Advances in biotechnology and clinical therapy in the field of peripheral nerve regeneration based on magnetism

Nuclear Magnetic Resonance Treatment Induces ßNGF Release from Schwann Cells and Enhances the Neurite Growth of Dorsal Root Ganglion Neurons In Vitro

Peripheral nerve regeneration depends on close interaction between neurons and Schwann cells (SCs). After nerve injury, SCs produce growth factors and cytokines that are crucial for axon re-growth. Previous studies revealed the supernatant of SCs exposed to nuclear magnetic resonance therapy (NMRT) treatment to increase survival and neurite formation of rat dorsal root ganglion (DRG) neurons in vitro. The aim of this study was to identify factors involved in transferring the observed NMRT-induced effects to SCs and consequently to DRG neurons. Conditioned media of NMRT-treated (CM NMRT) and untreated SCs (CM CTRL) were tested by beta-nerve growth factor (ßNGF) ELISA and multiplex cytokine panels to profile secreted factors. The expression of nociceptive transient receptor potential vanilloid 1 (TRPV1) channels was assessed and the intracellular calcium response in DRG neurons to high-potassium solution, capsaicin or adenosine triphosphate was measured mimicking noxious stimuli. NMRT induced the secretion of ßNGF and pro-regenerative-signaling factors. Blocking antibody experiments confirmed ßNGF as the main factor responsible for neurotrophic/neuritogenic effects of CM NMRT. The TRPV1 expression or sensitivity to specific stimuli was not altered, whereas the viability of cultured DRG neurons was increased. Positive effects of CM NMRT supernatant on DRG neurons are primarily mediated by increased ßNGF levels.

Nanomedicine in Neuroprotection, Neuroregeneration, and Blood-Brain Barrier Modulation: A Narrative Review

Nanomedicine is a newer, promising approach to promote neuroprotection, neuroregeneration, and modulation of the blood-brain barrier. This review includes the integration of various nanomaterials in neurological disorders. In addition, gelatin-based hydrogels, which have huge potential due to biocompatibility, maintenance of porosity, and enhanced neural process outgrowth, are reviewed. Chemical modification of these hydrogels, especially with guanidine moieties, has shown improved neuron viability and underscores tailored biomaterial design in neural applications. This review further discusses strategies to modulate the blood-brain barrier-a factor critically associated with the effective delivery of drugs to the central nervous system. These advances bring supportive solutions to the solving of neurological conditions and innovative therapies for their treatment. Nanomedicine, as applied to neuroscience, presents a significant leap forward in new therapeutic strategies that might help raise the treatment and management of neurological disorders to much better levels. Our aim was to summarize the current state-of-knowledge in this field.

Systematic review and meta-analysis of repetitive transcranial magnetic stimulation (rTMS) for activities of daily living in Alzheimer's disease

OBJECTIVE

This systematic review of randomised controlled trials (RCTs) was conducted to assess the effect of repetitive transcranial magnetic stimulation (rTMS) on activities of daily living (ADLs) in Alzheimer's disease (AD) patients.

DATA SOURCES

Ten databases were retrieved for pertinent Chinese and English literatures published up until January 2024.

REVIEW METHODS

All RCTs of rTMS for ADLs in AD were included in this meta-analysis. Two researchers independently selected the literatures, retrieved the data of included literatures, accessed risk-of-bias of literatures with the Cochrane Collaboration's quality criteria and then cross-checked. Meta-analysis was carried out with Cochrane's Review Manager (RevMan, version 5.4). The PRISMA guidelines were followed in this systematic review.

RESULTS

The 37 literatures involving 2461 patients with AD were included in this study. Compared with the control groups received the interventions such as routine pharmacotherapy, cognitive training, ect., with/without sham-rTMS, the experiment groups received the interventions of the control groups and rTMS. The findings were as follows: ADL scale [mean difference (MD) = -3.92, 95%CI (-4.93, -2.91), P < 0.00001]; Barthel Index (BI) [MD = 9.75, 95% CI (6.66, 12.85), P < 0.00001]; Modified Barthel Index (MBI) [MD = 5.43, 95% CI (3.13, 7.73), P < 0.00001]. The differences were statistically significant for all indicators. In 29 studies, rTMS stimulation sites were located in the dorsolateral prefrontal cortex (DLPFC).

