Pravin D. Potdar

Surface modification of nanofibrous polycaprolactone/gelatin composite scaffold by collagen type I grafting for skin tissue engineering

In the present study, a tri-polymer polycaprolactone (PCL)/gelatin/collagen type I composite nanofibrous scaffold has been fabricated by electrospinning for skin tissue engineering and wound healing applications. Firstly, PCL/gelatin nanofibrous scaffold was fabricated by electrospinning using a low cost solvent mixture [chloroform/methanol for PCL and acetic acid (80% v/v) for gelatin], and then the nanofibrous PCL/gelatin scaffold was modified by collagen type I (0.2-1.5wt.%) grafting. Morphology of the collagen type I-modified PCL/gelatin composite scaffold that was analyzed by field emission scanning electron microscopy (FE-SEM), showed that the fiber diameter was increased and pore size was decreased by increasing the concentration of collagen type I. Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis indicated the surface modification of PCL/gelatin scaffold by collagen type I immobilization on the surface of the scaffold. MTT assay demonstrated the viability and high proliferation rate of L929 mouse fibroblast cells on the collagen type I-modified composite scaffold. FE-SEM analysis of cell-scaffold construct illustrated the cell adhesion of L929 mouse fibroblasts on the surface of scaffold. Characteristic cell morphology of L929 was also observed on the nanofiber mesh of the collagen type I-modified scaffold. Above results suggest that the collagen type I-modified PCL/gelatin scaffold was successful in maintaining characteristic shape of fibroblasts, besides good cell proliferation. Therefore, the fibroblast seeded PCL/gelatin/collagen type I composite nanofibrous scaffold might be a potential candidate for wound healing and skin tissue engineering applications.

Ascorbic acid induces in vitro proliferation of human subcutaneous adipose tissue derived mesenchymal stem cells with upregulation of embryonic stem cell pluripotency markers Oct4 and SOX 2

Mesenchymal stem cells (MSCs) have immense therapeutic potential because of their ability to self-renew and differentiate into various connective tissue lineages. The in vitro proliferation and expansion of these cells is necessary for their use in stem cell therapy. Recently our group has developed and characterized mesenchymal stem cells from subcutaneous and visceral adipose tissue. We observed that these cells show a slower growth rate at higher passages and therefore decided to develop a supplemented medium, which will induce proliferation. Choi et al. have recently shown that the use of ascorbic acid enhances the proliferation of bone marrow derived MSCs. We therefore studied the effect of ascorbic acid on the proliferation of MSCs and characterized their phenotypes using stem cell specific molecular markers. It was observed that the use of 250 μM ascorbic acid promoted the significant growth of MSCs without loss of phenotype and differentiation potential. There was no considerable change in gene expression of cell surface markers CD105, CD13, Nanog, leukemia inhibitory factor (LIF) and Keratin 18. Moreover, the MSCs maintained in the medium supplemented with ascorbic acid for a period of 4 weeks showed increase in pluripotency markers Oct4 and SOX 2. Also cells in the experimental group retained the typical spindle shaped morphology. Thus, this study emphasizes the development of suitable growth medium for expansion of MSCs and maintenance of their undifferentiated state for further therapeutic use.

Fabrication and characterization of PCL/gelatin/chitosan ternary nanofibrous composite scaffold for tissue engineering applications

In the present study, we have fabricated a ternary composite nanofibrous scaffold from PCL/gelatin/chitosan, by electrospinning technique, using a solvent system—chloroform/methanol for polycaprolactone (PCL) and acetic acid for gelatin and chitosan, for tissue engineering applications. Field emission scanning electron microscopy (FE-SEM) was used to investigate the fiber morphology of the scaffold and it was found that the fiber morphology was influenced by the concentrations of PCL, gelatin, and chitosan in polymer solution during electrospinning. X-ray diffraction, Fourier transform infrared, and thermogravimetric (TG) analysis results showed some interactions among the molecules of PCL, gelatin, and chitosan within the scaffold. In-vitro cell culture studies were done by seeding L929 mouse fibroblasts on fabricated composite scaffold, which confirmed the cell viability, high cell proliferation rate, and cell adhesion on composite scaffold as indicated by MTT assay, DNA quantification, and FE-SEM analysis of cell-scaffold construct. Thus, the ternary composite scaffold made from the combination of PCL (synthetic polymer), gelatin, and chitosan (natural polymer) may find potential application in tissue engineering.

