Prevention of Chronic Diabetic Neuropathy and Diabetes-Associated Cognitive Impairment Using Medicinal Herbs (Cassia Angustifolia and Nigella Sativa).

Nodal regions, areas of intensive contact between Schwann cells and axons, may be exceptionally vulnerable to diabetes-induced changes because they are exposed to and impacted by the metabolic implications of diabetes. Insulin receptors, glucose transporters, Na+ and K+ channels, and mitochondria are abundant in nodes, all of which have been linked to the development and progression of Diabetic Peripheral Neuropathy (DPN) and Type 1 Diabetes Mellitus (T1DM)-associated cognitive impairment. Our study aimed to evaluate if the administration of Nigella sativa (NS) and Cassia angustifolia (CA) prevented diabetes-associated nervous system deficits in hyperglycemic mice. We developed T1DM mice through Streptozotocin (STZ) injections and validated the elevations in blood glucose levels. NS and CA were administered immediately upon the induction of diabetes. Behavioral analysis, histopathological evaluations, and assessment of molecular biomarkers (NR2A, MPZ, NfL) were performed to assess neuropathy and cognitive impairment. Improvements in memory, myelin loss, and the expression of synaptic proteins, even with the retention of hyperglycemia, were evident in the mice who were given a dose of herbal products upon the detection of hyperglycemia. NS was more beneficial in preventing memory impairments, demyelination, and synaptic dysfunction. The findings indicate that including these herbs in the diets of diabetic as well as pre-diabetic patients can reduce complications associated with T1DM, notably diabetic peripheral neuropathy and cognitive deficits associated with T1DM.

Chrysin-loaded PEGylated liposomes protect against alloxan-induced diabetic neuropathy in rats: the interplay between endoplasmic reticulum stress and autophagy.

BACKGROUND: Diabetic neuropathy (DN) is recognized as a significant complication arising from diabetes mellitus (DM). Pathogenesis of DN is accelerated by endoplasmic reticulum (ER) stress, which inhibits autophagy and contributes to disease progression. Autophagy is a highly conserved mechanism crucial in mitigating cell death induced by ER stress. Chrysin, a naturally occurring flavonoid, can be found abundantly in honey, propolis, and various plant extracts. Despite possessing advantageous attributes such as being an antioxidant, anti-allergic, anti-inflammatory, anti-fibrotic, and anticancer agent, chrysin exhibits limited bioavailability. The current study aimed to produce a more bioavailable form of chrysin and discover how administering chrysin could alter the neuropathy induced by Alloxan in male rats. METHODS: Chrysin was formulated using PEGylated liposomes to boost its bioavailability and formulation. Chrysin PEGylated liposomes (Chr-PLs) were characterized for particle size diameter, zeta potential, polydispersity index, transmission electron microscopy, and in vitro drug release. Rats were divided into four groups: control, Alloxan, metformin, and Chr-PLs. In order to determine Chr- PLs' antidiabetic activity and, by extension, its capacity to ameliorate DN, several experiments were carried out. These included measuring acetylcholinesterase, fasting blood glucose, insulin, genes dependent on autophagy or stress in the endoplasmic reticulum, and histopathological analysis. RESULTS: According to the results, the prepared Chr-PLs exhibited an average particle size of approximately 134 nm. They displayed even distribution of particle sizes. The maximum entrapment efficiency of 90.48 ± 7.75% was achieved. Chr-PLs effectively decreased blood glucose levels by 67.7% and elevated serum acetylcholinesterase levels by 40% compared to diabetic rats. Additionally, Chr-PLs suppressed the expression of ER stress-related genes (ATF-6, CHOP, XBP-1, BiP, JNK, PI3K, Akt, and mTOR by 33%, 39.5%, 32.2%, 44.4%, 40.4%, 39.2%, 39%, and 35.9%, respectively). They also upregulated the miR-301a-5p expression levels by 513% and downregulated miR-301a-5p expression levels by 65%. They also boosted the expression of autophagic markers (AMPK, ULK1, Beclin 1, and LC3-II by 90.3%, 181%, 109%, and 78%, respectively) in the sciatic nerve. The histopathological analysis also showed that Chr-PLs inhibited sciatic nerve degeneration. CONCLUSION: The findings suggest that Chr-PLs may be helpful in the protection against DN via regulation of ER stress and autophagy.

