Neuropathy among the diabetes control and complications trial cohort 8 years after trial completion

The prevalence and risk factors of peripheral neuropathy among patients with type 2 diabetes mellitus; the case of Jordan

BACKGROUND

Peripheral neuropathy is one of the most common microvascular complication of diabetes mellitus. This study is conducted to determine the prevalence of diabetic peripheral neuropathy (DPN) and its associated factors among patients with type 2 diabetes mellitus in Jordan.

METHODS

A cross-sectional study was conducted at the National Center for Diabetes, Endocrinology and Genetics, Jordan. A total of 1003 patients with type 2 diabetes were recruited. Data were collected from participants during a face-to-face structured interview. DPN was assessed using the translated version of Michigan Neuropathy Screening Instrument (MNSI).

RESULTS

The overall prevalence of DPN based on MNSI was 39.5%. The most frequently reported symptoms were numbness (32.3%) and pain with walking (29.7%), while the least reported symptoms were the history of amputation (1.3%) and loss of sensation in legs/feet while walking (3.8%). Logistic regression analysis revealed that unemployment, cardiovascular disease, dyslipidemia, diabetic retinopathy and long standing DM (diabetes of ≥ 5 years) were significantly associated with DPN.

CONCLUSION

Peripheral Neuropathy is highly prevalent among Jordanian patients with type 2 diabetes mellitus. DPN was significantly associated with duration of DM, dyslipidemia, diabetic retinopathy, cardiovascular disease, and unemployment. Early detection and appropriate intervention are mandatory among high-risk groups.

Therapeutic effect of human adipose-derived stem cells and their secretome in experimental diabetic pain

Painful neuropathy is one of the complications of diabetes mellitus that adversely affects patients'quality of life. Pharmacological treatments are not fully satisfactory, and novel approaches needed. In a preclinical mouse model of diabetes the effect of both human mesenchymal stromal cells from adipose tissue (hASC) and their conditioned medium (hASC-CM) was evaluated. Diabetes was induced by streptozotocin. After neuropathic hypersensitivity was established, mice were intravenously injected with either 1 × 10⁶ hASC or with CM derived from 2 × 10⁶ hASC. Both hASC and CM (secretome) reversed mechanical, thermal allodynia and thermal hyperalgesia, with a rapid and long lasting effect, maintained up to 12 weeks after treatments. In nerves, dorsal root ganglia and spinal cord of neuropathic mice we determined high IL-1β, IL-6 and TNF-α and low IL-10 levels. Both treatments restored a correct pro/antinflammatory cytokine balance and prevented skin innervation loss. In spleens of streptozotocin-mice, both hASC and hASC-CM re-established Th1/Th2 balance that was shifted to Th1 during diabetes. Blood glucose levels were unaffected although diabetic animals regained weight, and kidney morphology was recovered by treatments. Our data show that hASC and hASC-CM treatments may be promising approaches for diabetic neuropathic pain, and suggest that cell effect is likely mediated by their secretome.

Microvascular Complications Associated With Rapid Improvements in Glycemic Control in Diabetes

PURPOSE OF REVIEW

Aggressive glycemic control has become the standard clinical approach to diabetes care. Unintended consequences have included the development of microvascular complications that are related to the rapidity of glycemic improvement.

RECENT FINDINGS

Diabetic neuropathy may develop in up to 10% of individuals secondary to aggressive glycemic control. The neuropathy is predominantly small fiber sensory and autonomic, and the severity of the neuropathy is tied to the change in the glycosylated hemoglobin A1C. Other microvascular complications such as retinopathy and nephropathy are common and may occur in parallel with the neuropathy. Eating disorders are a common comorbid risk factor. Individuals with uncontrolled diabetes for prolonged periods, particularly those with a history of eating disorders involving insulin restriction for calorie purging, are at high risk for developing treatment-induced microvascular complications. Gradual glycemic improvements should be encouraged but future research is needed to optimize treatment and prevention strategies.

Association of aldose reductase gene polymorphism (C-106T) in susceptibility of diabetic peripheral neuropathy among north Indian population

AIM/HYPOTHESIS

Polymorphism in aldose reductase (ALR) gene at nucleotide C(-106)T (rs759853) in the promoter region is associated with susceptibility to development of diabetic peripheral neuropathy. The aim of this study was to detect the association of the C (-106)T polymorphism of ALR gene and its frequency among patients with type 2 diabetes mellitus with and without peripheral neuropathy.

METHODS

The study subjects were divided into three groups. Group I included 356 patients with diabetes having peripheral neuropathy. Group II included 294 patients with diabetes without peripheral neuropathy and group III included 181 healthy subjects. Genotyping of ALR C(-106)T SNPs was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing methods. The genetic risk among the groups was compared and tested by calculating odds ratio with 95% class interval.

RESULTS

ALR 106TT genotype was significantly higher in group I compared to group II with an odds ratio of 2.12 (95% CI: 1.22-3.67; p<0.01). Recessive model (CC+CT vs. TT), as well as T allele distribution also showed significant association to develop neuropathy with relative risk of 1.97 (95% CI: 1.16-3.35; p<0.01) and 1.36 (95% CI: 1.07-1.72; p=0.01) respectively.

CONCLUSION/INTERPRETATION

In conclusion, the ALR C-106T polymorphism was associated with higher risk of peripheral neuropathy in patients with type 2 diabetes mellitus.

Murine model and mechanisms of treatment-induced painful diabetic neuropathy

Diabetes mellitus represents a group of metabolic diseases that are characterized by hyperglycemia caused by either lack of insulin production or a reduced ability to respond to insulin. It is estimated that there were 347 million people worldwide who suffered from diabetes in 2008 and incidence is predicted to double by 2050. Neuropathy is the most common complication of long-term diabetes and approximately 30% of these subjects develop chronic neuropathic pain. A distinct acute, severe form of neuropathic pain, called insulin neuritis or treatment-induced painful neuropathy of diabetes (TIND), may also occur shortly after initiation of intensive glycemic control, with an incidence rate of up to 10.9%. The pathological mechanisms leading to TIND, which is mostly unresponsive to analgesics, are not yet understood, impeding the development of therapies. Studies to date have been clinical and with limited cohorts of patients. In the current study, we developed chronic and acute insulin-induced neuropathic pain in mice with type 2 insulin-resistant diabetes. Furthermore, we determined that insulin-induced acute allodynia is independent of glycemia levels, can also be induced with Insulin-like Growth Factor 1 (IGF1) and be prevented by inhibition of AKT, providing evidence of an insulin/IGF1 signaling pathway-based mechanism for TIND. This mouse model is useful for the elucidation of mechanisms contributing to TIND and for the testing of new therapeutic approaches to treat TIND.

Evidence-based recommendations and expert consensus on enteral nutrition in the adult patient with diabetes mellitus or hyperglycemia

OBJECTIVE

The aim of this study was to develop evidence-based recommendations for glycemic control of patients with diabetes mellitus or stress hyperglycemia who are receiving enteral nutrition (EN).