Isolation of Oct4+, Nanog+ and SOX2− mesenchymal cells from peripheral blood of a diabetes mellitus patient

Diabetes mellitus is a chronic metabolic disorder that affects millions of people worldwide. The most common form is type 2 diabetes mellitus, which results in impaired beta cell function combined with insulin resistance in peripheral organs. One recently proposed treatment approach is the use of adult stem cells derived from bone marrow in autologous stem cell transplantation. Alternatively, peripheral blood can be obtained in a more non-invasive manner. In this study, we isolated and cultured mesenchymal cells (MCs) from the peripheral blood of a diabetes mellitus patient. The cultured cells were large and elongated and had an in vitro migratory capacity in the culture dish. They expressed embryonic stem cell pluripotency markers Nanog and Oct 4 as well as mesenchymal markers CD105 and CD13, and they lacked expression of hematopoietic marker CD45. These characteristics suggest that these cells have a mesenchymal phenotype similar to that obtained from bone marrow cells. The SOX2 gene was downregulated in both the peripheral blood cells and the isolated mesenchymal cell line, indicating a defective mechanism of SOX2 in diabetes mellitus. The overall results of study demonstrate that peripheral blood can be used as a source of MCs from diabetes mellitus patients for use in future regenerative stem cell therapy and that this particular model system may be useful to study the mechanism of diabetes mellitus involving downregulation of the SOX2 cascade.

Fabrication and characterization of scaffold from cadaver goat-lung tissue for skin tissue engineering applications.

The present study aims to fabricate scaffold from cadaver goat-lung tissue and evaluate it for skin tissue engineering applications. Decellularized goat-lung scaffold was fabricated by removing cells from cadaver goat-lung tissue enzymatically, to have cell-free 3D-architecture of natural extracellular matrix. DNA quantification assay and Hematoxylin and eosin staining confirmed the absence of cellular material in the decellularized lung-tissue. SEM analysis of decellularized scaffold shows the intrinsic porous structure of lung tissue with well-preserved pore-to-pore interconnectivity. FTIR analysis confirmed non-denaturation and well maintainance of collagenous protein structure of decellularized scaffold. MTT assay, SEM analysis and H&E staining of human skin-derived Mesenchymal Stem cell, seeded over the decellularized scaffold, confirms stem cell attachment, viability, biocompatibility and proliferation over the decellularized scaffold. Expression of Keratin18 gene, along with CD105, CD73 and CD44, by human skin-derived Mesenchymal Stem cells over decellularized scaffold signifies that the cells are viable, proliferating and migrating, and have maintained their critical cellular functions in the presence of scaffold. Thus, overall study proves the applicability of the goat-lung tissue derived decellularized scaffold for skin tissue engineering applications.

Modification of Decellularized Goat-Lung Scaffold with Chitosan/Nanohydroxyapatite Composite for Bone Tissue Engineering Applications

Decellularized goat-lung scaffold was fabricated by removing cells from cadaver goat-lung tissue, and the scaffold was modified with chitosan/nanohydroxyapatite composite for the purpose of bone tissue engineering applications. MTT assay with osteoblasts, seeded over the chitosan/nanohydroxyapatite-modified decellularized scaffold, demonstrated significantly higher cell growth as compared to the decellularized scaffold without modification. SEM analysis of cell-seeded scaffold, after incubation for 7 days, represented a good cell adhesion, and the cells spread over the chitosan/nanohydroxyapatite-modified decellularized scaffold. Expression of bone-tissue-specific osteocalcin gene in the osteoblast cells grown over the chitosan/nanohydroxyapatite-modified decellularized scaffold clearly signifies that the cells maintained their osteoblastic phenotype with the chitosan/nanohydroxyapatite-modified decellularized scaffold. Therefore, it can be concluded that the decellularized goat-lung scaffold-modified with chitosan/nanohydroxyapatite composite, may provide enhanced osteogenic potential when used as a scaffold for bone tissue engineering.

Role of circulating tumor cells in future diagnosis and therapy of cancer

Circulating tumor cells (CTCs) have become a blistering topic of discussion for oncologists because of their tremendous potential in the diagnosis and treatment of cancer. Over the past few years, they have been doled with quite an amount of research in this area understanding that CTCs are shed from tumors and circulate in the bloodstream. This process can also occur at an early stage of cancer. The major limitation in isolation of CTCs is their availability in limited numbers. Hence, many techniques have been developed and are under continuous improvement to enhance their efficacy of CTC isolation and enumeration. They have shown their potentiality to not just indicate the presence of a tumor but also to provide us with its core information. They have also proven to be useful in detecting minor subgroups of cells present in the primary tissue which might eventually be the cause of treatment resistance or relapse of the disease. Hence, detecting and characterizing CTCs can definitely become an inevitable step in treating solid tumor malignancies. In this review, we have tried to comprehend the basics of CTCs including isolation, detection, characterization, and molecular mechanism of their circulation in the blood stream. We have mostly focused on the significance of CTCs in diagnosis and therapies of four most common types of cancers, namely, breast, prostate, lung, and colorectal. This review provides the coverage of most of the advancements with regards to different tumor malignancies and their probable use in predicting outcomes of the disease to realize the concept of personalized medicine.

