Causal relationships between circulating inflammatory cytokines and diabetic neuropathy: A Mendelian Randomization study

BACKGROUND

Emerging evidence suggests systemic inflammation as a critical mechanism underlying diabetic neuropathy. This study aimed to investigate the causal relationship between 41 circulating inflammatory cytokines and diabetic neuropathy.

METHODS

Summary statistics from previous Genome-Wide Association studies (GWAS) included pooled data on 41 inflammatory cytokines and diabetic neuropathy. A two-sample Mendelian Randomization (MR) design was employed, and the robustness of the results was confirmed through comprehensive sensitivity analyses.

RESULTS

Our study reveals that the linkage between increased levels of IFN_G (OR = 1.31, 95 %CI: 1.06-1.63; P = 0.014), IP_10 (OR = 1.18, 95 %CI: 1.01-1.36; P = 0.031) and an elevated risk of diabetic neuropathy. Conversely, higher levels of IL_9 (OR = 0.86, 95 %CI: 0.75-1.00; P = 0.048) and SCF (OR = 0.83, 95 %CI: 0.73-0.94; P = 0.003) are genetically determined to protect against diabetic neuropathy. Furthermore, the sensitivity analysis affirmed the results' dependability, revealing no heterogeneity or pleiotropy.

CONCLUSION

Our MR research identified four upstream inflammatory cytokines implicated in diabetic neuropathy. Overall, these findings suggest the potential for innovative therapeutic strategies. Further large-scale cohort studies are required for validation.

Improvement of diabetes-induced spinal cord axon injury with taurine via nerve growth factor-dependent Akt/mTOR pathway

Diabetic neuropathy (DN) is a common neurological complication caused by diabetes mellitus (DM). Axonal degeneration is generally accepted to be the major pathological change in peripheral DN. Taurine has been evidenced to be neuroprotective in various aspects, but its effect on spinal cord axon injury (SCAI) in DN remains barely reported. This study showed that taurine significantly ameliorated axonal damage of spinal cord (SC), based on morphological and functional analyses, in a rat model of DN induced by streptozotocin (STZ). Taurine was also found to induce neurite outgrowth in cultured cerebral cortex neurons with high glucose exposure. Moreover, taurine up-regulated the expression of nerve growth factor (NGF) and neurite outgrowth relative protein GAP-43 in rat DN model and cultured cortical neurons/VSC4.1 cells. Besides, taurine increased the activating phosphorylation signals of TrkA, Akt, and mTOR. Mechanistically, the neuroprotection by taurine was related to the NGF-pAKT-mTOR axis, because either NGF-neutralizing antibody or Akt or mTOR inhibitors was found to attenuate its beneficial effects. Together, our results demonstrated that taurine promotes spinal cord axon repair in a model of SCAI in STZ-induced diabetic rats, mechanistically associating with the NGF-dependent activation of Akt/mTOR pathway.

Therapeutic Effect of Schwann Cell-Like Cells Differentiated from Human Tonsil-Derived Mesenchymal Stem Cells on Diabetic Neuropathy in db/db Mice

BACKGROUND

Diabetic neuropathy (DN) is the most common complication of diabetes, and approximately 50% of patients with this disease suffer from peripheral neuropathy. Nerve fiber loss in DN occurs due to myelin defects and is characterized by symptoms of impaired nerve function. Schwann cells (SCs) are the main support cells of the peripheral nervous system and play important roles in several pathways contributing to the pathogenesis and development of DN. We previously reported that human tonsil-derived mesenchymal stem cells differentiated into SCs (TMSC-SCs), named neuronal regeneration-promoting cells (NRPCs), which cells promoted nerve regeneration in animal models with peripheral nerve injury or hereditary peripheral neuropathy.

METHODS

In this study, NRPCs were injected into the thigh muscles of BKS-db/db mice, a commonly used type 2 diabetes model, and monitored for 26 weeks. Von Frey test, sensory nerve conduction study, and staining of sural nerve, hind foot pad, dorsal root ganglia (DRG) were performed after NRPCs treatment.

RESULTS

Von Frey test results showed that the NRPC treatment group (NRPC group) showed faster responses to less force than the vehicle group. Additionally, remyelination of sural nerve fibers also increased in the NRPC group. After NRPCs treatment, an improvement in response to external stimuli and pain sensation was expected through increased expression of PGP9.5 in the sole and TRPV1 in the DRG.

CONCLUSION

The NRPCs treatment may alleviate DN through the remyelination and the recovery of sensory neurons, could provide a better life for patients suffering from complications of this disease.

Gastrointestinal symptom burden in diabetic autonomic and peripheral neuropathy - A Danes cohort study

OBJECTIVE

We investigated associations between gastrointestinal symptoms - evaluated as a combined weighted symptom score (CWSS) - Diabetic autonomic neuropathy (DAN), and distal symmetrical polyneuropathy (DSPN) in type 1 and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Cross-sectional study in a tertiary outpatient clinic. CWSS was calculated based on questionnaires: gastroparesis composite symptom index (GCSI) and gastrointestinal symptom rating score (GSRS). DAN and DSPN were addressed using the composite autonomic symptom score 31 (COMPASS-31) questionnaire, cardiac autonomic reflex tests (CARTs), electrochemical skin conductance (ESC), vibration perception threshold (VPT), Michigan Neuropathy Screening Instrument (MNSI), pain- and thermal sensation. Analyses were adjusted for age, sex, diabetes duration, smoking, LDL-cholesterol, HbA1C and systolic blood pressure. Type 1 and type 2 diabetes were evaluated separately.

RESULTS

We included 566 with type 1 diabetes and 377 with type 2 diabetes. Mean ± SD age was 58 ± 15 years and 565 (59.9 %) were women. A high CWSS was present in 143 (25 %) with type 1 and 142 (38 %) with type 2 diabetes. The odds of DAN by COMPASS-31 (p < 0.001) were higher in the high score group. For type 1 diabetes, odds of cardiac autonomic neuropathy were higher in the high CWSS group. The odds of DSPN by VPT and MNSI in type 1 diabetes, and by ESC, VPT and pain sensation in type 2 diabetes were higher in the high CWSS group.

CONCLUSIONS

A high symptom score was associated with neuropathy by COMPASS-31 and vibration perception. Gastrointestinal symptom burden associated inconsistently with other neuropathy tests between diabetes types.

Efficacy of electro-acupuncture versus sham acupuncture for diabetic peripheral neuropathy: study protocol for a three-armed randomised controlled trial

INTRODUCTION

Specific treatment for diabetic peripheral neuropathy (DPN) is still lacking, and acupuncture may relieve the symptoms. We intend to investigate the efficacy and safety of electro-acupuncture (EA) in alleviating symptoms associated with DPN in diabetes.

METHODS AND ANALYSIS

This multicentre, three-armed, participant- and assessor-blind, randomised, sham-controlled trial will recruit 240 eligible participants from four hospitals in China and will randomly assign (1:1:1) them to EA, sham acupuncture (SA) or usual care (UC) group. Participants in the EA and SA groups willl receive either 24-session EA or SA treatment over 8 weeks, followed by an 8-week follow-up period, while participants in the UC group will be followed up for 16 weeks. The primary outcome of this trial is the change in DPN symptoms from baseline to week 8, as rated by using the Total Symptom Score. The scale assesses four symptoms: pain, burning, paraesthesia and numbness, by evaluating the frequency and severity of each. All results will be analysed with the intention-to-treat population.

ETHICS AND DISSEMINATION

The protocol has been approved by the Ethics Committee of the Beijing University of Chinese Medicine (Identifier: 2022BZYLL0509). Every participant will be informed of detailed information about the study before signing informed consent. The results of this trial will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2200061408.

Micro-vascular complications of post-transplant diabetes mellitus in renal transplant recipients- an observational study

INTRODUCTION

The incidence of post-transplant diabetes mellitus (PTDM) ranges from 2.5% to 20% in kidney transplant recipients. Diabetic retinopathy (DR), diabetic kidney disease (DKD), and distal symmetric polyneuropathy (DSPN) are the microvascular complications frequently seen in both type 1 and 2 diabetes mellitus (DM). However, the data regarding these complications in patients with PTDM is lacking.

METHOD

A retrospective and prospective observational study of PTDM conducted at a tertiary care hospital from November 2018 to December 2020. 115 kidney transplant recipients who had PTDM of ≥5 years duration were included and analysed.

RESULTS

The mean duration of PTDM was 8.8 ± 3.0 years, and the mean of all available HbA1c values was 7.0 ± 0.9%. while none of the patients had evidence of diabetic retinopathy on direct ophthalmoscopy, 37.4% of patients (n = 43) had DSPN and this was associated with the duration of PTDM and age. The mean estimated glomerular filtration rate (eGFR) was 59.24 ± 21.82 ml/min/1.73m2, and patients had a median proteinuria of 620 mg/day (IQR 1290). Out of 115 patients, 20% of them (n = 23) underwent graft kidney biopsy, and 10 biopsies were diagnosed as de-novo DKD. Patients with biopsy proven DKD had a mean PTDM duration of 143.3 ± 52.4 months; a mean HbA1c level of 7.9 ± 1.3%; a mean eGFR of 44.8 ± 21.8 ml/min; and a median proteinuria of 2653 mg (IQR 2758). An additional analysis of all 23 biopsied patients showed that HbA1c level and degree of proteinuria were significantly associated with de-novo DKD.

CONCLUSION

PTDM in transplant patients had milder microvascular complications than usually expected in Type 1/2 diabetes in non-transplant patients. DR was not strongly associated with DKD in PTDM patients. Furthermore, de-novo DKD development was associated with poor glycaemic control and increased proteinuria.