METHODS

A Delphi survey method using Grading Recommendations Assessment, Development and Evaluation criteria was utilized for evaluation of suitable studies.

RESULTS

In patients with diabetes or stress hyperglycemia who were on EN support, the following results were found: CONCLUSIONS: These recommendations and suggestions regarding enteral feeding in patients with diabetes and hyperglycemia have direct clinical applicability.

Impaired Mitochondrial Respiration in Large Cerebral Arteries of Rats with Type 2 Diabetes

Mitochondrial dysfunction has been suggested as a potential underlying cause of pathological conditions associated with type 2 diabetes (T2DM). We have previously shown that mitochondrial respiration and mitochondrial protein levels were similar in the large cerebral arteries of insulin-resistant Zucker obese rats and their lean controls. In this study, we extend our investigations into the mitochondrial dynamics of the cerebral vasculature of 14-week-old Zucker diabetic fatty obese (ZDFO) rats with early T2DM. Body weight and blood glucose levels were significantly higher in the ZDFO group, and basal mitochondrial respiration and proton leak were significantly decreased in the large cerebral arteries of the ZDFO rats compared with the lean controls (ZDFL). The expression of the mitochondrial proteins total manganese superoxide dismutase (MnSOD) and voltage-dependent anion channel (VDAC) were significantly lower in the cerebral microvessels, and acetylated MnSOD levels were significantly reduced in the large arteries of the ZDFO group. Additionally, superoxide production was significantly increased in the microvessels of the ZDFO group. Despite evidence of increased oxidative stress in ZDFO, exogenous SOD was not able to restore mitochondrial respiration in the ZDFO rats. Our results show, for the first time, that mitochondrial respiration and protein levels are compromised during the early stages of T2DM.

Lipids: A Suitable Therapeutic Target in Diabetic Neuropathy?

Diabetic polyneuropathy (DPN) encompasses multiple syndromes with a common pathogenesis. Glycemic control shows a limited correlation with DPN, arguing in favor of major involvement of other factors, one of which is alterations of lipid and lipoprotein metabolism. Consistent associations have been found between plasma triglycerides/remnant lipoproteins and the risk of DPN. Studies in cultured nerve tissue or in murine models of diabetes have unveiled mechanisms linking lipid metabolism to DPN. Deficient insulin action increases fatty acids flux to nerve cells, inducing mitochondrial dysfunction, anomalous protein kinase C signaling, and perturbations in the physicochemical properties of the plasma membrane. Oxidized low-density lipoproteins bind to cellular receptors and promote generation of reactive oxygen species, worsening mitochondrial function and altering the electrical properties of neurons. Supplementation with specific fatty acids has led to prevention or reversal of different modalities of DPN in animal models. Post hoc and secondary analyses of clinical trials have found benefits of cholesterol reducing (statins and ezetimibe), triglyceride-reducing (fibrates), or lipid antioxidant (thioctic acid) therapies over the progression and severity of DPN. However, these findings are mostly hypothesis-generating. Randomized trials are warranted in which the impact of intensive plasma lipids normalization on DPN outcomes is specifically evaluated.

Peripheral and Autonomic Neuropathy in South Asians and White Caucasians with Type 2 Diabetes Mellitus: Possible Explanations for Epidemiological Differences

Objectives. To compare the prevalence of diabetic peripheral neuropathy (DPN) and that of cardiac autonomic neuropathy (CAN) between South Asians and White Caucasians with type 2 diabetes and to explore reasons for observed differences. Methods. A cross-sectional study of casually selected South Asian and White Caucasian adults attending a hospital-based diabetes clinic in the UK. DPN and CAN were assessed using the Michigan Neuropathy Screening Instrument (MNSI) and heart rate variability testing, respectively. Results. Patients (n = 266) were recruited (47.4% South Asians). DPN was more common in White Caucasians compared to South Asians (54.3% versus 38.1%, p = 0.008). Foot insensitivity as assessed by 10 g monofilament perception was more common in White Caucasians (43.9% versus 23.8%, p = 0.001). After adjustment for confounders, White Caucasians remained twice as likely to have DPN as South Asians, but the impact of ethnicity became nonsignificant after adjusting for adiposity measures or height. No difference in prevalence of standardized CAN test abnormalities was detected between ethnicities. Skin microvascular assessment demonstrated that South Asians had reduced heating flux but preserved acetylcholine response. Conclusions. South Asians with type 2 diabetes have fewer clinical signs of DPN compared to White Caucasians. Differences in adiposity (and its distribution) and height appear to explain these differences.

Urogenital Autonomic Dysfunction in Diabetes

This review details the epidemiology, possible mechanisms, and risk factors associated with urogenital autonomic dysfunction in diabetes. Autonomic neuropathy in diabetes is associated with various urological complications including bladder and sexual dysfunction. Several studies have reported the high prevalence of bladder and sexual dysfunction in both men and women. The DCCT/EDIC UroEDIC study examined the association between cardiovascular autonomic neuropathy and bladder and sexual dysfunction in a large cohort of participants with type 1 diabetes and was the first to report significant associations. Future studies are needed to further evaluate the association of urogenital complications and autonomic dysfunction in diabetes.

Mesenchymal Stem Cells as a Prospective Therapy for the Diabetic Foot

The diabetic foot is a serious complication of diabetes. Mesenchymal stem cells are an abundant source of stem cells which occupy a special position in cell therapies, and recent studies have suggested that mesenchymal stem cells can play essential roles in treatments for the diabetic foot. Here, we discuss the advances that have been made in mesenchymal stem cell treatments for this condition. The roles and functional mechanisms of mesenchymal stem cells in the diabetic foot are also summarized, and insights into current and future studies are presented.

Diabetic peripheral neuropathy may not be as its name suggests: evidence from magnetic resonance imaging

Diabetic peripheral neuropathy (DPN) affects up to 50% of patients with diabetes and is a major cause of morbidity and increased mortality. Its clinical manifestations include distressing painful neuropathic symptoms and insensitivity to trauma that result in foot ulcerations and amputations. Several recent studies have implicated poor glycemic control, duration of diabetes, hyperlipidemia (particularly hypertryglyceridaemia), elevated albumin excretion rates, and obesity as risk factors for the development of DPN. However, similar data are not available for painful DPN. Moreover, although there is now strong evidence for the importance of peripheral nerve microvascular disease in the pathogenesis of DPN, peripheral structural biomarkers of painful DPN are lacking. However, there is now emerging evidence for the involvement of the central nervous system in both painful and painless DPN afforded by magnetic resonance imaging. This review will focus on this emerging evidence for central changes in DPN, hitherto considered a peripheral nerve disease only.

