Clinical features and electrodiagnosis of diabetic peripheral neuropathy in the dysvascular patient

Are herbal medicines alone or in combination for diabetic peripheral neuropathy more effective than methylcobalamin alone? A systematic review and meta-analysis

BACKGROUND AND PURPOSE

In Asian countries, herbal medicines have been used to treat diabetic peripheral neuropathy (DPN) as an adjunctive therapy. This review aims to assess the effectiveness and safety of herbal medicines for the treatment of DPN.

METHODS

A literature search was conducted on PubMed, Embase, CENTRAL, Scopus, CINAHL, CNKI, DBPIA, and OASIS for randomized controlled trials that evaluated the effects of herbal medicines on DPN. The oral methylcobalamin administered group was selected as the control. The primary outcome measure was nerve conduction velocity (NCV), and the secondary outcome measure was the total efficacy rate (TER). The methodological quality of the included studies was assessed using the Cochrane risk of bias tool. A meta-analysis was conducted using Review Manager 5.4.1 software.

RESULTS

Seventy-two RCTs with a total of 6260 patients were included. The meta-analysis showed that herbal medicine and co-administration of herbal medicine and methylcobalamin (CHM) treatment for DPN significantly increased the sensory nerve conduction velocity (SNCV) and motor nerve conduction velocity (MNCV) of the median and common peroneal nerves than methylcobalamin treatment alone. Herbal medicine and CHM treatment for DPN also significantly improved the TER compared to the control group. Herbal medicine and CHM treatment was found to be relatively safe.

CONCLUSION

Our study suggests that herbal medicine and CHM might be more effective than methylcobalamin alone in the management of DPN. Further rigorous studies should be conducted to make more definite conclusions.

Prevalence of peripheral neuropathy in patients with diabetes: A systematic review and meta-analysis

AIMS

We aimed to determine pooled prevalence of diabetic peripheral neuropathy (DPN) in patients with diabetes and to explore the impacts of research variables on prevalence estimates.

METHODS

A systematic search was performed in PubMed, EMBASE, The Cochrane Library and Scopus from onset up to July 2018 to identify articles investigating the prevalence of DPN. Random-effects models were used to calculate the pooled prevalence of DPN. The heterogeneity of the study was estimated with the I² statistic. The publication bias was described by Egger's test and funnel plot.

RESULTS

A total of 29 studies with a total of 50,112 participants were included in this meta-analysis. The results showed that the pooled prevalence of DPN was 30% (95% confidence interval, CI 25-34%). The pooled prevalence of DPN among patients with type 2 diabetes mellitus was higher than patients with type 1 diabetes mellitus (31.5%, 95% CI 24.4-38.6% vs 17.5%, 95% CI 4.8-30.2%). The pooled prevalence of DPN of studies involving a mixed type of diabetes mellitus was 24.8% (95% CI 13.1-36.5%, I²=99.1%).

CONCLUSIONS

Medical staff should strengthen the evaluation and diagnosis of DPN. Moreover, they need to teach diabetic patients how to prevent this complication.

L-carnitine ameliorates peripheral neuropathy in diabetic mice with a corresponding increase in insulin‑like growth factor‑1 level

Diabetic peripheral neuropathy (DPN) is one of the common complications in diabetes, affecting more than half of patients with diabetes. L‑carnitine (LC) was recently demonstrated to serve a positive role in ameliorating DPN. Therefore, the aim of the present study was to investigate the underlying mechanisms of LC in ameliorating DPN. Male Kunming mice were randomly assigned into five groups, including the control group, diabetes mellitus group, pre‑treatment group, treatment group and post‑treatment group. Type 2 diabetes was induced in mice using a combination of high‑fat diet and streptozotocin injection. Subsequently, peripheral neuropathy was measured and the levels of LC, insulin and insulin‑like growth factor‑1 (IGF‑1) were detected. When diabetic mice were treated with LC, the levels of IGF‑1 in the plasma and pancreas were increased. In addition, hyperalgesia, as determined by the tail‑flick test as well as food intake, body weight and blood glucose levels were decreased. An amelioration of demyelination, axonal atrophy and mitochondria swelling in the nerve fibres of diabetic mice was also observed. The present study demonstrated that LC ameliorated peripheral neuropathy in type 2 diabetic mice and the effect of LC may in part be mediated by an increase in local and circulatory IGF‑1 levels.

A curcumin derivative J147 ameliorates diabetic peripheral neuropathy in streptozotocin (STZ)-induced DPN rat models through negative regulation AMPK on TRPA1

PURPOSE

To investigate the specific molecular mechanisms and effects of curcumin derivative J147 on diabetic peripheral neuropathy (DPN).