Attenuation of Streptozotocin-Induced Diabetic Neuropathic Allodynia by Flavone Derivative Through Modulation of GABA-ergic Mechanisms and Endogenous Biomarkers

Diabetic neuropathic pain is one of the most devasting disorders of peripheral nervous system. The loss of GABAergic inhibition is associated with the development of painful diabetic neuropathy. The current study evaluated the potential of 3-Hydroxy-2-methoxy-6-methyl flavone (3-OH-2'MeO6MF), to ameliorate peripheral neuropathic pain using an STZ-induced hyperglycemia rat model. The pain threshold was assessed by tail flick, cold, mechanical allodynia, and formalin test on days 0, 14, 21, and 28 after STZ administration accompanied by evaluation of several biochemical parameters. Administration of 3-OH-2'-MeO6MF (1,10, 30, and 100 mg/kg, i.p) significantly enhanced the tail withdrawal threshold in tail-flick and tail cold allodynia tests. 3-OH-2'-MeO6MF also increased the paw withdrawal threshold in mechanical allodynia and decreased paw licking time in the formalin test. Additionally, 3-OH-2'-MeO6MF also attenuated the increase in concentrations of myeloperoxidase (MPO), thiobarbituric acid reactive substances (TBARS), nitrite, TNF-α, and IL 6 along with increases in glutathione (GSH). Pretreatment of pentylenetetrazole (PTZ) (40 mg/kg, i.p.) abolished the antinociceptive effect of 3-OH-2'-MeO6MF in mechanical allodynia. Besides, the STZ-induced alterations in the GABA concentration and GABA transaminase activity attenuated by 3-OH-2'-MeO6MF treatment suggest GABAergic mechanisms. Molecular docking also authenticates the involvement of α2β2γ2L GABA-A receptors and GABA-T enzyme in the antinociceptive activities of 3-OH-2'-MeO6MF.

Therapeutic potential of orally applied KB-R7943 in streptozotocin-induced neuropathy in rats

Both peripheral neuropathy and depression can be viewed as neurodegeneration's consequences of diabetes, at least in part coexisting with or resulting from sodium-calcium dysbalance. This study aims to assess the therapeutic potential of the orally applied reverse-mode inhibitor of the sodium-calcium exchanger (NCX) KB-R7943 in the streptozotocin (STZ) diabetes model in rats. A pilot pharmacokinetic (PK) study with high-performance liquid chromatography with high-resolution tandem mass spectrometric detection revealed higher drug exposure (AUC), lower volume of distribution (Vd) and clearance (Cl), and faster decline of the plasma concentration (ƛ) in rats with diabetes vs. controls. Brain and heart accumulation and urinary excretion of the unmetabolized KB-R7943 at least 24 h were also demonstrated in all rats. However, heart and hippocampus KB-R7943 penetration (AUCtissue/AUCplasma) was higher in controls vs. diabetic rats. The development of thermal, mechanical, and chemical-induced allodynia was assessed with the Cold plate test (CPT), Randall-Stiletto (R-S) test, and 0.5% formalin test (FT). Amitriptyline 10 mg/kg, KB-R7943 5 mg/kg, or 10 mg/kg p.o once daily was applied from the 28th to the 49th day. The body weight, coat status, CPT, R-S, and FT were evaluated on days (-5), 0, and 42. On day 41, a forced swim test and 24-h spontaneous physical activities were assessed. The chronic treatment effects were calculated as % of the maximum. A dose-depended amelioration of neuropathic and depression-like effects was demonstrated. The oral application of KB-R7943 for potentially treating neurodegenerative consequences of diabetes merits further studies. The brain, heart, and kidneys are essential contributors to the PKs of this drug, and their safety involvement needs to be further characterized.

Metformin improves diabetic neuropathy by reducing inflammation through up-regulating the expression of miR-146a and suppressing oxidative stress

PURPOSE

Diabetic neuropathy (DN) is a notable complication of diabetes mellitus. The potential involvement of miR-146a in DN regulation is presently under investigation. Metformin, a commonly prescribed medication for diabetes, is the primary therapeutic intervention. This study aimed to unveil the potential protective effects of metformin on diabetic neuropathy and explore the mechanisms underlying its action.

METHOD

Six-weeks male Sprague Dawley rats (n = 40) were randomly divided into 5 groups. The rat model of diabetic neuropathy (DN) was established by administering streptozotocin (STZ). To investigate the effects on the sciatic nerve and resident Schwann cells (RSCs), metformin and miR-146a mimics were administered, and our research explored the potential underlying mechanism.

RESULT

The sciatic nerve samples obtained from diabetic rats exhibited noticeable morphological damage, accompanied by decreased miR-146a expression (2.61 ± 0.11 vs 5.0 ± 0.3, p < 0.01) and increased inflammation levels (p65: 1.89 ± 0.04 vs 0.82 ± 0.05, p < 0.01; TNF-α: 0.93 ± 0.03 vs 0.33 ± 0.03, p < 0.01). Notably, the administration of metformin effectively ameliorated the structural alterations in the sciatic nerve by suppressing the inflammatory pathway (p65: 1.15 ± 0.05 vs 1.89 ± 0.04, p < 0.01; TNF-α: 0.67 ± 0.04 vs 0.93 ± 0.03, p < 0.01) and reducing oxidative stress (NO: 0.062 ± 0.004 vs 0.154 ± 0.004umol/mg, p < 0.01; SOD: 3.08 ± 0.09 vs 2.46 ± 0.09 U/mg, p < 0.01). The miR-146a mimics intervention group exhibited comparable findings.

CONCLUSION

This study's findings implied that metformin can potentially mitigate diabetic neuropathy in rats through the modulation of miR-146a expression.

A muscarinic receptor antagonist reverses multiple indices of diabetic peripheral neuropathy: preclinical and clinical studies using oxybutynin

Preclinical studies indicate that diverse muscarinic receptor antagonists, acting via the M1 sub-type, promote neuritogenesis from sensory neurons in vitro and prevent and/or reverse both structural and functional indices of neuropathy in rodent models of diabetes. We sought to translate this as a potential therapeutic approach against structural and functional indices of diabetic neuropathy using oxybutynin, a muscarinic antagonist approved for clinical use against overactive bladder. Studies were performed using sensory neurons maintained in vitro, rodent models of type 1 or type 2 diabetes and human subjects with type 2 diabetes and confirmed neuropathy. Oxybutynin promoted significant neurite outgrowth in sensory neuron cultures derived from adult normal rats and STZ-diabetic mice, with maximal efficacy in the 1-100 nmol/l range. This was accompanied by a significantly enhanced mitochondrial energetic profile as reflected by increased basal and maximal respiration and spare respiratory capacity. Systemic (3-10 mg/kg/day s.c.) and topical (3% gel daily) oxybutynin reversed paw heat hypoalgesia in the STZ and db/db mouse models of diabetes and reversed paw tactile allodynia in STZ-diabetic rats. Loss of nerve profiles in the skin and cornea of db/db mice was also prevented by daily topical delivery of 3% oxybutynin for 8 weeks. A randomized, double-blind, placebo-controlled interventional trial was performed in subjects with type 2 diabetes and established peripheral neuropathy. Subjects received daily topical treatment with 3% oxybutynin gel or placebo for 6 months. The a priori designated primary endpoint, significant change in intra-epidermal nerve fibre density (IENFD) in skin biopsies taken before and after 20 weeks of treatments, was met by oxybutynin but not placebo. Secondary endpoints showing significant improvement with oxybutynin treatment included scores on clinical neuropathy, pain and quality of life scales. This proof-of-concept study indicates that muscarinic antagonists suitable for long-term use may offer a novel therapeutic opportunity for treatment of diabetic neuropathy. Trial registry number: NCT03050827.

How have services for diabetes, eye, hearing and foot health been integrated for adults? Protocol for a scoping review

INTRODUCTION

The global population is ageing, and by 2050, there will be almost 2.1 billion people over the age of 60 years. This ageing population means conditions such as diabetes are on the increase, as well as other conditions associated with ageing (and/or diabetes), including those that cause vision impairment, hearing impairment or foot problems. The aim of this scoping review is to identify the extent of the literature describing integration of services for adults of two or more of diabetes, eye, hearing or foot services.

METHODS AND ANALYSIS

The main database searches are of Medline and Embase, conducted by an information specialist, without language restrictions, for studies published from 1 January 2000 describing the integration of services for two or more of diabetes, eye, hearing and foot health in the private or public sector and at the primary or secondary level of care, primarily targeted to adults aged ≥40 years. A grey literature search will focus on websites of key organisations. Reference lists of all included articles will be reviewed to identify further studies. Screening and data extraction will be undertaken by two reviewers independently and any discrepancies will be resolved by discussion. We will use tables, maps and text to summarise the included studies and findings, including where studies were undertaken, which services tended to be integrated, in which sector and level of the health system, targeting which population groups and whether they were considered effective.

ETHICS AND DISSEMINATION

As our review will be based on published data, ethical approval will not be sought. This review is part of a project in Aotearoa New Zealand that aims to improve access to services for adults with diabetes or eye, hearing or foot conditions. The findings will be published in a peer-reviewed journal and presented at relevant conferences.

Skin keratinocyte-derived SIRT1 and BDNF modulate mechanical allodynia in mouse models of diabetic neuropathy

Diabetic neuropathy is a debilitating disorder characterized by spontaneous and mechanical pain. The role of skin mechanoreceptors in the development of mechanical pain (allodynia) is unclear. We discovered that mice with diabetic neuropathy had decreased sirtuin 1 (SIRT1) deacetylase activity in foot skin, leading to reduced expression of brain-derived neurotrophic factor (BDNF) and subsequent loss of innervation in Meissner corpuscles, a mechanoreceptor expressing the BDNF receptor TrkB. When SIRT1 was depleted from skin, the mechanical allodynia worsened in diabetic neuropathy mice, likely due to retrograde degeneration of the Meissner-corpuscle innervating Aβ axons and aberrant formation of Meissner corpuscles which may have increased the mechanosensitivity. The same phenomenon was also noted in skin BDNF knockout mice. Furthermore, overexpression of SIRT1 in skin induced Meissner corpuscle reinnervation and regeneration, resulting in significant improvement of diabetic mechanical allodynia. Overall, the findings suggested that skin-derived SIRT1 and BDNF function in the same pathway in skin sensory apparatus regeneration and highlighted the potential of developing topical SIRT1-activating compounds as a novel treatment for diabetic mechanical allodynia.

Association of Small Fiber Function with Microvascular Perfusion of Peripheral Nerves in Patients with Type 2 Diabetes : Study using Quantitative Sensory Testing and Magnetic Resonance Neurography

INTRODUCTION/AIMS

Diabetic small fiber neuropathy (SFN) is caused by damage to thinly myelinated A‑fibers (δ) and unmyelinated C‑fibers. This study aimed to assess associations between quantitative sensory testing (QST) and parameters of peripheral nerve perfusion obtained from dynamic contrast enhanced (DCE) magnetic resonance neurography (MRN) in type 2 diabetes patients with and without SFN.