Cinnamaldehyde protects SH-SY5Y cells against advanced glycation end-products induced ectopic cell cycle re-entry.

Accumulation of advanced glycation end-products (AGEs) in the brain contributes significantly to cognitive impairment in patients with diabetes by disrupting the post-mitotic state of neuronal cells, thereby triggering ectopic cell cycle re-entry (CCR) and subsequent neuronal apoptosis. Cinnamaldehyde (CINA), a potential mitigator of cognitive impairment due to its blood glucose-lowering properties, warrants exploration for its role in counteracting diabetes-related neurological damage. In this study, we examined the neuroprotective effect of CINA on AGE-damaged SH-SY5Y human neuroblastoma cells differentiated in vitro. We investigated the impact of CINA on AGE-induced neuronal CCR and apoptosis, finding that it substantially suppressed aberrant DNA replication, precluded cells from entering the mitotic preparatory phase, and diminished apoptosis. Additionally, CINA inhibited the expression of eIF4E without altering S6K1 phosphorylation. These findings indicate that CINA safeguards neuronal cells from AGE-related damage by preventing abnormal CCR, preserving the post-mitotic state of neuronal cells, and reducing AGE-induced apoptosis, potentially through the inhibition of eIF4E-controlled cell proliferation. Our results highlight the prospective utility of CINA in managing diabetic neuropathy.

NF-κB pathway as a molecular target for curcumin in diabetes mellitus treatment: Focusing on oxidative stress and inflammation.

Diabetes mellitus (DM) is a collection of metabolic disorder that is characterized by chronic hyperglycemia. Recent studies have demonstrated the crucial involvement of oxidative stress (OS) and inflammatory reactions in the development of DM. Curcumin (CUR), a natural compound derived from turmeric, exerts beneficial effects on diabetes mellitus through its interaction with the nuclear factor kappa B (NF-κB) pathway. Research indicates that CUR targets inflammatory mediators in diabetes, including tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6), by modulating the NF-κB signaling pathway. By reducing the expression of these inflammatory factors, CUR demonstrates protective effects in DM by improving pancreatic ß-cells function, normalizing inflammatory cytokines, reducing OS and enhancing insulin sensitivity. The findings reveal that CUR administration effectively lowered blood glucose elevation, reinstated diminished serum insulin levels, and enhanced body weight in Streptozotocin -induced diabetic rats. CUR exerts its beneficial effects in management of diabetic complications through regulation of signaling pathways, such as calcium-calmodulin (CaM)-dependent protein kinase II (CaMKII), peroxisome proliferator-activated receptor gamma (PPAR-γ), NF-κB, and transforming growth factor ß1 (TGFB1). Moreover, CUR reversed the heightened expression of inflammatory cytokines (TNF-α, Interleukin-1 beta (IL-1ß), IL-6) and chemokines like MCP-1 in diabetic specimens, vindicating its anti-inflammatory potency in counteracting hyperglycemia-induced alterations. CUR diminishes OS, avert structural kidney damage linked to diabetic nephropathy, and suppress NF-κB activity. Furthermore, CUR exhibited a protective effect against diabetic cardiomyopathy, lung injury, and diabetic gastroparesis. Conclusively, the study posits that CUR could potentially offer therapeutic benefits in relieving diabetic complications through its influence on the NF-κB pathway.

Diabetic Peripheral Neuropathy: Prevention and Treatment.

Diabetic peripheral neuropathy occurs in up to 50% of patients with diabetes mellitus and increases the risk of diabetic foot ulcers and infections. Consistent screening and clear communication are essential to decrease disparities in assessment of neuropathic symptoms and diagnosis. Physicians should address underlying risk factors such as poor glycemic control, vitamin B12 deficiency, elevated blood pressure, and obesity to reduce the likelihood of developing neuropathy. First-line drug therapy for painful diabetic peripheral neuropathy includes duloxetine, gabapentin, amitriptyline, and pregabalin; however, these medications do not restore sensation to affected extremities. Evidence for long-term benefit and safety of first-line treatment options is lacking. Second-line drug therapy includes nortriptyline, imipramine, venlafaxine, carbamazepine, oxcarbazepine, topical lidocaine, and topical capsaicin. Periodic, objective monitoring of medication response is critical because patients may not obtain desired pain reduction, adverse effects are common, and serious adverse effects can occur. Opioids should generally be avoided. Nondrug therapies with low- to moderate-quality evidence include exercise and neuromodulation with spinal cord stimulation or transcutaneous electrical nerve stimulation. Peripheral transcutaneous electrical nerve stimulation is well tolerated and inexpensive, but benefits are modest. Other treatments, such as acupuncture, alpha-lipoic acid, acetyl-L-carnitine, cannabidiol, and onabotulinumtoxinA need further study in patients with diabetic peripheral neuropathy.

