Kanjaksha Ghosh

Reproducible methodology for the isolation of mesenchymal stem cells from human umbilical cord and its potential for cardiomyocyte generation.

Mesenchymal stem cells (MSCs) are considered to be a source of stem cells in tissue regeneration and therapeutics, due to their ability to undergo proliferation and differentiation. Complications associated with bone marrow‐derived MSCs has prompted researchers to explore alternative sources of MSCs. The human umbilical cord is one such source; it is easily available and its collection is non‐invasive. The sources of MSCs are non‐controversial and thus they are not subjected to ethical constraints, as in the case of embryonic stem cells. MSCs are multipotent stem cells and has the ability to differentiate into various cell types of the mesodermal lineage. The aim of this study was to establish a reproducible method for the isolation of MSCs from human umbilical cord, as the few methods published till date gave inconsistent results and had a mixed population of contaminating endothelial cells. In our isolation strategy, we isolated a pure population of MSCs from Whartons jelly of the human umbilical cord, which is very rich in collagen, and we used a high concentration of collagenase enzyme in the isolation of MSCs. Extensive phenotypic characterization analysis of these cells, using flow cytometry and antibody staining methods, have shown that we were able to isolate a pure population of the mesenchymal lineage cells that is devoid of haematopoietic and endothelial cell contaminants. When these MSCs were subjected to cardiomyocyte differentiation, we observed a change in the morphological characteristics, which was accompanied by the formation of myotube structures and spontaneous beating after 21 days. Copyright

Fibrinolysis, inhibitors of blood coagulation, and monocyte derived coagulant activity in acute malaria

Different parameters of fibrinolytic systems like t‐PA, PAI, D‐dimer, and inhibitors of blood coagulation, i.e., protein C (PC), protein S(PS), and antithrombin III (AT‐III), have been studied in cases of acute malaria due to Plasmodium falciparum and plasmodium vivax infection, and these patients were followed up. It was observed that the plasma PAI‐1 was very high in cases of P. falciparum malaria infection as compared to normal controls and P. vivax infection. The changes in complicated cases of P. falciparum were remarkable as compared to uncomplicated ones. The PC, PS, and AT‐III levels were also low in P. falciparum, particularly so in complicated cases, and were normal in P. vivax infection. The factor VIII R:Ag levels were invariably high in acute malaria. On follow‐up of some of these cases the values came back to normal after the antiparasite treatment. The monocyte procoagulant activity was found to be significantly higher in P. falciparum infection as compared to that of P. vivax infection. All these findings therefore contribute towards the production of a hypercoagulable state in P. falciparum infection and partly explain the complications of P. falciparum infection like cerebral malaria. Am. J. Hematol. 54:23–29, 1997

Venous thromboembolism in young patients from western India: a study.