METHODS

A total of 18 patients with type 2 diabetes (T2D, 8 with SFN, 10 without SFN) and 10 healthy controls (HC) took part in this cross-sectional single-center study and underwent QST of the right leg and DCE-MRN of the right thigh with subsequent calculation of the sciatic nerve constant of capillary permeability (Ktrans), extravascular extracellular volume fraction (Ve), and plasma volume fraction (Vp).

RESULTS

The Ktrans (HC 0.031 min-1 ± 0.009, T2D 0.043 min-1 ± 0.015; p = 0.033) and Ve (HC 1.2% ± 1.5, T2D: 4.1% ± 5.1; p = 0.027) were lower in T2D patients compared to controls. In T2D patients, compound z‑scores of thermal and mechanical detection correlated with Ktrans (r = 0.73; p = 0.001, and r = 0.57; p = 0.018, respectively) and Ve (r = 0.67; p = 0.002, and r = 0.69; p = 0.003, respectively). Compound z‑scores of thermal pain and Vp (r = -0.57; p = 0.015) correlated negatively.

DISCUSSION

The findings suggest that parameters of peripheral nerve microcirculation are related to different symptoms in SFN: A reduced capillary permeability may result in a loss of function related to insufficient nutritional supply, whereas increased capillary permeability may be accompanied by painful symptoms related to a gain of function.

Streptozotocin-Induced Diabetic Rats Showed a Differential Glycine Receptor Expression in the Spinal Cord: A GlyR Role in Diabetic Neuropathy

In the spinal cord, attenuation of the inhibitory action of glycine is related to an increase in both inflammatory and diabetic neuropathic pain; however, the glycine receptor involvement in diabetic neuropathy has not been reported. We determined the expression of the glycine receptor subunits (α1-α3 and β) in streptozotocin-induced diabetic Long-Evans rats by qPCR and Western blot. The total mRNA and protein expression (whole spinal cord homogenate) of the α1, α3, and β subunits did not change during diabetes; however, the α2 subunit mRNA, but not the protein, was overexpressed 45 days after diabetes induction. By contrast, the synaptic expression of the α1 and α2 subunits decreased in all the studied stages of diabetes, but that of the α3 subunit increased on day 45 after diabetes induction. Intradermal capsaicin produced higher paw-licking behavior in the streptozotocin-induced diabetic rats than in the control animals. In addition, the nocifensive response was higher at 45 days than at 20 days. During diabetes, the expression of the glycine receptor was altered in the spinal cord, which strongly suggests its involvement in diabetic neuropathy.

The effects of Garcinia kola and curcumin on the dorsal root ganglion of the diabetic rat after peripheral nerve transection injury

OBJECTIVE

To test the protective effects of Garcinia kola and curcumin on the ganglion tissues of diabetic rats following the use of autologous vein graft in peripheral nerve transection injury.

METHODS

The sciatic nerve on the right side was transected, and anastomosis was performed between the proximal and distal ends using an autologous vein graft. Curcumin and Garcinia kola seed extract were administered daily by oral gavage. The ganglion tissues were harvested after a 90-day waiting period. Sensory neurons in the dorsal root ganglion at the L4 and L5 levels were used for stereological evaluations. Mean sensory neuron numbers were analyzed using a stereological technique. The size of the light and dark neurons was also estimated, and ultrastructural and immunohistochemical evaluations were performed.

RESULTS

A statistically significant difference in sensory neuron numbers was observed between the groups with and without Garcinia kola and curcumin applications. The immunohistochemical results showed that the s-100 protein is expressed selectively between cell types.

CONCLUSION

The results of this study show that curcumin and Garicinia kola prevented sensory neuron loss in diabetic rats following transection injury to the sciatic nerve.

Shear wave elastography of tibial nerve in patients with diabetic peripheral neuropathy-A cross-sectional study

OBJECTIVE

To explore the role of shear wave elastography of the tibial nerve as a potential ultrasonographic method for the diagnosis of tibial neuropathy in patients with type 2 diabetes.

MATERIALS AND METHODS

This cross-sectional study included 50 subjects each in case (patients with diabetic tibial neuropathy diagnosed on the basis of clinical features and nerve conduction study) and control groups (non-diabetic non-neuropathic healthy volunteers). The exclusion criteria included the presence of type 1 diabetes, a known history of neuropathy from other causes except for type 2 diabetes, or a history of leg or ankle fracture. Cross-sectional area and shear wave velocity values of the tibial nerve were measured in both groups. Demographic details and body mass index were obtained in both groups and additionally, the duration of type 2 diabetes and HbA1c values in the case group were also noted. Wilcoxon Mann-Whitney U test was used to compare these variables in study groups. ROC curve analysis provided additional findings.

RESULTS

Tibial nerve stiffness was significantly higher in the case group (p-value < 0.001). The study groups did not significantly differ in the Cross-sectional area of the tibial nerve (p-value 0.57). The case group exhibited a higher frequency of loss of the fascicular pattern of the tibial nerve (40% vs 18%, p-value 0.027). Duration of diabetes mellitus and HbA1c values did not significantly affect Shear wave velocity values in the case group. At the cut-off value of Shear wave velocity of 3.13 m/s, sensitivity and specificity to diagnose diabetic peripheral neuropathy were 94% and 88% respectively.

CONCLUSION

Increased nerve stiffness is seen in patients with diabetic peripheral neuropathy. Shear wave elastography might prove as a novel noninvasive technology for screening/early diagnosis of diabetic peripheral neuropathy.

Neuromuscular electrical stimulation for the treatment of diabetic sensorimotor polyneuropathy: A prospective, cohort, proof-of-concept study

OBJECTIVE

To assess a potential efficacy signal, safety and feasibility of neuromuscular electrical stimulation (NMES) therapy as an adjunct to standard care in patients with diabetic sensorimotor polyneuropathy (DSPN).

METHODS

In this single-centre, prospective, cohort, proof-of-concept study, 25 patients with DSPN consented to at least one daily 30-minute NMES therapy session (Revitive® IX) for 10 weeks, with 20 patients completing the study. The primary outcome measure was nerve conductivity assessed using a nerve conduction study of the sural, superficial peroneal, common peroneal and tibial nerves at 10 weeks compared to baseline. Secondary outcomes included superficial femoral artery (SFA) haemodynamics during NMES therapy compared to rest and quality-of-life at 10 weeks compared to baseline.

RESULTS

At 10 weeks, there were significant increases in sural sensory nerve action potential amplitude and conduction velocity (p < 0.001), superficial peroneal sensory nerve action potential amplitude (p = 0.001) and conduction velocity (p = 0.002), common peroneal nerve conduction velocity (p = 0.004) and tibial nerve compound muscle action potential amplitude (p = 0.002) compared to baseline. SFA volume flow and time-averaged mean velocity significantly increased (p ≤ 0.003) during NMES compared to rest. Patient-reported Michigan Neuropathy Screening Instrument scores significantly decreased (p = 0.028) at 10 weeks compared to baseline. Three unrelated adverse events occurred, and 15 participants adhered to treatment.

CONCLUSIONS

NMES therapy as an adjunct to standard care for 10 weeks significantly increased lower limb nerve conductivity in patients with DSPN and may be beneficial in the treatment of DSPN.

Bruns Garland Syndrome as the first presentation of type 2 diabetes: two case reports and a practical approach to diagnosis

BACKGROUND

Diabetes is a global health problem causing a significant burden on the healthcare systems both due to the disease itself and associated complications. Diabetic radiculoplexus neuropathies or Bruns-Garland syndrome constitutes a rare form of microvascular complications, more commonly affecting the lumbosacral plexus and, very rarely, the cervical plexus. We describe two Sri Lankan males who presented with diabetic lumbosacral radiculoplexus neuropathy and diabetic cervical radiculoplexus neuropathy as the initial manifestation of diabetes.

CASE DESCRIPTION

Case 1: a 49-year-old Sri Lankan hotel chef presented with subacute painful weakness and wasting of the left upper arm for 3 months and weight loss. Left upper limb proximal muscles were wasted with diminished power and reflexes. A nerve conduction study showed comparative amplitude reduction. An electromyogram revealed positive sharp waves, frequent fibrillations, and high amplitude polyphasic motor unit potentials with reduced recruitment in proximal muscles of left upper limb. Case-2: a 47-year-old Sri Lankan carpenter presented with subacute progressive asymmetrical painful weakness and wasting of bilateral thighs for 5 months and weight loss. Lower limb proximal muscles were wasted with reduced power and knee jerks. The nerve conduction study was normal. The electromyogram was similar to case 1 involving both quadratus femoris muscles, which was more prominent on the left side. The work up for an underlying etiology revealed only elevated fasting blood glucose and HbA1c, suggesting a new diagnosis of diabetes associated with neurological symptoms. Patient 1 was diagnosed with diabetic cervical radiculoplexus neuropathy and patient 2 with diabetic lumbosacral radiculoplexus neuropathy. Both showed significant improvement following optimization of glycemic control together with symptomatic treatment and physiotherapy.

CONCLUSION

Diagnosis of diabetic radiculoplexus neuropathy requires a comprehensive workup to rule out other sinister pathologies. This case report has a dual importance; it describes diabetic radiculoplexus neuropathy as the very first manifestation of two previously healthy people, giving rise to a new diagnosis of diabetes and, at the same time, reporting on diabetic cervical radiculoplexus neuropathy, which is extremely rare and has never been previously reported in Sri Lanka.

Pramipexole protects against diabetic neuropathy: Effect on oxidative stress, TLR4/IRAK-1/TRAF-6/NF-κB and downstream inflammatory mediators

BACKGROUND

Diabetic neuropathy (DN) is a serious microvascular complication and a major cause of morbidity and mortality in diabetes mellitus. It is characterized by neurodegeneration of terminal sensory nerve fibers with subsequent pain, loss of sensation, and paresthesia, thus compromising the quality of life of diabetic patients. It is considered the leading cause of non-traumatic amputations worldwide, reflecting the insufficiency of current therapies. Pramipexole (PPX) is a dopamine receptor agonist used for the treatment of Parkinson's disease. The current study aims to investigate the potential neuroprotective effect of PPX in an experimental model of DN.

