Efficacy of using adipose-derived stem cells and PRP on regeneration of 40 -mm long sciatic nerve defect bridged by polyglycolic-polypropylene mesh in canine model.

BACKGROUND: Sciatic nerve repair becomes a focus of research in neurological aspect to restore the normal physical ability of the animal to stand and walk. Tissue engineered nerve grafts (TENGs) provide a promising alternative therapy for regeneration of large gap defects. The present study investigates the regenerative capacity of PRP, ADSCs, and PRP mixed ADSCs on a long sciatic nerve defect (40-mm) bridged by a polyglycolic polypropylene (PGA-PRL) mesh which acts as a neural scaffold. MATERIALS AND METHODS: The study was conducted on 12 adult male mongrel dogs that were randomly divided into 4 groups: Group I (scaffold group); where the sciatic defect was bridged by a (PGA-PRL) mesh only while the mesh was injected with ADSCs in Group II (ADSCs group), PRP in Group III (PRP group). Mixture of PRP and ADSCs was allocated in Group IV (PRP + ADSCs group). Monthly, all animals were monitored for improvement in their gait and a numerical lameness score was recorded for all groups. 6 months-post surgery, the structural and functional recovery of sciatic nerve was evaluated electrophysiologically, and on the level of gene expression, and both sciatic nerve and the gastrocnemius muscle were evaluated morphometrically, histopathologically. RESULTS: Numerical lameness score showed improvement in the motor activities of both Group II and Group III followed by Group IV and the scaffold group showed mild improvement even after 6 months. Histopathologically, all treated groups showed axonal sprouting and numerous regenerated fascicles with obvious angiogenesis in proximal cut, and distal portion where Group IV exhibited a significant remyelination with the MCOOL technique. The regenerative ratio of gastrocnemius muscle was 23.81%, 56.68%, 52.06% and 40.69% for Group I, II, III and IV; respectively. The expression of NGF showed significant up regulation in the proximal portion for both Group III and Group IV (P ≤ 0.0001) while Group II showed no significant difference. PDGF-A, and VEGF expressions were up-regulated in Group II, III, and IV whereas Group I showed significant down-regulation for NGF, PDGF-A, and VEGF (P ≤ 0.0001). CONCLUSION: ADSCs have a great role in restoring the damaged nerve fibers by secreting several types of growth factors like NGF that have a proliferative effect on Schwann cells and their migration. In addition, PRP therapy potentiates the effect of ADSCs by synthesis another growth factors such as PDGF-A, VEGF, NGF for better healing of large sciatic gap defects.

Regenerative Strategies in Treatment of Peripheral Nerve Injuries in Different Animal Models.

BACKGROUND: Peripheral nerve damage mainly resulted from traumatic or infectious causes; the main signs of a damaged nerve are the loss of sensory and/or motor functions. The injured nerve has limited regenerative capacity and is recovered by the body itself, the recovery process depends on the severity of damage to the nerve, nowadays the use of stem cells is one of the new and advanced methods for treatment of these problems. METHOD: Following our review, data are collected from different databases "Google scholar, Springer, Elsevier, Egyptian Knowledge Bank, and PubMed" using different keywords such as Peripheral nerve damage, Radial Nerve, Sciatic Nerve, Animals, Nerve regeneration, and Stem cell to investigate the different methods taken in consideration for regeneration of PNI. RESULT: This review contains tables illustrating all forms and types of regenerative medicine used in treatment of peripheral nerve injuries (PNI) including different types of stem cells " adipose-derived stem cells, bone marrow stem cells, Human umbilical cord stem cells, embryonic stem cells" and their effect on re-constitution and functional recovery of the damaged nerve which evaluated by physical, histological, Immuno-histochemical, biochemical evaluation, and the review illuminated the best regenerative strategies help in rapid peripheral nerve regeneration in different animal models included horse, dog, cat, sheep, monkey, pig, mice and rat. CONCLUSION: Old surgical attempts such as neurorrhaphy, autogenic nerve transplantation, and Schwann cell implantation have a limited power of recovery in cases of large nerve defects. Stem cell therapy including mesenchymal stromal cells has a high potential differentiation capacity to renew and form a new nerve and also restore its function.

Correlates of self-efficacy for disease management in adolescent/young adult cancer survivors: A systematic review.

OBJECTIVE: The primary objective of this review was to summarize the literature regarding factors associated with self-efficacy for disease management (SEDM) in cross-sectional studies and the efficacy/effectiveness of psychosocial interventions that are designed to improve SEDM in adolescent and young adult (AYA) cancer survivors. The secondary aim was to assess the quality of included studies. METHOD: We conducted a systematic review using PsycINFO and PubMed to identify studies for review. Eligible studies were conducted in AYA cancer survivors ages 15 to 39; included a measure of SEDM assessed as an outcome or in a cross-sectional analysis; and were published in a peer-reviewed, English-language journal. RESULTS: From the 2,910 records screened, 7 cross-sectional studies and 4 intervention studies met criteria for inclusion. Eleven of the 12 SEDM measures in the studies were author-constructed, limiting the ability to draw conclusions across studies. All cross-sectional studies met at least 21 of 26 relevant quality assessment criteria, and intervention studies met between 4 and 11 of 14 criteria. Cross-sectional findings indicate that SEDM is positively associated with health-promoting behaviors and inversely related to physical and mental health problems. The intervention studies demonstrated that behavioral and educational interventions have the potential to increase SEDM. CONCLUSION: Directions for research include the need for validated measures of SEDM for AYA cancer survivors, as well as interventions that target both the health care team's and the patient's role in promoting SEDM. (PsycINFO Database Record