The goal of this article is to study the association of known markers of thrombophilia with venous thrombosis in young patients (< 45 years) from the Western part of India. A prospective study of 432 patients (252 males and 180 females, age 1-45 years) was conducted between 1994 and 2000 (6 years). The diagnosis was confirmed in all the patients by ultrasound with Doppler or by a computed tomograph (CT) scan of the brain with or without contrast depending on the case. Detailed clinical examination, and family history was taken to establish recurrent thrombosis and familial occurrence of thrombosis. The markers studied were protein C, protein S, antithrombin (AT) III, factor V Leiden mutation, prothrombin gene G20210A polymorphism, and the thermolabile MTHFR variant C677T polymorphism, using appropriate techniques. Lupus inhibitor was tested in the first 72 patients using Dilute Russel Viper Venom Time (DRVVT) test, and anticardiolipin antibodies were tested by enzyme-linked immunosorbent assay. Protein C, protein S, and AT III deficiency was detected in 9.5%, 6.5%, and 2.6%, respectively, among the patients. Anticardiolipin antibody was present in 9.9% of the patients, whereas lupus anticoagulant was present in 8.3% of patients; factor V Leiden mutation was detected in 3% of patients; thermolabile variant of MTHFR C677T polymorphism was present in 14.9% of patients with 1.2% homozygotes. Prothrombin G20210A polymorphism was not detected in any sample in this population. One hundred and four patients of 432 (24.9%) had recurrent attacks of thrombosis without any proximate precipitating cause, whereas 7.5 % of the patients had another close member of the family with a history of deep venous thrombosis. Eighty-six members from 28 families (out of 32 families giving family history of thrombosis) were investigated and found to have protein C and protein S deficiency in seven each; factor V Leiden was present in 6, and MTHFR C677T polymorphism was present in 5 cases. Hence, 25 of 86 members (28%) from the family of patients with familial history deep venous thrombosis had positive markers for thrombophilia. Thus, we could show that in young patients presenting with thrombosis, at least 34% of them had a demonstrable cause for thrombophilia. Prothrombin gene polymorphism G20210A seems to be nonexistent in our population and AT III deficiency also appears to be low compared to other markers of thrombophilia. There is a high prevalence of variant MTHFR C677T in our series, but the incidence of MTHFR C677T in our general population is also high. Hence, the significance of this finding in our cases of deep venous thrombosis remains to be seen, but we did not see any homozygotes when we tested 70 randomly selected asymptomatic persons, whereas in the present series, 1.8% of the patients had homozygosity for the MTHFR C677T polymorphism.

Matrix metalloproteinase and its drug targets therapy in solid and hematological malignancies: An overview

Matrix metalloproteinase (MMP) comprises a family of zinc-dependent endopeptidases that degrade various components of the extracellular matrix (ECM) and basement membrane. MMPs are involved in solid and hematological malignancy through modification of cell growth, activation of cancer cells and modulation of immune functions. Several polymorphisms of different MMPs such as MMP-1 (-1607 1G/2G), MMP-2 (-1306 C/T), MMP-3 (-1171 5A/6A) & MMP-9 (-1562 C/T) and their expression levels have been well documented in different types of solid cancer. These polymorphic variations were found to be associated with angiogenesis, cancer progression, invasion and metastasis. There is paucity of data available in the field of hematological malignancies. Hence the field of matrix biology of hematological malignancies is an area of active exploration. A number of MMP inhibitors (MMPIs) have been developed for the cancer treatment. The most extensively studied classes of MMP inhibitors include Batimastat, Marismastat, Salimatat, Prinomastat and Tanomastat. However, their efficacy and action have not been confirmed and more data is required. The application of one or more selective targeted MMPIs in combination with conventional anti-leukemic treatment may represent a positive approach in combat against hematopoietic malignancies. Balance of MMPs and TIMPs is altered in different malignancies and biochemical pathways. These alternations will add another dimension in the matrix biology of both solid tumor and leukemia. MMP and TIMP singly and in combination are increasingly being recognized as an important player in basic cellular biology. Exploration and exploitation of MMP and TIMP balance in various malignant and nonmalignant lesions is going to be one of the most interesting facets of future use of this system for human health care.

Acquired hemophilia a: diagnosis, aetiology, clinical spectrum and treatment options.

Acquired hemophilia A (AHA) is a rare disorder with an incidence of approximately 1 per million/year with a high mortality rate of more than 20%. The disease occurs due to autoantibodies against coagulation factor VIII (FVIII) which neutralize its procoagulant function and result in severe, often life-threatening bleeding. The antibodies arise in individuals with no prior history of hemophilia A. AHA may be associated with pregnancy, autoimmune diseases, malignancy, infections or medication and occurs most commonly in the elderly. Approximately 50% of the patients remain idiopathic with no known underlying pathological condition. Clinical manifestations include spontaneous hemorrhages into the skin, muscles or soft tissues or excessive bleeding during surgery. Hemarthrosis which is the hallmark of congenital severe hemophilia A seldom occurs in AHA. The diagnosis of AHA is based on the isolated prolongation of activated partial thromboplastin time (APTT) which does not normalize after the addition of normal plasma along with reduced FVIII levels. The treatment involves two aspects-eradication of antibodies and maintaining effective hemostasis during a bleeding episode. The protocols for eradication of antibodies include immunoadsorption, immunosuppression or immune tolerance induction (ITI). The treatment of acute bleeding episodes involves use of different bypassing agents like recombinant activated factor VIIa (rFVIIa, NovoSeven®) and activated prothrombin complex concentrate (aPCC, (FEIBA®) in case of patients with high titer inhibitors or with antifibrinolytics,1-deamino-8-D-arginine vasopressin (DDAVP) or FVIII concentrates in low titer inhibitor patients. The anti CD20 monoclonal antibody, rituximab, has shown very good results either singly or in combination with immunosuppressive regimens in patients who do not respond to standard immunosuppressors. The present review summarizes the diagnostic, aetiological, clinical and treatment aspects of AHA focusing on the recent advances in this area.

