Avinash Bardia

Current concept in neural regeneration research: NSCs isolation, characterization and transplantation in various neurodegenerative diseases and stroke: A review

Since last few years, an impressive amount of data has been generated regarding the basic in vitro and in vivo biology of neural stem cells (NSCs) and there is much far hope for the success in cell replacement therapies for several human neurodegenerative diseases and stroke. The discovery of adult neurogenesis (the endogenous production of new neurons) in the mammalian brain more than 40 years ago has resulted in a wealth of knowledge about stem cells biology in neuroscience research. Various studies have done in search of a suitable source for NSCs which could be used in animal models to understand the basic and transplantation biology before treating to human. The difficulties in isolating pure population of NSCs limit the study of neural stem behavior and factors that regulate them. Several studies on human fetal brain and spinal cord derived NSCs in animal models have shown some interesting results for cell replacement therapies in many neurodegenerative diseases and stroke models. Also the methods and conditions used for in vitro culture of these cells provide an important base for their applicability and specificity in a definite target of the disease. Various important developments and modifications have been made in stem cells research which is needed to be more specified and enrolment in clinical studies using advanced approaches. This review explains about the current perspectives and suitable sources for NSCs isolation, characterization, in vitro proliferation and their use in cell replacement therapies for the treatment of various neurodegenerative diseases and strokes.

Repopulation of decellularized whole organ scaffold using stem cells: an emerging technology for the development of neo-organ

Demand of donor organs for transplantation in treatment of organ failure is increasing. Hence there is a need to develop new strategies for the alternative sources of organ development. Attempts are being made to use xenogenic organs by genetic manipulation but the organ rejection against human always has been a major challenge for the survival of the graft. Advancement in the genetic bioengineering and combination of different allied sciences for the development of humanized organ system, the therapeutic influence of stem cell fraction on the reconstitution of organ architecture and their regenerative abilities in different tissues and organs provides a better approach to solve the problem of organ shortage. However, the available strategies for generating the organ/tissue scaffolds limit its application due to the absence of complete three-dimensional (3D) organ architecture, mechanical strength, long-term cell survival, and vascularization. Repopulation of whole decellularized organ scaffolds using stem cells has added a new dimension for creating new bioengineered organs. In recent years, several studies have demonstrated the potential application of decellularization and recellularization approach for the development of functional bio-artificial organs. With the help of established procedures for conditioning, extensive stem cells and organ engineering experiments/transplants for the development of humanized organs will allow its preclinical evaluation for organ regeneration before translation to the clinic. This review focuses on the major aspects of organ scaffold generation and repopulation of different types of whole decellularized organ scaffolds using stem cells for the functional benefit and their confines.

Macrophage migration inhibitory factor, Toll-like receptor 4, and CD14 polymorphisms with altered expression levels in patients with ulcerative colitis

Ulcerative colitis is a multifactorial disease in which genetic factors play a major role. Functional mutations in the genes related to innate immune response exacerbate mucosal damage coupled with persistent inflammation. The cytokine macrophage migration inhibitory factor (MIF), CD14, and Toll-like receptor 4 (TLR4) are the central players with clearly defined roles in inflammation. The aim of this study was to investigate the association between MIF-173G > C, CD14-159C > T, and TLR4-299A > G polymorphisms and mononuclear cell expression in patients with ulcerative colitis (UC). Genotyping of MIF-173G > C, CD14-159C > T, and TLR4-299A > G polymorphisms was performed by amplification refractory mutation system-polymerase chain reaction and allele-specific amplification in 139 and 176 patients with UC and controls, respectively. Simultaneously, the expression levels of intracellular MIF, mCD14, and mTLR4 were determined in mononuclear cells using a flow cytometer. Polymorphisms in CD14-159C > T and TLR4-299A > G significantly affected mCD14 and mTLR4 expression levels and also increased susceptibility to UC. Although intracellular MIF expression levels differed among patient and control groups, the polymorphism in MIF 173G > C was not observed to be associated with a risk of UC.

