Gauthaman Kalamegam

Chondrocyte and mesenchymal stem cell-based therapies for cartilage repair in osteoarthritis and related orthopaedic conditions

Osteoarthritis (OA) represents a final and common pathway for all major traumatic insults to synovial joints. OA is the most common form of degenerative joint disease and a major cause of pain and disability. Despite the global increase in the incidence of OA, there are no effective pharmacotherapies capable of restoring the original structure and function of damaged articular cartilage. Consequently cell-based and biological therapies for osteoarthritis (OA) and related orthopaedic disorders have become thriving areas of research and development. Autologous chondrocyte implantation (ACI) has been used for treatment of osteoarticular lesions for over two decades. Although chondrocyte-based therapy has the capacity to slow down the progression of OA and delay partial or total joint replacement surgery, currently used procedures are associated with the risk of serious adverse events. Complications of ACI include hypertrophy, disturbed fusion, delamination, and graft failure. Therefore there is significant interest in improving the success rate of ACI by improving surgical techniques and preserving the phenotype of the primary chondrocytes used in the procedure. Future tissue-engineering approaches for cartilage repair will also benefit from advances in chondrocyte-based repair strategies. This review article focuses on the structure and function of articular cartilage and the pathogenesis of OA in the context of the rising global burden of musculoskeletal disease. We explore the challenges associated with cartilage repair and regeneration using cell-based therapies that use chondrocytes and mesenchymal stem cells (MSCs). This paper also explores common misconceptions associated with cell-based therapy and highlights a few areas for future investigation.

Mesenchymal stem cells in regenerative medicine: Focus on articular cartilage and intervertebral disc regeneration

Musculoskeletal disorders represent a major cause of disability and morbidity globally and result in enormous costs for health and social care systems. Development of cell-based therapies is rapidly proliferating in a number of disease areas, including musculoskeletal disorders. Novel biological therapies that can effectively treat joint and spine degeneration are high priorities in regenerative medicine. Mesenchymal stem cells (MSCs) isolated from bone marrow (BM-MSCs), adipose tissue (AD-MSCs) and umbilical cord (UC-MSCs) show considerable promise for use in cartilage and intervertebral disc (IVD) repair. This review article focuses on stem cell-based therapeutics for cartilage and IVD repair in the context of the rising global burden of musculoskeletal disorders. We discuss the biology MSCs and chondroprogenitor cells and specifically focus on umbilical cord/Whartons jelly derived MSCs and examine their potential for regenerative applications. We also summarize key components of the molecular machinery and signaling pathways responsible for the control of chondrogenesis and explore biomimetic scaffolds and biomaterials for articular cartilage and IVD regeneration. This review explores the exciting opportunities afforded by MSCs and discusses the challenges associated with cartilage and IVD repair and regeneration. There are still many technical challenges associated with isolating, expanding, differentiating, and pre-conditioning MSCs for subsequent implantation into degenerate joints and the spine. However, the prospect of combining biomaterials and cell-based therapies that incorporate chondrocytes, chondroprogenitors and MSCs leads to the optimistic view that interdisciplinary approaches will lead to significant breakthroughs in regenerating musculoskeletal tissues, such as the joint and the spine in the near future.

Evaluation of the Effects of Airborne Particulate Matter on Bone Marrow-Mesenchymal Stem Cells (BM-MSCs): Cellular, Molecular and Systems Biological Approaches

Particulate matter (PM) contains heavy metals that affect various cellular functions and gene expression associated with a range of acute and chronic diseases in humans. However, the specific effects they exert on the stem cells remain unclear. Here, we report the effects of PM collected from the city of Jeddah on proliferation, cell death, related gene expression and systems of biological analysis in bone marrow mesenchymal stem cells (BM-MSCs), with the aim of understanding the underlying mechanisms. PM2.5 and PM10 were tested in vitro at various concentrations (15 to 300 µg/mL) and durations (24 to 72 h). PMs induced cellular stress including membrane damage, shrinkage and death. Lower concentrations of PM2.5 increased proliferation of BM-MSCs, while higher concentrations served to decrease it. PM10 decreased BM-MSCs proliferation in a concentration-dependent manner. The X-ray fluorescence spectrometric analysis showed that PM contains high levels of heavy metals. Ingenuity Pathway Analysis (IPA) and hierarchical clustering analyses demonstrated that heavy metals were associated with signaling pathways involving cell stress/death, cancer and chronic diseases. qRT-PCR results showed differential expression of the apoptosis genes (BCL2, BAX); inflammation associated genes (TNF-α and IL-6) and the cell cycle regulation gene (p53). We conclude that PM causes inflammation and cell death, and thereby predisposes to chronic debilitating diseases.

