Solomon Sathishkumar

In vitro Differentiation Potential of Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) represent a class of multipotent progenitor cells that have been isolated from multiple tissue sites. Of these, adipose tissue and bone marrow offer advantages in terms of access, abundance, and the extent of their documentation in the literature. This review focuses on the in vitro differentiation capability of cells derived from adult human tissue. Multiple, independent studies have demonstrated that MSCs can commit to mesodermal (adipocyte, chondrocyte, hematopoietic support, myocyte, osteoblast, tenocyte), ectodermal (epithelial, glial, neural), and endodermal (hepatocyte, islet cell) lineages. The limitations and promises of these studies in the context of tissue engineering are discussed.

Attitude of medical students towards Early Clinical Exposure in learning endocrine physiology

BackgroundDifferent teaching-learning methods have been used in teaching endocrine physiology for the medical students, so as to increase their interest and enhance their learning. This paper describes the pros and cons of the various approaches used to reinforce didactic instruction in endocrine physiology and goes on to describe the value of adding an Early Clinical Exposure program (ECE) to didactic instruction in endocrine physiology, as well as student reactions to it as an alternative approach.DiscussionVarious methods have been used to reinforce didactic instruction in endocrine physiology such as case-stimulated learning, problem-based learning, patient-centred learning and multiple-format sessions. We devised a teaching-learning intervention in endocrine physiology, which comprised of traditional didactic lectures, supplemented with an ECE program consisting of case based lectures and a hospital visit to see patients. A focus group discussion was conducted with the medical students and, based on the themes that emerged from it, a questionnaire was developed and administered to further enquire into the attitude of all the students towards ECE in learning endocrine physiology.The students in their feedback commented that ECE increased their interest for the subject and motivated them to read more. They also felt that ECE enhanced their understanding of endocrine physiology, enabled them to remember the subject better, contributed to their knowledge of the subject and also helped them to integrate their knowledge. Many students said that ECE increased their sensitivity toward patient problems and needs. They expressed a desire and a need for ECE to be continued in teaching endocrine physiology for future groups of students and also be extended for teaching other systems as well. The majority of the students (96.4%) in their feedback gave an overall rating of the program as good to excellent on a 5 point Likert scale.SummaryThe ECE program was introduced as an alternative approach to reinforce didactic instruction in endocrine physiology for the first year medical students. The study demonstrated that students clearly enjoyed the experience and perceived that it was valuable. This method could potentially be used for other basic science topics as well.

A novel composition for the culture of human adipose stem cells which includes complement C3

Adipose tissue is an easily accessible and abundant source of stem cells. Adipose stem cells (ASCs) are currently being researched as treatment options for repair and regeneration of damaged tissues. The standard culture conditions used for expansion of ASCs contain fetal bovine serum (FBS) which is undefined, could transmit known and unknown adventitious agents, and may cause adverse immune reactions. We have described a novel culture condition which excludes the use of FBS and characterised the resulting culture. Human ASCs were cultured in the novel culture medium, which included complement protein C3. These cultures, called C-ASCs, were compared with ASCs cultured in medium supplemented with FBS. Analysis of ASCs for surface marker profile, proliferation characteristics and differentiation potential indicated that the C-ASCs were similar to ASCs cultured in medium containing FBS. Using a specific inhibitor, we show that C3 is required for the survival of C-ASCs. This novel composition lends itself to being developed into a defined condition for the routine culture of ASCs for basic and clinical applications.

Improving the effectiveness of physiology record books as a learning tool for first-year medical students in India

In compliance with the Medical Council of India, preclinical medical students maintain a record of their laboratory work in physiology. The physiology record books also contain a set of questions to be answered by the students. Faculty members and students had indicated that responding to these questions did not serve the intended purpose of being an effective learning tool. The purpose of this study was to obtain the views of the medical students and faculty members at our institution concerning the usefulness of responding to the questions and to gather suggestions for possible improvement. Data were collected through focus groups and questionnaires to first-year medical students and faculty members in physiology and were analyzed using qualitative and quantitative methods. The students and faculty members viewed the physiology record books as a potentially useful learning aid, but lack of time led the students to write the answers without understanding the topic rather than generating their own responses to the questions. Faculty members and students recommended that the students should write the responses to the questions on site during the practical classes, using relevant on-site resources and interacting with faculty members. The findings of the present study may be of value to other medical colleges in India and outside India with modifications based on their specific needs to improve the effectiveness of physiology record books as a learning tool.

Reserve or Resident Progenitors in Cartilage? Comparative Analysis of Chondrocytes versus Chondroprogenitors and Their Role in Cartilage Repair

Introduction Articular cartilage is made up of hyaline tissue embodying chondrocytes, which arise from mesenchymal stromal cells (MSCs) and specialized extracellular matrix. Despite possessing resident progenitors in and around the joint primed for chondrogenesis, cartilage has limited intrinsic capacity of repair and cell turnover. Advances in isolation, culture, and characterization of these progenitors have raised the possibility for their use in cell-based cartilage repair. Chondroprogenitors (CPCs) have been classified as MSCs and have been postulated to play a vital role in injury response and are identified by their colony forming ability, proliferative potential, telomere dynamics, multipotency, and expression of stem cell markers. The combined presence of CPCs and chondrocytes within the same tissue compartments and the ability of chondrocytes to dedifferentiate and acquire stemness during culture expansion has obscured our ability to define and provide clear-cut differences between these 2 cell populations. Objective This review aims to evaluate and summarize the available literature on CPCs in terms of their origin, growth kinetics, molecular characteristics, and differential and therapeutic potential with emphasis on their difference from daughter chondrocytes. Design For this systematic review, a comprehensive electronic search was performed on PubMed and Google Scholar using relevant terms such as chondrocytes, chondroprogenitors, and surface marker expression. Results and Conclusion Our comparative analysis shows that there is an ill-defined distinction between CPCs and chondrocytes with respect to their cell surface expression (MSC markers and CPC-specific markers) and differentiation potential. Accumulating evidence indicates that the 2 subpopulations may be distinguished based on their growth kinetics and chondrogenic marker.

