An integrated perspective on diabetic, alcoholic, and drug-induced neuropathy, etiology, and treatment in the US

Early evidence of beneficial and protective effects of Protectin DX treatment on behavior responses and type-1 diabetes mellitus related-parameters: A non-clinical approach

Protectin DX (PDX), a specialized pro-resolving lipid mediator, presents potential therapeutic applications across various medical conditions due to its anti-inflammatory and antioxidant properties. Since type-1 diabetes mellitus (T1DM) is a disease with an inflammatory and oxidative profile, exploring the use of PDX in addressing T1DM and its associated comorbidities, including diabetic neuropathic pain, depression, and anxiety becomes urgent. Thus, in the current study, after 2 weeks of T1DM induction with streptozotocin (60 mg/kg) in Wistar rats, PDX (1, 3, and 10 ng/animal; i.p. injection of 200 μl/animal) was administered specifically on days 14, 15, 18, 21, 24, and 27 after T1DM induction. We investigated the PDX's effectiveness in alleviating neuropathic pain (mechanical allodynia; experiment 1), anxiety-like and depressive-like behaviors (experiment 2). Also, we studied whether the PDX treatment would induce antioxidant effects in the blood plasma, hippocampus, and prefrontal cortex (experiment 3), brain areas involved in the modulation of emotions. For evaluating mechanical allodynia, animals were repeatedly submitted to the Von Frey test; while for studying anxiety-like responses, animals were submitted to the elevated plus maze (day 26) and open field (day 28) tests. To analyze depressive-like behaviors, the animals were tested in the modified forced swimming test (day 28) immediately after the open field test. Our data demonstrated that PDX consistently increased the mechanical threshold throughout the study at the two highest doses, indicative of antinociceptive effect. Concerning depressive-like and anxiety-like behavior, all PDX doses effectively prevented these behaviors when compared to vehicle-treated T1DM rats. The PDX treatment significantly protected against the increased oxidative stress parameters in blood plasma and in hippocampus and prefrontal cortex. Interestingly, treated animals presented improvement on diabetes-related parameters by promoting weight gain and reducing hyperglycemia in T1DM rats. These findings suggest that PDX improved diabetic neuropathic pain, and induced antidepressant-like and anxiolytic-like effects, in addition to improving parameters related to the diabetic condition. It is worth noting that PDX also presented a protective action demonstrated by its antioxidant effects. To conclude, our findings suggest PDX treatment may be a promising candidate for improving the diabetic condition per se along with highly disabling comorbidities such as diabetic neuropathic pain and emotional disturbances associated with T1DM.

Effectiveness of Nicotinamide Phosphoribosyltransferase/Pre-B Cell Colony-enhancing Factor/Visfatin in preventing High Glucose-induced Neurotoxicity in an In-vitro Model of Diabetic Neuropathy

Introduction

Diabetic neuropathy is a well-known complication of diabetes. Recently, hyperglycemia-induced toxicity has been confirmed to participates in multiple cellular pathways typical for neural deterioration. Nicotinamide phosphoribosyltransferase/pre-b cell colony-enhancing factor (Nampt/PBEF)/visfatin is a novel endogenous ligand that some studies have shown its neuroprotective effects on neurodegenerative disease. Therefore, we hypothesized that visfatin may prevent high glucose (HG)-induced neurotoxicity by inhibiting apoptosis, autophagy, and reactive oxygen species (ROS) responses properly.

Methods

In this study, pheochromocytoma cell line 12 (PC12) cells were exposed to both HG concentrations (50, 75, 100, 125, 150 mM) and visfatin (50, 100, 150 ng/mL) at different time -points to determine the optimum time and dose of glucose and visfatin. To investigate the effects of visfatin on HG-induced damage in the PC12 diabetic neuropathy model, we examined ROS response, apoptosis, and autophagy using ROS detection kit, flow cytometry, and real-time PCR/Western blot, respectively.

Results

We determined that HG concentration significantly increased the ROS level and apoptosis of diabetic PC12 cells. However, visfatin treatment significantly decreased the ROS production (P<0.05) and apoptosis of diabetic PC12 cells (P<0.0001). Beclin-1 messenger ribonucleic acid (mRNA) level (P<0.05) and light chain 3 (Lc3)-II protein level (P<0.05) showed that the autophagy pathway is impaired by HG concentrations.

Conclusion

We concluded that visfatin can sufficiently decrease neural damage caused by ROS production and apoptosis under HG-induced toxicity.

Highlights

High glucose significantly increased the ROS level and apoptosis of diabetic PC12 cells;The autophagy pathway is impaired by high glucose;Nampt/PBEF/visfatin can significantly reduce neural damage caused by ROS production and apoptosis of diabetic PC12 cells.

Plain Language Summary

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia resulting from a failure in insulin secretion, insulin action, or both. Visfatin (Nampt/PBEF) has insulin-mimetic effects. So far, no study has assessed its effects on diabetic neuropathy. Therefore, we examined the neuroprotective effects of visfatin on cell line 12 (PC12) against glucose-induced neurotoxicity. Based on the results, it was concluded that the Nampt/PBEF/visfatin can significantly reduce neural damage caused by production of reactive oxygen species and apoptosis of diabetic PC12 cell.

Chronic alcohol induced mechanical allodynia by promoting neuroinflammation: A mouse model of alcohol-evoked neuropathic pain

BACKGROUND AND PURPOSE

Chronic pain is considered a key factor contributing to alcohol use disorder (AUD). The mechanisms responsible for chronic pain associated with chronic alcohol consumption are unknown. We evaluated the development of chronic pain in a mouse model of alcohol dependence and investigate the role of neuroinflammation.

