Basan Gowda S. Kurkalli

Engineered human mesenchymal stem cells: a novel platform for skeletal cell mediated gene therapy

Human mesenchymal stem cells (hMSCs) are pluripotent cells that can differentiate to various mesenchymal cell types. Recently, a method to isolate hMSCs from bone marrow and expand them in culture was described. Here we report on the use of hMSCs as a platform for gene therapy aimed at bone lesions.

The potential use of adult stem cells for the treatment of multiple sclerosis and other neurodegenerative disorders.

No specific treatment exists for patients with multiple sclerosis (MS) who fail to respond to conventional immunosuppressive and immunomodulating modalities. Furthermore, no method is available for regeneration of existing defect in the central nervous system (CNS). The ultimate goals of MS treatment, similarly to other autoimmune diseases, are twofold: first, to eliminate self-reactive lymphocytes and to prevent de novo development of self-reactivity by induction of self-tolerance. Second, attempting regeneration and repair of existing damage. In the case of MS, there is a need to stop the ongoing process of inflammation against the CNS by self-reactive lymphocytes thus facilitating spontaneous re-myelinization while in parallel attempt to recover existing neurological deficits caused by the autoimmune process resulting in demyelinization. Cell therapy stands out as the most rationale approach for neurological regeneration. In the absence of clinically applicable approaches involving the use of embryonic stem cells, we are investigating the feasibility and efficacy of enriched autologous mesenchymal stromal cells (MSC) injected intrathecally and intravenously to induce in situ immunomodulation and neuroprotection and possibly facilitate repair of the CNS in patients with MS and other neurodegenerative disorders. Our preclinical results suggest that bone marrow cells may provide a source of stem cells with a potential for migration into inflamed CNS and differentiate into cells expressing neuronal and glial cell markers. Based on the preclinical data, we are currently evaluating the safety of a similar therapeutic approach in a small group of patients with MS and other neurodegenerative diseases.

Reconstruction of Cartilage, Bone, and Hematopoietic Microenvironment with Demineralized Bone Matrix and Bone Marrow Cells

Highly specialized hard tissues, such as cartilage, bone, and stromal microenvironment supporting hematopoiesis, originate from a common type of mesenchymal progenitor cell (MPC). We hypothesized that MPCs present in bone marrow cell suspension and demineralized bone matrix (DBM) that possess natural conductive and inductive features might constitute a unit containing all the essential elements for purposive bone and cartilage induction. Using a rodent preclinical model, we found that implantation of a composite comprising DBM and MPCs into A) a damaged area of a joint; B) an ablated bone marrow cavity, and C) a calvarial defect resulted in the generation of A) a new osteochondral complex comprising articular cartilage and subchondral bone; B) trabecular bone and stromal microenvironment supporting hematopoiesis, and C) flat bone, respectively. The new tissue formation followed differentiation pathways controlled by site–specific physiological conditions, thus developing tissues that precisely met local demands.

Repair of Bone Defect Using Bone Marrow Cells and Demineralized Bone Matrix Supplemented with Polymeric Materials

We present a novel, reverse thermo-responsive (RTR) polymeric osteogenic composite comprising demineralized bone matrix (DBM) and unmanipulated bone marrow cells (BMC) for repair of bone defects. The polymers investigated were low viscosity aqueous solutions at ambient temperature, which gel once they heat up and reach body temperature. Our goal to supplement DBM-BMC composite with RTR polymers displaying superior rheological properties, was to improve graft integrity and stability, during tissue regeneration. The osteogenic composite when implanted under kidney capsule of mice, proved to be biocompatible and biodegradable, with no residual polymer detected in the newly formed osteohematopoietic site. Implantation of the osteogenic composite into a large area of missing area of parietal bone of the skull of rats, resulted in an extensive remodeling of DBM particles, fully reconstituted hematopoietic microenvironment and well integrated normal flat bone within thirty days. The quality and shape of the newly created bone were comparable to the original bone and neither local or systemic inflammatory reactions nor fibrosis at the junction of the new and old calvarium could be documented. Furthermore, combined laser capture microdissection (LCM) technique and PCR analysis of male BMC in female rats confirmed the presence of male derived cells captured from the repaired/ regenerated flat bone defect. The use of active self sufficient osteogenic DBM-BMC composite supported by a viscous polymeric scaffold for purposive local hard tissue formation, may have a significant potential in enhancement of bone regeneration and repair following trauma, degenerative or inflamatory lesion, iatrogenic interventions and cosmetic indications.