one million deaths each year. The incidence of HCC is expected to increase in the next two decades, largely due to hepatitis C infection and secondary cirrhosis. We have reported a case of hepatocellular carcinoma in a 56-year-old man with peritoneal metastasis. Diagnostic imaging (Ultra sonogram & CT-Scan) shown: a large hypo density, irregular outline lesion noted in right lower liver, post contrast image shown patchy enhancement of the lesion. His serum Alpha-Feto Protein (AFP) level was very high with elevated serum alanine amino transaminase (ALT) enzyme and prothrombin time. Histopathological (microscopic) features are compatible with Hepatocellular carcinoma. His Hepatitis C viral DNA load e.g., core protein variants and genotype 1, have been reported. The patient was treated by surgical resection followed by conservative treatment includes sorafenib & interferon alpha. This case report aims to outlines the epidemiology of HCC in chronic HCV, risk factors and pathophysiology that contribute to this disease process, related pathophysiology of patient's clinical features, screening recommendations, and the available statistics on the impact of new direct-acting antiviral treatment on the development on HCC.
  19. Mamidi MK, Singh G, Husin JM, Nathan KG, Sasidharan G, Zakaria Z, et al.
    J Transl Med, 2012;10:229.
    PMID: 23171323 DOI: 10.1186/1479-5876-10-229
    Numerous preclinical and clinical studies have investigated the regenerative potential and the trophic support of mesenchymal stem cells (MSCs) following their injection into a target organ. Clinicians favor the use of smallest bore needles possible for delivering MSCs into vascular organs like heart, liver and spleen. There has been a concern that small needle bore sizes may be detrimental to the health of these cells and reduce the survival and plasticity of MSCs.
  20. Lokman Hakim NYDB, Noble S, Thomas NV, Geegana Gamage BS, Maxwell GK, Govindasamy V, et al.
    Eur J Ophthalmol, 2022 Jan 17.
    PMID: 35037488 DOI: 10.1177/11206721211073430
    Over the last decades, the strategy of using stem cells has gained a lot of attention in treating many diseases. Recently, DR was identified as one of the common complications experienced by diabetic patients around the world. The current treatment strategy needs to be addressed since the active progression of DR may lead to permanent blindness. Interestingly, varieties of stem cells have emerged to optimize the therapeutic effects. It is also known that stem cells possess multilineage properties and are capable of differentiating, expanding in vitro and undergoing genetic modification. Moreover, modified stem cells have shown to be an ideal resource to prevent the degenerative disease and exhibit promising effects in conferring the migratory, anti-apoptotic, anti-inflammatory and provide better homing for cells into the damaged tissue or organ as well promoting healing properties. Therefore, the understanding of the functional properties of the stem cells may provide the comprehensive guidance to understand the manipulation of stem cells making them useful for long-term therapeutic applications. Hence in this review the potential use and current challenges of genetically modified stem cells to treat DR will be discussed along with its future perspectives.
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