EXPERIMENTAL APPROACH

The chronic-intermittent ethanol two-bottle choice CIE-2BC paradigm generates three groups: alcohol-dependent with escalating alcohol intake, nondependent (moderate drinking) and alcohol-naïve control male and female mice. We measured mechanical allodynia during withdrawal and after the last voluntary drinking. Immunoblotting was used to evaluate the protein levels of IBA-1, CSFR, IL-6, p38 and ERK2/1 in spinal cord tissue of dependent and non-dependent animals.

KEY RESULTS

We found significant escalation of drinking in the dependent group in male and female compared with the non-dependent group. The dependent group developed mechanical allodynia during 72 h of withdrawal, which was completely reversed after voluntary drinking. We observed an increased pain hypersensitivity compared with the naïve in 50% of non-dependent group. Increased IBA-1 and CSFR expression was observed in spinal cord tissue of both hypersensitivity-abstinence related and neuropathy-alcohol mice, and increased IL-6 expression and ERK1/2 activation in mice with hypersensitivity-related to abstinence, but not in mice with alcohol-evoked neuropathic pain.

CONCLUSIONS AND IMPLICATIONS

The CIE-2BC model induces two distinct pain conditions specific to the type of ethanol exposure: abstinence-related hypersensitivity in dependent mice and alcohol-evoked neuropathic pain in about a half of the non-dependent mice.

Preclinical nerve conduction: Nerve battery options for primate studies

Electrophysiological neurodiagnostic tests of nerve conduction (NC) are key assays included in preclinical safety and toxicology programs to assess the peripheral neuropathy (PN) liability of a new drug. Despite their increased use, standardization of nerve conduction studies (NCS) is lacking in the preclinical space, with limited regulatory guidelines stipulating type and number of nerves or minimum combinations appropriate for each stage of drug development or indication. Detection of subtle peripheral toxicities depends on choosing appropriate nerve targets for testing, especially when functional changes remain above the lower limit of normal values. To support robust preclinical toxicology study designs, the current short communication provides options and recommendations for selecting peripheral nerves for clinically translatable nerve conduction batteries applicable to toxicology and gene therapy, with a focus on clinically translatable primate models. A comprehensive compilation of accessible nerve locations is offered including lower and upper extremity motor nerves, and sensory nerves with origin at multiple DRG levels. Rankings of technique difficulty and repeatability across serial collections are presented for each assay informed by serial nerve conduction from 500 adult primates. The goal of this communication is to support the standardization and preclinical implementation of this important assay.

The 7-Hydroxyflavone attenuates chemotherapy-induced neuropathic pain by targeting inflammatory pathway

Vincristine and paclitaxel are widely used chemotherapeutic drugs for the treatment of brain tumors, breast cancer, leukemia, lymphomas, and malignant solid tumors. Though, these drugs are associated with some severe adverse effects including peripheral neuropathic pain. The anti-nociceptive and anti-inflammatory properties of the 7-Hydroxyflavone (7HF) were evaluated in the mice using thermally- and chemically-induced nociception, naloxone antagonistic test, and carrageenan-induced paw edema models. Initially, the in-vitro cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitory assays were carried out. Peripheral neuropathic pain was induced in the Sprague Dawley (SD) rats by administration of paclitaxel (4 mg/kg) and vincristine (200 µg/kg) on days 1, 3, 5, 7, and 9, respectively. The protective effect of 7HF was assessed against the chemotherapy-induced peripheral neuropathy in the rats. Moreover, the expression of the inflammatory mediators in the spinal cord was investigated through RT-PCR. In addition, a computational study was performed to find the potential therapeutic targets and the binding mechanism of 7HF. The 7HF caused concentration-dependent inhibition of COX-2 and 5-LOX, it attenuated the nociceptive pain, carrageenan-induced paw edema, and the development of mechanical and cold allodynia, and hyperalgesia dose-dependently without causing motor coordination deficit. Likewise, the 7HF decreased the vincristine-induced increased expression of different inflammatory mediators including COX-2, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and nuclear factor-kappa B (NF-κB). The computational study showed the effective interactions of 7HF with the binding sites of NF-κB, COX-2, and 5-LOX, exert its inhibitory activities. These findings reveal that the 7HF has anti-nociceptive, anti-inflammatory, and anti-neuropathic potentials.

Time to diabetic neuropathy and its predictors among newly diagnosed type 2 diabetes mellitus patients in Northwest Ethiopia

Introduction

Despite the high number of patients suffering from the negative impact of diabetic neuropathy (DN) in Ethiopia, evidence regarding the time to DN and its predictors are not well document in Ethiopia. Therefore, the current study aimed to determine time to DN and its predictors among newly diagnosed type 2 diabetes patients (T2DM) in North West Ethiopia.

Methods

Institutional based retrospective cohort study was conducted among 463 T2DM. Cox proportional hazard model was fitted to identify predictors of time to DN. The adjusted hazard ratio (AHR) with its 95% confidence interval was used to declare the presence and strength of association.

Results

From a total 463 study participants, 77 (16.63%), (95% CI 13.23%, 20.03%) had developed diabetic neuropathy. The median time to develop DN was 233.77 months. About 40 (51.95%) diabetic neuropathy cases occurred within 6 years of diagnosis of diabetic mellitus. The incidence density was 2.01/100 PY with 95% CI of [1.60, 2.53]. In the multivariable Cox proportional hazard analysis; being aged 65–69 [AHR = 2.78; 95% CI 1.20, 6.46], living with diabetes for less than 4 years [AHR = 3.77; 95% CI 1.82, 7.76], having anaemia [AHR = 3.82; 95% CI 1.66, 8.82] and having other complications [AHR = 1.68; 95% CI 1.03, 2.76 were significant predictors of DN.