Clinical and preclinical evidence that angiotensin-converting enzyme inhibitors and angiotensin receptor blockers prevent diabetic peripheral neuropathy.

Given possible involvement of the central and peripheral angiotensin system in pain processing, we conducted clinical and preclinical studies to test whether pharmacological inhibition of the angiotensin system would prevent diabetic peripheral neuropathy (DPN) accompanying type 2 diabetes mellitus (T2DM). In the preclinical study, the nociceptive sensitivity was determined in leptin-deficient ob/ob mice, a T2DM model. A clinical retrospective cohort study was conducted, using the medical records of T2DM patients receiving antihypertensives at three hospitals for nearly a decade. In the ob/ob mice, daily treatment with perindopril, an angiotensin-converting enzyme inhibitor (ACEI), or telmisartan, an angiotensin receptor blocker (ARB), but not amlodipine, an L-type calcium channel blocker (CaB), significantly inhibited DPN development without affecting the hyperglycemia. In the clinical study, the enrolled 7464 patients were divided into three groups receiving ACEIs, ARBs and the others (non-ACEI, non-ARB antihypertensives). Bonferroni's test indicated significantly later DPN development in the ARB and ACEI groups than the others group. The multivariate Cox proportional analysis detected significant negative association of the prescription of ACEIs or ARBs and ß-blockers, but not CaBs or diuretics, with DPN development. Thus, our study suggests that pharmacological inhibition of the angiotensin system is beneficial to prevent DPN accompanying T2DM.

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-1ß 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.

Protective effect of alirocumab, a PCSK9 inhibitor, on the sciatic nerve of rats with diabetic peripheral neuropathy.

Dyslipidemia has been considered a risk factor for diabetic peripheral neuropathy. Proprotein convertase subtilisin-like/Kexin 9 inhibitor (PCSK9) inhibitors are a new type of lipid-lowering drug currently in clinical use. The role of PCSK9 in diabetic peripheral neuropathy is still unclear. In this study, the effect of alirocumab, a PCSK9 inhibitor, on the sciatic nerve in rats with diabetic peripheral neuropathy and its underlying mechanisms were investigated. The diabetic peripheral neuropathy rat model was established by using a high-fat diet combined with streptozotocin injection, and experimental subjects were divided into normal, diabetic peripheral neuropathy, and alirocumab groups. The results showed that Alirocumab improved nerve conduction, morphological changes, and small fiber deficits in rats with DPN, possibly related to its amelioration of oxidative stress and the inflammatory response.

Withametelin, a steroidal lactone, isolated from datura innoxa attenuates STZ-induced diabetic neuropathic pain in rats through inhibition of NF-kB/MAPK signaling.

Diabetic neuropathic pain is one of the microvascular complications of diabetes mellitus characterized by symmetrical pain and sensory abnormalities. A steroidal lactone isolated from the datura innoxa plant, withametelin (WMT), exhibited significant neuroprotective, anti-inflammatory, antioxidant, and anticancer properties. The current study aimed to investigate anti-neuropathic pain activity and the molecular mechanism of WMT against streptozotocin (STZ)-induced diabetic neuropathy. Rats were given a single injection of STZ (60 mg/kg, intraperitoneally (i.p.)) for induction of diabetes on the first day of the study. After the onset of diabetic neuropathy, pregabalin (10 mg/kg, i.p.) and WMT (0.1 and 1 mg/kg, i.p.) treatments were started from day 14 up to day 42. It was found that STZ-induced neuropathic pain behaviors were markedly reduced by WMT. It inhibited the STZ-associated histopathological changes and genotoxicity in the sciatic nerve and spinal cord. Additionally, Fourier transforms infrared (FTIR) spectroscopy results revealed that STZ-induced alterations in the biochemical components of the sciatic nerve's myelin sheath were inhibited by WMT. In the spinal cord, it markedly reduced the immunoreactivity of mitogen-activated protein kinases (MAPKs) signaling components such as p38-MAPK, c-Jun N-terminal kinase (JNK), extracellular-signal-regulated-kinase (ERK), and activator-protein 1 (AP-1). It also reduced the expression levels of nuclear factor-kappa-B (NF-κB), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). The production of inflammatory cytokines was considerably reduced by WMT. This study provides convincing evidence that WMT treatment attenuated STZ-induced diabetic neuropathic pain by inhibition of MAPK/NF-κB signaling.