Glanzmann's thrombasthenia: updated

Glanzmanns thrombasthenia is an autosomal recessive disorder, rare in a global context, but a relatively more common platelet function defect in communities where consanguineous marriages are more frequent. On clinical grounds alone, it cannot be distinguished from other congenital platelet function defects. Epistaxis, gum bleeding, menorrhagia are the common clinical manifestations, whereas large muscle hematoma or hemarthrosis seldom occur in these patients. Essential diagnostic features are a normal platelet count and morphology, a greatly prolonged bleeding time, absence of platelet aggregation in response to ADP, collagen, epinephrine, thrombin and to all aggregating agents which ultimately depend on fibrinogen binding to platelets for this effect, flow cytometry, studies of GPIIb-IIIa receptors on the platelet membrane surface using monoclonal antibodies. The present review describes some of the uncommon features of the disorders and the currently available options which the treating physicians should be aware of during the management of these patients. Although by definition all patients with Glanzmanns thrombasthenia have a virtually complete failure of platelet aggregation, a number of variant forms of GT have been described in which the glycoproteins are present in normal or near normal amounts but are functionally defective. Understanding the pathophysiology of the disorder by the treating physicians is of utmost importance. Presence of high affinity platelet receptors resulting in thrombasthennia-like phenotype may require an antagonistic treatment atypical of classical GT management. It has now been established that different genetic mutations of either GPIIb or IIIa genes results in such a heterogeneity of thrombasthenia phenotype. Glanzmanns thrombasthenia is a paradigm for treating coronary artery disease patients with GPIIb-IIIa antibody and inhibitors. By using these medicines we create a temporary GT-like situation. Hence, understanding this disease is of utmost importance to the practicing cardiologist. As mutations for different variant forms of GT become known, our understanding of how GPIIb-IIIa molecules can be activated to act as a receptor for fibrinogen molecules will be increased. Such understanding undoubtedly will help us to devise better drugs with GPIIb-IIIa inhibitors. Molecular biology techniques have enabled us to equivocally detect heterozygote carriers who are clinically asymptomatic. However, there may be several laboratories in the developing world, which have no access to molecular biology techniques. Development of more robust techniques of quantitation of platelet receptors has enabled an accurate diagnosis of heterozygote carriers or an unborn fetus in the second trimester. The importance of the GPIIb-IIIa polymorphisms in carrier and prenatal diagnosis has not been properly studied. Nowadays the less direct method of PLA1 typing (determination of the levels of platelet antigen) of the foetal platelets as early as 16 weeks of intrauterine life can be used for prenatal diagnosis of GT.

Changes in platelet glycoprotein receptors after smoking--a flow cytometric study.