In vitro characterization of human articular chondrocytes and chondroprogenitors derived from normal and osteoarthritic knee joints

Objective Cell based therapy optimization is constantly underway since regeneration of genuine hyaline cartilage is under par. Although single source derivation of chondrocytes and chondroprogenitors is advantageous, lack of a characteristic differentiating marker obscures clear identification of either cell type which is essential to create a biological profile and is also required to assess cell type superiority for cartilage repair. This study was the first attempt where characterization was performed on the two cell populations derived from the same human articular cartilage samples. Design Cells obtained from normal/osteoarthritic knee joints were expanded in culture (up to passage 10). Characterization studies was performed using flow cytometry, gene expression was studied using RT-PCR, growth kinetics and tri-lineage differentiation was also studied to construct a better biological profile of chondroprogenitors as well as chondrocytes. Results and conclusions Our results suggest that sorting based on CD34(-), CD166(+) and CD146(+), instead of isolation using fibronectin adhesion assay (based on CD49e+/CD29+), would yield a population of cells primarily composed of chondroprogenitors which when derived from normal as opposed to osteoarthritic cartilage, could provide translatable results in terms of enhanced chondrogenesis and reduced hypertrophy; both indispensable for the field of cartilage regeneration.

Comparison of Electrophysiological Properties and Gene Expression between Human Chondrocytes and Chondroprogenitors Derived from Normal and Osteoarthritic Cartilage

Objectives Bone-marrow mesenchymal stem cells (MSCs) and chondrocytes are currently used for cell-based therapy in cartilage repair. Chondroprogenitors (CPs), resident cells of articular cartilage, demonstrate likeness to stem cells. Reports suggest that chondrocytes phenotype is altered in culture, thus making differentiation between the two cell populations difficult. Our objectives were to electrophysiologically assess chondrocytes and CPs, compare their mRNA expression with that of ionic channels already reported in MSCs, and to observe the effect of time in culture and osteoarthritic damage on cells. Design and Results Chondrocytes and CPs at passages 0 (p0) and 5 (p5) derived from normal and osteoarthritic (OA) knee joints were used. Ionic currents were recorded by subjecting cells to depolarizing voltage pulses, and reverse transcriptase-polymerase chain reaction (RT-PCR) was used for studying ion channel expression. Our results demonstrated that both chondrocytes and CPs showed the presence of similar currents belonging to voltage-gated potassium channel subfamily, with RT-PCR confirming high mRNA expression of Maxi K, HKv1.1, HKv1.4, HKv4.2, and hEAG1 channels. Our finding also suggested that CPs were comparatively more sensitive to increased time in culture and inflammatory processes as observed in OA, as was evidenced by the significant decrease in mean current density (p0 normal CP: 183.171 ± 50.80 pA/pF; p5 normal CP: 50.225 ± 17.63 pA/pF; P = 0.0280) and significant increase in cellular size (p0 normal CP: 21.564 ± 2.98 pF; p0 OA CP: 37.939 ± 3.55 pF; P = 0.0057). Conclusion Both cell types appear to be optimal candidates for cell-based therapy although initial seeding density, cell source (normal vs. OA), and time in culture are matters of concern, prior to cell-type selection.

Self-directed learning readiness of Indian medical students: a mixed method study

BackgroundSelf-directed learning (SDL) is defined as learning on one’s own initiative, with the learner having primary responsibility for planning, implementing, and evaluating the effort. Medical education institutions promote SDL, since physicians need to be self-directed learners to maintain lifelong learning in the ever-changing world of medicine and to obtain essential knowledge for professional growth. The purpose of the study was to measure the self-directed learning readiness of medical students across the training years, to determine the perceptions of students and faculty on factors that promote and deter SDL and to identify the role of culture and curriculum on SDL at the Christian Medical College, Vellore, India.MethodsGuglielmino’s SDL Readiness Scale (SDLRS) was administered in 2015 to six student cohorts (452 students) at admission, end of 1st, 2nd, 3rd and 4th year of training, and at the beginning of internship in the undergraduate medicine (MBBS) program. Analysis of variance (ANOVA) was used to compare SDL scores between years of training. 5 student focus groups and 7 interviews with instructors captured perceptions of self-direction. Transcripts were coded and analyzed thematically.ResultsThe overall mean SDLRS score was 212.91. There was no significant effect of gender and age on SDLR scores. There was a significant drop in SDLRS scores on comparing students at admission with students at subsequent years of training. Qualitative analysis showed the prominent role of culture and curriculum on SDL readiness.ConclusionsGiven the importance of SDL in medicine, the current curriculum may require an increase in learning activities that promote SDL. Strategies to change the learning environment that facilitates SDL have to be considered.