l-Methylfolate in Diabetic Peripheral Neuropathy: A Narrative Review

Spinal neuron-glial crosstalk and ion channel dysregulation in diabetic neuropathic pain

Diabetic neuropathic pain (DNP) is one of the most prevalent complications of diabetes, characterized by a high global prevalence and a substantial affected population with limited effective therapeutic options. Although DNP is closely associated with hyperglycemia, an increasing body of research suggests that elevated blood glucose levels are not the sole inducers of DNP. The pathogenesis of DNP is intricate, involving the release of inflammatory mediators, alterations in synaptic plasticity, demyelination of nerve fibers, and ectopic impulse generation, yet the precise mechanisms remain to be elucidated. The spinal dorsal horn coordinates dynamic interactions between peripheral and central pain pathways, wherein dorsal horn neurons, microglia, and astrocytes synergize with Schwann cell-derived signals to process nociceptive information flow. Abnormally activated neurons can alter signal transduction by modifying the local microenvironment, compromising myelin integrity, and diminishing trophic support, leading to neuronal sensitization and an amplifying effect on peripheral pain signals, which in turn triggers neuropathic pain. Ion channels play a pivotal role in signal conduction, with the modulation of sodium, potassium, and calcium channels being particularly crucial for the regulation of pain signals. In light of the rising incidence of diabetes and the current scarcity of effective DNP treatments, a thorough investigation into the interactions between neurons and glial cells, especially the mechanisms of ion channel function in DNP, is imperative for identifying potential drug targets, developing novel therapeutic strategies, and thereby enhancing the prospects for DNP management.

The MTHFR C677T/A1298C polymorphism is associated with increased risk of microangiopathy in type 2 diabetes mellitus: A systematic review and meta-analysis

Extensive case-control association studies have been conducted over the past few decades to investigate the relationship between MTHFR polymorphism and type 2 diabetes mellitus (T2DM) microangiopathy. However, the strength of the evidence and clinical significance are unclear. Consequently, a meta-analysis was performed to examine the correlations between two prevalent MTHFR single nucleotide polymorphisms, MTHFR C677T and A1298C, and T2DM microangiopathy. Randomized controlled trials were systematically searched in PubMed, Cochrane, Embase, Web of Science, CNKI, VIP database, China Biology Medicine, and Wanfang until August 2023. A total of 42 studies were included. Random-effect models were utilized to estimate odds ratios (ORs) with 95% confidence intervals (CIs) to assess the association between MTHFR polymorphisms and T2DM microangiopathy susceptibility. T2DM microangiopathy was significantly associated with the MTHFR C677T polymorphism in the overall population (T vs C, OR = 1.43, 95% CI = 1.25-1.64; TT + CT vs CC: OR = 1.56, 95% CI = 1.30-1.88; TT vs CT + CC: OR = 1.66, 95% CI = 1.38-1.99; TT vs CC: OR = 2.03, 95% CI = 1.58-2.60). Additionally, the dominant model revealed that the MTHFR A1298C polymorphism was associated with T2DM microangiopathy (OR = 1.27, 95% CI: 1.09-1.47). This meta-analysis revealed that MTHFR may be involved in the pathogenesis of T2DM microangiopathy, providing a reference for early diagnosis and treatment of T2DM.

Effect of L-Methylfolate Supplementation on Sleep for Patients with Reduced Methylenetetrahydrofolate Reductase Activity

INTRODUCTION

Clinicians have limited options outside controlled substances to address sleep disturbance, which left untreated can negatively affect patient outcomes in cardiovascular health, mental health, immunologic function, and more. For some, genetic factors may influence sleep disturbances. L-methylfolate, the active form of folate, plays a critical role in regulation of monoamine neurotransmitters known to have significant impact on sleep regulation: dopamine, serotonin, norepinephrine. Single nucleotide polymorphisms of the enzyme methylene-tetrahydrofolate-reductase are common and can impact monoamine production. The goal of this study was to evaluate effects of L-methylfolate supplementation on sleep in a cohort with reduced methylene tetrahydrofolate reductase (MTHFR) activity.

METHODS

A retrospective cohort of patients being treated with L-methylfolate in a concierge medical clinic setting was studied. Patients presenting with sleep complaints were evaluated using the Patient-Reported Outcomes Measurement Information System at baseline. Patients with known MTHFR polymorphisms at either C667T and/or A1298C were recommended 5 mg of L-methylfolate daily and were reevaluated at 2 wks, at 4 wks, and at 8 wks of supplementation. Statistical comparisons were made utilizing ANOVA and T-test comparisons.

RESULTS

Ten were included in the final cohort: six male and four female, average age 43 ± 16 years. Beginning at wk 2, average sleep disturbance improved significantly by -6.94 points (p = 0.005) and by 8 wks, all patients had improvement with a -14.34 change in disturbance from baseline (p = 0.001).

CONCLUSION

Improvement in sleep disturbance was seen in both low and intermediate function phenotypes. L-methylfolate may be useful for improving sleep in patients with MTHFR polymorphism.