Long-term effects of l-serine supplementation upon a mouse model of diabetic neuropathy.

Deoxysphingolipids (1-deoxySLs) are neurotoxic sphingolipids associated with obesity and diabetic neuropathy (DN) and have been linked to severity of functional peripheral neuropathies. While l-serine supplementation can reduce 1-deoxySL accumulation and improve insulin sensitivity and sensory nerve velocity, long-term outcomes have not yet been examined. To assess this, we treated 2 month old db/db mice, a model of DN, with 5-20 % oral l-serine for 6 months and longitudinally quantified the extent of functional neuropathy progression. We examined putative biomarkers of neuropathy in blood and tissue and quantified levels of small fiber neuropathy, looking for associations between lowered 1-deoxySL and phenotypes. Toxic 1-deoxySLs were suppressed long-term in plasma and various tissue including the sciatic nerve, which is particularly targeted in DN. Functional neuropathy and sensory modalities were significantly improved in the treatment group well into advanced stages of disease. However, structural assessments revealed prominent axonal degeneration, apoptosis and Schwann cell pathology, suggesting that neuropathy was ongoing. Hyperglycemia and dyslipidemia persisted during our study, and high levels of glutathione were seen in the spinal cord. Our results demonstrate that despite significant functional improvements, l-serine does not prevent chronic degenerative changes specifically at the structural level, pointing to other processes such as oxidative damage and hyperglycemia, that persist despite 1-deoxySL reduction.

Neuroprotective validation of pectin in T2DM-induced allodynia and hyperalgesia in diabetic peripheral neuropathic pain.

AIM: To validate neuroprotective effect of pectin against neuropathic pain in diabetic rodents. MATERIAL AND METHOD: Pectin was isolated and characterised from different sources to validate its neuroprotective effect against T2DM associated neuropathic pain. The antioxidant activity of pectins was done by the DPPH method. Type-2 diabetes mellitus (T2DM) was induced in Wistar albino rats by high-fat diet and high-fat emulsion feeding for 2 weeks followed by a single i.p. of Sterptozotocin in 3rd week. The animals were grouped as positive control and Citrus sinensis (L.) Osbeck peel pectin (CSL-OP) as test group and treated for the next 4 weeks. Body weight and blood glucose were measured up to 8 weeks; however, behavioural assessment was done at the end of 5th to 8th week. RESULT: CSL-OP restored the reduced body weight and elevated blood glucose with increased pain threshold and improved walking performance. CONCLUSION: CSL-OP prevented progression of early diabetic neuropathy with anti-oxidant activity.

Hypertension the 'Missed Modifiable Risk Factor' for Diabetic Neuropathy: a Systematic Review.

Diabetes and hypertension stand as the major non-infectious diseases affecting 34.2 million and 1.28 billion people respectively. The literature on the impact of diabetes on hypertension and vice versa is evolving. The major objectives of this review were to compile the evolving literature establishing the role of hypertension in diabetic neuropathy, derive the exact mechanisms for its pathogenesis, and describe evidence-based precise individualized management of diabetic neuropathy in patients having diabetes complicated by hypertension. A systematic review was conducted by searching databases of PubMed, Embase, and Scopus covering the literature from inception to 2022. We included all observational and experimental studies, including both human and animal studies looking into the correlation between diabetic neuropathy and hypertension. Hypertension poses to be the leading modifiable risk factor for the development of diabetic neuropathy, especially distal symmetrical polyneuropathy, producing abnormal nerve conduction parameters and increased vibration perception threshold in patients with diabetes mellitus. Thus, we advocate that good glycemic control in patients with diabetes needs to be supported with strict blood pressure control for preventing and delaying the onset of diabetic neuropathy.

