The effect of thiamine and its metabolites on peripheral neuropathic pain induced by cisplatin in rats

Effects of Nutraceutical Compositions Containing Rhizoma Gastrodiae or Lipoic Acid in an In Vitro Induced Neuropathic Pain Model

BACKGROUND

Peripheral neuropathy is caused by a malfunction in the axons and myelin sheaths of peripheral nerves and motor and sensory neurons. In this context, nonpharmacological treatments with antioxidant potential have attracted much attention due to the issues that some conventional pharmaceutical therapy can generate. Most of these treatments contain lipoic acid, but issues have emerged regarding its use. Considering this, the present study evaluated the beneficial effects of nutraceuticals based on Gastrodiae elata dry extract 10:1 or lipoic acid in combination with other substances (such as citicholine, B vitamins, and acetyl L-carnitine).

METHOD

To assess the combination's absorption and biodistribution and exclude cytotoxicity, its bioavailability was first examined in a 3D intestinal barrier model that replicated oral ingestion. Subsequently, a 3D model of nerve tissue was constructed to investigate the impacts of the new combination on the significant pathways dysregulated in peripheral neuropathy.

RESULTS

Our findings show that the novel combination outperformed in initial pain relief response and in recovering the mechanism of nerve healing following Schwann cell injury by successfully crossing the gut barrier and reaching the target site.

CONCLUSION

This article describes a potential alternative nutraceutical approach supporting the effectiveness of combinations with Gastrodiae elata extract in decreasing neuropathy and regulating pain pathways.

Mechanisms of action of vitamin B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) in pain: a narrative review

Pain is a complex sensory and emotional experience with nociceptive, nociplastic, and neuropathic components. An involvement of neurotropic B vitamins (B1 - thiamine, B6 - pyridoxine, and B12 - cyanocobalamin) as modulators of inflammation and pain has been long discussed. New evidence suggests their therapeutic potential in different pain conditions. In this review, we discuss the main role of neurotropic B vitamins on different nociceptive pathways in the nervous system and to describe their analgesic action mechanisms. The performed literature review showed that, through different mechanisms, these vitamins regulate several inflammatory and neural mediators in nociceptive and neuropathic pain. Some of these processes include aiming the activation of the descending pain modulatory system and in specific intracellular pathways, anti-inflammatory, antioxidative and nerve regenerative effects. Moreover, recent data shows the antinociceptive, antiallodynic, and anti-hyperalgesic effects of the combination of these vitamins, as well as their synergistic effects with known analgesics. Understanding how vitamins B1, B6, and B12 affect several nociceptive mechanisms can therefore be of significance in the treatment of various pain conditions.

Effect of Pd2Spermine on Mice Brain-Liver Axis Metabolism Assessed by NMR Metabolomics

Cisplatin (cDDP)-based chemotherapy is often limited by severe deleterious effects (nephrotoxicity, hepatotoxicity and neurotoxicity). The polynuclear palladium(II) compound Pd₂Spermine (Pd₂Spm) has emerged as a potential alternative drug, with favorable pharmacokinetic/pharmacodynamic properties. This paper reports on a Nuclear Magnetic Resonance metabolomics study to (i) characterize the response of mice brain and liver to Pd₂Spm, compared to cDDP, and (ii) correlate brain-liver metabolic variations. Multivariate and correlation analysis of the spectra of polar and lipophilic brain and liver extracts from an MDA-MB-231 cell-derived mouse model revealed a stronger impact of Pd₂Spm on brain metabolome, compared to cDDP. This was expressed by changes in amino acids, inosine, cholate, pantothenate, fatty acids, phospholipids, among other compounds. Liver was less affected than brain, with cDDP inducing more metabolite changes. Results suggest that neither drug induces neuronal damage or inflammation, and that Pd₂Spm seems to lead to enhanced brain anti-inflammatory and antioxidant mechanisms, regulation of brain bioactive metabolite pools and adaptability of cell membrane characteristics. The cDDP appears to induce higher extension of liver damage and an enhanced need for liver regeneration processes. This work demonstrates the usefulness of untargeted metabolomics in evaluating drug impact on multiple organs, while confirming Pd₂Spm as a promising replacement of cDDP.

