Promoting nerve regeneration in a neurotmesis rat model using poly(DL-lactide-ε-caprolactone) membranes and mesenchymal stem cells from the Wharton's jelly: in vitro and in vivo analysis.

In peripheral nerves MSCs can modulate Wallerian degeneration and the overall regenerative response by acting through paracrine mechanisms directly on regenerating axons or upon the nerve-supporting Schwann cells. In the present study, the effect of human MSCs from Wharton's jelly (HMSCs), differentiated into neuroglial-like cells associated to poly (DL-lactide-ε-caprolactone) membrane, on nerve regeneration, was evaluated in the neurotmesis injury rat sciatic nerve model. Results in vitro showed successful differentiation of HMSCs into neuroglial-like cells, characterized by expression of specific neuroglial markers confirmed by immunocytochemistry and by RT-PCR and qPCR targeting specific genes expressed. In vivo testing evaluated during the healing period of 20 weeks, showed no evident positive effect of HMSCs or neuroglial-like cell enrichment at the sciatic nerve repair site on most of the functional and nerve morphometric predictors of nerve regeneration although the nociception function was almost normal. EPT on the other hand, recovered significantly better after HMSCs enriched membrane employment, to values of residual functional impairment compared to other treated groups. When the neurotmesis injury can be surgically reconstructed with an end-to-end suture or by grafting, the addition of a PLC membrane associated with HMSCs seems to bring significant advantage, especially concerning the motor function recovery.

A moderate dose of caffeine ingestion does not change energy expenditure but decreases sleep time in physically active males: a double-blind randomized controlled trial.

Research on the effect of caffeine on energy expenditure (EE), physical activity (PA), and total sleep time (TST) during free-living conditions using objective measures is scarce. We aimed to determine the impact of a moderate dose of caffeine on TST, resting EE (REE), physical activity EE (PAEE), total EE (TEE), and daily time spent in sedentary, light, moderate, and vigorous intensity activities in a 4-day period and the acute effects on heart rate (HR) and EE in physically active males. Using a double-blind crossover trial (ClinicalTrials.gov ID: NCT01477294) with two conditions (4 days each with 3-day washout) randomly ordered as caffeine (5 mg/kg of body mass/day) and placebo (maltodextrin) administered twice per day (2.5 mg/kg), 30 nonsmoker males, low-caffeine users (<100 mg/day), aged 20-39, were followed. Body composition was assessed by dual-energy X-ray absorptiometry. PA was assessed by accelerometry, while a combined HR and movement sensor estimated EE and HR on the second hour after the first administration dose. REE was assessed by indirect calorimetry, and PAEE was calculated as [TEE - (REE + 0.1TEE)]. TST and daily food records were obtained. Repeated measures ANOVA and ANCOVA were used. After a 4-day period, adjusting for fat-free mass, PAEE, and REE, TST was reduced (p = 0.022) under caffeine intake, while no differences were found between conditions for REE, PAEE, TEE, and PA patterns. Also, no acute effects on HR and EE were found between conditions. Though a large individual variability was observed, our findings revealed no acute or long-term effects of caffeine on EE and PA but decreased TST during free-living conditions in healthy males.

Use of PLGA 90:10 scaffolds enriched with in vitro-differentiated neural cells for repairing rat sciatic nerve defects.

Poly(lactic-co-glycolic acid) (PLGA) nerve tube guides, made of a novel proportion (90:10) of the two polymers, poly(L-lactide): poly(glycolide) and covered with a neural cell line differentiated in vitro, were tested in vivo for promoting nerve regeneration across a 10-mm gap of the rat sciatic nerve. Before in vivo testing, the PLGA 90:10 tubes were tested in vitro for water uptake and mass loss and compared with collagen sheets. The water uptake of the PLGA tubes was lower, and the mass loss was more rapid and higher than those of the collagen sheets when immersed in phosphate-buffered saline (PBS) solution. The pH values of immersing PBS did not change after soaking the collagen sheets and showed to be around 7.4. On the other hand, the pH values of PBS after soaking PLGA tubes decreased gradually during 10 days reaching values around 3.5. For the in vivo testing, 22 Sasco Sprague adult rats were divided into four groups--group 1: gap not reconstructed; group 2: gap reconstructed using an autologous nerve graft; group 3: gap reconstructed with PLGA 90:10 tube guides; group 4: gap reconstructed with PLGA 90:10 tube guides covered with neural cells differentiated in vitro. Motor and sensory functional recovery was evaluated throughout a healing period of 20 weeks using sciatic functional index, static sciatic index, extensor postural thrust, withdrawal reflex latency, and ankle kinematics. Stereological analysis was carried out on regenerated nerve fibers. Both motor and sensory functions improved significantly in the three experimental nerve repair groups, although the rate and extent of recovery was significantly higher in the group where the gap was reconstructed using the autologous graft. The presence of neural cells covering the inside of the PLGA tube guides did not make any difference in the functional recovery. By contrast, morphometric analysis showed that the introduction of N1E-115 cells inside PLGA 90:10 tube guides led to a significant lower number and size of regenerated nerve fibers, suggesting thus that this approach is not adequate for promoting peripheral nerve repair. Further studies are warranted to assess the role of other cellular systems as a foreseeable therapeutic strategy in peripheral nerve regeneration.