Pallavi Gupta

Mesenchymal stem cell-based therapy: a new paradigm in regenerative medicine

•  Introduction •  Mesenchymal stem cells and its characteristics •  Experimental/preclinical MSC‐based studies –  MSC transplantation –  Genetically modified MSC‐based therapy –  MSC‐based protein therapy –  Tissue engineering using MSCs •  Clinical studies •  Challenges and future prospects

Stem cell therapy: a novel & futuristic treatment modality for disaster injuries.

Stem cell therapy hold the potential to meet the demand for transplant cells/tissues needed for treating damages resulting from both natural and man-made disasters. Pluripotency makes embryonic stem cells and induced pluripotent stem cells ideal for use, but their teratogenic character is a major hindrance. Therapeutic benefits of bone marrow transplantation are well known but characterizing the potentialities of haematopoietic and mesenchymal cells is essential. Haematopoietic stem cells (HSCs) have been used for treating both haematopoietic and non-haematopoietic disorders. Ease of isolation, in vitro expansion, and hypoimmunogenecity have brought mesenchymal stem cells (MSCs) into limelight. Though differentiation of MSCs into tissue-specific cells has been reported, differentiation-independent mechanisms seem to play a more significant role in tissue repair which need to be addressed further. The safety and feasibility of MSCs have been demonstrated in clinical trials, and their use in combination with HSC for radiation injury treatment seems to have extended benefit. Therefore, using stem cells for treatment of disaster injuries along with the conventional medical practice would likely accelerate the repair process and improve the quality of life of the victim.

Mechanical, corrosion and biocompatibility behaviour of Mg-3Zn-HA biodegradable composites for orthopaedic fixture accessories

Development of biodegradable implants has grown into one of the important areas in medical science. Degradability becomes more important for orthopaedic accessories used to support fractured and damaged bones, in order to avoid second surgery for their removal after healing. Clinically available biodegradable orthopaedic materials are mainly made of polymers or ceramics. These orthopaedic accessories have an unsatisfactory mechanical strength, when used in load-bearing parts. Magnesium and its alloys can be suitable candidate for this purpose, due to their outstanding strength to weight ratio, biodegradability, non-toxicity and mechanical properties, similar to natural bone. The major drawback of magnesium is its low corrosion resistance, which also influences its mechanical and physical characteristics in service condition. An effort has been taken in this research to improve the corrosion resistance, bioactivity and mechanical strength of biodegradable magnesium alloys by synthesizing Mg-3wt% Zn matrix composite, reinforced with thermally treated hydroxyapatite(HA) [Ca10(PO4)6(OH)2], a bioactive and osteogenic ceramic. Addition of 5wt% HA is found effective in reducing the corrosion rate by 42% and improvement in the compressive yield strength of biodegradable magnesium alloy by 23%. In-vitro evaluation, up to 56 days, reveal improved resistance to degradation with HA reinforcement to Mg. Osteoblast cells show better growth and proliferation on HA reinforced surfaces of the composite. Mg-HA composite structure shows impressive potential to be used in orthopaedic fracture fixing accessories.

Aligned carbon nanotube containing scaffolds for neural tissue regeneration.

Neuropathologies include the deterioration and damage of the nervous system, especially neurons present in the brain, spinal cord and peripheral nervous system. Damage or alternations in neurons makes their structure and functionality abnormal. Every year over 90,000 people get affected by neurodegenerative diseases in the USA. Among all the neurological pathologies, the spinal cord injuries alone influence 10,000 people in the USA every year. Millions of cases of neurodegenerative pathologies are registered worldwide. Without proper treatment and cure to these cases, the toll for patients suffering from neurode-generative disease is expected to reach at least 12 million in the USA 30 years from now (John, 2015).

Sustained drug release from surface modified UHMWPE for acetabular cup lining in total hip implant

Despite sterilization and aseptic procedure, bacterial infection remains a key challenge in total hip arthroplasties. This fact emphasizes the urgent need for development of new implant systems, which should releases the drug in a controlled manner without sparing its mechanical and tribological properties. In this study, the lining material of the acetabular cup, in total hip implant, has been modified for sustained release of drugs, which should be available throughout the site of implantation to fight the post-operation bacterial infection. A modified solvent based etching and lypolization technique has been used to engineer a thin porous surface layer on ultra-high molecular weight polyethylene (UHMWPE) substrate, which is clinically used as acetabular-cup lining. Gentamicin loaded chitosan solution has been impregnated into modified surface, which suitably gets released over a long period. The main challenge was to keep the mechanical and tribological behavior of this lining material unaffected after the modification. Modified surface offers reduction in friction coefficient and wear rate, by 26% and 19%, respectively, in comparison to UHMWPE, which is encouraging towards the intended application. Hardness and elastic modulus decreases slightly, by 27% and 20%, respectively, possibly due to improper impregnation of chitosan inside porous surface. However, after drug release, the modified surface regains the mechanical and tribological behavior similar to unmodified UHMWPE. Surface modified UHMWPE have shown an impressive release profile for drug up to 26days and released >94.11% of the total drug content. In vitro antibacterial tests have proven that the modified surface of UHMWPE can effectively release the drug and fight against infection. This surface engineered acetabular cup lining is a promising candidate in the area of drug eluting implant, which can bring a significant advancement to the functionality of commercially used orthopedic implants by providing inherent capacity for fighting infections in-vivo.