Effect of multivitamin drug on intractable dry eye symptoms

Dry eye is a disorder of tear film and ocular surface characterized by ocular discomforts. It is associated with multiple causes and sometimes intractable. We investigated the effect of oral multivitamin supplementation (MVG) on dry eyes. Tear break-up time (TBUT), fluorescein ocular surface staining score, and tear secretion Schirmer test were measured in dry eye patients refractory to conventional topical treatment. The ocular surface disease index (OSDI), visual analog pain score (VAS), and modified standardized patient evaluation of eye dryness questionnaire were analyzed. In total, 42 eyes of 42 patients were included. TBUT increased at 1 and 3 months compared to baseline (p < 0.05). OSDI decreased at 1 and 3 months compared to baseline (p < 0.05). VAS score, impact on life, and frequency of total symptoms decreased at 3 months compared to baseline (p < 0.05). Oral administration of MVG, a vitamin complex formulation, was effective in stabilizing tear stability and alleviating symptoms in patients with intractable dry eye. Thus, it may be a viable treatment option for intractable dry eye.

The Role of Vascular-Immune Interactions in Modulating Chemotherapy Induced Neuropathic Pain

Chemotherapy causes sensory disturbances in cancer patients that results in neuropathies and pain. As cancer survivorships has dramatically increased over the past 10 years, pain management of these patients is becoming clinically more important. Current analgesic strategies are mainly ineffective and long-term use is associated with severe side effects. The issue being that common analgesic strategies are based on ubiquitous pain mediator pathways, so when applied to clinically diverse neuropathic pain and neurological conditions, are unsuccessful. This is principally due to the lack of understanding of the driving forces that lead to chemotherapy induced neuropathies. It is well documented that chemotherapy causes sensory neurodegeneration through axonal atrophy and intraepidermal fibre degeneration causing alterations in pain perception. Despite the neuropathological alterations associated with chemotherapy-induced neuropathic pain being extensively researched, underlying causes remain elusive. Resent evidence from patient and rodent studies have indicated a prominent inflammatory cell component in the peripheral sensory nervous system in effected areas post chemotherapeutic treatment. This is accompanied by modulation of auxiliary cells of the dorsal root ganglia sensory neurons such as activation of satellite glia and capillary dysfunction. The presence of a neuroinflammatory component was supported by transcriptomic analysis of dorsal root ganglia taken from mice treated with common chemotherapy agents. With key inflammatory mediators identified, having potent immunoregulatory effects that directly influences nociception. We aim to evaluate the current understanding of these immune-neuronal interactions across different cancer therapy drug classes. In the belief this may lead to better pain management approaches for cancer survivors.

Metabolic Impact of Anticancer Drugs Pd2Spermine and Cisplatin on the Brain of Healthy Mice

The new palladium agent Pd2Spermine (Spm) has been reported to exhibit promising cytotoxic properties, while potentially circumventing the known disadvantages associated to cisplatin therapeutics, namely acquired resistance and high toxicity. This work presents a nuclear magnetic resonance (NMR) metabolomics study of brain extracts obtained from healthy mice, to assess the metabolic impacts of the new Pd2Spm complex in comparison to that of cisplatin. The proton NMR spectra of both polar and nonpolar brain extracts were analyzed by multivariate and univariate statistics, unveiling several metabolite variations during the time course of exposition to each drug (1–48 h). The distinct time-course dependence of such changes revealed useful information on the drug-induced dynamics of metabolic disturbances and recovery periods, namely regarding amino acids, nucleotides, fatty acids, and membrane precursors and phospholipids. Putative biochemical explanations were proposed, based on existing pharmacokinetics data and previously reported metabolic responses elicited by the same metal complexes in the liver of the same animals. Generally, results suggest a more effective response of brain metabolism towards the possible detrimental effects of Pd2Spm, with more rapid recovery back to metabolites’ control levels and, thus, indicating that the palladium drug may exert a more beneficial role than cDDP in relation to brain toxicity.