METHODS

Sprague Dawley rats were randomly assigned into five groups: normal control, Normal + PPX (1 mg/kg) group, STZ control, STZ + PPX (0.25 and 1 mg/kg/day for eight weeks). The neuroprotective effect of PPX in rats was evaluated in terms of sciatic nerve histological alterations, oxidative stress, and protein expression of TLR4/MyD88/IRAK-1/TRAF-6/NF-κB axis and downstream inflammatory mediators.

RESULTS

PPX administration ameliorated histopathological signs of neuronal inflammation and apoptosis. Additionally, PPX attenuated STZ-induced sciatic nerve oxidative stress and downregulated neural tissue expression of TLR4, MyD88, IRAK-1, TRAF-6, NF-κB and downstream mediators (TNF-α, IL-1β and ICAM-1).

CONCLUSION

Collectively, the current study sheds light on PPX as a potential protective medication to alleviate neuropathy progression in diabetic patients. PPX neuroprotective effect can be attributed to modulating TLR4/ MyD88/IRAK-1/TRAF-6/ NF-κB axis signaling in nerve tissues with subsequent attenuation of oxidative stress and inflammation.

A neuroprotective effect of pentoxifylline in rats with diabetic neuropathy: Mitigation of inflammatory and vascular alterations

BACKGROUND

Treatment of diabetic neuropathic pain does not change the natural history of neuropathy. Improved glycemic control is the recommended treatment in these cases, given that no specific treatment for the underlying nerve damage is available, so far. In the present study, the potential neuroprotective effect of pentoxifylline in streptozotocin (50 mg/kg) induced diabetic neuropathy in rats was investigated.

METHODS

Pentoxifylline was administered at doses equivalent to 50, 100 & 200 mg/kg, in drinking water, starting one week after streptozotocin injection and for 7 weeks. Mechanical allodynia, body weight and blood glucose level were assessed weekly. Epidermal thickness of the footpad skin, and neuroinflammation and vascular alterations markers were assessed.

RESULTS

Tactile allodynia was less in rats that received pentoxifylline at doses of 100 and 200 mg/kg (60 % mechanical threshold increased by 48 % and 60 %, respectively). The decrease in epidermal thickness of footpad skin was almost completely prevented by the same doses. This was associated with a decrease in spinal tumor necrosis factor alpha (TNFα) and nuclear factor kappa B levels and a decrease in microglial ionized calcium binding adaptor molecule 1 immunoreactivity, compared to the control diabetic group. In sciatic nerve, there was decrease in TNF-α and vascular endothelial growth factor levels and intercellular adhesion molecule immunoreactivity.

CONCLUSION

Pentoxifylline showed a neuroprotective effect in streptozotocin-induced diabetic neuropathy, which was associated with a suppression of both the inflammatory and vascular pathogenic pathways that was not associated with a hypoglycemic effect. Thus, it may represent a potential neuroprotective drug for diabetics.

Diabetic peripheral neuropathy among adult type 2 diabetes patients in Adama, Ethiopia: health facility-based study

Diabetic peripheral neuropathy is the most prominent microvascular complication of diabetes mellitus and the leading cause of ulceration, amputation, and extended hospitalization. Evidence regarding the magnitude and factors associated with diabetic peripheral neuropathy is not well documented in Ethiopia, particularly in the study area. A facility-based cross-sectional study was conducted among 293 adult type 2 diabetic patients who were on treatment and follow-up from May to June 31, 2023. To select participants in the study, a systematic random sampling method was utilized. Data were collected using semi-structured questionnaires and medical record reviews. The Michigan Neuropathy Screening Instrument (MNSI) was employed to assess diabetic peripheral neuropathy. To model the association between diabetic peripheral neuropathy and independent variables, binary logistic regression model was used. An adjusted odds ratio with a 95% confidence interval was used to estimate the association and statistical significance was proclaimed at a p-value < 0.05. The magnitude of diabetic peripheral neuropathy was 14.3% (95% CI 10.4-18.0). It was 13.4% (95% CI 8.4-19.1) among males and 15.4% (95% CI 10.1-22.2) among females. Age above 60 years (AOR = 5.06, 95% CI 1.60-15.96), being rural resident (AOR = 2.41; 95% CI 1.15-5.06), duration of diabetes above 5 years (AOR = 2.48, 95% CI 1.16-5.27) and having comorbid hypertension (AOR = 2.56, 95% CI 1.24-5.28) were independently associated with diabetic peripheral neuropathy. One in seven adult type 2 diabetes patients in the study area had diabetic peripheral neuropathy. Factors such as age, place of residence, duration of diabetes, and comorbid hypertension showed positive associations with diabetic peripheral neuropathy. Thus, it is imperative to give special consideration to diabetic patients who are elderly, living in rural areas, experiencing a prolonged duration of diabetes, or dealing with comorbid hypertension.

Electroacupuncture efficacy in diabetic polyneuropathy: Study protocol for a double-blinded randomized controlled multicenter clinical trial

BACKGROUND

Diabetic peripheral neuropathy (DPN) is the most common complication of type 2 diabetes mellitus (T2DM); its diagnosis and treatment are based on symptomatic improvement. However, as pharmacological therapy causes multiple adverse effects, the implementation of acupunctural techniques, such as electroacupuncture (EA) has been suggested as an alternative treatment. Nonetheless, there is a lack of scientific evidence, and its mechanisms are still unclear. We present the design and methodology of a new clinical randomized trial, that investigates the effectiveness of EA for the treatment of DPN.

METHODS

This study is a four-armed, randomized, controlled, multicenter clinical trial (20-week intervention period, plus 12 weeks of follow-up after concluding intervention). A total of 48 T2DM patients with clinical signs and symptoms of DPN; and electrophysiological signs in the Nerve Conduction Study (NCS); will be treated by acupuncture specialists in outpatient units in Mexico City. Patients will be randomized in a 1:1 ratio to one of the following four groups: (a) short fibre DPN with EA, (b) short fibre DPN with sham EA, (c) axonal DPN with EA and (d) axonal DPN with sham EA treatment. The intervention will consist of 32 sessions, 20 min each, per patient over two cycles of intervention of 8 weeks each and a mid-term rest period of 4 weeks. The primary outcome will be NCS parameters, and secondary outcomes will include DPN-related symptoms and pain by Michigan Neuropathy Screening Instrument (MNSI), Michigan Diabetic Neuropathy Score (MDNS), Dolour Neuropatique Score (DN-4), Semmes-Westein monofilament, Numerical Rating Scale (NRS) for pain assessment, and the 36-item Short Form Health Survey (SF-36). To measure quality of life and improve oxidative stress, the inflammatory response; and genetic expression; will be analysed at the beginning and at the end of treatment.

DISCUSSION

This study will be conducted to compare the efficacy of EA versus sham EA combined with conventional diabetic and neuropathic treatments if needed. EA may improve NCS, neuropathic pain and symptoms, oxidative stress, inflammatory response, and genetic expression, and it could be considered a potential coadjutant treatment for the management of DPN with a possible remyelinating effect.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT05521737 Registered on 30 August 2022. International Clinical Trials Registry Platform (ICTRP) ISRCTN97391213 Registered on 26 September 2022 [2b].

Review of lipocalin-2-mediated effects in diabetic retinopathy

BACKGROUND

Studies have uncovered LCN2 as a marker of inflammation strongly related to obesity, insulin resistance, and abnormal glucose metabolism in humans, and is involved in vascular diseases, inflammatory diseases, and neurological diseases. In recent years, studies have shown that elevated levels of LCN2 have a strong association with diabetic retinopathy (DR), but the pathogenesis is unknown. Here, we reviewed the relevant literature and compiled the pathogenesis associated with LCN2-induced DR.

METHODS

We searched PubMed and Web of Science electronic databases using "lipocalin-2, diabetic retinopathy, retinal degeneration, diabetic microangiopathies, diabetic neuropathy and inflammation" as subject terms.

RESULTS

In diabetic retinal neuropathy, LCN2 causes impaired retinal photoreceptor function and retinal neurons; in retinal microangiopathy, LCN2 induces apoptosis of retinal vascular endothelial cells and promotes angiogenesis; in retinal inflammation, increased secretion of LCN2 recruits inflammatory cells and induces pro-inflammatory cytokines. Moreover, LCN2 has the potential as a biomarker for DR. Recent studies have shown that retinal damage can be attenuated by silencing LCN2, which may be associated with the inhibition of caspase-1-mediated pyroptosis, and LCN2 may be a new target for the treatment of DR.

CONCLUSIONS

In conclusion, LCN2, involved in the development of diabetic retinopathy, is a key factor in diabetic retinal microangiopathy, neurodegeneration, and retinal inflammation. LCN2 is likely to be a novel molecular target leading to DR, and a more in-depth study of the pathogenesis of DR caused by LCN2 may provide considerable benefits for clinical research and potential drug development.

Implementing a contextually appropriate foot-ankle exercise programme in primary care for the prevention of modifiable risk factors for ulcers in people with diabetes: protocol for a hybrid type 2 study

INTRODUCTION

Diabetes is a highly prevalent disease that negatively impacts people's health and quality of life. It can result in diabetic peripheral neuropathy (DPN) and foot complications, which in turn lead to ulcers and amputations. The international guidelines on diabetic foot included specific foot-ankle exercises as preventive strategy capable of modifying the risk factors for ulcers. Our aim is to test the effectiveness and to implement a contextually appropriate preventive intervention-a foot-ankle exercises programme alongside educational strategies-in a primary care setting to improve range of motion (ROM), strength, functionality of foot-ankle, and quality of life in people with diabetes.

METHODS AND ANALYSIS

This is a hybrid type 2 implementation-effectiveness study organised in four phases, being undertaken in Limeira, São Paulo. Phase 1, preimplementation, aims to gather information about the contextual characteristics, barriers, and facilitators and to form the implementation team. In phase 2, the implementation team will structure the foot-ankle programme, adapting it to the context of primary healthcare, and develop the training for health professionals. In phase 3, effectiveness of the 12 week group-based intervention will be tested by a cluster randomised controlled trial. Primary care units (18 clusters) will be randomly allocated to a control or intervention group, with a total sample of 356 people. Primary outcomes will be DPN symptoms and ankle and first metatarsal phalangeal joint ROM. Reach, adoption, and implementation will be evaluated by Reach, Effectiveness, Adoption, Implementation, and Maintenance framework. In phase 4, maintenance and expansion of the programme in the municipality will be assessed.