Hepatic stem cells: A viable approach for the treatment of liver cirrhosis

Liver cirrhosis is characterized by distortion of liver architecture, necrosis of hepatocytes and regenerative nodules formation leading to cirrhosis. Various types of cell sources have been used for the management and treatment of decompensated liver cirrhosis. Knowledge of stem cells has offered a new dimension for regenerative therapy and has been considered as one of the potential adjuvant treatment modality in patients with end stage liver diseases (ESLD). Human fetal hepatic progenitor cells are less immunogenic than adult ones. They are highly propagative and challenging to cryopreservation. In our earlier studies we have demonstrated that fetuses at 10-18 wk of gestation age contain a large number of actively dividing hepatic stem and progenitor cells which possess bi-potent nature having potential to differentiate into bile duct cells and mature hepatocytes. Hepatic stem cell therapy for the treatment of ESLD is in their early stage of the translation. The emerging technology of decellularization and recellularization might offer a significant platform for developing bioengineered personalized livers to come over the scarcity of desired number of donor organs for the treatment of ESLD. Despite these significant advancements long-term tracking of stem cells in human is the most important subject nowadays in order to answer several unsettles issues regarding the route of delivery, the choice of stem cell type(s), the cell number and the time-point of cell delivery for the treatment in a chronic setting. Answering to these questions will further contribute to the development of safer, noninvasive, and repeatable imaging modalities that could discover better cell therapeutic approaches from bench to bed-side. Combinatorial approach of decellularization and nanotechnology could pave a way towards the better understanding in determination of cell fate post-transplantation.

Association of genetic variants of mannan-binding (MBL) lectin-2 gene, MBL levels and function in ulcerative colitis and Crohn’s disease

Ulcerative colitis and Crohn’s disease are the two major forms of inflammatory bowel disease (IBD). A series of reports have hypothesized interplay of genetic and environmental factors in the pathogenesis of IBD. Polymorphism in the mannan-binding lectin-2 (MBL-2) gene is known to affect the structural assembly and function thereby predisposing subjects to various diseases. The present study was designed to evaluate effect of MBL-2 gene polymorphism on MBL levels and function in IBD patients. Genomic DNA was isolated from blood samples collected from 157 ulcerative colitis, 42 Crohn’s disease and 204 control subjects. Genotyping for different polymorphic sites at exon1 of MBL-2 gene was performed by refractory mutation system-PCR and amplification followed by restriction digestion (PCR-RFLP). Serum MBL concentration and C4 deposition levels were estimated using ELISA. Mannan-binding lectin-2 genotypic variants were calculated in IBD and healthy controls. The frequency of single nucleotide polymorphisms at codon 54 was significantly higher in ulcerative colitis patients than controls (P < 0.0001). Ulcerative colitis patients with ‘codon 54’-variation showed low serum MBL concentrations coupled with altered MBL function compared to controls. In conclusion, single nucleotide polymorphism in the MBL-2 gene is an important risk factor significantly affecting MBL levels and function in the development of ulcerative colitis among Indians.

In vitro quantitative and relative gene expression analysis of pancreatic transcription factors Pdx-1, Ngn-3, Isl-1, Pax-4, Pax-6 and Nkx-6.1 in trans-differentiated human hepatic progenitors.

Diabetes is a major health concern throughout the world because of its increasing prevalence in epidemic proportions. β‐Cell deterioration in the pancreas is a crucial factor for the progression of diabetes mellitus. Therefore, the restoration of β‐cell mass and its function is of vital importance for the development of effective therapeutic strategies and most accessible cell sources for the treatment of diabetes mellitus.

Relevance of Helicobacter pylori genotypes in gastric pathology and its association with plasma malondialdehyde and nitric oxide levels

Persistent infection with Helicobacter pylori confers an increased risk of peptic ulceration and gastric adenocarcinoma. Reactive oxygen and nitrogen species play a crucial role in the progression from normal gastric mucosa to cancer. The aim of the present study was to investigate the plasma malondialdehyde and nitric oxide levels in H. pylori related gastroduodenal diseases and associate their levels with gastric pathology and genotypes of H. pylori. Malondialdehyde and nitric oxide levels in plasma samples of 250 subjects were spectrophotometrically determined. Subsequently, genotypic and histopathological assessment was performed in gastric biopsies obtained during endoscopy. The levels of MDA and NO exceeded in subjects infected with genotype-1 of Hp than those with other genotypes suggesting more precise interaction of highly virulent strains of Hp in eliciting severe tissue damage. In conclusion, the study demonstrates close relationship between the plasma malondialdehyde and nitric oxide levels, gastric histopathology and genotypes of H. pylori.