Long-term cost-effectiveness of initiating treatment for painful diabetic neuropathy with pregabalin, duloxetine, gabapentin, or desipramine

Painful diabetic neuropathy (PDN) affects nearly half of patients with diabetes. The objective of this study was to compare the cost-effectiveness of starting patients with PDN on pregabalin (PRE), duloxetine (DUL), gabapentin (GABA), or desipramine (DES) over a 10-year time horizon from the perspective of third-party payers in the United States. A Markov model was used to compare the costs (2013 $US) and effectiveness (quality-adjusted life-years [QALYs]) of first-line PDN treatments in 10,000 patients using microsimulation. Costs and QALYs were discounted at 3% annually. Probabilities and utilities were derived from the published literature. Costs were average wholesale price for drugs and national estimates for office visits and hospitalizations. One-way and probabilistic (PSA) sensitivity analyses were used to examine parameter uncertainty. Starting with PRE was dominated by DUL as DUL cost less and was more effective. Starting with GABA was extendedly dominated by a combination of DES and DUL. DES and DUL cost $23,468 and $25,979, while yielding 3.05 and 3.16 QALYs, respectively. The incremental cost-effectiveness ratio for DUL compared with DES was $22,867/QALY gained. One-way sensitivity analysis showed that the model was most sensitive to the adherence threshold and utility for mild pain. PSA showed that, at a willingness-to-pay (WTP) of $50,000/QALY, DUL was the most cost-effective option in 56.3% of the simulations, DES in 29.2%, GABA in 14.4%, and PRE in 0.1%. Starting with DUL is the most cost-effective option for PDN when WTP is greater than $22,867/QALY. Decision makers may consider starting with DUL for PDN patients.

Is Stem Cell Transplantation Ready for Prime Time in Diabetic Polyneuropathy?

Diabetic polyneuropathy (DPN) is the most common complication that emerges early in patients who have diabetes. Curative treatment for overt or symptomatic DPN has not been established, requiring much effort to explore new modalities. Thus, the use of various kinds of stem cells as a potential therapeutic option for DPN is of particular interest. The beneficial effects were proposed to be attributed to either cytokine released from transplanted stem cells or the differentiation of stem cells to substitute the damaged peripheral nerve. Furthermore, based on the concept that humoral factors secreted from stem cells play a pivotal role in tissue regeneration, the utilization of conditioned medium derived from the stem cell culture serves as a novel tool for regenerative therapy. However, many questions have not been yet answered to determine whether stem cell therapy is essential in clinical application of DPN. In this report, we review the current status of preclinical studies on stem cell therapy for DPN and discuss future prospects.

The relationship between obstructive sleep apnea and intra-epidermal nerve fiber density, PARP activation and foot ulceration in patients with type 2 diabetes

BACKGROUND

Obstructive sleep apnea (OSA) is associated with increased nitrosative stress, endothelial dysfunction, and peripheral neuropathy in patients with type 2 diabetes. We hypothesized that OSA is associated with Poly ADP ribose polymerase (PARP) activation, lower intra-epidermal nerve fiber density (IENFD), and diabetic foot ulceration (DFU).

METHODS

A cross-sectional study of adults with type 2 diabetes recruited from a secondary care hospital in the UK. OSA was assessed by multi-channel home-based cardio-respiratory device (Alice PDX, Philips Respironics). DPN was assessed using the Michigan Neuropathy Screening Instrument (MNSI). IENFD and % PAR stained nuclei were assessed using immunohistochemistry staining on skin biopsies. DFU was assessed based on MNSI.

RESULTS

Skin biopsies and DFU data were available from 52 and 234 patients respectively. OSA was associated with lower IENFD (12.75±1.93 vs. 10.55±1.62 vs. 9.42±1.16 fibers/mm of epidermis for no OSA, mild OSA and moderate to severe OSA respectively, p<0.001). Following adjustment, mild (B=-2.19, p=0.002) and moderate to severe OSA (B=-3.45, p<0.001) were independently associated with IENFD. The apnea hypopnea index (AHI) was associated with IENFD following adjustment (B=-2.45, p<0.001). AHI was associated with percentage of PAR stained nuclei following adjustment (B=13.67, p=0.025). DFU prevalence was greater in patients with OSA (7.1% vs. 28.1% vs. 26.2% for patients with no OSA, mild OSA and moderate to severe OSA respectively, p=0.001). Following adjustment, OSA was associated with DFU (OR 3.34, 95% CI 1.19-9.38, p=0.022).

CONCLUSIONS

OSA is associated with lower IENFD, PARP activation and DFU in patients with type 2 diabetes. Our findings suggest that OSA is associated with small fiber neuropathy. PARP activation is a potential mechanisms linking OSA to DPN and endothelial dysfunction in patients with type 2 diabetes. Whether OSA treatment will have a favorable impact on these parameters and DFU requires interventional studies.

Making Insulin Accessible: Does Inhaled Insulin Fill an Unmet Need?

Glycemic control is fundamental to the management of diabetes. However, studies suggest that a significant proportion of people with diabetes, particularly those using insulin, are not achieving glycemic targets. The reasons for this are likely to be multifactorial. The real and perceived risk of hypoglycemia and the need for multiple daily injections are widely recognized as key barriers to effective insulin therapy. Therefore, there is a clear unmet need for a treatment option which can help mitigate these barriers. Alternative methods of insulin administration have been under investigation for several years, and pulmonary delivery has shown the most promise to date. Inhaled Technosphere(®) Insulin (TI; Afrezza(®); MannKind Corporation) was approved in 2014 for use as prandial insulin in people with diabetes. TI shows a more rapid onset of action and a significantly faster decline in activity than current subcutaneous rapid-acting insulin analogs (RAAs), and TI is more synchronized to the physiologic timing of the postprandial glucose excursion. This results in lower postprandial hypoglycemia with similar glycemic control compared with RAAs, and less weight gain. Together with the ease of use of the TI inhaler and the reduction in the number of daily injections, these findings imply that TI may be useful in helping to overcome patient resistance to insulin, improve adherence and mitigate clinical inertia in health-care providers, with potential beneficial effects on glycemic control.

FUNDING

Writing and editorial support in the preparation of this publication was funded by Sanofi US, Inc., Bridgewater, New Jersey, USA. Funding for the article processing charges for this publication was provided by MannKind Corporation.

Recognition and management of psychosocial issues in diabetic neuropathy

Although psychosocial aspects of diabetic neuropathy (DN) have received far less attention than biological aspects, research conducted over the last decade has begun to illuminate several important pathways between DN and psychosocial outcomes, including depression, anxiety, and self-management of diabetic foot ulcer (DFU)-risk. Growing body of evidence indicates that DN is a risk factor for depression predicting both the severity and increments in depression over time. Whereas painful DN contributes to depression, postural instability is the DN symptom with the strongest, cumulative effect on depression. Furthermore, depression and foot self-care, while having no impact on the development of recurrent diabetic foot ulcers (DFU), play a substantial role in incident first DFU. Patient common sense misconceptions about DFU risks and associated emotional responses play an important role in shaping foot self-care. Depression, and especially DFU-specific emotions, may be linked to DFU chronicity through biological and behavioral pathways that are at present under investigation in several ongoing trials. Integrative approaches that target psychological factors such as anxiety and depression while concurrently optimizing treatment and self-management may therefore be most powerful. Cognitive behavioral therapy-based techniques that are informed by these findings deserve investigation.