CONCLUSION

The rTMS could improve the ADLs in AD patients, and the DLPFC was a frequently used stimulation site of the rTMS for AD treatment.

Low-Dose Ionizing Radiation Exposure on Human Male Gametes: Damage or Benefit

With the improvement of medical devices for diagnosis and radiotherapy, concerns about the effects of low doses of ionizing radiation are also growing. There is no consensus among scientists on whether they might have beneficial effects on humans in certain cases or pose more risks, making the exposure unreasonable. While the damaging consequences of high-dose radiation have been known since the discovery of radioactivity, low-dose effects present a much bigger investigative challenge. They are highly specific and include radio-adaptive responses, bystander effects, and genomic instability. Current data regarding the consequences of exposure to low-dose radiation on the quality of male gametes and fertility potential are contradictory. The reports suggest two directions: indirect impact on male gametes-through spermatogenesis-or direct effects at low doses on already mature spermatozoa. Although mature gametes are used for observation in both models, they are fundamentally different, leading to varied results. Due to their unique physiological characteristics, in certain cases, exposure of spermatozoa to low-dose ionizing radiation could have positive effects. Despite the findings indicating no beneficial effects of low-dose exposure on male fertility, it is essential to research its impact on mature spermatozoa, as well.

Immune-cell-mediated tissue engineering strategies for peripheral nerve injury and regeneration

During the process of peripheral nerve repair, there are many complex pathological and physiological changes, including multi-cellular responses and various signaling molecules, and all these events establish a dynamic microenvironment for axon repair, regeneration, and target tissue/organ reinnervation. The immune system plays an indispensable role in the process of nerve repair and function recovery. An effective immune response not only involves innate-immune and adaptive-immune cells but also consists of chemokines and cytokines released by these immune cells. The elucidation of the orchestrated interplay of immune cells with nerve regeneration and functional restoration is meaningful for the exploration of therapeutic strategies. This review mainly enumerates the general immune cell response to peripheral nerve injury and focuses on their contributions to functional recovery. The tissue engineering-mediated strategies to regulate macrophages and T cells through physical and biochemical factors combined with scaffolds are discussed. The dynamic immune responses during peripheral nerve repair and immune-cell-mediated tissue engineering methods are presented, which provide a new insight and inspiration for immunomodulatory therapies in peripheral nerve regeneration.

Different Effect Sizes of Motor Skill Training Combined with Repetitive Transcranial versus Trans-Spinal Magnetic Stimulation in Healthy Subjects

Repetitive transcranial magnetic stimulation (rTMS) is used to enhance motor training (MT) performance. The use of rTMS is limited under certain conditions, such as after a stroke with severe damage to the corticospinal tract. This raises the question as to whether repetitive trans-spinal magnetic stimulation (rSMS) can also be used to improve MT. A direct comparison of the effect size between rTMS and rSMS on the same MT is still lacking. Before conducting the study in patients, we determined the effect sizes of different stimulation approaches combined with the same motor training in healthy subjects. Two experiments (E1 and E2) with 96 subjects investigated the effect size of combining magnetic stimulation with the same MT. In E1, high-frequency rTMS, rSMS, and spinal sham stimulation (sham-spinal) were applied once in combination with MT, while one group only received the same MT (without stimulation). In E2, rTMS, rSMS, and sham-spinal were applied in combination with MT over several days. In all subjects, motor tests and motor-evoked potentials were evaluated before and after the intervention period. rTMS had the greatest effect on MT, followed by rSMS and then sham-spinal. Daily stimulation resulted in additional training gains. This study suggests that rSMS increases excitability and also enhances MT performance. This current study provides a basis for further research to discover whether patients who cannot be treated effectively with rTMS would benefit from rSMS.