ETHICS AND DISSEMINATION

This protocol and the informed consent to be signed by the participants were approved by the Ethics Committee of the School of Medicine of the University of São Paulo (CAAE:63457822.0.0000.0068, 29 November 2022). The project will generate and share data in a public repository. Results will be disseminated through peer-reviewed journals, conference proceedings, and electronic communications for health professionals.

TRIAL REGISTRATION NUMBER

NCT05639478.

Natural products as pharmacological modulators of mitochondrial dysfunctions for the treatment of diabetes and its complications: An update since 2010

Diabetes, characterized as a well-known chronic metabolic syndrome, with its associated complications pose a substantial and escalating health and healthcare challenge on a global scale. Current strategies addressing diabetes are mainly symptomatic and there are fewer available curative pharmaceuticals for diabetic complications. Thus, there is an urgent need to identify novel pharmacological targets and agents. The impaired mitochondria have been associated with the etiology of diabetes and its complications, and the intervention of mitochondrial dysfunction represents an attractive breakthrough point for the treatments of diabetes and its complications. Natural products (NPs), with multicenter characteristics, multi-pharmacological activities and lower toxicity, have been caught attentions as the modulators of mitochondrial functions in the therapeutical filed of diabetes and its complications. This review mainly summarizes the recent progresses on the potential of 39 NPs and 2 plant-extracted mixtures to improve mitochondrial dysfunction against diabetes and its complications. It is expected that this work may be useful to accelerate the development of innovative drugs originated from NPs and improve upcoming therapeutics in diabetes and its complications.

A diminished sciatic nerve structural integrity is associated with distinct peripheral sensory phenotypes in individuals with type 2 diabetes

AIMS/HYPOTHESIS

Quantitative sensory testing (QST) allows the identification of individuals with rapid progression of diabetic sensorimotor polyneuropathy (DSPN) based on certain sensory phenotypes. Hence, the aim of this study was to investigate the relationship of these phenotypes with the structural integrity of the sciatic nerve among individuals with type 2 diabetes.

METHODS

Seventy-six individuals with type 2 diabetes took part in this cross-sectional study and underwent QST of the right foot and high-resolution magnetic resonance neurography including diffusion tensor imaging of the right distal sciatic nerve to determine the sciatic nerve fractional anisotropy (FA) and cross-sectional area (CSA), both of which serve as markers of structural integrity of peripheral nerves. Participants were then assigned to four sensory phenotypes (participants with type 2 diabetes and healthy sensory profile [HSP], thermal hyperalgesia [TH], mechanical hyperalgesia [MH], sensory loss [SL]) by a standardised sorting algorithm based on QST.

RESULTS

Objective neurological deficits showed a gradual increase across HSP, TH, MH and SL groups, being higher in MH compared with HSP and in SL compared with HSP and TH. The number of participants categorised as HSP, TH, MH and SL was 16, 24, 17 and 19, respectively. There was a gradual decrease of the sciatic nerve's FA (HSP 0.444, TH 0.437, MH 0.395, SL 0.382; p=0.005) and increase of CSA (HSP 21.7, TH 21.5, MH 25.9, SL 25.8 mm2; p=0.011) across the four phenotypes. Further, MH and SL were associated with a lower sciatic FA (MH unstandardised regression coefficient [B]=-0.048 [95% CI -0.091, -0.006], p=0.027; SL B=-0.062 [95% CI -0.103, -0.020], p=0.004) and CSA (MH β=4.3 [95% CI 0.5, 8.0], p=0.028; SL B=4.0 [95% CI 0.4, 7.7], p=0.032) in a multivariable regression analysis. The sciatic FA correlated negatively with the sciatic CSA (r=-0.35, p=0.002) and markers of microvascular damage (high-sensitivity troponin T, urine albumin/creatinine ratio).

CONCLUSIONS/INTERPRETATION

The most severe sensory phenotypes of DSPN (MH and SL) showed diminishing sciatic nerve structural integrity indexed by lower FA, likely representing progressive axonal loss, as well as increasing CSA of the sciatic nerve, which cannot be detected in individuals with TH. Individuals with type 2 diabetes may experience a predefined cascade of nerve fibre damage in the course of the disease, from healthy to TH, to MH and finally SL, while structural changes in the proximal nerve seem to precede the sensory loss of peripheral nerves and indicate potential targets for the prevention of end-stage DSPN.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03022721.

Topical Nigella sativa L. product: a new candidate for the management of diabetic peripheral neuropathy

BACKGROUND

Diabetic neuropathy is one of the most common complications of diabetes. The synthetic drugs available in the market have side effects and limitations for diabetic patients, the vast majority of whom are in the upper age group. In this regard, based on Persian medicinal sources, Nigella sativa (N. sativa) has proved to have beneficial effects on neuropathic pain and neurological disorders. In this study, the effect of N. sativa is investigated topically in patients with diabetic neuropathy.

METHODS

This study was performed as a double-blind clinical trial on 120 neuropathic patients. The patients were divided into three groups. The first group received a topical N. sativa product as an ointment, the second group was given a topical placebo, and the third received 300 mg gabapentin capsules. The blindness was done in first and second groups. Diabetic neuropathy was assessed before the study using the Michigan Neuropathy Screening Instrument (MNSI). In addition, neuropathy symptoms were evaluated after the trial using the MNSI questionnaire.

RESULTS

The data were elicited from the patients' answers to a number of questions in the Michigan questionnaire. There were statistically significant differences between the group that received the topical N. sativa product and the other two groups in terms of legs and feet numbness (p value = 0.001), burning pain in feet or legs (p value = 0.001), muscle cramps in feet or legs (p value = 0.001), prickling fleeing in feet or legs (p value = 0.001), hurting of the skin when the bed covers touch it (p value = 0.005), aggravated symptoms at night (p value = 0.001) and hurting feelings in the legs when walking (p value = 0.032). However, the three studied groups were not statistically different in distinguishing hot water from cold water.

CONCLUSION

According to the results of this study, the topical use of N. sativa, compared to the current drugs, has acceptable improving effects on diabetic neuropathic patients.

Gut Microbiota Modulation and Its Implications on Neuropathic Pain: A Comprehensive Literature Review

Neuropathic pain (NP) is a chronic pain disorder arising from somatosensory nervous system impairment. Extensive evidence supports the notion that the gut microbiota (GM) is crucial in maintaining human health by performing vital tasks. At the same time, its disruption has been linked to the emergence and advancement of an expanding range of disorders, including NP, in which GM could play a role in its pathophysiology. The crosstalk between the nervous system and GM happens through immune mediators, metabolites, and nervous structures and involves both central and peripheral nervous systems. This literature review aims to thoroughly investigate the function of modulating GM in the treatment of NP. It will achieve this by integrating existing knowledge, identifying underlying mechanisms, and evaluating the possible clinical consequences of exploiting the gut-brain axis. We will cover the main therapeutic applications of the described GM-modulators, such as probiotics, faecal microbiota transplantation, dietary supplements and emotional support, to the main kinds of NP in which any evidence, even if only pre-clinical, has been unravelled in recent years. The explored NP areas include chemotherapy-induced peripheral neuropathy, diabetic neuropathy, trauma-induced neuropathic pain, trigeminal neuralgia, postherpetic neuralgia and low back pain.

Ginger alleviates mechanical hypersensitivity and anxio-depressive behavior in rats with diabetic neuropathy through beneficial actions on gut microbiome composition, mitochondria, and neuroimmune cells of colon and spinal cord

The relationship among gut microbiota, mitochondrial dysfunction/neuroinflammation, and diabetic neuropathic pain (DNP) has received increased attention. Ginger has antidiabetic and analgesic effects because of its anti-inflammatory property. We examined the effects of gingerols-enriched ginger (GEG) supplementation on pain-associated behaviors, gut microbiome composition, and mitochondrial function and neuroinflammation of colon and spinal cord in DNP rats. Thirty-three male rats were randomly divided into 3 groups: control group, DNP group (high-fat diet plus single dose of streptozotocin at 35 mg/kg body weight, and GEG group (DNP+GEG at 0.75% in the diet for 8 weeks). Von Frey and open field tests were used to assess pain sensitivity and anxio-depressive behaviors, respectively. Colon and spinal cord were collected for gene expression analysis. 16S rRNA gene sequencing was done from cecal samples and microbiome data analysis was performed using QIIME 2. GEG supplementation mitigated mechanical hypersensitivity and anxio-depressive behavior in DNP animals. GEG supplementation suppressed the dynamin-related protein 1 protein expression (colon) and gene expression (spinal cord), astrocytic marker GFAP gene expression (colon and spinal cord), and tumor necrosis factor-α gene expression (colon, P < .05; spinal cord, P = .0974) in DNP rats. GEG supplementation increased microglia/macrophage marker CD11b gene expression in colon and spinal cord of DNP rats. GEG treatment increased abundance of Acinetobacter, Azospirillum, Colidextribacter, and Fournierella but decreased abundance of Muribaculum intestinale in cecal feces of rats. This study demonstrates that GEG supplementation decreased pain, anxio-depression, and neuroimmune cells, and improved the composition of gut microbiomes and mitochondrial function in rats with diabetic neuropathy.

A study on prevalence of diabetic peripheral neuropathy in diabetic patients attending a rural health and training centre

Introduction

Diabetic neuropathy is a common complication, affecting up to half the diabetics. Diabetic peripheral neuropathy (DPN) predominantly affects the hands and lower limbs. It leads to loss of protective sensation, resulting in continuous injury to insensitive feet. The early detection of DPN using an objective screening test followed by its appropriate management is important, as up to 50% of diabetic peripheral neuropathies may be asymptomatic.

Objectives

To screen diabetic patients attending a Rural Health and Training Centre of a medical college in Tamil Nadu for DPN. To assess the association between DPN and sociodemographic factors, duration of diabetes, glycemic control, physical activity, body mass index, smoking and habit of alcohol consumption.

Materials and Methods

The study was conducted among 206 diabetic patients attending a Rural Health and Training Centre. Participants were assessed using the Michigan Neuropathy Screening Instrument (MNSI), which involves using a questionnaire followed by a physical examination.