Mesenchymal stem cells to treat diabetic neuropathy: a long and strenuous way from bench to the clinic

As one of the most common complications of diabetes, diabetic neuropathy often causes foot ulcers and even limb amputations. Inspite of continuous development in antidiabetic drugs, there is still no efficient therapy to cure diabetic neuropathy. Diabetic neuropathy shows declined vascularity in peripheral nerves and lack of angiogenic and neurotrophic factors. Mesenchymal stem cells (MSCs) have been indicated as a novel emerging regenerative therapy for diabetic neuropathy because of their multipotency. We will briefly review the pathogenesis of diabetic neuropathy, characteristic of MSCs, effects of MSC therapies for diabetic neuropathy and its related mechanisms. In order to treat diabetic neuropathy, neurotrophic or angiogenic factors in the form of protein or gene therapy are delivered to diabetic neuropathy, but therapeutic efficiencies are very modest if not ineffective. MSC treatment reverses manifestations of diabetic neuropathy. MSCs have an important role to repair tissue and to lower blood glucose level. MSCs even paracrinely secrete neurotrophic factors, angiogenic factors, cytokines, and immunomodulatory substances to ameliorate diabetic neuropathy. There are still several challenges in the clinical translation of MSC therapy, such as safety, optimal dose of administration, optimal mode of cell delivery, issues of MSC heterogeneity, clinically meaningful engraftment, autologous or allogeneic approach, challenges with cell manufacture, and further mechanisms.

Glucotoxic Mechanisms and Related Therapeutic Approaches

Neuropathy is the earliest and commonest complication of diabetes. With increasing duration of diabetes, frequency and severity of neuropathy are worsened. Long-term hyperglycemia is therefore implicated in the development of this disorder. Nerve tissues require glucose energy to function and survive. Upon excessive glucose entry into the peripheral nerve, the glycolytic pathway and collateral glucose-utilizing pathways are overactivated and initiate adverse effects on nerve tissues. During hyperglycemia, flux through the polyol pathway, formation of advanced glycation end-products, production of free radicals, flux into the glucosamine pathway, and protein kinase C activity are all enhanced to negatively influence nerve function and structure. Suppression of these aberrant metabolic pathways has succeeded in prevention and inhibition of the development of neuropathy in animal models with diabetes. Satisfactory results were not attained, however, in patients with diabetes and further clinical trials are required. In this review, the author summarizes the hitherto proposed theories on the pathogenesis of diabetic neuropathy related to glucose metabolism and future prospects for the effective treatment of neuropathy.

Neuropathy in the DCCT/EDIC-What Was Done Then and What We Would Do Better Now

The Diabetes Control and Complications Trial (DCCT) and its epidemiological follow-up, the Epidemiology of Diabetes Interventions and Complications (EDIC) provide important insight on the natural history of distal symmetrical polyneuropathy and cardiovascular autonomic neuropathy in patients with type 1 diabetes and on the impact of intensive treatment of hyperglycemia on disease progression. This chapter summarizes the design and methods used for neuropathy evaluations both in the DCCT and in EDIC, the characteristics of the DCCT/EDIC patient population, and summarizes the findings of the DCCT/EDIC relative to neuropathic complications of type 1 diabetes. Lessons learned from the DCCT and EDIC experiences of longitudinal assessments of neuropathic complications are also reviewed.

Prediction of protective sensory loss, neuropathy and foot ulceration in type 2 diabetes

OBJECTIVES

To prospectively determine clinical and biochemical characteristics associated with the development of peripheral neuropathy, loss of protective sensation, and foot ulceration in persons with type 2 diabetes mellitus (DM) over 7 years.

RESEARCH DESIGN AND METHODS

Graded monofilament (MF) testing, vibration perception threshold, and neuropathy symptom questionnaires were undertaken in 206 participants with type 2 DM without peripheral vascular disease or history of foot ulceration and 71 healthy participants without DM at baseline and after 7 years. 6 monthly glycosylated hemoglobin (HbA1c) levels and annual serum lipid profiles were measured during follow-up of those with DM. Incident foot ulceration was recorded at follow-up.

RESULTS

Taller stature and higher quartiles of serum triglyceride and HbA1c levels were associated with neuropathy at follow-up (p=0.008). Remission of baseline neuropathy was observed in 7 participants at follow-up. 9 participants with type 2 DM developed foot ulcers by the end of the study, only 1 at low risk. Mean HbA1c levels were higher in those who developed foot ulceration (p<0.0001). 1 participant with neuropathy throughout developed a Charcot foot. Failure to perceive 2 or more 2, 4 and 6 g MF stimuli at baseline predicted loss of protective sensation at follow-up.

CONCLUSIONS

Tall stature and worse metabolic control were associated with progression to neuropathy. Mean HbA1c levels were higher in those who developed foot ulcers. Graded MF testing may enrich recruitment to clinical trials and assignation of high risk for foot ulceration.

Antinociceptive effects of fisetin against diabetic neuropathic pain in mice: Engagement of antioxidant mechanisms and spinal GABAA receptors

Peripheral painful neuropathy is one of the most common complications in diabetes and necessitates improved treatment. Fisetin, a naturally occurring flavonoid, has been reported to exert antidepressant-like effect in previous studies. As antidepressant drugs are employed clinically to treat neuropathic pain, this work aimed to investigate whether fisetin possess beneficial effect on diabetic neuropathic pain and explore the mechanism(s). We subjected mice to diabetes by a single intraperitoneal (i.p.) injection of streptozotocin (200mg/kg), and von Frey test or Hargreaves test was used to assess mechanical allodynia or thermal hyperalgesia, respectively. Chronic treatment of diabetic mice with fisetin not only ameliorated the established symptoms of thermal hyperalgesia and mechanical allodynia, but also arrested the development of neuropathic pain when given at low doses. Although chronic fisetin administration did not impact on the symptom of hyperglycemia in diabetic mice, it reduced exacerbated oxidative stress in tissues of spinal cord, dorsal root ganglion (DRG) and sciatic verve. Furthermore, the analgesic actions of fisetin were abolished by repetitive co-treatment with the reactive oxygen species (ROS) donor tert-butyl hydroperoxide (t-BOOH), but potentiated by the ROS scavenger phenyl-N-tert-butylnitrone (PBN). Finally, acute blockade of spinal GABAA receptors by bicuculline totally counteracted such fisetin analgesia. These findings indicate that chronic fisetin treatment can delay or correct neuropathic hyperalgesia and allodynia in mice with type 1 diabetes. Mechanistically, the present fisetin analgesia may be associated with its antioxidant activity, and spinal GABAA receptors are likely rendered as downstream targets.