Conclusion

More than half of diabetic neuropathy cases occurred within a short period of diagnosed with T2DM. Significant predictors for the time to DN were age, duration, having anaemia and other DM complication. Therefore, we recommend that early screening for DM and its complication for risky groups. While doing that due consideration should be assumed for old and anemic patients.

Botulinum toxin type A for painful diabetic neuropathy: an open-label study

Background

A large proportion of painful diabetic neuropathy cases either do not respond or are intolerant to the currently available oral and physical therapies. There is encouraging evidence from a small number of studies that those patients can improve using botulinum toxin injection. The aim of the study was to evaluate the effect of intradermal injection of botulinum toxin type A on painful diabetic neuropathy. Eight adult patients with diabetic peripheral neuropathy (DPN), confirmed by nerve conduction studies, were refractory to a minimum of two neuropathic pain treatments for 6 months or more were recruited. All cases received intradermal injection of 48 units of botulinum toxins—type A in each foot in 6×4 distribution. Follow-up was done after 8 weeks using the Neuropathic Pain Scale (NPS), Pittsburgh Sleep Quality Index (PSQI), and Overall Disability Sum Scale (ODSS).

Results

After 8 weeks, there was a significant change in NPS from 55.8 (7.8) to 38.5 (8.1) (p value 0.007), also there was significant improvement in ODDS from 4 (IQR, 2.25-4.75) to 2.5 (IQR, 0.5-3) (p value 0.01). However, there was no significant change in PSQI.

Conclusion

Botulinum toxin type A injection is a promising treatment option in Egyptian DPN adults in this study.

Lamiophlomis herba: A comprehensive overview of its chemical constituents, pharmacology, clinical applications, and quality control

Lamiophlomis rotata (Benth.) Kudo (LR) is an extensively used Chinese herbal medicine. It contains a variety of chemical constituents with significant biological activities that were first recorded in the classical masterpiece of Tibetan Medicine, Somaratsa. In this review, we summarize the information regarding the traditional uses, chemical constituents, pharmacological effects, clinical applications, quality control, toxicology, and pharmacokinetics of LR. At least 223 chemical constituents have been isolated from LR, including phenylethanoid glycosides, flavonoids, iridoids, volatile oils, et al. Their various physiological activities have been demonstrated as analgesic, hemostatic, anti-inflammatory, anti-tumor, marrow-supplementing, anti-bacterial, and immunity-strengthening. The clinical applications of LR and quality control are also discussed, as well as some existing problems. This article aims to provide more comprehensive information on the chemical composition, pharmacological activity, and clinical application of LR, so as to provide a theoretical basis for the further reasonable development of LR in clinical practice and of new drugs.

Special Issue on Toxicologic Neuropathology of the Peripheral Nervous System: A Special Compendium of Past, Present, and Future Developments in a Neglected Field

Neuropathology of the peripheral nervous system (PNS) is an underappreciated area in toxicologic pathology. Toxicity to nerves and ganglia can result from toxic insults following exposure to environmental, occupational, and industrial chemicals; drugs and biologics; cosmetics and food additives; and even physical agents such as noise. The following introduction provides an overview of this special issue of Toxicologic Pathology on toxicologic neuropathology of the PNS and highlights the range of key topics in this field that are reviewed in this compilation.

Angiotensin receptors and neuropathic pain

Growing evidence implicates the renin-angiotensin system (RAS) in multiple facets of neuropathic pain (NP). This narrative review focuses primarily on the major bioactive RAS peptide, Angiotensin II (Ang II), and its receptors, namely type 1 (AT1R) and type 2 (AT2R). Both receptors are involved in the development of NP and represent potential therapeutic targets. We first discuss the potential role of Ang II receptors in modulation of NP in the central nervous system. Ang II receptor expression is widespread in circuits associated with the perception and modulation of pain, but more studies are required to fully characterize receptor distribution, downstream signaling, and therapeutic potential of targeting the central nervous system RAS in NP. We then describe the peripheral neuronal and nonneuronal distribution of the RAS, and its contribution to NP. Other RAS modulators (such as Ang (1-7)) are briefly reviewed as well. AT1R antagonists are analgesic across different pain models, including NP. Several studies show neuronal protection and outgrowth downstream of AT2R activation, which may lead to the use of AT2R agonists in NP. However, blockade of AT2R results in analgesia. Furthermore, expression of the RAS in the immune system and a growing appreciation of neuroimmune crosstalk in NP add another layer of complexity and therapeutic potential of targeting this pathway. A growing number of human studies also hint at the analgesic potential of targeting Ang II signaling. Altogether, Ang II receptor signaling represents a promising, far-reaching, and novel strategy to treat NP.

Pharmacological Evidence on Augmented Antiallodynia Following Systemic Co-Treatment with GlyT-1 and GlyT-2 Inhibitors in Rat Neuropathic Pain Model

The limited effect of current medications on neuropathic pain (NP) has initiated large efforts to develop effective treatments. Animal studies showed that glycine transporter (GlyT) inhibitors are promising analgesics in NP, though concerns regarding adverse effects were raised. We aimed to study NFPS and Org-25543, GlyT-1 and GlyT-2 inhibitors, respectively and their combination in rat mononeuropathic pain evoked by partial sciatic nerve ligation. Cerebrospinal fluid (CSF) glycine content was also determined by capillary electrophoresis. Subcutaneous (s.c.) 4 mg/kg NFPS or Org-25543 showed analgesia following acute administration (30-60 min). Small doses of each compound failed to produce antiallodynia up to 180 min after the acute administration. However, NFPS (1 mg/kg) produced antiallodynia after four days of treatment. Co-treatment with subanalgesic doses of NFPS (1 mg/kg) and Org-25543 (2 mg/kg) produced analgesia at 60 min and thereafter meanwhile increased significantly the CSF glycine content. This combination alleviated NP without affecting motor function. Test compounds failed to activate G-proteins in spinal cord. To the best of our knowledge for the first time we demonstrated augmented analgesia by combining GlyT-1 and 2 inhibitors. Increased CSF glycine content supports involvement of glycinergic system. Combining selective GlyT inhibitors or developing non-selective GlyT inhibitors might have therapeutic value in NP.