Results

Of the 206 patients, 61.2% were male, and 38.8% were female. The mean age was 50.86 years (standard deviation [SD] = 12.26 years). The mean duration of diabetes was 8.3 years (SD = 5.5 years). The proportion of diabetics who were screened positive for peripheral neuropathy was 16.5% and 21.8% using the MNSI questionnaire and examination, respectively. Age of 60 years and above was significantly associated with DPN.(OR = 3.982, P value = 0.0001). Duration of more than 5 years of diabetes was also significantly associated with DPN.(OR = 6.01, P value = 0.003).

Conclusion

A high proportion of diabetics were screened positive for peripheral neuropathy, and many of them were unaware of having the complication. Many risk factors associated with DPN were reported in this study. Thus, early diagnosis and management with MNSI or any other validated screening tool in health care institutions is essential.

The effectiveness of neurodynamic techniques in patients with diabetic peripheral neuropathy: Study protocol for a randomized sham-controlled trial

Background

Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes mellitus (DM). DPN is the primary risk factor for diabetic foot ulcers that can cause amputation. Although several observational studies have investigated the morphological and biomechanical characteristics of peripheral nerves in DPN, interventional studies regarding the effectiveness of neurodynamic techniques (NDT) in DPN patients are confined to a handful. The effects of NDT on neuropathy severity, nerve conduction parameters, quality of life (QoL), and mechanosensitivity have not been explored yet in this population.

Materials and Methods

Forty type 2 DPN (T2DPN) patients, diagnosed based on an electrodiagnosis study, will be recruited into two groups. The experimental group will receive the tibial nerve's real proximal and distal slider techniques in addition to DPN standard treatment as a basic treatment, and the control group will receive the tibial nerve's sham proximal and distal slider techniques along with the basic treatment for eight sessions twice a week. Baseline and post-intervention assessments will be based on the Michigan diabetic neuropathy score (MDNS) (primary outcome), tibial nerve conduction parameters, neuropathy-specific quality of life (Neuro QoL) questionnaire, and straight leg raising range of motion (SLR ROM) (secondary outcomes).

Results

This study is expected to last approximately seven months, depending on recruitment. The results of the study will be published in a peer-reviewed journal.

Conclusions

The present study will evaluate the efficacy of NDT on the primary and secondary outcome measurements in DPN patients.

Glial cell alterations in diabetes-induced neurodegeneration

Type 2 diabetes mellitus is a global epidemic that due to its increasing prevalence worldwide will likely become the most common debilitating health condition. Even if diabetes is primarily a metabolic disorder, it is now well established that key aspects of the pathogenesis of diabetes are associated with nervous system alterations, including deleterious chronic inflammation of neural tissues, referred here as neuroinflammation, along with different detrimental glial cell responses to stress conditions and neurodegenerative features. Moreover, diabetes resembles accelerated aging, further increasing the risk of developing age-linked neurodegenerative disorders. As such, the most common and disabling diabetic comorbidities, namely diabetic retinopathy, peripheral neuropathy, and cognitive decline, are intimately associated with neurodegeneration. As described in aging and other neurological disorders, glial cell alterations such as microglial, astrocyte, and Müller cell increased reactivity and dysfunctionality, myelin loss and Schwann cell alterations have been broadly described in diabetes in both human and animal models, where they are key contributors to chronic noxious inflammation of neural tissues within the PNS and CNS. In this review, we aim to describe in-depth the common and unique aspects underlying glial cell changes observed across the three main diabetic complications, with the goal of uncovering shared glial cells alterations and common pathological mechanisms that will enable the discovery of potential targets to limit neuroinflammation and prevent neurodegeneration in all three diabetic complications. Diabetes and its complications are already a public health concern due to its rapidly increasing incidence, and thus its health and economic impact. Hence, understanding the key role that glial cells play in the pathogenesis underlying peripheral neuropathy, retinopathy, and cognitive decline in diabetes will provide us with novel therapeutic approaches to tackle diabetic-associated neurodegeneration.

Neuroprotective Effects of Isolated Mangiferin from Swertia chirayita Leaves Regulating Oxidative Pathway on Streptozotocin-Induced Diabetic Neuropathy in Experimental Rats

BACKGROUND

Oxidative stress has an important role in the pathogenesis and development of diabetic peripheral neuropathy (DPN), the most common and debilitating complication of diabetes mellitus. Swertia chirayita is a rich source of phenolic constituents and has hypoglycemic, anti-inflammatory, and antioxidant properties.

AIMS

This study was performed to evaluate the neuroprotective effect in diabetes by enhancing antioxidant defense against oxidative stress, which exhibits a neuroprotective effect in streptozotocin- induced diabetic rats.

OBJECTIVES

The objective of this study was to elucidate the therapeutic potential of bioactive compounds of Swertia chirayita for diabetic complications.

METHODS

The present work focused on isolating the bioactive from the leaves of Swertia absinthe for acute toxicity studies, assessing its protective effects against diabetes and diabetic neuropathy as well as its mode of action in STZ-induced Wistar rats. The local area of Moradabad is the place from where the leaves of Swertia chirayita were gathered. Mangiferin was isolated and identified using spectroscopic techniques, such as UV, HPLC, 1H NMR, C13 NMR, MAS, and FTIR. Mangiferin was administered in doses of 15 and 30 mg/kg to test its effect on experimentally induced diabetes. The sciatic nerves of all groups were examined histopathologically. The protective effect of the drug against diabetes and diabetic neuropathy was demonstrated by measures, such as blood glucose level, body weight, food intake, thermal hyperalgesia, grip strength, spontaneous locomotor test, and lipid profile analysis. Sciatic nerve cells of the treated groups showed less inflammation, degeneration, and necrosis.

RESULTS

The results of this study confirmed that mangiferin alleviated diabetic neuropathic pain, possibly by reducing inflammatory cytokines (TNF-α, TGF-β1, IL-1β, and IL-6), strong antioxidant activity, and NGF in sciatic nerves. It may be a therapeutic agent.

CONCLUSION

Our results suggested that active phytochemicals of Swertia chirayita showed preventive and curative effects against STZ-induced diabetic neuropathy in rats, which might be due to its antioxidant, anti-inflammatory, and anti-apoptotic properties.

Behavior of neuropathy symptom score and neuropathy disability score in patients with and without peripheral diabetic neuropathy: A retrospective cohort study

BACKGROUND

This study aimed to stablish cut-off of early diagnosis of diabetic polyneuropathy (PDN) based on neuropathy symptom score (NSS) and neuropathy disability score (NDS); to determine the behavior of NDD and NDS in patients with and without PDN; and to verify the association between clinical and demographic variables with both tests.

METHODS

This retrospective cohort included 86 patients with diabetes. The NSS and NDS evaluations were collected in medical records in two moments: initial (entry into service) and final (after three years). Individuals were categorized in three groups: G1- PDN in both evaluations (N = 27); G2- PDN only in the final evaluation (N = 16); G3-individuals without PDN (N = 43). A ROC curve was performed to evaluate the sensitivity and specificity of NSS and NDS for PDN diagnosis. ANOVA was used to compare NSS and NDS between groups and evaluations, and multiple regression was performed to find predictors of PDN.

RESULTS

The NSS and NDS showed excellent sensitivity and specificity (NDS ≥1.5 and NSS ≥6.5) for PDN diagnosis. There was a significant difference between groups in initial (p = 0.000) and final (p = 0.000) NDS and NSS evaluations. There was an association between peripheral arterial disease (PAD) and increase in NSS (p = 0.024) in G2; and association between loss of protective sensation (LOPS) and increase in NSS in G3 (p < 0.001).

CONCLUSION

NSS and NDS tests showed excellent sensitivity and specificity for early PDN diagnosis. Behavior of both tests can differ patients with and without PDN. Furthermore, PAD and LOPS can be a predictor of PDN evolution.

Peripheral Nerve Stimulation With a High-Frequency Electromagnetic Coupled Powered Implanted Receiver at the Posterior Tibial Nerve for the Treatment of Chronic Pain in the Foot

INTRODUCTION

Peripheral neuropathy has several causes, with diabetes being the most common. Conservative management may fail to control pain. Our study aimed at evaluating the use of peripheral nerve stimulation of the posterior tibial nerve for treating peripheral neuropathy.

MATERIALS AND METHODS

This was an observational study of 15 patients who received peripheral nerve stimulation at the posterior tibial nerve to treat peripheral neuropathy. Outcomes measured were improvement of pain scores and Patient Global Impression of Change (PGIC) at 12 months compared with before the implant.

RESULTS

Mean pain scores with the verbal rating scale were 3 ± 1.8 at >12 months compared with 8.6 ± 1.2 at baseline, a reduction of 65% (p < 0.001). Median satisfaction with the PGIC at >12 months was 7 of 7, with most subjects reporting a 6 (better) or a 7 (a great deal better).

CONCLUSION

Peripheral nerve stimulation of the posterior tibial nerve can be a safe and effective modality for treating chronic pain symptoms related to peripheral neuropathy of the foot.

Midnight Cortisol is Associated with Changes in Systolic Blood Pressure and Diabetic Neuropathy in Subjects with Type 1 Diabetes Undergoing Simultaneous Kidney-Pancreas Transplantation

INTRODUCTION

An increased midnight cortisol (MC) has been described in end-stage kidney disease (ESKD) and type 1 diabetes (T1D). Lower circulating levels of the cytokine soluble tumor necrosis factor (TNF)-like weak inducer of apoptosis (sTWEAK) have been found in T1D and ESKD and associated with cardiovascular (CV) events in the latter. We aimed to study MC and sTWEAK in simultaneous pancreas-kidney transplant (SPKT) recipients, and the association of these markers with CV risk factors and transplant outcomes.

METHODS

This was a retrospective cohort study including subjects with T1D who received a first SPKT between 2008 and 2020. MC and sTWEAK at baseline were correlated with CV risk factors and evolution 1 year after SPKT.

RESULTS

We included 29 subjects (58.6% women, mean age 43.5 ± 7.5 years, diabetes duration 31.9 ± 9.4 years). Systolic blood pressure (SBP) increased directly with MC quartiles, despite similar hypertension prevalence (p < 0.05). At 1 year, antihypertensive treatment was deintensified in those in lower MC quartiles (p < 0.05). Diabetic neuropathy prevalence decreased progressively in higher cortisol quartiles (p for trend = 0.005). Low MC was associated with delayed kidney graft function (p for trend = 0.044), and high sTWEAK with kidney graft rejection (p for trend = 0.018). In multivariate analyses, MC (standardized-β 0.505, p = 0.004) and age (standardized-β - 0.460, p = 0.040) were independently correlated with SBP, and MC was independently associated with the presence of diabetic neuropathy (OR 0.633, 95% CI 0.425-0.944, p = 0.025), adjusted for confounders.