METHODS

We constructed streptozotocin (STZ)-induced DPN rat models to detected mechanical withdrawal threshold (MWT) in vivo using Von Frey filaments. In vitro, we measured cell viability and apoptosis, adenosine 5'-monophosphate-activated protein kinase (AMPK) and transient receptor potential A1 (TRPA1) expression using MTT, flow cytometry, qRT-PCR and western blot. Then, TRPA1 expression level and calcium reaction level were assessed in agonist AICAR treated RSC96cells.

RESULTS

The results showed that J147reduced MWT in vivo, increased the mRNA and protein level of AMPK, reduced TRPA1 expression and calcium reaction level in AITCR treated RSC96 cells, and had no obvious effect on cell viability and apoptosis. Besides, AMPK negative regulated TRPA1 expression in RSC96 cells.

CONCLUSIONS

J147 could ameliorate DPN via negative regulation AMPK on TRPA1 in vivo and in vitro. A curcumin derivative J147might be a new therapeutic potential for the treatment of DPN.

Efficacy and safety of prostaglandin E1 plus lipoic acid combination therapy versus monotherapy for patients with diabetic peripheral neuropathy

The aim of this report was to evaluate the efficacy and safety of prostaglandin E1 (PGE1) plus lipoic acid (LA) for the treatment of diabetic peripheral neuropathy (DPN) compared with that of PGE1 or LA monotherapy. Randomized controlled trials (RCT) published up to 3 August 2014 were reviewed. A random or fixed effect model was used to analyze outcomes expressed as risk ratios (RR) or mean difference (MD) with a 95% confidence interval (CI). I(2) statistic was used to assess heterogeneity. Subgroup and sensitivity analyses were performed. The outcomes measured were as follows: clinical efficacy, median motor nerve conduction velocity (MNCV), median sensory nerve conduction velocity (SNCV), peroneal MNCV, peroneal SNCV and adverse effects. Thirty-one RCT with 2676 participants were included. Clinical efficacy of PGE1+LA combination therapy was significantly better than monotherapy (p<0.00001, RR=1.32, 95% CI 1.26 to 1.38). Compared with monotherapy, PGE1+LA combination therapy led to significant improvements in median MNCV (p<0.00001, MD=4.69, 95% CI 3.16 to 6.23), median SNCV (p<0.00001, MD=5.46, 95% CI 4.04 to 6.88), peroneal MNCV (p<0.00001, MD=5.19, 95% CI 3.71 to 6.67) and peroneal SNCV (p<0.00001, MD=5.50, 95% CI 3.30 to 7.70). There were no serious adverse events associated with drug intervention. PGE1+LA combination therapy is superior to PGE1 or LA monotherapy for improvement of neuropathic symptoms and nerve conduction velocities in patients with DPN. These findings should be further validated by larger well-designed and high-quality RCT.

Chinese herbal medicine for diabetic peripheral neuropathy: an updated meta-analysis of 10 high-quality randomized controlled studies

BACKGROUND

Diabetic peripheral neuropathy (DPN) is very common in people with diabetes. Chinese herbal medicine (CHM) therapy has been developed for DPN empirically over the years. The aim of this systematic review and meta-analysis was to assess the efficacy and safety of CHMs for patients suffering from DPN.

METHODS

We performed a meta-analysis of randomized-controlled clinical trials (RCTs) evaluating the efficacy and safety of CHM on DPN. Six databases were searched up to November 2012. The primary outcome measures were the absolute values or changing of motor or sensory nerve conduction velocity (NCV), and the secondary outcome measurements were clinical symptoms improvements and adverse events. The methodological quality was assessed by Jadad scale and the twelve criteria recommended by the Cochrane Back Review Group.

RESULTS

One hundred and sixty-three studies claimed RCTs. Ten studies with 653 individuals were further identified based on the Jadad score ≥ 3. These 10 studies were all of high methodological quality with a low risk of bias. Meta-analysis showed the effects of NCV favoring CHMs when compared with western conventional medicines (WCM) (P<0.05 or P<0.01). There is a significant difference in the total efficacy rate between the two groups (P<0.001). Adverse effects were reported in all of the ten included studies, and well tolerated in all patients with DPN.

CONCLUSION

Despite of the apparently positive findings and low risk of bias, it is premature to conclude the efficacy of CHMs for the treatment of DPN because of the high clinical heterogeneity and small sample sizes of the included studies. However, CHM therapy was safe for DPN. Further standardized preparation, large sample-size and rigorously designed RCTs are required.