Magnetic nanoparticle tagged stem cell transplantation in spinal cord injury: A promising approach for targeted homing of cells at the lesion site

Spinal cord injury (SCI) is a devastating condition that leads to significant morbidity. It results in a permanent neurological deficit due to damage of motor neurons. The resultant lesion is a barrier for “communication” between the brain and peripheral tissues, both at the effector as well as the receptor level. One of the primary goals of tissue engineering is to bridge the gap created by SCI and reestablish the damaged connections.[1,2] Stem cell transplantation has a great potential in designing effective therapies for SCI. Despite extensive therapeutic benefits, lack of a noninvasive and efficient cell delivery system, and poor engraftment limits the current role of stem cell therapies in SCI. Application of nanotechnology has already proven its potential in addressing some of these fundamental issues. The development of superparamagnetic iron oxide nanoparticles (SPIONPs) has provided a better pathway for the efficient delivery of stem cells at the target location.[3] A recent study by Tukmachev et al. has demonstrated the potential of SPIONPs in facilitating the homing of mesenchymal stem cells (MSCs) at the lesion site in a rat model of SCI.[4] The study demonstrated the accumulation of SPIO‐labeled MSCs in the vicinity of the lesion site from a distance of 10 cm from the site of injury by using an external magnetic system of 1.2T [Figure 1]. This study provides a better hope for future magnetic nanoparticle‐based delivery of stem cells at the desired site. However, few of the most important issues in cell‐based therapies for SCI are the formation of a glial scar and the regeneration of neurons and glia that undergo cell death soon after injury. Therefore, selection of the appropriate variety of stem cells has to be done for an effective treatment. In the same direction, our center has developed a novel gadolinium‐SPIO (Gd‐SPIO) magnetic nanoparticle by a soft chemical approach that provides a high biocompatibility. Gd‐SPIONPs produce enhanced sensitivity by decreasing the relaxation time of the proton longitudinally (T1) as well as transversely (T2). Thus, it may be a better choice for obtaining a contrast magnetic resonance imaging. The extremely low concentrations of the magnetic nanoparticles prevents the toxic side effects of free gadolinium ions from developing. Apart from its use in the generation of excellent contrast images, Gd‐SPIONPs have also shown a paramagnetic behavior due to their much greater proton relaxation per atom of iron than gadolinium. The paramagnetic activity of Gd‐SPIONPs in the presence of external magnetic fields is accompanied by its safe degradation and clearance from the biological system (unpublished data). Hence, directed transplantation of neuronal cells labeled with Gd‐SPIONPs may be considered as a better strategy for obtaining high contrast imaging and noninvasive cell trapping at the desired site. This combinational strategy of Gd‐SPIO labeled neuronal cells for the regeneration of chronically injured spinal cord would overcome the effects of the glial scar, inhibitory molecules, and help in utilizing tissue engineering strategies to bridge the lesion more effectively. Correspondence

Phylogenetic analysis, based on EPIYA repeats in the cagA gene of Indian Helicobacter pylori, and the implications of sequence variation in tyrosine phosphorylation motifs on determining the clinical outcome.

The population of India harbors one of the world’s most highly diverse gene pools, owing to the influx of successive waves of immigrants over regular periods in time. Several phylogenetic studies involving mitochondrial DNA and Y chromosomal variation have demonstrated Europeans to have been the first settlers in India. Nevertheless, certain controversy exists, due to the support given to the thesis that colonization was by the Austro-Asiatic group, prior to the Europeans. Thus, the aim was to investigate pre-historic colonization of India by anatomically modern humans, using conserved stretches of five amino acid (EPIYA) sequences in the cagA gene of Helicobacter pylori. Simultaneously, the existence of a pathogenic relationship of tyrosine phosphorylation motifs (TPMs), in 32 H. pylori strains isolated from subjects with several forms of gastric diseases, was also explored. High resolution sequence analysis of the above described genes was performed. The nucleotide sequences obtained were translated into amino acids using MEGA (version 4.0) software for EPIYA. An MJ-Network was constructed for obtaining TPM haplotypes by using NETWORK (version 4.5) software. The findings of the study suggest that Indian H. pylori strains share a common ancestry with Europeans. No specific association of haplotypes with the outcome of disease was revealed through additional network analysis of TPMs.

Isolation and Characterization of Stem Cells Sub Population within the Human Fetal Liver

Isolation and Characterization of Stem Cells Sub Populationwithin the Human Fetal Liver Human fetal liver is the potential source of both hematopoietic and non-hematopoietic stem cells which can be identified using phenotypic markers. Isolation of homogenous populations of hepatic progenitor cells and their sub-populations is an essential prerequisite for investigating specific markers and appropriate cell types for their possible clinical applications. Several studies have demonstrated the presence of a variety of stem cell populations within the fetal liver. The present study was undertaken to identify specialized cell populations, their valuable growth potential and bi-potential differentiation capability derived from human fetal liver using CD133.