Pelleted bone marrow derived mesenchymal stem cells are better protected from the deleterious effects of arthroscopic heat shock

Introduction: The impact of arthroscopic temperature on joint tissues is poorly understood and it is not known how mesenchymal stem cells (MSCs) respond to the effects of heat generated by the device during the process of arthroscopy assisted experimental cell-based therapy. In the present study, we isolated and phenotypically characterized human bone marrow mesenchymal stem cells (hBMMSCs) from osteoarthritis (OA) patients, and evaluated the effect of arthroscopic heat on cells in suspension and pellet cultures. Methods: Primary cultures of hBMMSCs were isolated from bone marrow aspirates of OA patients and cultured using DMEM supplemented with 10% FBS and characterized for their stemness. hBMMSCs (1 × 106 cells) cultured as single cell suspensions or cell pellets were exposed to an illuminated arthroscope for 10, 20, or 30 min. This was followed by analysis of cellular proliferation and heat shock related gene expression. Results: hBMMSCs were viable and exhibited population doubling, short spindle morphology, MSC related CD surface markers expression and tri-lineage differentiation into adipocytes, chondrocytes and osteoblasts. Chondrogenic and osteogenic differentiation increased collagen production and alkaline phosphatase activity. Exposure of hBMMSCs to an illuminated arthroscope for 10, 20, or 30 min for 72 h decreased metabolic activity of the cells in suspensions (63.27% at 30 min) and increased metabolic activity in cell pellets (62.86% at 10 min and 68.57% at 20 min). hBMMSCs exposed to 37, 45, and 55°C for 120 s demonstrated significant upregulation of BAX, P53, Cyclin A2, Cyclin E1, TNF-α, and HSP70 in cell suspensions compared to cell pellets. Conclusions: hBMMSC cell pellets are better protected from temperature alterations compared to cell suspensions. Transplantation of hBMMSCs as pellets rather than as cell suspensions to the cartilage defect site would therefore support their viability and may aid enhanced cartilage regeneration.

The Third International Genomic Medicine Conference (3rd IGMC, 2015): overall activities and outcome highlights

The Third International Genomic Medicine Conference (3rd IGMC) was organised by the Centre of Excellence in Genomic Medicine Research (CEGMR) at the King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia (KSA). This conference is a continuation of a series of meetings, which began with the first International Genomic Medicine Conference (1st IGMC, 2011) followed by the second International Genomic Medicine Conference (2nd IGMC, 2013). The 3rd IGMC meeting presented as a timely opportunity to bring scientists from across the world to gather, discuss, and exchange recent advances in the field of genomics and genetics in general as well as practical information on using these new technologies in different basic and clinical applications. The meeting undoubtedly inspired young male and female Saudi researchers, who attended the conference in large numbers, as evidenced by the oversubscribed oral and poster presentations. The conference also witnessed the launch of the first content for npj Genomic Medicine, a high quality new journal was established in partnership by CEGMR with Springer Nature and published as part of the Nature Partner Journal series. Here, we present a brief summary report of the 2-day meeting including highlights from the oral presentations, poster presentations, workshops, poster prize-winners and comments from the distinguished scientists.

Incidence and potential causative factors associated with chronic benign neutropenia in the Kingdom of Saudi Arabia

BackgroundBenign neutropenia often presents in certain populations without any genotype nor phenotype. Middle East countries are among the regions where endemic cases of chronic benign neutropenia are reported in the general population with an incidence of approximately between 10-15%. Not many studies have been performed to ascertain the cause or burden associated with this condition. The objective of the current study was to identify the frequency and characterize the consequences of chronic benign neutropenia in the country of Saudi Arabia.ResultsBenign neutropenia was found to be high in the Saudi Arabia general population (up to 20%), with an average neutrophil count of 1.48 (range 0.99 – 1.95 × 109cells/L), with Saudis having a higher incidence of chronic benign neutropenia compared to non-Saudis (p = <0.05). Complete blood count analyses showed significant difference in the total white cell count of neutrophils (p < 0.0001), WBC (p < 0.0001), lymphocytes (p < 0.001), monocytes (p < 0.001), eosinophils (p = 0.013) as well as the CD19 B cells (p = 0.008).ConclusionsOur study is the first to carefully quantitate benign neutropenia in Saudi Arabia. We identified that this condition is prevalent in the middle aged population (18 years to 55 years). These individuals not only had lower neutrophil counts, but also reduced peripheral blood cells types, especially the B-lymphocyte population (CD19 subset). As B-lymphocytes are involved in antibody production and antigen recognition, a decrease might easily predispose the individuals to infectious agents. As such more mechanistic studies need to be undertaken to understand the cause and potential long-term consequences of benign neutropenia.