Alpha-lipoic acid activates AMPK to protect against oxidative stress and apoptosis in rats with diabetic peripheral neuropathy.

PURPOSE: To investigate the AMPK pathway-mediated effect of alpha-lipoic acid (ALA) on the dorsal root ganglia (DRGs) of rats with diabetic peripheral neuropathy (DPN) and to attempt to elucidate the underlying mechanism. METHODS: Sprague-Dawley rats (n = 15) were randomly divided into three groups. The control group was fed a standard diet, and the other groups were fed a high-carbohydrate/high-fat diet. Diabetes was established by a single streptozotocin (STZ) (30 mg/kg) injection, and control rats were injected with an equal volume of citrate buffer. ALA (60 mg/kg/day) was administered for 12 weeks. The nerve conduction velocity (NCV) of the sciatic nerve was measured. Glutathione (GSH) and malondialdehyde (MDA) concentrations in serum were measured with the thiobarbituric acid method and biochemistry. Pathological changes in the rat DRGs were observed. AMPK, phospho-AMPK (p-AMPK), nuclear factor erythroid-2-related factor 2 (Nrf2), phospho-nuclear factor erythroid-2-related factor 2 (p-Nrf2), heme oxygenase 1 (HO-1), quinone oxidoreductase 1 (NQO1), Forkhead box O3 (FoxO3a), phospho-Forkhead box O3 (p-FoxO3a), and Bcl-2 interacting mediator of cell death (Bim) expression levels were assessed by immunohistochemistry and western blotting. RESULTS: ALA improved the motor NCV (MNCV) and sensory NCV (SNCV) of rats with DPN and reduced their mechanical pain threshold. ALA increased serum GSH concentrations and decreased serum MDA concentrations. Additionally, AMPK was activated by ALA. Nrf2, p-Nrf2, HO-1, and NQO1 expression was upregulated, while FoxO3a, p-FoxO3a, and Bim expression was downregulated. ALA reduced oxidative stress and apoptosis in DRG. CONCLUSION: ALA alleviates DPN and improves peripheral nerve function. ALA reduces oxidative stress by activating Nrf2 through AMPK and inhibits FoxO3a and Bim thereby reducing neuronal apoptosis.

Bacoside-A Improves Antioxidant Enzymes and Alleviates Oxidative Stress Coexist with Markers of Renal Function in a Rat Model of Type 2 Diabetes Mellitus.

Oxidative stress, imbalanced antioxidants, and dysregulated renal lipids are closely linked with diabetic nephropathy and eventual cause of end-stage renal failure. This study was performed to investigate the protective effect of bacoside-A on markers of lipid peroxidation, renal lipids, and markers of renal function in diabetic rats. Experimental diabetes was induced in Wistar rats by a single dose of streptozotocin [40 mg/kg body weight (BW)] via intraperitoneal injection. Oral administration of bacoside-A (10 mg/kg BW) and glibenclamide, a reference drug, continued for 45 days. Diabetic rats showed a significant increase in the levels of plasma glucose, renal lipids, markers of renal lipid peroxidation, and plasma biomarkers of renal function such as urea, uric acid, and creatinine. A significant decrease in the levels of plasma insulin, nonenzymatic antioxidants, and the activity of enzymatic antioxidants was seen compared with the normal controls. Bacoside-A (10 mg/kg BW) and glibenclamide (600 µg/kg BW) administered to diabetic rats resulted in a significant decrease in plasma glucose and renal lipids but a significant increase in the plasma insulin level. In addition, bacoside-A achieved a remarkable increase in the activity of enzymatic antioxidants and the levels of nonenzymatic antioxidants in the renal tissue of diabetic rats, along with significant decreases in the markers of lipid peroxidation and those of renal function, consequently substantiating the protecting effectiveness of bacoside-A in a diabetic state. These biochemical observations were supported by a histopathological study of the renal tissue. The present study suggested that bacoside-A, a triterpenoid, offers a higher renoprotective effect to counter abnormal parameters of renal function in diabetes-induced renal injury.