Secoisolariciresinol diglycoside, a flaxseed lignan, exerts analgesic effects in a mouse model of type 1 diabetes: Engagement of antioxidant mechanism

Peripheral painful neuropathy is one of the most common complications in diabetes and necessitates improved treatment. Secoisolariciresinol diglycoside (SDG), a predominant lignan in flaxseed, has been shown in our previous studies to exert antidepressant-like effect. As antidepressant drugs are clinically used to treat chronic neuropathic pain, this work aimed to investigate the potential analgesic efficacy of SDG against diabetic neuropathic pain in a mouse model of type 1 diabetes. We subjected mice to diabetes by a single intraperitoneal (i.p.) injection of streptozotocin (STZ, 200 mg/kg), and Hargreaves test or von Frey test was used to assess thermal hyperalgesia or mechanical allodynia, respectively. Chronic instead of acute SDG treatment (3, 10 or 30 mg/kg, p.o., twice per day for three weeks) ameliorated thermal hyperalgesia and mechanical allodynia in diabetic mice, and these analgesic actions persisted about three days when SDG treatment was terminated. Although chronic treatment of SDG to diabetic mice did not impact on the symptom of hyperglycemia, it greatly attenuated excessive oxidative stress in sciatic nerve and spinal cord tissues, and partially counteracted the condition of weight decrease. Furthermore, the analgesic actions of SDG were abolished by co-treatment with the reactive oxygen species donor tert-butyl hydroperoxide (t-BOOH), but potentiated by the reactive oxygen species scavenger phenyl-N-tert-butylnitrone (PBN). These findings indicate that chronic SDG treatment can correct neuropathic hyperalgesia and allodynia in mice with type 1 diabetes. Mechanistically, the analgesic actions of SDG in diabetic mice may be associated with its antioxidant activity.

Glycemic control paradox: Poor glycemic control associated with higher one-year and eight-year risks of all-cause hospitalization but lower one-year risk of hypoglycemia in patients with type 2 diabetes

OBJECTIVE

The relationship between glycemic control and adverse outcomes found in a population with diabetes has seldom been evaluated in patients with type 2 diabetes. We explored the association between hemoglobin A1c (HbA1c) and hospitalization risks within one-year and eight-year follow-up periods.

METHODS

We conducted a retrospective cohort study on 57,061 patients with type 2 diabetes from National Diabetes Case Management Program during 2002-2004 in Taiwan. HbA1c at baseline and in-hospital mortality, all-cause and cause-specific hospitalization over one year and eight years were analyzed.

RESULTS

After multivariate adjustment, one-year risk was higher for cases with HbA1c level <6%, 9-10%, ≥10% versus 6-7% for all-cause hospitalization (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 1.03-1.20; 1.08, 1.01-1.16, and 1.19, 1.12-1.26, respectively) and for ≥10% for diabetes-related hospitalization (1.68, 1.46-1.92). Yet each 1-step increment in HbA1c category (<6.0, 6.0-6.9, 7.0-7.9, 8.0-8.9, 9.0-9.9 and ≥10.0%) showed linkage with lower risk of hypoglycemia hospitalization (0.81, 95% CI: 0.74-0.88). For eight-year risk, subjects with HbA1c level <6%, and ≥10% were more likely to have in-hospitality mortality (1.16, 1.03-1.31, and 1.23, 1.11-1.35, respectively). Each 1-step increment in HbA1c category showed an association with higher risks of all-cause and diabetes-related hospitalization (1.04, 1.03-1.05, and 1.15, 1.14-1.17, respectively).

CONCLUSIONS

Higher HbA1c level correlated with lower one-year risk due to hypoglycemia hospitalization but increased one-year and eight-year risks due to all-cause and diabetes-specific hospitalization among Chinese people with type 2 diabetes in Taiwan. Future study must ascertain how to meet HbA1c targets and improve outcome without risk to this population.

A Genome-wide Association Study Provides Evidence of Sex-specific Involvement of Chr1p35.1 (ZSCAN20-TLR12P) and Chr8p23.1 (HMGB1P46) With Diabetic Neuropathic Pain

Neuropathic pain is defined as pain arising as a direct consequence of a lesion or a disease affecting the somatosensory system and it affects around 1 in 4 diabetic patients in the UK. The purpose of this genome-wide association study (GWAS) was to identify genetic contributors to this disorder. Cases of neuropathic pain were defined as diabetic patients with a multiple prescription history of at least one of five drugs specifically indicated for the treatment of neuropathic pain. Controls were diabetic individuals who were not prescribed any of these drugs, nor amitriptyline, carbamazepine, or nortriptyline. Overall, 961 diabetic neuropathic pain cases and 3260 diabetic controls in the Genetics of Diabetes Audit and Research Tayside (GoDARTS) cohort were identified. We found a cluster in the Chr1p35.1 (ZSCAN20-TLR12P) with a lowest P value of 2.74 × 10(- 7) at rs71647933 in females and a cluster in the Chr8p23.1, next to HMGB1P46 with a lowest P value of 8.02 × 10(- 7) at rs6986153 in males. Sex-specific narrow sense heritability was higher in males (30.0%) than in females (14.7%). This GWAS on diabetic neuropathic pain provides evidence for the sex-specific involvement of Chr1p35.1 (ZSCAN20-TLR12P) and Chr8p23.1 (HMGB1P46) with the disorder, indicating the need for further research.

Delayed Gastric Emptying Is Associated With Early and Long-term Hyperglycemia in Type 1 Diabetes Mellitus

BACKGROUND & AIMS

After the Diabetes Control and Complications Trial (DCCT), the Epidemiology of Diabetes Interventions and Complications (EDIC) study continued to show persistent benefit of prior intensive therapy on neuropathy, retinopathy, and nephropathy in type 1 diabetes mellitus (DM). The relationship between control of glycemia and gastric emptying (GE) is unclear.

METHODS

We assessed GE with a (13)C-spirulina breath test and symptoms in 78 participants with type 1 diabetes at year 20 of EDIC. The relationship between delayed GE and glycated hemoglobin (HbA1c), complications of DM, and gastrointestinal symptoms were evaluated.

RESULTS

GE was normal (37 participants; 50%), delayed (35 participants; 47%), or rapid (2 participants; 3%). The latest mean HbA1c was 7.7%. In univariate analyses, delayed GE was associated with greater DCCT baseline HbA1c and duration of DM before DCCT (P ≤ .04), greater mean HbA1c over an average of 27 years of follow-up evaluation (during DCCT-EDIC, P = .01), lower R-R variability during deep breathing (P = .03) and severe nephropathy (P = .05), and a greater composite upper gastrointestinal symptom score (P < .05). In multivariate models, retinopathy was the only complication of DM associated with delayed GE. Separately, DCCT baseline HbA1c (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1-2.3) and duration of DM (OR, 1.2; 95% CI, 1.01-1.3) before DCCT entry and mean HbA1c during DCCT-EDIC (OR, 2.2; 95% CI, 1.04-4.5) were associated independently with delayed GE.