Beneficial effect of TNF-α inhibition on diabetic peripheral neuropathy

Background

Tumor necrosis factor-α (TNF-α) is an important inflammatory factor produced by activated macrophages and monocytes and plays an important role in the pathogenesis of diabetic peripheral neuropathy (DPN). To evaluate the effect of TNF-α signaling suppression and the potential of TNF-α in the treatment of DPN, a recombinant human TNF-α receptor-antibody fusion protein (rhTNFR:Fc) was used. We focused on the pathophysiology of the sciatic nerve and examined the expression of myelin basic protein (MBP) under DPN status with or without TNF-α inhibition.

Methods

The DPN rat model was generated by intraperitoneal injection of streptozotocin and by feeding with a high-fat, high-sugar diet. The nerve conduction velocity (NCV) in sciatic nerve of rat was monitored over a period of four weeks. The histopathological changes in nerve tissue were examined through traditional tissue histology and ultrastructure transmission electron microscopy (TEM). The expression of MBP was examined through western blot analysis.

Results

The DPN induced rats showed significant signs of nerve damage including lower NCV, demyelination of nerve fibers, disorganization of lamellar and axonal structures, and decreased expression of MBP in the nerve tissue. The inhibition of TNF-α in the DPN rats resulted in a significant recovery from those symptoms compared to the DPN rats.

Conclusions

Our study demonstrates that TNF-α plays a key role in the pathogenesis of DPN and its inhibition by rhTNFR:Fc can prove to be a useful therapeutic strategy for the treatment of and/or prevention from DPN symptoms.

Chinese herbal medicine in treatment of diabetic peripheral neuropathy: a systematic review and meta-analysis

AIM OF STUDY

There are multimodal and multidisciplinary approaches to treat diabetic peripheral neuropathy (DPN). However, the intractable adverse effects limited their widespread use. Chinese herbal medicine (CHM) is increasingly used for the treatment of DPN. The aim of this study was to review existing evidence on the effectiveness of CHM for the treatment of DPN.

MATERIALS AND METHODS

Searches were performed with Medline, Embase, Cochrane Central Register of Controlled Trials, CNKI, CBM and Wangfan databases. Controlled trials comparing CHM with other medicine for the treatment of DPN were analyzed.

RESULTS

Eighteen trials met the inclusion criteria. All trials used vitamin B12 and/or B1 as control. Clinical therapeutic effect, divided by three grades including marked effective, effective and ineffective according to the improved degree of subjective symptom, tendon reflex, and nerve conduction velocity, was the only end point reported in all trials, and thus evaluated. The results showed CHM treatment was associated with a superiority in marked effective (odds ratio [OR], 2.40; 95% confidence interval [CI]: 0.94 to 2.97; p<0.001), and effective (OR, 1.39; 95% CI: 1.16 to 1.67; p<0.001). Patients who received CHM treatment was associated with a less likely to report ineffective (OR, 0.26; 95% CI: 0.21 to 0.33, p<0.001). No adverse events were reported in any of the included trials.

CONCLUSIONS

According to the pooled results of our study and the poor quality of the included trials, it might be uncertainty that there was a superiority of CHM for treating DPN. More rigorous controlled trials are required to substantiate or refute these early findings.

In situ transverse elasticity and blood perfusion change of sciatic nerves in normal and diabetic rats

BACKGROUND

Diabetic neuropathy is the most pervasive complication of diabetes mellitus and its etiopathology is not completely elucidated. The existing literature focuses on the histological and structural changes as well as the longitudinal mechanical properties of nerves. The main objective of this study is to investigate the in situ transverse biomechanical properties and changes of microcirculation of sciatic nerves in diabetic and normal control rats.

METHODS

Quasi-static circular compression experiments were conducted on sciatic nerves of six normal and six diabetic Wistar rats. Local blood perfusion during the compression was also measured by laser Doppler flowmetry. The compressive stress and strain were estimated, in order to calculate the apparent Young's modulus. The impact of diabetes on peripheral nerves was examined by analyzing the transverse elasticity and microcirculation changes.

FINDINGS

The mean transverse apparent Young's modulus of the sciatic nerves in diabetic rats was 210.7 kPa, which was nearly two times greater than that of normal controls (116.3 kPa). The pressure threshold that blood perfusion started to decrease in diabetic rats (24.1 mm Hg) was smaller than in the normal controls (47.1 mm Hg).

INTERPRETATION

These results suggest that the sciatic nerve was stiffer in the diabetic rats. The structural changes in microvessels might lead to earlier decrease of blood perfusion in diabetic nerves under radial compression. These results provide information about the biomechanical and microcirculation changes of peripheral nerves inflicted by diabetes and may also serve as a reference for clinical nerve repair and regeneration for patients with diabetic neuropathy.