[Experimental research progress in traditional Chinese medicine prevention and treatment of diabetic peripheral neuropathy based on autophagy].

Diabetic peripheral neuropathy(DPN) is a chronic complication resulted from peripheral nerve injury in the late stage of diabetes. It involves a variety of pathological changes such as oxidative stress, endoplasmic reticulum stress, neuroinflammation, and apoptosis of Schwann cells(SCs). DPN is the main factor leading to lower limb disability or amputation in diabetic patients, with high incidence, long disease course, and poor prognosis. The modern medicine treatment of DPN mainly focuses on controlling blood glucose and improving microcirculation and nerve nutrition, which can only mitigate the clinical symptoms and not fundamentally reverse the pathological changes of peripheral nerves. Autophagy is a self-clearing mechanism that maintains cellular homeostasis by removing excess metabolites. Traditional Chinese medicine(TCM), featuring the holistic concept and syndrome differentiation, can treat chronic diseases in a multi-target, multi-pathway, and wide-range manner. Modern studies have shown that the occurrence and development of DPN are related to a variety of pathological changes, and autophagy is a key mechanism associated with DPN. The environment with persistent high glucose can lead to the inhibition or over-activation of peripheral nerve cells, which causes irreversible damage of nerve cells and the occurrence and development of DPN. Therefore, restoring autophagy balance and reducing nerve damage is one of the key ways to treat DPN. The recent studies have confirmed that some active ingredients in traditional Chinese medicines and TCM compound prescriptions can inhibit the oxidative stress, endoplasmic reticulum stress, mitochondrial damage, inflammation, and apoptosis of SCs in DPN by regulating the autophagy pathway, thus playing a role in the prevention and treatment of DPN. However, the systematic induction in this field remains to be carried out. This paper reviewed the relevant literature, explained the mechanism of TCM in the prevention and treatment of DPN by regulating autophagy, and summarized the potential targets of TCM in the treatment of DPN, with a view to providing new ideas for clinical research and drug development.

Preventing diabetes-related foot ulcers through early detection of peripheral neuropathy.

BACKGROUND: Peripheral neuropathy, peripheral arterial disease and diabetes-related foot ulcers are the most important risk factors for future amputation. Up to 50% of people with diabetes have distal symmetrical polyneuropathy as a complication of diabetes. Distal symmetrical polyneuropathy results in loss of protective sensation in the feet, increasing the risk of diabetes-related foot ulceration. OBJECTIVE: The aim of this article is to provide structured guidance for detecting diabetes-related peripheral neuropathy, appropriate referral based on risk assessment and prevention of diabetes­related foot ulceration. DISCUSSION: As a result of the often-asymptomatic nature of diabetes-related peripheral neuropathy, general practice is an ideal location for screening all adults with diabetes for loss of protective sensation. Loss of protective sensation in a person with diabetes indicates an at-risk foot. Increased frequency of foot examination, education in self-care, appropriate footwear and referral to podiatry for non­ulcerative foot problems can reduce the development of diabetes-related foot ulcers.

Metformin prevents morphine-induced apoptosis in rats with diabetic neuropathy: a possible mechanism for attenuating morphine tolerance.

Morphine is a drug of choice for the treatment of severe and chronic pain, but tolerance to the antinociceptive effect limits its use. The development of tolerance to morphine has recently been associated with neuronal apoptosis. In this study, our aim was to investigate the effects of metformin on morphine-induced neuronal apoptosis and antinociceptive tolerance in diabetic rats. Three days of cumulative dosing were administered to establish morphine tolerance in rats. The antinociceptive effects of metformin (50 mg/kg) and test dose of morphine (5 mg/kg) were considered at 30-min intervals by thermal antinociceptive tests. To induce diabetic neuropathy, streptozotocin (STZ, 65 mg/kg) was injected intraperitoneally. ELISA kits were used to measure caspase-3, bax, and bcl-2 levels from dorsal root ganglion (DRG) tissue. Semi-quantitative scoring system was used to evaluate apoptotic cells with the the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) method. The findings suggest that co-administration of metformin with morphine to diabetic rats showed a significant increase in antinociceptive effect compared to morphine alone. The antinociceptive tests indicated that metformin significantly attenuated morphine antinociceptive tolerance in diabetic rats. In addition, metformin decreased the levels of apoptotic proteins caspase 3 and Bax in DRG neurons, while significantly increased the levels of antiapoptotic Bcl-2. Semi-quantitative scoring showed that metformin provided a significant reduction in apoptotic cell counts in diabetic rats. These data revealed that metformin demonstrated antiapoptotic activity in diabetic rat DRG neurons and attenuated morphine tolerance. The antiapoptotic activity of metformin probably plays a significant role in reducing morphine tolerance.