CONCLUSIONS

In this exploratory study, lower MC was associated with a lower baseline SBP, an improvement of antihypertensive treatment 1 year after transplant, and a higher diabetic neuropathy prevalence in SPKT recipients.

Emerging links between FOXOs and diabetic complications

Diabetes and its complications are increasing worldwide in the working population as well as in elders. Prolonged hyperglycemia results in damage to blood vessels of various tissues followed by organ damage. Hyperglycemia-induced damage in small blood vessels as in nephrons, retina, and neurons results in diabetic microvascular complications which involve nephropathy, retinopathy, and diabetic neuropathy. Additionally, damage in large blood vessels is considered as a macrovascular complication including diabetic cardiomyopathy. These long-term complications can result in organ failure and thus becomes the leading cause of diabetic-related mortality in patients. Members of the Forkhead Box O family (FOXO) are involved in various body functions including cell proliferation, metabolic processes, differentiation, autophagy, and apoptosis. Moreover, increasing shreds of evidence suggest the involvement of FOXO family members FOXO1, FOXO3, FOXO4, and FOXO6 in several chronic diseases including diabetes and diabetic complications. Hence, this review focuses on the role of FOXO transcription factors in the regulation of diabetic complications.

Utilizing a quality of life tool to examine the presence of fatigue in subjects with diabetes mellitus

Introduction

The prevalence of fatigue in patients with diabetes mellitus (DM) can be as high as 50 %. Physical, mental, and psychosocial components of fatigue negatively impact quality of life (QOL), morbidity and mortality. Several tools have been developed to address fatigue, but none specifically for measuring fatigue in DM. The aim of this study was to assess the impact of diabetes and neuropathy on fatigue using the Norfolk QOL-Fatigue (QOL-F) survey.

Methods

605 adult participants from [Anonymous] were recruited (400 subjects with type 1 or type 2 DM and 205 subjects without diabetes (controls)). All subjects completed the Norfolk QOL-F. Demographics, weight, BMI, and duration of diabetes were obtained. The Norfolk QOL-F, a 35-item validated questionnaire, assesses five domains: subjective fatigue, physical and cognitive fatigue, reduced activities, impaired activities of daily living, and depression.

Results

Subjects with DM reported significantly higher fatigue total scores (52.63vs33.89, p < 0.0001) and in all five domains when compared to controls. Patients with DM with neuropathy were significantly more fatigued than those without (59.72vs27.83, p < 0.0001). Fatigue scores in patients with DM without neuropathy were similar to controls (27.83vs33.89, p = NS). In multivariate analysis, age, gender, and presence of neuropathy significantly impacted fatigue scores.

Conclusions

The Norfolk QOL-F questionnaire can potentially identify the impact of chronic diseases such as diabetes on fatigue. Assessing the different components of fatigue is important for clinicians in improving disease management and outcomes. Further investigations are needed to confirm these observations in specific cohorts with other comorbidities.

The role of micro-RNAs in neuropathic pain-a scoping review

Neuropathic pain can be caused by a lesion or disease of the somatosensory system characterised by pathological neuro-immune alterations. At a molecular level, microRNAs (miRNAs) act as regulators of gene expression orchestrating both immune and neuronal processes. Thus, miRNAs may act as essential modulators of processes for the establishment and maintenance of neuropathic pain. The objective/aims of this scoping review was to explore and chart the literature to identify miRNAs that are dysregulated in neuropathic pain. The following databases were searched from inception to March 2023: PubMed, EBSCO, CINAHL, Cochrane Library, and SCOPUS. Two independent reviewers screened, extracted data, and independently assessed the risk of bias in included studies. The JBI critical appraisal checklist was used for critical appraisal. A narrative synthesis was used to summarise the evidence. Seven studies (total of 384 participants) that met our eligibility criteria were included in this scoping review. Our review has identified different miRNAs that are commonly involved in the chronic neuropathic pain conditions including miR-132, miR-101, and miR-199a. Our review findings further suggest that expression of miRNAs to be significantly associated with increased diabetic disease duration, HbA1C levels, and fibrinogen levels. Our review findings suggest that there is clear association between miRNA expression and chronic neuropathic pain conditions. Therefore, increasing the specificity by selecting a candidate miRNA and identifying its target mRNA is an area of future research.

Perceptions of primary and secondary care clinicians treating diabetic foot: A pan India study and quantitative analysis

AIM

The study quantifies clinicians' perceptions and challenges during different stages of diabetic foot treatment. Diabetic neuropathy (DN), which is a major consequence of diabetes, significantly increases the risk of lower limb amputation. This can be prevented to a large extent by foot care, early detection, and lesion treatment.

METHODS

Ninety-two Indian clinicians of various demographics, medical specializations, and experiences were interviewed. Diabetic foot treatment by primary and secondary care clinicians was assessed. This study evaluates aspects related to patient awareness, compliance, and shortcomings of current diagnostic techniques.

RESULTS

A two-sample Mann-Whitney statistical method was used to infer the perceptions of clinicians on hypothesis questions. Primary and secondary care clinicians' perceptions differed for the hypotheses related to objective assessment (p-value = 0.001), operator variability (p-value = 0.03), and patient compliance (p-value = 0.047). Conversely, both groups held comparative perspectives for the awareness (p-value = 0.369) and examination time (p-value = 0.276) hypotheses.

CONCLUSIONS

All clinicians strongly supported the need for an objective assessment to reduce the misdiagnosis of DN. Further, DNis often underdiagnosed due to a lack of awareness and knowledgeamong people with diabetes. Secondary care clinicians acknowledged a need for trained operators to reduce reliability errors. These insights provide directions for future research in this field.

Effect of Hesperidin on Sciatic Nerve Damage in STZ-Induced Diabetic Neuropathy: Modulation of TRPM2 Channel

Diabetic neuropathy (DNP) is a severe complication of diabetes mellitus. In this study, we examined the potential of hesperidin (HES) to attenuate DNP and the involvement of the TRPM2 channel in this process. The rats were given a single dose of 45 mg/kg of streptozotocin (STZ) intraperitoneally to induce diabetic neuropathic pain. On the third day, we confirmed the development of diabetes in the DNP and DNP + HES groups. The HES groups were treated with 100 mg/kg and intragastric gavage daily for 14 days. The results showed that treatment with HES in diabetic rats decreased STZ-induced hyperglycemia and thermal hyperalgesia. Furthermore, in the histopathological examination of the sciatic nerve, HES treatment reduced STZ-induced damage. The immunohistochemical analysis also determined that STZ-induced increased TRPM2 channel, type-4 collagen, and fibrinogen immunoactivity decreased with HES treatment. In addition, we investigated the TRPM2 channel activation in the sciatic nerve damage mechanism of DNP model rats created by STZ application using the ELISA method. We determined the regulatory effect of HES on increased ROS, and PARP1 and TRPM2 channel activation in the sciatic nerves of DNP model rats. These findings indicated that hesperidin treatment could attenuate diabetes-induced DNP by reducing TRPM2 channel activation.

Health-related quality of life and spinal cord stimulation in painful diabetic neuropathy

Peripheral neuropathic pain, including painful diabetic neuropathy (PDN), is associated with marked negative impact on health-related quality of life (HRQoL). The magnitude of reduction of HRQoL experienced by individual PDN patients appears to be strongly associated with their level of pain and disease severity. In spite of the availability of a range of pharmacotherapy, a substantive proportion of PDN patients continue to experience suboptimal HRQoL. Such patients are potential candidates for spinal cord stimulation (SCS) devices. Three randomised controlled trials in over 300 patients with refractory PDN have shown that the addition of SCS to standard of care therapy results in important health gains, including pain reduction and enhancement of HRQoL. Sham-controlled RCTs that enable blinding of patients, clinicians and researchers are needed to confirm the role of SCS in PDN.

Where does spinal cord stimulation fit into the international guidelines for refractory painful diabetic neuropathy? a consensus statement

BACKGROUND

Although pharmacotherapy with anticonvulsants and/or antidepressants can be effective for many people with painful diabetic neuropathy (PDN), albeit with frequent side-effects, a critical juncture occurs when neuropathic pain no longer responds to standard first- and second-step mono- and dual therapy and becomes refractory. Subsequent to these pharmacotherapeutic approaches, third-line treatment options for PDN may include opioids (short-term), capsaicin 8% patches, and spinal cord stimulation (SCS).

AIM

This document summarizes consensus recommendations regarding appropriate treatment for refractory peripheral diabetic neuropathy (PDN), based on outcomes from an expert panel convened on December 10, 2022, as part of the Worldwide Initiative for Diabetes Education Virtual Global Summit, "Advances in the Management of Painful Diabetic Neuropathy."

PARTICIPANTS

Nine attendees, eminent physicians and academics, comprising six diabetes specialists, two pain specialists, and one health services expert.

EVIDENCE

For individuals with refractory PDN, opioids are a high-risk option that do not provide a long-term solution and should not be used. For appropriately selected individuals, SCS is an effective, safe, and durable treatment option. In particular, high-frequency (HF) SCS (10 kHz) shows strong efficacy and improves quality of life. To ensure treatment success, strict screening criteria should be used to prioritize candidates for SCS.

CONSENSUS PROCESS

Each participant voiced their opinion after reviewing available data, and a verbal consensus was reached during the meeting.

CONCLUSION

Globally, the use of opioids should rarely be recommended for refractory, severe PDN. Based on increasing clinical evidence, SCS, especially HF-SCS, should be considered as a treatment for PDN that is not responsive to first- or second-line monotherapy/dual therapy.

Diabetes knowledge and foot care practices among type 2 diabetes patients attending the chronic ambulatory care unit of a public health hospital in eastern Ethiopia: a cross-sectional study

OBJECTIVE

To assess diabetes knowledge and foot care practices among type 2 diabetes patients.

DESIGN

An institution-based cross-sectional study was undertaken from 1 January to 31 January 2021.

SETTING

Eastern Ethiopia.

PARTICIPANTS

Randomly selected type 2 diabetes patients who were available during the data collection period were included.