Alcohol-Induced Neuropathy in Chronic Alcoholism: Causes, Pathophysiology, Diagnosis, and Treatment Options

Purpose of the Review

Alcohol abuse causes a wide range of disorders that affect the nervous system. These include confusion, cerebellar ataxia, peripheral neuropathy, and cognitive impairment. Chronic and excessive alcohol consumption is the primary cause of peripheral neuropathy. It is worth noting that peripheral neuropathy has no reliable treatment due to the poor understanding of its pathology.

Recent Findings

Coasting is a major feature of alcoholic neuropathy, largely due to chronic alcohol abuse. Its major features are hyperalgesia, allodynia, and burning pain. Even though much research was done in this area, still we do not have a full understanding of the mechanism of alcoholic neuropathy. However, some theories have been proposed. These include direct or indirect effects of alcohol metabolites, impaired axonal transport, suppressed excitatory nerve pathway activity, or imbalance in neurotransmitters. Activation of spinal cord microglia, mGlu5 spinal cord receptors, and hypothalamic-pituitary-adrenal axis also seem to be implicated in the pathophysiology of this alcoholic neuropathy. The goal of treatment is to impede further damage to the peripheral nerves while also restoring their normal physiology. Alcohol abstinence, intake of balanced diets, and treatment with medications are suggested including benfotiamine, alpha-lipoic acid, acetyl-l-carnitine, vitamin E, methylcobalamin, myo-inositol, N-acetylcysteine, capsaicin, tricyclic antidepressants, or antiepileptic drugs.

Summary

This review focuses on the many pathways that play a role in the onset and development of alcohol-induced neuropathy, as well as present the possible treatment strategies of this disorder, providing insights into a further search of new treatment modalities.

Chronic postoperative inguinal pain: A narrative review

Inguinodynia or chronic postoperative inguinal pain is a growing problem between patients who undergo surgical repair of an inguinal hernia. The change in results measurement proposed by many authors towards Patient Reported Outcome Measurement has underlined the importance of chronic postoperative inguinal pain, because of the great limitations in everyday life and the huge socioeconomic impact that it causes. In this article a narrative review of the available literature in PUBMED, EMBASE and Cochrane Library is performed and the most relevant aspects about epidemiology, etiology prevention, diagnosis and treatment of chronic postoperative inguinal pain are discussed. A new management algorithm is also proposed. The variability in its incidence and clinical presentation makes diagnosis of chronic postoperative inguinal pain a very challenging issue. There is no standardized therapy and an adequate etiological diagnosis is key point for a successful treatment. There are many treatment options that have to be sequentially used and adjusted to each patient and their clinical features.

The Effectiveness of Topical Cannabidiol Oil in Symptomatic Relief of Peripheral Neuropathy of the Lower Extremities

Background:

Peripheral neuropathy can significantly impact the quality of life for those who are affected, as therapies from the current treatment algorithm often fail to deliver adequate symptom relief. There has, however, been an increasing body of evidence for the use of cannabinoids in the treatment of chronic, noncancer pain. The efficacy of a topically delivered cannabidiol (CBD) oil in the management of neuropathic pain was examined in this four-week, randomized and placebocontrolled trial.

Methods:

In total, 29 patients with symptomatic peripheral neuropathy were recruited and enrolled. 15 patients were randomized to the CBD group with the treatment product containing 250 mg CBD/3 fl. oz, and 14 patients were randomized to the placebo group. After four weeks, the placebo group was allowed to crossover into the treatment group. The Neuropathic Pain Scale (NPS) was administered biweekly to assess the mean change from baseline to the end of the treatment period.

Results:

The study population included 62.1% males and 37.9% females with a mean age of 68 years. There was a statistically significant reduction in intense pain, sharp pain, cold and itchy sensations in the CBD group when compared to the placebo group. No adverse events were reported in this study.

Conclusions:

Our findings demonstrate that the transdermal application of CBD oil can achieve significant improvement in pain and other disturbing sensations in patients with peripheral neuropathy. The treatment product was well tolerated and may provide a more effective alternative compared to other current therapies in the treatment of peripheral neuropathy.

Axon degeneration: mechanistic insights lead to therapeutic opportunities for the prevention and treatment of peripheral neuropathy

Peripheral neuropathy is the most common neurodegenerative disease affecting hundreds of millions of patients worldwide and is an important cause of chronic pain. Typical peripheral neuropathies are characterized by dysesthesias including numbness, crawling skin, a sensation of "pins and needles," and burning and stabbing pain. In addition, peripheral neuropathy can affect the motor and autonomic systems leading to symptoms such as weakness, constipation, and dysregulation of blood pressure. Peripheral neuropathies can be either hereditary or acquired and are a common consequence of diabetes and treatment with chemotherapy agents. Many neuropathies are due to degeneration of long axons; however, the mechanisms driving axon loss were unknown, and so no therapies are available to preserve vulnerable axons and prevent the development of peripheral neuropathy. With the recent identification of SARM1 as an injury-activated NADase enzyme that triggers axon degeneration, there is now a coherent picture emerging for the mechanism of axonal self-destruction. Here, we will present evidence that inhibiting the SARM1 pathway can prevent the development of peripheral neuropathy, describe the emerging mechanistic understanding of the axon degeneration program, and discuss how these mechanistic insights may be translated to the clinic for the prevention and treatment of peripheral neuropathy and other neurodegenerative disorders.