CONCLUSIONS

In the DCCT/EDIC study, delayed GE was remarkably common and associated with gastrointestinal symptoms and with measures of early and long-term hyperglycemia. ClinicalTrials.gov numbers NCT00360815 and NCT00360893.

Development and validation of a cost-utility model for Type 1 diabetes mellitus

AIMS

To develop a health economic model to evaluate the cost-effectiveness of new interventions for Type 1 diabetes mellitus by their effects on long-term complications (measured through mean HbA1c ) while capturing the impact of treatment on hypoglycaemic events.

METHODS

Through a systematic review, we identified complications associated with Type 1 diabetes mellitus and data describing the long-term incidence of these complications. An individual patient simulation model was developed and included the following complications: cardiovascular disease, peripheral neuropathy, microalbuminuria, end-stage renal disease, proliferative retinopathy, ketoacidosis, cataract, hypoglycemia and adverse birth outcomes. Risk equations were developed from published cumulative incidence data and hazard ratios for the effect of HbA1c , age and duration of diabetes. We validated the model by comparing model predictions with observed outcomes from studies used to build the model (internal validation) and from other published data (external validation). We performed illustrative analyses for typical patient cohorts and a hypothetical intervention.

RESULTS

Model predictions were within 2% of expected values in the internal validation and within 8% of observed values in the external validation (percentages represent absolute differences in the cumulative incidence).

CONCLUSIONS

The model utilized high-quality, recent data specific to people with Type 1 diabetes mellitus. In the model validation, results deviated less than 8% from expected values.

Pharmacological treatment of diabetic peripheral neuropathy

Pain modulation is a key treatment goal for diabetic peripheral neuropathy patients. Guidelines have recommended antidepressant, anticonvulsant, analgesic, and topical medications-both approved and off-label-to reduce pain in this population.

Significance of functional GRP78 polymorphisms in predicting the onset of type 2 diabetic peripheral neuropathy in Chinese population

OBJECTIVE

The objective of this study is to investigate the significance of functional GRP78 polymorphisms in predicting the risk of type 2 diabetic peripheral neuropathy in Chinese population.

METHODS

Between the years of 2006 and 2010, a total of 295 definitely diagnosed type 2 diabetes mellitus (T2DM) patients were included into our study cohort and followed for 3 years. At baseline and annual re-examinations, the patients underwent physical examinations, laboratory tests and evaluation of Michigan diabetic neuropathy score (MDNS). Age, gender, disease course, waist-hip circumference ratio (WHR), body mass index (BMI), triglycerine (TG), total cholesterol (Tch), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glycosylated haemoglobin (HbA1c), uric acid elimination rate (UAER) and uric acid (UA) were recorded and GRP78 polymorphisms were tested by direct sequencing. The prognostic significance of GRP78 polymorphisms were analysed using monovariate and multivariate logistic regression.

RESULTS

Three years after baseline, 32.9% (97/295) of the T2DM patients had suffered the development of diabetic peripheral neuropathy and GRP78 rs391957 promoter polymorphism is a significant risk factor for the onset of type 2 diabetic peripheral neuropathy. In monovariate regression model, the OR values of GRP78 rs391957 promoter polymorphism were 2.233 (C/T) and 2.734 (T/T). As for the model calibrated with demographic and laboratory indexes, the OR values were, respectively, 2.124 (C/T) and 2.423 (T/T).

CONCLUSION

Our study suggested that the GRP78 rs391957 promoter polymorphism is a potential risk factor for type 2 diabetic peripheral neuropathy.

Incidence, prevalence, and trend analysis of the use of insulin delivery systems in the United States (2005 to 2011)

OBJECTIVE

Estimate the incidence and prevalence rates and assess overall trends among patients with diabetes using insulin vial/syringe and pens over time.

METHODS

A retrospective study was conducted using the Truven MarketScan database from 1 July 2004 to 31 December 2011. The database contained medical and pharmacy claims of >20 million US residents insured by commercial health plans. Patients with diabetes who utilized vial/syringe and pens were included. Incidence rate was defined as the proportion of patients initiating a new insulin type for the first time with vial/syringe and pens within each year from 2005 to 2011 among the total number of patients initiating that particular insulin type for the first time. Prevalence rate was defined as the proportion of patients using vial/syringe or pens among patients with diabetes using that insulin type within each year from 2005 to 2011. A linear trend over time was assessed by Cochran-Armitage Trend tests and Generalized Estimating Equations.

RESULTS

Incidence of patients initiating vial/syringe decreased from 2005 to 2011 (basal analog [90.5% to 31.3%]; mealtime analog [67.6% to 37.1%]), while patients initiating pens increased (basal analog [9.5% to 68.7%]; mealtime analog [32.4% to 62.9%]). There was a significant trend over time indicating increased usage of pens relative to vial/syringe; the number of pen users increased (all p < 0.0001 except mealtime human). Prevalence of patients using vial/syringe decreased from 2005 to 2011 (basal analog [93.8% to 41.2%]; mealtime analog [71.0% to 50.6%]), while patients using pens increased (basal analog [6.2% to 58.8%]; mealtime analog [29.0% to 49.4%]). From 2005 to 2011, patients were more likely to use pens than vial/syringe (all p < 0.0001 except for human mixtures and mealtime human).

CONCLUSIONS

The incidence and prevalence of patients using the traditional vial/syringe decreased over time, while the use of pens increased. Some patient populations may be under-represented, limiting generalizability of results.

Peripheral arterial disease and revascularization of the diabetic foot

Diabetes is a complex disease with many serious potential sequelae, including large vessel arterial disease and microvascular dysfunction. Peripheral arterial disease is a common large vessel complication of diabetes, implicated in the development of tissue loss in up to half of patients with diabetic foot ulceration. In addition to peripheral arterial disease, functional changes in the microcirculation also contribute to the development of a diabetic foot ulcer, along with other factors such as infection, oedema and abnormal biomechanical loading. Peripheral arterial disease typically affects the distal vessels, resulting in multi-level occlusions and diffuse disease, which often necessitates challenging distal revascularisation surgery or angioplasty in order to improve blood flow. However, technically successful revascularisation does not always result in wound healing. The confounding effects of microvascular dysfunction must be recognised--treatment of a patient with a diabetic foot ulcer and peripheral arterial disease should address this complex interplay of pathophysiological changes. In the case of non-revascularisable peripheral arterial disease or poor response to conventional treatment, alternative approaches such as cell-based treatment, hyperbaric oxygen therapy and the use of vasodilators may appear attractive, however more robust evidence is required to justify these novel approaches.

Haemoglobin A1c in the diagnosis and monitoring of diabetes mellitus

Haemoglobin A(1c) (HbA(1c)) is due to celebrate its 40th birthday. Many people would argue that the clinical studies relating the test to diabetes complications while in its late 20s are likely to be its finest ever achievement. However, this article looks at how HbA(1c) has matured since then and discusses in detail how its many strengths and idiosyncrasies as a marker of glycaemic risk have, as a 30-something, become more clearly understood. As HbA(1c) approaches middle age, this paper also describes how the test appears to be developing a mid-life crisis, as debate over how its results should be expressed seems likely to divide opinion among clinicians for some time to come.