Neuroinflammatory Process Involved in Different Preclinical Models of Chemotherapy-Induced Peripheral Neuropathy

Peripheral neuropathies are characterized by nerves damage and axonal loss, and they could be classified in hereditary or acquired forms. Acquired peripheral neuropathies are associated with several causes, including toxic agent exposure, among which the antineoplastic compounds are responsible for the so called Chemotherapy-Induced Peripheral Neuropathy (CIPN). Several clinical features are related to the use of anticancer drugs which exert their action by affecting different mechanisms and structures of the peripheral nervous system: the axons (axonopathy) or the dorsal root ganglia (DRG) neurons cell body (neuronopathy/ganglionopathy). In addition, antineoplastic treatments may affect the blood brain barrier integrity, leading to cognitive impairment that may be severe and long-lasting. CIPN may affect patient quality of life leading to modification or discontinuation of the anticancer therapy. Although the mechanisms of the damage are not completely understood, several hypotheses have been proposed, among which neuroinflammation is now emerging to be relevant in CIPN pathophysiology. In this review, we consider different aspects of neuro-immune interactions in several CIPN preclinical studies which suggest a critical connection between chemotherapeutic agents and neurotoxicity. The features of the neuroinflammatory processes may be different depending on the type of drug (platinum derivatives, taxanes, vinca alkaloids and proteasome inhibitors). In particular, recent studies have demonstrated an involvement of the immune response (both innate and adaptive) and the stimulation and secretion of mediators (cytokines and chemokines) that may be responsible for the painful symptoms, whereas glial cells such as satellite and Schwann cells might contribute to the maintenance of the neuroinflammatory process in DRG and axons respectively. Moreover, neuroinflammatory components have also been shown in the spinal cord with microglia and astrocytes playing an important role in CIPN development. Taking together, better understanding of these aspects would permit the development of possible strategies in order to improve the management of CIPN.

Anti-inflammatory and antioxidative effects of thiamin supplements in patients with gestational diabetes mellitus

OBJECTIVE

The aim of this study was to evaluate the effects of thiamin supplementation on biomarkers of inflammation and oxidative stress in patients with gestational diabetes mellitus (GDM).

METHODS

This randomized, double-blind, placebo-controlled trial was conducted among 60 patients with GDM. Patients were randomly allocated into two groups to receive either 100 mg/day thiamin supplements (n = 30) or placebo (n = 30) for 6 weeks.

RESULTS

Thiamin supplementation significantly decreased serum high-sensitivity C-reactive protein (hs-CRP) (β - 0.98 mg/L; 95% CI, -1.54, -0.42; p = .001) and plasma malondialdehyde (MDA) levels (β - 0.86 µmol/L; 95% CI, -1.15, -0.57; p < .001) when compared with the placebo. In addition, thiamin supplementation downregulated gene expression of tumor necrosis factor-alpha (TNF-α) (p = .002) in peripheral blood mononuclear cells of patients with GDM. Thiamin supplementation did not affect other biomarkers of inflammation and oxidative stress.

CONCLUSION

Overall, thiamin supplementation for 6 weeks to patients with GDM significantly reduced hs-CRP and MDA levels, and gene expression of TNF-α, but did not affect other biomarkers of inflammation and oxidative stress.

CLINICAL TRIAL REGISTRATION NUMBER

Clinical Trials.govIdentifier no. http://www.irct.ir: IRCT20170513033941N58.

Effect of Combined Diclofenac and B Vitamins (Thiamine, Pyridoxine, and Cyanocobalamin) for Low Back Pain Management: Systematic Review and Meta-analysis

BACKGROUND

Cumulative evidence suggests an analgesic effect of thiamine, pyridoxine, and cyanocobalamin (TPC) in monotherapy, and also when combined with nonsteroidal anti-inflammatory drugs (NSAIDs), particularly diclofenac, in a synergistic manner. The aim of this review was to determine the effects of diclofenac combined with TPC compared with diclofenac monotherapy for low back pain (LBP) management.

METHODS

We searched for randomized clinical trials on the MEDLINE, EMBASE, LILACS, and Cochrane databases of records of clinical trials, among other sources. We evaluated the risk of bias regarding randomization, allocation concealment, blinding, incomplete outcome data, selective reporting, and other biases. A random-effects meta-analysis to examine patients with acute LBP (N = 1,108 adults) was performed, along with a subsequent sensitivity analysis.

RESULTS

Five studies in patients with LBP were included in the qualitative synthesis. Four of these studies in acute LBP were included in the first meta-analysis. A sensitivity test based on risk of bias (three moderate- to high-quality studies) found that the combination therapy of diclofenac plus TPC was associated with a significant reduction in the duration of treatment (around 50%) compared with diclofenac monotherapy (odds ratio = 2.23, 95% confidence interval = 1.59 to 3.13, P < 0.00001). We found no differences in the safety profile and patient satisfaction.