Does Vitamin D Affect Diabetic Neuropathic Pain and Balance?

Purpose

This randomized, placebo-controlled study examined the effect of vitamin D replacement therapy on neuropathic symptoms and balance in patients with diabetic neuropathic pain and low vitamin D levels.

Patients and Methods

Among the 258 patients, the results in a total of 57 volunteers (32 in the treatment and 25 in the control arm) meeting the inclusion criteria are reported. Symptoms of neuropathic pain were assessed using Douleur Neuropathique 4 (DN4) questionnaire, and presence of polyneuropathy (PNP) was determined by performing electromyography (EMG). Balance was assessed using Berg balance test (BBT). After undergoing these examinations, the patients in the treatment group were intramuscularly (IM) injected with 300,000 IU vitamin D in a liquid formulation and those in the placebo group were IM injected with physiological saline. The DN4 and BBT were repeated after 12 weeks, and the results were compared.

Results

The patients in the treatment group showed a significant decrease in total DN4 scores from baseline to the study endpoint compared with the patients in the placebo group (p=0.008). The patients in the treatment group also showed a significant increase in BBT scores from baseline to the study endpoint compared with the patients in the placebo group (p=0.001). Furthermore, in subgroup analysis, these patients showed a significant decrease in electric shock and burning sensation scores from baseline to the study endpoint compared with the patients in the placebo group (p=0.006, p=0.001, respectively).

Conclusion

In patients with diabetic neuropathic pain, vitamin D levels should be measured and vitamin D replacement therapy should be administered as required to resolve neuropathic symptoms and to improve balance.

Altered touch perception and associated risk factors in individuals with diabetes mellitus

ABSTRACT Objective: To evaluate the prevalence of altered touch perception in the feet of individuals with diabetes mellitus and the associated risk factors. Method: Cross-sectional study with 224 individuals with diabetes mellitus conducted in an endocrinology clinic at a public hospital in Campina Grande, Paraíba. The evaluation used touch sensitivity and perception, and a descriptive and multivariate analysis with Poisson regression was performed. Results: We found the prevalence of altered touch perception to be 53.1%. The risk factors that had a significant and joint impact on its occurrence were: female gender; previous ulcer; diabetes mellitus type 2; burning sensation, cracks, fissures, calluses, and Charcot foot. Conclusions: This study found a high prevalence of altered perception of touch, and this should support the planning of actions aimed at preventing the problem. The study showed the relevance of the phenomenon as a nursing diagnosis that could be included in NANDA-International.

Medical complications associated with substance use disorders in patients with type 2 diabetes and hypertension: electronic health record findings

BACKGROUND AND AIMS

Screening for substance use disorder (SUD) in general medical settings may be particularly important in patients with comorbid health conditions exacerbated by SUD. This study evaluated whether SUD is associated with type 2 diabetes mellitus (T2DM) complications in patients with co-occurring T2DM and hypertension.

DESIGN

Analysis of a limited data set obtained through IBM Watson Health Explorys, a platform integrating data from electronic health records. Matched controls were defined for each of five SUDs: tobacco use disorder (TUD), opioid use disorder (OUD), cocaine use disorder, cannabis use disorder (CUD) and alcohol use disorder (AUD) using Mahalanobis distance within propensity score calipers.

SETTING

All patients were seen in the MetroHealth System (Cleveland, OH, USA) and had diagnosis codes for T2DM and hypertension.

PARTICIPANTS

SUD group participants had a diagnosis of abuse/dependence for the substance of interest. Controls for each SUD group had no diagnosis code related to the SUD of interest and were selected to match the SUD patients on demographics, residential zip code median income and body mass index. Total sample sizes for each SUD-control comparison ranged from 1160 for CUD to 22 128 for TUD.

MEASUREMENTS

Outcome was diagnosis (yes/no) of four T2DM complications (cerebrovascular accident, diabetic neuropathy, diabetic renal disease, myocardial infarction) and all-cause mortality.

FINDINGS

Logistic regressions revealed that SUD was significantly associated with greater risk of cerebrovascular accident [TUD odds ratio (OR) = 1.79, OUD-OR = 1.94, cocaine use disorder OR = 2.67], diabetic neuropathy [TUD-adjusted OR (aOR) = 1.47, cocaine use disorder-aOR = 1.35, AUD-aOR = 1.27], diabetic renal disease (TUD-aOR = 1.25, OUD-OR = 1.34), myocardial infarction (TUD-OR = 1.96, OUD-OR = 2.01, cocaine use disorder-OR = 2.68, CUD-OR = 2.48, AUD-OR = 1.42) and mortality (TUD-OR = 1.15, cocaine use disorder-OR = 1.61, CUD-OR = 1.49, AUD-OR = 1.35).

CONCLUSIONS

Among patients in Ohio USA with both type 2 diabetes mellitus (T2DM) and hypertension, those with substance use disorders appear to have greater risk for T2DM complications and all-cause mortality.

Are Ergothioneine Levels in Blood Associated with Chronic Peripheral Neuropathy in Colorectal Cancer Patients Who Underwent Chemotherapy?