Mitochondrial hormesis and diabetic complications

The concept that excess superoxide production from mitochondria is the driving, initial cellular response underlying diabetes complications has been held for the past decade. However, results of antioxidant-based trials have been largely negative. In the present review, the data supporting mitochondrial superoxide as a driving force for diabetic kidney, nerve, heart, and retinal complications are reexamined, and a new concept for diabetes complications--mitochondrial hormesis--is presented. In this view, production of mitochondrial superoxide can be an indicator of healthy mitochondria and physiologic oxidative phosphorylation. Recent data suggest that in response to excess glucose exposure or nutrient stress, there is a reduction of mitochondrial superoxide, oxidative phosphorylation, and mitochondrial ATP generation in several target tissues of diabetes complications. Persistent reduction of mitochondrial oxidative phosphorylation complex activity is associated with the release of oxidants from nonmitochondrial sources and release of proinflammatory and profibrotic cytokines, and a manifestation of organ dysfunction. Restoration of mitochondrial function and superoxide production via activation of AMPK has now been associated with improvement in markers of renal, cardiovascular, and neuronal dysfunction with diabetes. With this Perspective, approaches that stimulate AMPK and PGC1α via exercise, caloric restriction, and medications result in stimulation of mitochondrial oxidative phosphorylation activity, restore physiologic mitochondrial superoxide production, and promote organ healing.

Methods and initial findings from the Durham Diabetes Coalition: Integrating geospatial health technology and community interventions to reduce death and disability

OBJECTIVE

The Durham Diabetes Coalition (DDC) was established in response to escalating rates of disability and death related to type 2 diabetes mellitus, particularly among racial/ethnic minorities and persons of low socioeconomic status in Durham County, North Carolina. We describe a community-based demonstration project, informed by a geographic health information system (GHIS), that aims to improve health and healthcare delivery for Durham County residents with diabetes.

MATERIALS AND METHODS

A prospective, population-based study is assessing a community intervention that leverages a GHIS to inform community-based diabetes care programs. The GHIS integrates clinical, social, and environmental data to identify, stratify by risk, and assist selection of interventions at the individual, neighborhood, and population levels.

RESULTS

The DDC is using a multifaceted approach facilitated by GHIS to identify the specific risk profiles of patients and neighborhoods across Durham County. A total of 22,982 patients with diabetes in Durham County were identified using a computable phenotype. These patients tended to be older, female, African American, and not covered by private health insurance, compared with the 166,041 persons without diabetes. Predictive models inform decision-making to facilitate care and track outcomes. Interventions include: 1) neighborhood interventions to improve the context of care; 2) intensive team-based care for persons in the top decile of risk for death or hospitalization within the coming year; 3) low-intensity telephone coaching to improve adherence to evidence-based treatments; 4) county-wide communication strategies; and 5) systematic quality improvement in clinical care.

CONCLUSIONS

To improve health outcomes and reduce costs associated with type 2 diabetes, the DDC is matching resources with the specific needs of individuals and communities based on their risk characteristics.

Effect of intensive diabetes therapy on the progression of diabetic retinopathy in patients with type 1 diabetes: 18 years of follow-up in the DCCT/EDIC

The Diabetes Control and Complications Trial (DCCT) demonstrated that a mean of 6.5 years of intensive therapy aimed at near-normal glucose levels reduced the risk of development and progression of retinopathy by as much as 76% compared with conventional therapy. The Epidemiology of Diabetes Interventions and Complications study (EDIC) observational follow-up showed that the risk of further progression of retinopathy 4 years after the DCCT ended was also greatly reduced in the former intensive group, despite nearly equivalent levels of HbA1c, a phenomenon termed metabolic memory. Metabolic memory was shown to persist through 10 years of follow-up. We now describe the risk of further progression of retinopathy, progression to proliferative diabetic retinopathy, clinically significant macular edema, and the need for intervention (photocoagulation or anti-VEGF) over 18 years of follow-up in EDIC. The cumulative incidence of each retinal outcome continues to be lower in the former intensive group. However, the year-to-year incidence of these outcomes is now similar, owing in large part to a reduction in risk in the former conventional treatment group.

Selection of aptamers specific for glycated hemoglobin and total hemoglobin using on-chip SELEX

Blood glycated hemoglobin (HbA1c) levels reflecting average glucose concentrations over the past three months are fundamental for the diagnosis, monitoring, and risk assessment of diabetes. It has been hypothesized that aptamers, which are single-stranded DNAs or RNAs that demonstrate high affinity to a large variety of molecules ranging from small drugs, metabolites, or proteins, could be used for the measurement of HbA1c. Aptamers are selected through an in vitro process called systematic evolution of ligands by exponential enrichment (SELEX), and they can be chemically synthesized with high reproducibility at relatively low costs. This study therefore aimed to select HbA1c- and hemoglobin (Hb)-specific single-stranded DNA aptamers using an on-chip SELEX protocol. A microfluidic SELEX chip was developed to continuously and automatically carry out multiple rounds of SELEX to screen specific aptamers for HbA1c and Hb. HbA1c and Hb were first coated onto magnetic beads. Following several rounds of selection and enrichment with a randomized 40-mer DNA library, specific oligonucleotides were selected. The binding specificity and affinity were assessed by competitive and binding assays. Using the developed microfluidic system, the incubation and partitioning times were greatly decreased, and the entire process was shortened dramatically. Both HbA1c- and Hb-specific aptamers selected by the microfluidic system showed high specificity and affinity (dissociation constant, Kd = 7.6 ± 3.0 nM and 7.3 ± 2.2 nM for HbA1c and Hb, respectively). With further refinements in the assay, these aptamers may replace the conventional antibodies for in vitro diagnostics applications in the near future.

Screening and treatment by the primary care provider of common diabetes complications

Diabetes is the leading cause of end-stage renal disease, blindness, and nontraumatic lower-limb amputation. The largest reductions in cardiovascular events are seen when multiple risk factors are addressed simultaneously. The benefit of aspirin as secondary prevention in patients with previous stroke or myocardial infarction has been well established. Regular, dilated eye examinations are effective in detecting sight-threatening diabetic retinopathy and have been shown to prevent blindness. The use of appropriate tools and clinical examination/inspection provides greater than 87% specificity in detecting diabetic peripheral neuropathy. Early treatment of risk factors, including hypertension, hyperglycemia, and dyslipidemia can delay or prevent diabetic nephropathy.