CONCLUSIONS

This meta-analysis demonstrated that combination therapy of diclofenac with TPC might have an analgesic superiority compared with diclofenac monotherapy in acute LBP. However, there is not enough evidence to recommend this therapy in other types of pain due to the scarcity of high-quality studies.

A metabolomic study on the gender-dependent effects of maternal exposure to fenvalerate on neurodevelopment in offspring mice

BACKGROUND

The general population is widely exposed to fenvalerate. However, the effects of maternal exposure to fenvalerate on neurodevelopment in offspring and the underlying metabolic mechanism are largely unknown.

METHODS

Pregnant mice were exposed to fenvalerate for 11 consecutive days. The forced swimming test (FST) was performed in 35 day-old offspring to investigate the effects of fenvalerate on neurobehavioral responses. Blood serum free T4 and free T3 concentrations were measured using commercial ELISA. Blood and thyroid samples were used for metabolomic analyses with UPLC Q-Exactive. The expression levels of neurotransmitter metaolite receptors were determined in the frontal cortex of offspring using real-time PCR.

RESULTS

The immobility time, free T4 and free T3, and expression levels of Htr1a and Htr2a were statistically changed in offspring male mice. Metabolomic analysis revealed that the pentose phosphate pathway, starch and sucrose metabolism, glutamic acid metabolism were the key changed pathways in the blood, and thiamine metabolism was the key changed pathway in the thyroid.

CONCLUSION

Prenatal exposure to fenvalerate affected neurodevelopment in male offspring mice both via the changed abundances of metabolites involved in glycolysis related metabolism and medium-chain fatty acid metabolism, and the changes in 5-HT receptor expression.

Effects of anakinra on the small intestine mucositis induced by methotrexate in rats

Intestinal mucositis is an important problem in the patients receiving cancer treatment. We aimed to investigate the effect of anakinra, which is a well known anti-oxidant and anti-inflammatory agent, on methotrexate-induced small intestine mucositis in rats. Forty rats were divided into 4 groups with 10 in each group. The healthy group (HG) and the methotrexate group (MTXG) were given distilled water, while the methotrexate + anakinra 50 (MTX+ANA50) and the methotrexate + anakinra 100 (MTX+ANA100) groups were intraperitoneally administered 50 and 100 mg/kg of anakinra. After one hour, the MTXG, MTX+ANA50 and MTX+ANA100 groups were given oral methotrexate at a dose of 5 mg/kg. This procedure was repeated once a day for 7 days. After the rats had been sacrificed, the small intestine tissue of rats were removed for the assesment of biochemical markers, histopathological evaluation and gene expression analyze. Statistical analyses of the data were performed using one-way ANOVA. Malondialdehyde (MDA), myeloperoxidase (MPO) and interleukin-6 (IL-6) levels were significantly higher, whereas total glutathione (tGSH) levels were significantly lower in MTXG (P<0.001) compared to other groups. MTX also increased IL-1β and TNF-α gene expression levels in MTXG (P<0.001). Inflammatory cell infiltration and damage to the villus were observed histopathologically in the MTXG group, whereas only mild inflammation was seen in the MTX+ANA100 group. A dose of 100 mg/kg of anakinra prevented the increase of the biochemical markers and gene expression levels better than a dose of 50 mg/kg. Intestinal mucositis caused by MTX may be preventible by co-administered anakinra.

Oral High-Dose Thiamine Improves the Symptoms of Chronic Cluster Headache

Cluster headache is a rare painful primary disorder occurring in either episodic or chronic patterns. Several authors found that the hypothalamus, the brain region regulating endocrine function and autonomic system, is involved in the pathophysiology of cluster headache. Some authors have found in patients affected by this disease abnormality in glucose metabolism. Considering the role of thiamine in brain function, in energetic metabolism, and in pain modulation, we treated a patient affected by cluster headache with oral high-dose thiamine. We report a 41-year-old man suffering from primary chronic cluster headache since the age of 15 years. The patient began oral therapy with high-dose thiamine in December 2016. Oral thiamine supplementation led to a dramatic improvement of the symptoms. The therapy was effective in reversing all the symptoms of the disease. Our observation suggests that a thiamine deficiency due to enzymatic abnormalities or to dysfunction of the circulation of thiamine in the intracellular space could cause a neuronal selective impairment in the centers that are involved in this disease and could have an important role in the pathogenesis of the symptoms of cluster headache.