Cigarette smoking is accepted to be one of the major factors which increase the risk of coronary artery disease, peripheral vascular disease and stroke. A number of studies have been carried out on the acute and chronic effects of tobacco smoking on platelet activation. An enhancing effect of high nicotine cigarette smoking on platelet aggregation has been reported. Since platelet receptors are involved in the final stage of platelet aggregation, the intention of this study was to investigate platelet receptors in acute and chronic smokers before and after smoking. Nineteen chronic smokers, 18 acute smokers and 18 healthy non-smoking controls were included in the present study. Platelet aggregation was carried out using ristocetin, adenosine diphosphate (ADP) and collagen both before and after smoking in acute and chronic smokers. Flow cytometric studies of platelets were carried out utilizing fluorescein isothiocyanate (FITC)-labelled anti-human fibrinogen antibody in unstimulated and ADP-stimulated platelets, FITC-labelled anti-GP IIb/IIIa antibody, FITC-labelled anti-GP Ib/IX antibody and FITC-labelled P-selectin antibody. The intensity of fluorescence was graded into three groups and expressed in arbitrary units. The interesting data generated in the present work is that in vivo platelet activation occurs immediately after smoking a cigarette which is detected by using FITC-labelled anti-human fibrinogen antibody binding to platelet and by P-selectin expression. It is also quite evident from the present study that a significant number of circulating platelets are in the activated state in chronic smokers. Therefore this study suggests that smoking-induced platelet activation may be an important contributory mechanism for acute coronary events in smokers.

Contribution of natural anticoagulant and fibrinolytic factors in modulating the clinical severity of haemophilia patients

The role of natural anticoagulants, fibrinolytic cascade factors and common prothrombotic gene polymorphisms in modulating disease severity were studied in 35 ‘clinically mild’ and 37 ‘clinically severe’ haemophilia patients with severe factor VIII or IX deficiency (<0·01 IU/ml). Strong association of deficiencies of proteins C and S, antithrombin III, tissue factor pathway inhibitor and tissue plasminogen activator, together with factor V Leiden and endothelial protein C receptor 23 bp insertion polymorphisms were observed in the ‘clinically milder’ group as compared with the ‘clinically severe’ group. These results indicate a synergistic modulation of bleeding tendency in haemophilia patients by factors in the anticoagulant and fibrinolytic systems.

Milder clinical presentation of haemophilia A with severe deficiency of factor VIII as measured by one-stage assay.

During the course of investigations we encountered 11 patients with haemophilia A who had severe factor VIII deficiency as measured by one‐stage assay but had surprisingly mild clinical presentation. Four of these patients had either a brother, nephew or maternal uncle with severe clinical manifestations. Two patients had low protein S levels, and one was heterozygous for the factor V Leiden mutation. One patient had a combined deficiency of protein C and antithrombin III. Four patients had a two‐stage factor VIII assay value that was much higher than the one‐stage assay value. Five patients were heterozygous for the MTHFR gene C677T polymorphism, of whom two patients were also deficient for protein S and one had two‐stage factor assay values higher than the one‐stage assay values. The patient who was both factor VIII deficient and heterozygous for factor V Leiden had mild clinical presentation as compared to his maternal uncle who was only factor‐VIII deficient. The maternal cousin of the same patient was heterozygous for factor V Leiden and had suffered two thrombotic episodes. Thus, the present study advocates that the physiological inhibitors of blood coagulation also play an important role in cases of haemophilia A in the final outcome of haemostasis in vivo.

Pathogenesis of anemia in malaria : a concise review

Anemia is a common complication in malarial infection, although the consequences are more pronounced with Plasmodium falciparum malaria (Ghosh, Indian J Hematol Blood Tranfus 21(53):128–130, 2003). Anemia in this infection is caused by a variety of pathophysiologic mechanisms, and in areas where malaria infection is endemic, co-morbidities like other parasitic infestations, iron, folate and Vitamin B12 deficiency, deficiency of other nutrients, and anemia, which is aggravated by anti-malarial drugs both through immune and non-immune mechanisms, are important considerations. In different endemic areas, β-thalassemia, α-thalassemia, Hb S, Hb E, G6PD deficiency, or ovalocytosis in different proportions interact with this infection. Finally, aberrant immune response to repeated or chronic falciparum malarial infection may produce tropical splenomegaly syndrome, a proportion of which show clonal proliferation of B lymphocytes. Cooperation between chronic malarial infection and infection with E-B virus infection in producing Burkitt’s lymphoma is well known. In this review, the fascinating and multifaceted pathophysiolgoy of malarial anemia has been discussed.