OUTCOMES

Patients' diabetes knowledge was assessed with the revised diabetes knowledge test questionnaire. Five items were used to evaluate foot self-care practices.

RESULTS

The study population comprised of 549 patients. About 52.5% of the patients had adequate diabetes knowledge (95% CI: 48.2% to 56.7%). Patients with an educational level of secondary school and above (adjusted OR (AOR): 2.04, 95% CI: 1.13 to 3.71), (AOR: 5.28, 95% CI: 2.28 to 12.22), and those with medium and above wealth status (AOR: 3.81, 95% CI: 2.24 to 6.47), (AOR: 3.46, 95% CI: 1.98 to 6.04), were found to have better odds of having adequate diabetes knowledge. However, those aged >55 years (AOR: 0.47, 95% CI: 0.22 to 0.99) were found to have lower odds of adequate diabetes knowledge.Of the total included patients, 20.2% (95% CI: 16.9% to 23.8%) had good foot care practices. Knowledge of the target fasting plasma glucose (AOR: 3.18, 95% CI: 1.94 to 5.22) and adequate diabetes knowledge (AOR: 3.40, 95% CI: 1.95 to 5.91) were significantly associated with good foot care practices.

CONCLUSION

According to this study, about half of individuals with type 2 diabetes have adequate levels of knowledge about the disease. In addition, only one out of every five patients has good foot care habits. Diabetes education should emphasise the significance of rigorous adherence to daily foot care practices.

Oral proniosomal amitriptyline and liraglutide for management of diabetic neuropathy: Exceptional control over hyperglycemia and neuropathic pain

Exploitation of nanocarriers provides a compartment for enclosing drugs to protect them from degradation and potentiate their therapeutic efficiency. In the current study, amitriptyline- and liraglutide-loaded proniosomes were constructed for management of diabetic neuropathy, a serious complication associated with diabetes, that triggers spontaneous pain in patients and results in impaired quality of life. The developed therapeutic proniosomes were extensively characterized via dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and Fourier transform-infrared spectroscopy. High entrapment efficiency could be attained for both drugs in the proniosomes, and the reconstituted amitriptyline- and liraglutide-loaded niosomes possessed spherical morphology and particle sizes of 585.3 nm and 864.4 nm, respectively. In a diabetic neuropathy rat model, oral administration of the developed amitriptyline- and liraglutide-loaded proniosomes significantly controlled blood glucose levels, reduced neuropathic pain, oxidative stress and inflammatory markers, and improved histological structure of the sciatic nerve as compared to the oral and subcutaneous administration of amitriptyline and liraglutide, respectively. Loading of the tricyclic antidepressant amitriptyline and the antidiabetic peptide liraglutide into proniosomes resulted in exceptional control over hyperglycemia and neuropathic pain, and thus could provide an auspicious delivery system for management of neuropathic pain and control of blood glucose levels.

Current advancement in the preclinical models used for the assessment of diabetic neuropathy

Diabetic neuropathy is one of the prevalent and debilitating microvascular complications of diabetes mellitus, affecting a significant portion of the global population. Relational preclinical animal models are essential to understand its pathophysiology and develop effective treatments. This abstract provides an overview of current knowledge and advancements in such models. Various animal models have been developed to mimic the multifaceted aspects of human diabetic neuropathy, including both type 1 and type 2 diabetes. These models involve rodents (rats and mice) and larger animals like rabbits and dogs. Induction of diabetic neuropathy in these models is achieved through chemical, genetic, or dietary interventions, such as diabetogenic agents, genetic modifications, or high-fat diets. Preclinical animal models have greatly contributed to studying the intricate molecular and cellular mechanisms underlying diabetic neuropathy. They have shed light on hyperglycemia-induced oxidative stress, neuroinflammation, mitochondrial dysfunction, and altered neurotrophic factor signaling. Additionally, these models have allowed for the investigation of morphological changes, functional alterations, and behavioral manifestations associated with diabetic neuropathy. These models have also been crucial for evaluating the efficacy and safety of potential therapeutic interventions. Novel pharmacological agents, gene therapies, stem cell-based approaches, exercise, dietary modifications, and neurostimulation techniques have been tested using these models. However, limitations and challenges remain, including physiological differences between humans and animals, complex neuropathy phenotypes, and the need for translational validation. In conclusion, preclinical animal models have played a vital role in advancing our understanding and management of diabetic neuropathy. They have enhanced our knowledge of disease mechanisms, facilitated the development of novel treatments, and provided a platform for translational research. Ongoing efforts to refine and validate these models are crucial for future treatment developments for this debilitating condition.

Novel therapeutical approaches based on neurobiological and genetic strategies for diabetic polyneuropathy - A review

BACKGROUND

Neuropathy is among the most often reported consequences of diabetes and the biggest cause of morbidity and mortality in people suffering from this life-long disease. Although different therapeutic methods are available for diabetic neuropathy, it is still the leading cause of limb amputations, and it significantly decreases patients' quality of life.

AIM

This study investigates potential novel therapeutic options that could ameliorate symptoms of DN.

METHODOLOGY

Research and review papers from the last 10 years were taken into consideration.

RESULTS

There are various traditional drugs and non-pharmacological methods used to treat this health condition. However, the research in the area of pathogenic-oriented drugs in the treatment of DN showed no recent breakthroughs, mostly due to the limited evidence about their effectiveness and safety obtained through clinical trials. Consequently, there is an urgent demand for the development of novel therapeutic options for diabetic neuropathy.

CONCLUSION

Some of the latest novel diagnostic methods for diagnosing diabetic neuropathy are discussed as well as the new therapeutic approaches, such as the fusion of neuronal cells with stem cells, targeting gene delivery and novel drugs.

New Horizons in Diabetic Neuropathies: An Updated Review on their Pathology, Diagnosis, Mechanism, Screening Techniques, Pharmacological, and Future Approaches

BACKGROUND

One of the largest problems for global public health is diabetes mellitus (DM) and its micro and macrovascular consequences. Although prevention, diagnosis, and treatment have generally improved, its incidence is predicted to keep rising over the coming years. Due to the intricacy of the molecular mechanisms, which include inflammation, oxidative stress, and angiogenesis, among others, discovering treatments to stop or slow the course of diabetic complications is still a current unmet need.

METHODS

The pathogenesis and development of diabetic neuropathies may be explained by a wide variety of molecular pathways, hexosamine pathways, such as MAPK pathway, PARP pathway, oxidative stress pathway polyol (sorbitol) pathway, cyclooxygenase pathway, and lipoxygenase pathway. Although diabetic neuropathies can be treated symptomatically, there are limited options for treating the underlying cause.

RESULT

Various pathways and screening models involved in diabetic neuropathies are discussed, along with their possible outcomes. Moreover, both medicinal and non-medical approaches to therapy are also explored.

CONCLUSION

This study highlights the probable involvement of several processes and pathways in the establishment of diabetic neuropathies and presents in-depth knowledge of new therapeutic approaches intended to stop, delay, or reverse different types of diabetic complications.

Preparation, characterization, and pharmacological application of oral Honokiol-loaded solid lipid nanoparticles for diabetic neuropathy

Honokiol is a phytochemical component with a variety of pharmacological properties. However, the major limitation of Honokiol is its poor solubility and low oral bioavailability. In this study, we formulated and characterized oral Honokiol-loaded solid lipid nanoparticles (SLNs) to enhance bioavailability and then evaluated their effectiveness in experimental diabetic neuropathy (DN). The finalized formulation has a spherical morphology, a particle size (PS) of 121.31 ± 9.051 nm, a polydispersity index (PDI) of 0.249 ± 0.002, a zeta potential (ZP) of -20.8 ± 2.72 mV, and an entrapment efficiency (% EE) of 88.66 ± 2.30 %. In-vitro release data shows, Honokiol-SLNs displayed a sustained release profile at pH (7.4). The oral bioavailability of Honokiol-SLNs was remarkably greater (8-fold) than Honokiol-Pure suspension. The neuroprotective property of Honokiol-SLNs was initially demonstrated against hydrogen peroxide H2O2-stimulated PC12 (pheochromocytoma) cells. Furthermore, results of in-vivo studies demonstrated that treatment with Honokiol-SLNs significantly (p < 0.001) suppressed oxidative stress by inhibition of nuclear factor kappa B (NF-κB) and significant (p < 0.001) upregulation of nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling in the spinal cord. The expression of transient receptor potential melastatin 8(TRPM8) and transient receptor potential vanilloid 1 (TRPV1) was significantly (p < 0.001) downregulated. Honokiol-SLNs inhibited apoptosis by significant (p < 0.001) downregulation of cleaved caspase-3 expression in the spinal cord. These findings demonstrate that Honokiol-SLNs providedbetter neuroprotection in DN because of higher oral bioavailability.

Neuroprotective effects of Bauhinia variegata in ameliorating diabetic neuropathy and neurodegeneration

INTRODUCTION

In diabetic neuropathy with neurodegeneration (DNN), a serious diabetes consequence, extreme hyperglycemia destroys neurons in the brain and limbs. The main therapies for this condition are glucose control and pain management. Phytopharmacology is thought to be more successful in addressing the pain and blood sugar management issues associated with DNN. The objective of this study was to investigate how Bauhinia variegata (BV) could offer protection against streptozotocin (STZ)-induced diabetic neuropathy.

METHODOLOGY

STZ-associated DNN was induced in rats, and these diabetic rats were treated with BV at 200 mg/kg and 400 mg/kg doses for 28 days. Blood glucose (BG), serum nitrite, lipid peroxidation, antioxidants, C-reactive protein, behavioral, and histopathological parameters were assessed.

RESULTS

BV dramatically reduced BG and HbA1c levels in diabetic rats, according to the findings. The levels of superoxide dismutase and catalase both rose significantly. Both lipid peroxidation and serum nitrite levels were drastically decreased with BV treatment. In this study, it was found that BV has anti-hyperglycemic and anti-inflammatory effects on DNN. This was shown by a significant drop in C-reactive protein in diabetic rats, which was a key factor in diabetic neuropathy. Thermal hyperalgesia was significantly alleviated after BV therapy, and diabetic rats' pain thresholds improved.

CONCLUSION

Present study concluded that BV treatment has excellent glycemic control, a high antioxidant status, and relevant pain-relieving potential in diabetic neuropathy with neurodegeneration by reversing thermal hyperalgesia and decreasing hypeglycemia in diabetic rats.