Repetitive TMS in treatment of resistant diabetic neuropathic pain

Diagnostic Tools, Biomarkers, and Treatments in Diabetic polyneuropathy and Cardiovascular Autonomic Neuropathy

The various manifestations of diabetic neuropathy, including distal symmetric sensorimotor polyneuropathy (DSPN) and cardiovascular autonomic neuropathy (CAN), are among the most prevalent chronic complications of diabetes. Major clinical complications of diabetic neuropathies, such as neuropathic pain, chronic foot ulcers, and orthostatic hypotension, are associated with considerable morbidity, increased mortality, and diminished quality of life. Despite the substantial individual and socioeconomic burden, the strategies to diagnose and treat diabetic neuropathies remain insufficient. This review provides an overview of the current clinical aspects and recent advances in exploring local and systemic biomarkers of both DSPN and CAN assessed in human studies (such as biomarkers of inflammation and oxidative stress) for better understanding of the underlying pathophysiology and for improving early detection. Current therapeutic options for DSPN are (I) causal treatment, including lifestyle modification, optimal glycemic control, and multifactorial risk intervention, (II) pharmacotherapy derived from pathogenetic concepts, and (III) analgesic treatment against neuropathic pain. Recent advances in each category are discussed, including non-pharmacological approaches, such as electrical stimulation. Finally, the current therapeutic options for cardiovascular autonomic complications are provided. These insights should contribute to a broader understanding of the various manifestations of diabetic neuropathies from both the research and clinical perspectives.

Prospects for the application of transcranial magnetic stimulation in diabetic neuropathy

Encouraging results have been reported for the use of transcranial magnetic stimulation-based nerve stimulation in studies of the mechanisms of neurological regulation, nerve injury repair, and nerve localization. However, to date, there are only a few reviews on the use of transcranial magnetic stimulation for diabetic neuropathy. Patients with diabetic neuropathy vary in disease progression and show neuropathy in the early stage of the disease with mild symptoms, making it difficult to screen and identify. In the later stage of the disease, irreversible neurological damage occurs, resulting in treatment difficulties. In this review, we summarize the current state of diabetic neuropathy research and the prospects for the application of transcranial magnetic stimulation in diabetic neuropathy. We review significant studies on the beneficial effects of transcranial magnetic stimulation in diabetic neuropathy treatment, based on the outcomes of its use to treat neurodegeneration, pain, blood flow change, autonomic nervous disorders, vascular endothelial injury, and depression. Collectively, the studies suggest that transcranial magnetic stimulation can produce excitatory/inhibitory stimulation of the cerebral cortex or local areas, promote the remodeling of the nervous system, and that it has good application prospects for the localization of the injury, neuroprotection, and the promotion of nerve regeneration. Therefore, transcranial magnetic stimulation is useful for the screening and early treatment of diabetic neuropathy. Transcranial magnetic stimulation can also alleviate pain symptoms by changing the cortical threshold and inhibiting the conduction of sensory information in the thalamo-spinal pathway, and therefore it has therapeutic potential for the treatment of pain and pain-related depressive symptoms in patients with diabetic neuropathy. Additionally, based on the effect of transcranial magnetic stimulation on local blood flow and its ability to change heart rate and urine protein content, transcranial magnetic stimulation has potential in the treatment of autonomic nerve dysfunction and vascular injury in diabetic neuropathy. Furthermore, oxidative stress and the inflammatory response are involved in the process of diabetic neuropathy, and transcranial magnetic stimulation can reduce oxidative damage. The pathological mechanisms of diabetic neuropathy should be further studied in combination with transcranial magnetic stimulation technology.

Non-invasive neuromodulation effects on painful diabetic peripheral neuropathy: a systematic review and meta-analysis

Diabetic Peripheral Neuropathy (DPN) typically is accompanied by painful symptoms. Several therapeutic agents have been tried for symptomatic relief, but with varying results. The use of non-invasive neuromodulation (NINM) is a potential treatment option for DPN. The objective of our study is to evaluate NINM effects on pain rating and nerve conduction velocity in DPN patients. The search was carried out in seven databases until Aug 30th, 2019. Finally, twenty studies met the inclusion criteria. We found a significant reduction of pain scores by central NINMs (effect size [ES] =  - 0.75, 95% CI =  - 1.35 to - 0.14), but not by the overall peripheral techniques (electrical and electromagnetic) (ES =  - 0.58, 95% CI =  - 1.23 to 0.07). However, the subgroup of peripheral electrical NINMs reported a significant higher effect (ES =  - 0.84, 95% CI =  - 1.57 to - 0.11) compared to electromagnetic techniques (ES = 0.21; 95% CI =  - 1.00 to 1.42, I2 = 95.3%) . Other subgroup analysis results show that NINMs effects are higher with intensive protocols and in populations with resistant symptoms or intolerance to analgesic medications. Besides, NINMs can increase motor nerves velocity (ES = 1.82; 95% CI = 1.47 to 2.17), and there were no effects on sensory nerves velocity (ES = 0.01, 95% CI =  - 0.79 to 0.80). The results suggest that central and peripheral electrical NINMs could reduce neuropathic pain among DPN patients, without reported adverse events. Well-powered studies are needed to confirm that NINM techniques as an alternative effective and safe treatment option.