Objective: Chronic Chemotherapy-Induced Peripheral Neuropathy (CIPN) is highly prevalent among colorectal cancer (CRC) patients. Ergothioneine (ET) - a dietary antioxidant -protected against CIPN in experimental models, but human studies are lacking. We explored whether whole blood ET levels were associated with chronic peripheral neuropathy among CRC patients who had completed chemotherapy.Methods: At diagnosis, median ET-concentration in whole blood of 159 CRC patients was 10.2 μg/ml (7.2-15.8). Patients completed questionnaires on peripheral neuropathy 6 months after completion of chemotherapy. We calculated prevalence ratios (PR) to assess associations of ET-concentrations and prevalence of peripheral neuropathy and used linear regression to assess associations with severity of peripheral neuropathy.Results: Prevalence of total and sensory peripheral neuropathy were both 81%. Higher ET-concentrations tended to be associated with lower prevalence of total and sensory peripheral neuropathy, but not statistically significant (highest versus lowest tertile of ET: PR = 0.93(0.78, 1.11) for total neuropathy, and PR = 0.84(0.70, 1.02) for sensory neuropathy). ET-concentrations were not associated with severity of neuropathy.Conclusion: Statistically significant associations were not observed, possibly because of limited sample size. Although data may putatively suggest higher levels of ET to be associated with a lower prevalence of neuropathy, analyses should be repeated in larger populations with larger variability in ET-concentrations.

Glycine transporter inhibitors: A new avenue for managing neuropathic pain

Interneurons operating with glycine neurotransmitter are involved in the regulation of pain transmission in the dorsal horn of the spinal cord. In addition to interneurons, glycine release also occurs from glial cells neighboring glutamatergic synapses in the spinal cord. Neuronal and glial release of glycine is controlled by glycine transporters (GlyTs). Inhibitors of the two isoforms of GlyTs, the astrocytic type-1 (GlyT-1) and the neuronal type-2 (GlyT-2), decrease pain sensation evoked by injuries of peripheral sensory neurons or inflammation. The function of dorsal horn glycinergic interneurons has been suggested to be reduced in neuropathic pain, which can be reversed by GlyT-2 inhibitors (Org-25543, ALX1393). Several lines of evidence also support that peripheral nerve damage or inflammation may shift glutamatergic neurochemical transmission from N-methyl-D aspartate (NMDA) NR1/NR2A receptor- to NR1/NR2B receptor-mediated events (subunit switch). This pathological overactivation of NR1/NR2B receptors can be reduced by GlyT-1 inhibitors (NFPS, Org-25935), which decrease excessive glycine release from astroglial cells or by selective antagonists of NR2B subunits (ifenprodil, Ro 25-6981). Although several experiments suggest that GlyT inhibitors may represent a novel strategy in the control of neuropathic pain, proving this concept in human beings is hampered by lack of clinically applicable GlyT inhibitors. We also suggest that drugs inhibiting both GlyT-1 and GlyT-2 non-selectively and reversibly, may favorably target neuropathic pain. In this paper we overview inhibitors of the two isoforms of GlyTs as well as the effects of these drugs in experimental models of neuropathic pain. In addition, the possible mechanisms of action of the GlyT inhibitors, i.e. how they affect the neurochemical and pain transmission in the spinal cord, are also discussed. The growing evidence for the possible therapeutic intervention of neuropathic pain by GlyT inhibitors further urges development of drugable compounds, which may beneficially restore impaired pain transmission in various neuropathic conditions.

Effect of Histone Deacetylase Inhibitor on Ethanol Withdrawal-Induced Hyperalgesia in Rats

BACKGROUND

Increased pain sensitivity is observed following alcohol withdrawal, and attempts to alleviate this hyperalgesia can contribute to the cycle of addiction. The aim of this study was to determine if alcohol withdrawal-induced hyperalgesia was observed in a chronic ethanol exposure model and if this pain was affected by histone deacetylase inhibitors, thus revealing an epigenetic mechanism.

METHODS

Adult male Sprague Dawley rats received Lieber-DeCarli liquid control or ethanol (9% v/v) diet for 15 days. Mechanical sensitivity was measured with von Frey hair stimulation of the hindpaw during ethanol administration and 24- and 72-hour withdrawal.

RESULTS

Ethanol withdrawal produced severe and sustained mechanical hyperalgesia, an effect not observed in the control or ethanol-maintained groups. Furthermore, this hyperalgesia was attenuated by the histone deacetylase inhibitor, suberoylanilide hydroxamic acid treatment.

CONCLUSIONS

Heightened pain sensitivity was observed following withdrawal from chronic ethanol exposure, and histone deacetylase inhibitors could be novel treatments for this alcohol withdrawal-induced hyperalgesia.

Uremic neuropathy: an overview of the current literature

INTRODUCTION

Peripheral neuropathy is a disorder that affects the cell body, axon or myelin of motor or peripheral sensory neurons and occurs in 60-100% of patients who are submitted to dialysis due to chronic kidney disease. Uremic neuropathy (UN) is attributed to the accumulation of organic waste, evident in patients with reduced glomerular filtration rate.

OBJECTIVES

This review aims to make clinical characteristics of uremic neuropathy evident enabling early diagnosis and treatment.

METHODS

This is a literature review of articles published on PubMed over the last 10 years using "Uremic Neuropathy" as "Title/Abstract".

RESULTS

A total of nine articles that met the inclusion criteria were included. UN is a distal symmetric sensorimotor polyneuropathy that occurs due to the accumulation of uremic toxins associated with an oxidative stress-related free radical activity. Hyperkalemia is thought to play an important role in its pathophysiology. Diagnosis depends on nerve conduction studies, and treatment includes dialysis or renal transplant.