Evaluation of anti-metastatic effect of chitosan nanoparticles on esophageal cancer-associated fibroblasts

Evaluation of anti-metastatic effect of chitosan nanoparticles on esophageal cancer-associated fibroblasts Pravin D. Potdar, Aashutosh U. Shetti Department of Molecular Medicine and Biology, Jaslok Hospital and Research Centre, Mumbai 400026, India. Correspondence to: Dr. Pravin D. Potdar, Department of Molecular Medicine and Biology, Jaslok Hospital and Research Centre, Mumbai 400026, India. E-mail: ppravin012@gmail.com Aim: Esophageal cancer is one of the major types of cancers, causing death of approximately 5% of all cancer deaths. This is due, in large part, to both relatively ineffectual and unavailable treatment. In order to develop an effective treatment strategy against esophageal cancer, it is important to target metastatic genes. In the present study, we have used a cancer-associated fibroblast (CAF) cell line derived from culturing peripheral blood mononuclear cells from a metastatic esophageal cancer patient to see whether chitosan nanoparticles (Ch-Np) treatment can modulate the metastatic phenotype of CAF cells by using various cellular and molecular markers. Methods: A CAF cell line was developed from peripheral blood mononuclear cells (PBMC) from a metastatic esophageal cancer patient. The cells were treated with 100 μg/mL of chitosan nanoparticle in vitro for the morphological and oncogenic characteristic studies, along with the expression of various genes involved in process of tumor development and metastasis. Techniques such as Light and Phase Contrast Microscopy, cell growth rate, Scratch metastatic assay, and molecular profiling were carried out to see changes in CAF cells before and after Ch-Np treatment. Results: It was observed that CAF cells grew in monolayer and had a doubling time of 25 ± 0.38 h. Morphologically, the cells had a fibroblastic appearance. After treatment with 100 μg/mL of Ch-Np in vitro, there was an increased doubling time to 30 ± 0.83 h. Similarly, Scratch Assay showed an inhibition in the metastatic property of these cells. These findings were confirmed with gene expression studies. It was also observed that there was complete down-regulation of metastatic genes MMP1 and MMP9 and chemokines such as CXCR-4, CXCR-7, CCR-5, and SDF-1, indicating that Ch-Np inhibited the metastatic characteristic of CAF cells. Conclusion: This study has shown that there was an inhibition of metastatic properties of CAF cells after treatment with Ch-Np, suggesting that Ch-Np can be a delivery system used for targeting cancer cells for treatment of esophageal cancer.

Development and Molecular Characterization of Human Placental Mesenchymal Stem Cells from Human Aborted Fetal Tissue as a Model to Study Mechanism of Spontaneous Abortion

Mesenchymal stem cells (MSCs) have become an important component in stem cell therapies and can be isolated from various adult tissues. The human placenta is a fetomaternal organ having a high population of multipotent stem cells with better plasticity and differential potential. It is interesting to see the molecular phenotypes of these stem cells in placenta obtained from aborted fetus to understand the mechanism of spontaneous abortion. In the present study, we have proposed to isolate multipotent stem cells from human aborted placental tissue and characterized them by using molecular and morphological analysis. Our study has shown that the placenta derived Mesenchymal stem cells (hPMSCs) have elongated epithelioid like morphology and showed high pluripotency potential by expressing Oct4, Nanog and Sox2 along with expression of Mesenchymal, hematopoietic, cytokine and chemokine markers. We have further shown that hPMSCs cells have the capacity for spontaneous differentiation into cardiomyocytes and osteocytes which have confirmed the expression of specific cardiac and osteogenic markers. Interestingly, this study has clearly shown that there is an abnormal expression of CD 73, CD 100, CD 45, Ki67 and Vimentin in aborted fetal tissue thus indicates some role of these genes in the maintenance of pregnancies. Thus, this study concludes that hPMSCs cells can be used as an in vitro model system for the evaluation of the mechanism of spontaneous abortion. Similarly, due to their multipotent characteristic they can be used for future regenerative therapies for various disorders.

Profiling of circulating tumor cells in liquid biopsies from metastatic cancer patients

Aim: Circulating tumor cells (CTCs) are crucial to tumor metastasis and valuable for prediction of clinical outcome in patients with solid tumors. Here, the authors aimed to establish a method for enumeration and characterization of CTCs from liquid biopsies. Methods: Peripheral blood mononuclear cells (PBMCs) were separated from blood samples from patients with metastatic cancer using Ficoll-Hypaque gradients and cultured to isolate and enumerate CTCs. Cultured CTCs were morphologically characterized by light and phase contrast microscopy. The tumorigenicity of Ficoll-Hypaque-separated PBMCs was examined, in addition to their expression of mRNA metastasis markers. Results: CTCs were isolated in culture and enumerated by counting under phase contrast microscopy, demonstrating that 0.01-0.04% of total PBMCs were CTCs. CTCs were dormant, with large, oval-shaped, spiky morphology. PBMCs obtained from liquid biopsies exhibited anchorage-independent growth, forming numerous colonies in soft agar assays. Molecular profiling demonstrated expression of several metastatic genes, but not of cadherin 1 (encoding the adhesion protein), in all patients. Conclusion: The authors successfully isolated, enumerated, and characterized CTCs from liquid biopsies of metastatic cancer patients. This study has potential to facilitate the development of new diagnostic and therapeutic methods using liquid biopsies, for application in metastatic cancers.