Skin advanced glycation end products glucosepane and methylglyoxal hydroimidazolone are independently associated with long-term microvascular complication progression of type 1 diabetes

Six skin collagen advanced glycation end products (AGEs) originally measured near to the time of the Diabetes Control and Complications Trial (DCCT) closeout in 1993 may contribute to the "metabolic memory" phenomenon reported in the follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study. We have now investigated whether the addition of four originally unavailable AGEs (i.e., glucosepane [GSPNE], hydroimidazolones of methylglyoxal [MG-H1] and glyoxal, and carboxyethyl-lysine) improves associations with incident retinopathy, nephropathy, and neuropathy events during 13-17 years after DCCT. The complete 10-AGE panel is associated with three-step Early Treatment of Diabetic Retinopathy Study scale worsening of retinopathy (P ≤ 0.002), independent of either mean DCCT or EDIC study A1C level. GSPNE and fructose-lysine (furosine [FUR]) correlate with retinopathy progression, independently of A1C level. The complete panel also correlates with microalbuminuria (P = 0.008) and FUR with nephropathy independently of A1C level (P ≤ 0.02). Neuropathy correlates with the complete panel despite adjustment for A1C level (P ≤ 0.005). MG-H1 and FUR are dominant, independent of A1C level (P < 0.0001), whereas A1C loses significance after adjustment for the AGEs. Overall, the added set of four AGEs enhances the association of the original panel with progression risk of retinopathy and neuropathy (P < 0.04) but not nephropathy, while GSPNE and MG-H1 emerge as the principal new risk factors. Skin AGEs are robust long-term markers of microvascular disease progression, emphasizing the importance of early and sustained implementation of intensive therapy.

Treatment-induced neuropathy of diabetes: an acute, iatrogenic complication of diabetes

Treatment-induced neuropathy in diabetes (also referred to as insulin neuritis) is considered a rare iatrogenic small fibre neuropathy caused by an abrupt improvement in glycaemic control in the setting of chronic hyperglycaemia. The prevalence and risk factors of this disorder are not known. In a retrospective review of all individuals referred to a tertiary care diabetic neuropathy clinic over 5 years, we define the proportion of individuals that present with and the risk factors for development of treatment-induced neuropathy in diabetes. Nine hundred and fifty-four individuals were evaluated for a possible diabetic neuropathy. Treatment-induced neuropathy in diabetes was defined as the acute onset of neuropathic pain and/or autonomic dysfunction within 8 weeks of a large improvement in glycaemic control-specified as a decrease in glycosylated haemoglobin A1C (HbA1c) of ≥2% points over 3 months. Detailed structured neurologic examinations, glucose control logs, pain scores, autonomic symptoms and other microvascular complications were measured every 3-6 months for the duration of follow-up. Of 954 patients evaluated for diabetic neuropathy, 104/954 subjects (10.9%) met criteria for treatment-induced neuropathy in diabetes with an acute increase in neuropathic or autonomic symptoms or signs coinciding with a substantial decrease in HbA1c. Individuals with a decrease in HbA1c had a much greater risk of developing a painful or autonomic neuropathy than those individuals with no change in HbA1c (P < 0.001), but also had a higher risk of developing retinopathy (P < 0.001) and microalbuminuria (P < 0.001). There was a strong correlation between the magnitude of decrease in HbA1c, the severity of neuropathic pain (R = 0.84, P < 0.001), the degree of parasympathetic dysfunction (R = -0.52, P < 0.01) and impairment of sympathetic adrenergic function as measured by fall in blood pressure on tilt-table testing (R = -0.63, P < 0.001). With a decrease in HbA1c of 2-3% points over 3 months there was a 20% absolute risk of developing treatment-induced neuropathy in diabetes, with a decrease in HbA1c of >4% points over 3 months the absolute risk of developing treatment-induced neuropathy in diabetes exceeded 80%. Treatment-induced neuropathy of diabetes is an underestimated iatrogenic disorder associated with diffuse microvascular complications. Rapid glycaemic change in patients with uncontrolled diabetes increases the risk of this complication.

Puerarin prevents high glucose-induced apoptosis of Schwann cells by inhibiting oxidative stress

Oxidative stress may be the unifying factor for the injury caused by hyperglycemia in diabetic peripheral neuropathy. Puerarin is the major isoflavonoid derived from Radix puerariae and has been shown to be effective in increasing superoxide dismutase activity. This study sought to investigate the neuroprotective effect of puerarin on high glucose-induced oxidative stress and Schwann cell apoptosis in vitro. Intracellular reactive oxygen radicals and mitochondrial transmembrane potential were detected by flow cytometry analysis. Apoptosis was confirmed by TUNEL and oxidative stress was monitored using an enzyme-linked immunosorbent assay for the DNA marker 8-hydroxy-2-deoxyguanosine. The expression levels of bax and bcl-2 were analyzed by quantitative real-time reverse transcriptase-PCR, while protein expression of cleaved caspase-3 and -9 were analyzed by means of western blotting. Results suggested that puerarin treatment inhibited high glucose-induced oxidative stress, mitochondrial depolarization and apoptosis in a dose-dependent manner. Furthermore, puerarin treatment downregulated Bax expression, upregulated bcl-2 expression and attenuated the activation of caspase-3 and -9. Overall, our results indicated that puerarin antagonized high glucose-induced oxidative stress and apoptosis in Schwann cells.

The outcome of care in people with type 1 diabetes after switching to insulin glargine-based regimens in a real-life setting: a long-term observational study

BACKGROUND

Different insulin preparations are used as basal insulins in type 1 diabetes. The aim of this study was to assess long-term efficacy and safety of insulin glargine after switching from other basal insulins in type 1 diabetes in a real-life setting.

METHODS

In the clinic's database, 87 subjects treated with glargine for > 1 year were identified. In all patients, HbA1c level, insulin doses, episodes of severe hypoglycaemia, diabetic complications, comorbidities, body mass index (BMI), blood pressure and concomitant medications' use were monitored throughout the entire follow-up period.

RESULTS

During observation, lasting mean 61.9 ± 27.6 months HbA1c level decreased from 8.86 ± 1.60% (73.3 mmol/mol) to 8.25 ± 1.40% (66.7 mmol/mol), p < 0.001. This improvement was maintained up to 8 years. Frequency of severe hypoglycaemia was 6.24/100 patient-years. Total insulin requirement did not changed significantly. BMI increased from 23.57 ± 2.90 to 24.52 ± 3.46 kg/m(2) (p < 0.001). Significant weight gain (> 5%) occurred in 30 subjects, while 10 patients lost weight. Mean systolic blood pressure (SBP) increased from 136.3 ± 13.4 to 140.7 ± 15.1 mmHg (p = 0.008), while diastolic blood pressure remained unchanged. Development or progression of diabetic complications was revealed in 11 subjects.

CONCLUSIONS

Following switch from other basal insulins to insulin glargine in type 1 diabetic patients, glycaemic control significantly improved, with unchanged total insulin requirement and with low risk of severe hypoglycaemia. Weight gain and elevation of SBP observed in this study require special attention and educational efforts. In summary, insulin glargine can be recommended as an effective and safe basal insulin in type 1 diabetes in a real-life setting.