CONCLUSION

Clinical presentations of UN are broad and non-specific; nonetheless, it is important to detect early changes in order to avoid its progression. The earlier UN is diagnosed and treated, the more successful are the clinical outcomes.

Small-fiber neuropathy definition, diagnosis, and treatment

In the last 30 years, improvement of diagnostic methods enabled routine evaluation of small A-delta and C nerve fibers impairment, which results with the clinical condition known as a small-fiber neuropathy (SFN). This syndrome develops as a result of metabolic, toxic, immune-mediated, or genetic factors. The main clinical features include neuropathic pain and autonomic disturbance, which are occasionally disclaimed due to outstanding fatigue, daily performance decline, anxiety, and depression. As clinical, neurological, nerve conduction, and electromyography studies are commonly normal, diagnosis often depends on the finding of decreased intra-epidermal density of nerve fibers, per skin biopsy. This review highlights the etiology, clinical, diagnostic aspects, and SFN treatment.

Initial researches on neuro-functional status and evolution in chronic ethanol consumers with recent traumatic spinal cord injury

We found differences related to the neuro-functional deficiency and clinical progress, among non-consumers and chronic consumers of ethanol, with recent traumatic spinal cord injury (SCI). We present a synthesis of related data on lesion mechanisms in post-traumatic myelogenous disorders, namely some of the alcohols and their actions on the nervous system, with details on the influences exerted, in such afflictions, by the chronic consumption of ethanol. The subject is not frequently approached - according to a literature review with systematic elements, which we have done before - thus constituting a niche that deserves to be further explored. The applicative component of the article highlights statistical data resulted from a retrospective study regarding the specialized casuistry from the Neuromuscular Recovery Clinic of the "Bagdasar Arseni" Emergency Clinical Hospital, following the comparative analysis of two groups of patients with recent SCI: non-consumers - the control group (n=780) - and chronic ethanol consumers - the study group (n=225) - with the addition of a prospective pilot component. Data processing has been achieved with SPSS 24. The American Spinal Injury Association Impairment Scale (AIS) mean motor scores differ significantly (tests: Mann-Whitney and t) between the control and study group in favor of the second, both at admission (p<0.001) and at discharge (p<0.001). AIS mean sensitive scores differ between the two lots, and also in favor of the study, but statistically significant only at discharge (p=0.048); the difference at admission is not significant (p=0.51) - possibly because of alcoholic-nutritional polyneuropathy. These findings, with numerous related details, later presented in the text, are surprising, which requires further studies and attempts of understanding.

Uremic neuropathy: an overview of the current literature

INTRODUCTION

Peripheral neuropathy is a disorder that affects the cell body, axon or myelin of motor or peripheral sensory neurons and occurs in 60-100% of patients who are submitted to dialysis due to chronic kidney disease. Uremic neuropathy is attributed to the accumulation of organic waste, evident in patients with reduced glomerular filtration rate.

OBJECTIVES

This review aims to make clinical characteristics of uremic neuropathy evident enabling early diagnosis and treatment.

METHODS

This is a literature review of articles published on PubMed over the last 10 years using "Uremic Neuropathy" as "Title/Abstract".

RESULTS

A total of nine articles that met the inclusion criteria were included. UN is a distal symmetric sensorimotor polyneuropathy that occurs due to the accumulation of uremic toxins associated with an oxidative stress-related free radical activity. Hyperkalemia is thought to play an important role in its pathophysiology. Diagnosis depends on nerve conduction studies, and treatment includes dialysis or renal transplant.

CONCLUSION

Clinical presentations of UN are broad and non-specific; nonetheless, it is important to detect early changes in order to avoid its progression. The earlier UN is diagnosed and treated, the more successful are the clinical outcomes.

Proportion of neuropathic pain in the back region in chronic low back pain patients -a multicenter investigation

Neuropathy can contribute to low back pain (LBP) in the region of the back. Our study investigated the proportion of neuropathic pain (NP) in low back region in chronic LBP patients from multicenter and clinics in China and identified associated factors. Assessment was made using a questionnaire and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS, only tested in low back region), as well as Quantitative Sensory Testing (QST, merely applied to the low back region), the Hospital Anxiety and Depression Scale (HADS) and the Oswestry Disability Index (ODI). Our questionnaire collected demographic information, behavioral habits and medical records. 2116 outpatients over 18 years old complaining of LBP lasting more than 3 months were enrolled in this study. The NP proportion in low back region in chronic LBP patients was 2.8%. Multivariable logistic regression analysis showed that histories of lumbar surgery, abdominal or pelvic surgery, and drinking alcohol were independent positive predictors for LBP of predominantly neuropathic origin (LBNPO), while history of low back sprain and frequently carrying weight as independent negative predictor. Using these parameters may help the identification of patients with chronic LBP likely to develop NP leading to improved treatment outcomes.

Definition and diagnosis of small fiber neuropathy: consensus from the Peripheral Neuropathy Scientific Department of the Brazilian Academy of Neurology

The aim of this study was to describe the results of a Brazilian Consensus on Small Fiber Neuropathy (SFN). Fifteen neurologists (members of the Brazilian Academy of Neurology) reviewed a preliminary draft. Eleven panelists got together in the city of Fortaleza to discuss and finish the text for the manuscript submission. Small fiber neuropathy can be defined as a subtype of neuropathy characterized by selective involvement of unmyelinated or thinly myelinated sensory fibers. Its clinical picture includes both negative and positive manifestations: sensory (pain/dysesthesias/pruritus) or combined sensory and autonomic complaints, associated with an almost entirely normal neurological examination. Standard electromyography is normal. A growing list of medical conditions is associated with SFN. The classification of SFN may also serve as a useful terminology to uncover minor discrepancies in the normal values from different neurophysiology laboratories. Several techniques may disclose sensory and/or autonomic impairment. Further studies are necessary to refine these techniques and develop specific therapies.