Evaluation of the effect of Nigella sativa extract on human hepatocellular adenocarcinoma cell line (HepG2) in vitro

Background Cancer is a dreadful disease and remains a major cause of mortality world-wide. Plant derived compounds such as vincristine, vinblastine, etoposide, camptothecin etc. are widely used in cancer therapeutics. Nigella sativa (Figure 1) is claimed to have antihypertensive, analgesic, diuretic, anti-bacterial and liver protective effects [1]; however, there are only very few scientific evidence. In the present study, we attempt to explore the anticancer cancer claims of Nigella sativa, on human hepatocellular adenocarcinoma (HepG2) cell line in vitro.

Evaluation of in vitro chondrocytic differentiation: A stem cell research initiative at the King Abdulaziz University, Kingdom of Saudi Arabia

Mesenchymal stem cells (MSCs) from various sources have been used in cartilage differentiation with variable success. Therefore, it is of interest to evaluate the in vitro differentiation potential of the hWJSCs derived from the human umbilical cords into chondrocytes at the stem cell research facility at the King Abdulaziz University. hWJSCs are an attractive choice for tissue engineering and regenerative medical applications including cartilage regeneration. We evaluated the hWJSCs using classical histological and cartilage related gene expression studies. Some of the known parameters were re-examined for consistency at the current laboratory conditions. Early passages (P1-P4) showed short fibroblastic morphology and high expression of MSC related surface markers namely CD29 (99.9%), CD44 (97.8%), CD73 (99.6%), CD90 (95.1%) and CD105 (98.9%). MTT assay showed time dependent increase in hWJSCs proliferation by 61.06% and 206.31% at 48h and 72h respectively. Toluidine blue histology showed that hWJSCs were successfully differentiated into chondrocytes in chondrocytic differentiation medium for 21 days. Differentiated hWJSCs also showed significantly increased expression of collagen type II, aggrecan and SOX9 compared to the undifferentiated control. It should be noted that the determination of the average cell yield, the population doubling time and histological staining wtih alcian blue and/or safronin O is required in future studies for improved evaluation of differentiation. Painless derivation, abundance of stem cells that are hypo-immunogenic and safety issues makes this method advantages to MSCs derived from other sources.

Primary ovarian cancer cell inhibition by human Wharton's Jelly stem cells (hWJSCs): Mapping probable mechanisms and targets using systems oncology.

Ovarian cancer is one of the most lethal gynaecological cancers. Its subtle onset and absence of symptoms in early stages are associated with poor prognosis and high mortality. Identification of early biomarkers would aid in ovarian cancer control. Mesenchmal stem cells (MSCs) and/or their secretory products are identified to have cancer inhibitory properties. Therefore, it is of interest to study the anticancer properties of human Whartons jelly stem cells conditioned medium (hWJSCs-CM) on primary ovarian carcinoma cells in vitro. Primary cultures of epithelial ovarian carcinoma cells (EOCs) and hWJSCs were used in this study. EOCs were exposed to hWJSC-CM (100%) for 24h-72h and changes in mophology and cell proliferation were monitored. Treatment with hWJSC-CM showed altered morphological changes that resulted in death of EOCs. Colorimetric assay [MTT, (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide)] showed mean decreases in EOC proliferation by 16.21%, 23.89% and 40.08% at 24h, 48h and 72h respectively compared to control. Ingenuity Pathway Analysis (IPA, Igenuity Systems, USA) deduced important molecular pathways and signaling networks associated with cancer cell death and these correlated with significant expression of tumour suppresors and apoptotic genes in hWJSCs. Secretory products of hWJSC-CM induced cell death of EOCs via apoptosis. IPA identification of canonical genes/pathways involved in EOCs that overlap with hWJSCs tumour suppressors and apoptosis genes further support this hypotheis. Additional in vitro and in vivo studies are necessary to validate EOCs inhibition with hWJSC-extracts towards their mechanism of action.

Method of delivery of bone marrow stem cells to the articular joint influences their survival during arthroscopy

Background Cartilage poor capacity to regenerate can eventually lead to osteoarthritis. We aim to restore cartilage regeneration by introducing autologus bone marrow MSCs (BMMSCs) into the damaged joint using arthroscopy. The arthroscopic procedure involves variations in temperature either to supraphysiologic or subphysiologic levels following low-flow irrigation or cryotherapy respectively [1,2]. The aim of this study was to assess whether such temperature fluctuations would influence the viability and function of delivered BMMSCs and hence the outcome of the arthroscopic procedure.