Towards prevention of diabetic peripheral neuropathy: clinical presentation, pathogenesis, and new treatments.

Diabetic peripheral neuropathy (DPN) occurs in up to half of individuals with type 1 or type 2 diabetes. DPN results from the distal-to-proximal loss of peripheral nerve function, leading to physical disability and sometimes pain, with the consequent lowering of quality of life. Early diagnosis improves clinical outcomes, but many patients still develop neuropathy. Hyperglycaemia is a risk factor and glycaemic control prevents DPN development in type 1 diabetes. However, glycaemic control has modest or no benefit in individuals with type 2 diabetes, probably because they usually have comorbidities. Among them, the metabolic syndrome is a major risk factor for DPN. The pathophysiology of DPN is complex, but mechanisms converge on a unifying theme of bioenergetic failure in the peripheral nerves due to their unique anatomy. Current clinical management focuses on controlling diabetes, the metabolic syndrome, and pain, but remains suboptimal for most patients. Thus, research is ongoing to improve early diagnosis and prognosis, to identify molecular mechanisms that could lead to therapeutic targets, and to investigate lifestyle interventions to improve clinical outcomes.

Glycemia Reduction in Type 2 Diabetes - Microvascular and Cardiovascular Outcomes.

BACKGROUND: Data are lacking on the comparative effectiveness of commonly used glucose-lowering medications, when added to metformin, with respect to microvascular and cardiovascular disease outcomes in persons with type 2 diabetes. METHODS: We assessed the comparative effectiveness of four commonly used glucose-lowering medications, added to metformin, in achieving and maintaining a glycated hemoglobin level of less than 7.0% in participants with type 2 diabetes. The randomly assigned therapies were insulin glargine U-100 (hereafter, glargine), glimepiride, liraglutide, and sitagliptin. Prespecified secondary outcomes with respect to microvascular and cardiovascular disease included hypertension and dyslipidemia, confirmed moderately or severely increased albuminuria or an estimated glomerular filtration rate of less than 60 ml per minute per 1.73 m2 of body-surface area, diabetic peripheral neuropathy assessed with the Michigan Neuropathy Screening Instrument, cardiovascular events (major adverse cardiovascular events [MACE], hospitalization for heart failure, or an aggregate outcome of any cardiovascular event), and death. Hazard ratios are presented with 95% confidence limits that are not adjusted for multiple comparisons. RESULTS: During a mean 5.0 years of follow-up in 5047 participants, there were no material differences among the interventions with respect to the development of hypertension or dyslipidemia or with respect to microvascular outcomes; the mean overall rate (i.e., events per 100 participant-years) of moderately increased albuminuria levels was 2.6, of severely increased albuminuria levels 1.1, of renal impairment 2.9, and of diabetic peripheral neuropathy 16.7. The treatment groups did not differ with respect to MACE (overall rate, 1.0), hospitalization for heart failure (0.4), death from cardiovascular causes (0.3), or all deaths (0.6). There were small differences with respect to rates of any cardiovascular disease, with 1.9, 1.9, 1.4, and 2.0 in the glargine, glimepiride, liraglutide, and sitagliptin groups, respectively. When one treatment was compared with the combined results of the other three treatments, the hazard ratios for any cardiovascular disease were 1.1 (95% confidence interval [CI], 0.9 to 1.3) in the glargine group, 1.1 (95% CI, 0.9 to 1.4) in the glimepiride group, 0.7 (95% CI, 0.6 to 0.9) in the liraglutide group, and 1.2 (95% CI, 1.0 to 1.5) in the sitagliptin group. CONCLUSIONS: In participants with type 2 diabetes, the incidences of microvascular complications and death were not materially different among the four treatment groups. The findings indicated possible differences among the groups in the incidence of any cardiovascular disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; GRADE ClinicalTrials.gov number, NCT01794143.).