Clinical evidence and mechanisms of growth factors in idiopathic and diabetes-induced carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by compression and irritation of the median nerve, which travels through the carpal tunnel in the wrist. Increased fibrosis is a hallmark of the development and pathology of CTS. Different growth factors have been demonstrated to play a potential role in the development of CTS. Studies have described an increase in the expression of growth factors, including Transforming Growth Factor (TGF-β), Vascular Endothelial Growth Factor (VEGF) and interleukins (growth factors for immune and inflammatory cells) in SSCT (sub-synovial connective tissue) in CTS patients. Additionally, SSCT fibrosis is also marked by increased activation of canonical TGF-β second messenger Smads, increased expression of downstream fibrotic mediators such as connective tissue growth factor (CTGF), increased production of collagen type I, II, III and IV, and decreased expression of matrix metalloproteinases. Anti-fibrotic such as anti-TGF treatment may prove beneficial in idiopathic patients, however, anti VEGF therapy can be successful in the diabetic CTS patients. The present review describes the clinical evidence stating the role of different growth factors in the development of fibrosis in idiopathic and diabetes induced CTS.

KCNQ2/3/5 channels in dorsal root ganglion neurons can be therapeutic targets of neuropathic pain in diabetic rats

Background

Diabetic neuropathic pain is poorly controlled by analgesics, and the precise molecular mechanisms underlying hyperalgesia remain unclear. The KCNQ2/3/5 channels expressed in dorsal root ganglion neurons are important in pain transmission. The expression and activity of KCNQ2/3/5 channels in dorsal root ganglion neurons in rats with diabetic neuropathic pain were investigated in this study.

Methods

The mRNA levels of KCNQ2/3/5 channels were analyzed by real-time polymerase chain reaction. The protein levels of KCNQ2/3/5 channels were evaluated by Western blot assay. KCNQ2/3/5 channel expression in situ in dorsal root ganglion neurons was detected by double fluorescent labeling technique. M current (I_M) density and neuronal excitability were determined by whole-cell voltage and current clamp recordings. Mechanical allodynia and thermal hyperalgesia were assessed by von Frey filaments and plantar analgesia tester, respectively.

Results

The mRNA and protein levels of KCNQ2/3/5 channels significantly decreased, followed by the reduction of I_M density and elevation of neuronal excitability of dorsal root ganglion neurons from diabetic rats. Activation of KCNQ channels with retigabine reduced the hyperexcitability and inhibition of KCNQ channels with XE991 enhanced the hyperexcitability. Administration of retigabine alleviated both mechanical allodynia and thermal hyperalgesia, while XE991 augmented both mechanical allodynia and thermal hyperalgesia in diabetic neuropathic pain in rats.

Conclusion

The findings elucidate the mechanisms by which downregulation of the expression and reduction of the activity of KCNQ2/3/5 channels in diabetic rat dorsal root ganglion neurons contribute to neuronal hyperexcitability, which results in hyperalgesia. These data provide intriguing evidence that activation of KCNQ2/3/5 channels might be the potential new targets for alleviating diabetic neuropathic pain symptoms.

Risk prediction and impaired tactile sensory perception among cancer patients during chemotherapy

Objectives:

to estimate the prevalence of impaired tactile sensory perception, identify risk factors, and establish a risk prediction model among adult patients receiving antineoplastic chemotherapy.

Method:

historical cohort study based on information obtained from the medical files of 127 patients cared for in the cancer unit of a private hospital in a city in Minas Gerais, Brazil. Data were analyzed using descriptive and bivariate statistics, with survival and multivariate analysis by Cox regression.

Results:

57% of the 127 patients included in the study developed impaired tactile sensory perception. The independent variables that caused significant impact, together with time elapsed from the beginning of treatment up to the onset of the condition, were: bone, hepatic and regional lymph node metastases; alcoholism; palliative chemotherapy; and discomfort in lower limbs.

Conclusion:

impaired tactile sensory perception was common among adult patients during chemotherapy, indicating the need to implement interventions designed for early identification and treatment of this condition.

The role of miR-190a-5p contributes to diabetic neuropathic pain via targeting SLC17A6

Introduction

MicroRNAs play a key role in neuropathic pain. In a previous study, miR-190a-5p was significantly downregulated in diabetic neuropathic pain (DNP). However, the role and pathological mechanism of miR-190a-5p in DNP still remain unclear.

Materials and methods

DNP model was established. The paw withdrawal thresholds were measured to assess the mechanical nociceptive response. Dual-luciferase reporter assay was used to confirm the target gene of microRNA. The expressions of microRNA, gene, and protein were detected by the quantitative real-time polymerase chain reaction or Western blot. The levels of IL-1β and IL-6 were detected with the enzyme-linked immuno sorbent assay.

Results

Compared with the control sample, the expression of miR-190a-5p was decreased and SLC17A6 was increased in the spinal tissue from those developing DNP. The bioinformatics and luciferase reporter assay demonstrated that SLC17A6 is a direct target of miR-190a-5p. Up-regulation of miR-190a-5p and inhibition of SLC17A6 could significantly weaken the painful behavior and reduce IL-1β and IL-6 level in DNP.

Conclusion

miR-190a-5p is involved in DNP via targeting SLC17A6, and miR-190a-5p and SLC17A6 may be the therapeutic targets of this disease.