Immunomodulatory effects of mesenchymal stem cells in peripheral nerve injury

Various immune cells and cytokines are present in the aftermath of peripheral nerve injuries (PNI), and coordination of the local inflammatory response is of great significance for the recovery of PNI. Mesenchymal stem cells (MSCs) exhibit immunosuppressive and anti-inflammatory abilities which can accelerate tissue regeneration and attenuate inflammation, but the role of MSCs in the regulation of the local inflammatory microenvironment after PNI has not been widely studied. Here, we summarize the known interactions between MSCs, immune cells, and inflammatory cytokines following PNI with a focus on the immunosuppressive role of MSCs. We also discuss the immunomodulatory potential of MSC-derived extracellular vesicles as a new cell-free treatment for PNI.

Relationship of Anti-interleukin-6 Receptor Antibody to Interleukin-6 Level and Inducible Nitrite Oxide Levels in Peripheral Nerve Injury in Chronic Constriction Injury-Induced Rats: A Case-Control Study in Indonesia

BACKGROUND: Interleukin-6 (IL-6) and inducible Nitric oxide Synthase (iNOS) have an effect on neuropathic pain in the inflammatory process in peripheral nerve injuries. AIM: This study aims to examine the effect of anti-IL-6 receptor antibody on IL-6 and iNOS levels as a consideration for the treatment of neuropathic pain in a rat model of peripheral nerve injury. METHODS: Twenty-eight young adult male Wistar rats were treated for peripheral nerve injury and then divided into two groups. Fourteen treatment groups (Group P) were given anti-IL-6 receptor antibody by injection at a dose of 100 g/day by injection into the saphenous vein in the rat’s leg for 3 days. In both groups, the serum IL-6 and iNOS levels were assessed on the 3rd day after administration of anti-IL-6 receptor antibody in group P, using the sandwich ELISA method. RESULTS: The results showed that the administration of anti-IL-6 receptor antibody did not have a significant effect on reducing IL-6 and iNOS levels in group P (p > 0.05). Administration of anti-IL-6 receptor antibody had more effect on IL-6 levels on iNOS levels, where a decrease in IL-6 levels caused a decrease in iNOS levels in group P (p = 0.004 and r = 0.693). CONCLUSIONS: We conclude that the present administration of anti-IL-6 receptor antibody cannot be considered as a treatment for neuropathic pain in peripheral nerve injuries, but can be used to influence IL-6 levels on iNOS levels.

Acquired peripheral nerve injuries associated with severe COVID-19

We diagnosed 63 peripheral nerve injuries in 32 patients who survived severe COVID-19. We combine our latest data with published case series re-analyzed here (106 nerve injuries; 49 patients) to provide a comprehensive accounting of lesion sites. The most common are ulnar (26.0%), common fibular (16.0%), median (10.7%), sciatic (10.7%), brachial plexus (9.5%) and radial (8.3%) nerves. Nerve injury prevention should be prioritized during acute care of COVID-19 patients. To this end, we report proof of concept data of a wearable, wireless pressure sensor to provide real time monitoring in the intensive care unit setting.

Primary Repair of Upper Extremity Peripheral Nerve Injuries: An NSQIP Analysis From 2010 to 2016

Background To identify the rate of 30-day complications after primary repair of upper extremity peripheral nerve injuries, associated diagnoses, and postoperative complication rate. Methods The American College of Surgeons National Surgical Quality Improvement Program database was reviewed from 2010 to 2016. Current Procedural Terminology codes consistent with primary nerve repair of the upper extremity were identified and included in the analysis. Patient demographics, comorbidities, type of procedure (elective/emergent), wound class, operative time, and 30-day complications were recorded. Patients with isolated upper extremity nerve injuries (isolated) were compared with those with peripheral nerve injuries in addition to bone, tendon, or soft tissue injuries (multiple). Results In all, 785 patients were identified as having upper extremity nerve repairs (0.16%). Of them, 64% were men and 36% were women; the average patient age was 40 years. The most common indication for surgery was injury to the digits (54% of cases). Thirty-day adverse events occurred in 3% of all cases. Isolated nerve injury occurred in 43% of patients, whereas 57% had additional injuries. The multiple injury group had a significantly higher complication rate compared with the isolated group (1% vs 4.5%) ( P = .007). Repair of tendon at forearm or wrist was the most common concurrent procedure performed. Conclusions Thirty-day complications among upper extremity peripheral nerve injuries are low, accounting for 3% of cases. Return to the operating room accounted for nearly half of all complications. Patients in the multiple injury group accounted for more than half of these and had a significantly higher complication rate compared with patients with isolated nerve injuries.

Highly Flexible Polyaniline-Based Implantable Electrode Materials for Neural Sensing/Stimulation Applications

Implantable bioelectrodes have the potential to advance neural sensing and muscle stimulation, mainly in patients with peripheral nerve injuries. They function as the transducer at the interface between the damaged nerve and the muscle which is controlled by that nerve. This work reports the fabrication and characterization of novel, low-cost, flexible bioelectrodes based on polyaniline (PANI) and supported with silicone polymer. The fabricated electrodes were evaluated for their electrical and mechanical characteristics. PANI was used as the main transducer component in this fabrication. The characterization methods included electrical conductivity, capacitive behavior, long-term electrical impedance, and mechanical evaluation. The results of the fabricated PANI-silicone-based samples displayed a bulk impedance of 0.6 kΩ with an impedance of 1.6 kΩ at the frequency of 1 kHz. Furthermore, the bioelectrodes showed a charge storage capacity range from 0.0730 to 4.3124 C/cm2. The samples were stable when subjected to cyclic voltammetry tests. The bioelectrodes revealed very flexible mechanical properties as observed from the value of Young’s modulus (in the order of MPa) which was less than that of skin. Hence, the PANI-based bioelectrodes reported herein showed promising electrochemical characteristics with high flexibility.

Peripheral Nerve Regeneration Using Different Germ Layer-Derived Adult Stem Cells in the Past Decade

Peripheral nerve injuries (PNIs) are some of the most common types of traumatic lesions affecting the nervous system. Although the peripheral nervous system has a higher regenerative ability than the central nervous system, delayed treatment is associated with disturbances in both distal sensory and functional abilities. Over the past decades, adult stem cell-based therapies for peripheral nerve injuries have drawn attention from researchers. This is because various stem cells can promote regeneration after peripheral nerve injuries by differentiating into neural-line cells, secreting various neurotrophic factors, and regulating the activity of in situ Schwann cells (SCs). This article reviewed research from the past 10 years on the role of stem cells in the repair of PNIs. We concluded that adult stem cell-based therapies promote the regeneration of PNI in various ways.