Lipid modulation in insulin-dependent diabetes mellitus: effect on microvascular outcomes

Quantification of lipoproteins by proton nuclear magnetic resonance spectroscopy (1H-NMRS) improves the prediction of cardiac autonomic dysfunction in patients with type 1 diabetes

AIMS

To assess if advanced characterization of serum glycoprotein and lipoprotein profile, measured by proton nuclear magnetic resonance spectroscopy (1H-NMRS) improves a predictive clinical model of cardioautonomic neuropathy (CAN) in subjects with type 1 diabetes (T1D).

METHODS

Cross-sectional study (ClinicalTrials.gov Identifier: NCT04950634). CAN was diagnosed using Ewing's score. Advanced characterization of macromolecular complexes including glycoprotein and lipoprotein profiles in serum samples were measured by 1H-NMRS. We addressed the relationships between these biomarkers and CAN using correlation and regression analyses. Diagnostic performance was assessed by analyzing their areas under the receiver operating characteristic curves (AUCROC).

RESULTS

Three hundred and twenty-three patients were included (46% female, mean age and duration of diabetes of 41 ± 13 years and 19 ± 11 years, respectively). The overall prevalence of CAN was 28% [95% confidence interval (95%CI): 23; 33]. Glycoproteins such as N-acetylglucosamine/galactosamine and sialic acid showed strong correlations with inflammatory markers such as high-sensitive C-reactive protein, fibrinogen, IL-10, IL-6, and TNF-α. On the contrary, we did not find any association between the former and CAN. A stepwise binary logistic regression model (R2 = 0.078; P = 0.003) retained intermediate-density lipoprotein-triglycerides (IDL-TG) [β:0.082 (95%CI: 0.005; 0.160); P = 0.039], high-density lipoprotein-triglycerides (HDL-TGL)/HDL-Cholesterol [β:3.633 (95%CI: 0.873; 6.394); P = 0.010], and large-HDL particle number [β: 3.710 (95%CI: 0.677; 6.744); P = 0.001] as statistically significant determinants of CAN. Adding these lipoprotein particles to a clinical prediction model of CAN that included age, duration of diabetes, and A1c enhanced its diagnostic performance, improving AUCROC from 0.546 (95%CI: 0.404; 0.688) to 0.728 (95%CI: 0.616; 0.840).

CONCLUSIONS

When added to clinical variables, 1H-NMRS-lipoprotein particle profiles may be helpful to identify those patients with T1D at risk of CAN.

Molecular mechanism of renal lipid accumulation in diabetic kidney disease

Diabetic kidney disease (DKD) is a leading cause of end stage renal disease with unmet clinical demands for treatment. Lipids are essential for cell survival; however, renal cells have limited capability to metabolize overloaded lipids. Dyslipidaemia is common in DKD patients and renal ectopic lipid accumulation is associated with disease progression. Unveiling the molecular mechanism involved in renal lipid regulation is crucial for exploring potential therapeutic targets. In this review, we focused on the mechanism underlying cholesterol, oxysterol and fatty acid metabolism disorder in the context of DKD. Specific regulators of lipid accumulation in different kidney compartment and TREM2 macrophages, a lipid-related macrophages in DKD, were discussed. The role of sodium-glucose transporter 2 inhibitors in improving renal lipid accumulation was summarized.

HMG CoA reductase inhibitors (statins) for people with chronic kidney disease not requiring dialysis

BACKGROUND

Cardiovascular disease is the most frequent cause of death in people with early stages of chronic kidney disease (CKD), and the absolute risk of cardiovascular events is similar to people with coronary artery disease. This is an update of a review first published in 2009 and updated in 2014, which included 50 studies (45,285 participants).

OBJECTIVES

To evaluate the benefits and harms of statins compared with placebo, no treatment, standard care or another statin in adults with CKD not requiring dialysis.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 4 October 2023. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov. An updated search will be undertaken every three months.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs that compared the effects of statins with placebo, no treatment, standard care, or other statins, on death, cardiovascular events, kidney function, toxicity, and lipid levels in adults with CKD (estimated glomerular filtration rate (eGFR) 90 to 15 mL/min/1.73 m2) were included.

DATA COLLECTION AND ANALYSIS

Two or more authors independently extracted data and assessed the study risk of bias. Treatment effects were expressed as mean difference (MD) for continuous outcomes and risk ratios (RR) for dichotomous benefits and harms with 95% confidence intervals (CI). The risk of bias was assessed using the Cochrane risk of bias tool, and the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 63 studies (50,725 randomised participants); of these, 53 studies (42,752 participants) compared statins with placebo or no treatment. The median duration of follow-up was 12 months (range 2 to 64.8 months), the median dosage of statin was equivalent to 20 mg/day of simvastatin, and participants had a median eGFR of 55 mL/min/1.73 m2. Ten studies (7973 participants) compared two different statin regimens. We were able to meta-analyse 43 studies (41,273 participants). Most studies had limited reporting and hence exhibited unclear risk of bias in most domains. Compared with placebo or standard of care, statins prevent major cardiovascular events (14 studies, 36,156 participants: RR 0.72, 95% CI 0.66 to 0.79; I2 = 39%; high certainty evidence), death (13 studies, 34,978 participants: RR 0.83, 95% CI 0.73 to 0.96; I² = 53%; high certainty evidence), cardiovascular death (8 studies, 19,112 participants: RR 0.77, 95% CI 0.69 to 0.87; I² = 0%; high certainty evidence) and myocardial infarction (10 studies, 9475 participants: RR 0.55, 95% CI 0.42 to 0.73; I² = 0%; moderate certainty evidence). There were too few events to determine if statins made a difference in hospitalisation due to heart failure. Statins probably make little or no difference to stroke (7 studies, 9115 participants: RR 0.64, 95% CI 0.37 to 1.08; I² = 39%; moderate certainty evidence) and kidney failure (3 studies, 6704 participants: RR 0.98, 95% CI 0.91 to 1.05; I² = 0%; moderate certainty evidence) in people with CKD not requiring dialysis. Potential harms from statins were limited by a lack of systematic reporting. Statins compared to placebo may have little or no effect on elevated liver enzymes (7 studies, 7991 participants: RR 0.76, 95% CI 0.39 to 1.50; I² = 0%; low certainty evidence), withdrawal due to adverse events (13 studies, 4219 participants: RR 1.16, 95% CI 0.84 to 1.60; I² = 37%; low certainty evidence), and cancer (2 studies, 5581 participants: RR 1.03, 95% CI 0.82 to 1.30; I² = 0%; low certainty evidence). However, few studies reported rhabdomyolysis or elevated creatinine kinase; hence, we are unable to determine the effect due to very low certainty evidence. Statins reduce the risk of death, major cardiovascular events, and myocardial infarction in people with CKD who did not have cardiovascular disease at baseline (primary prevention). There was insufficient data to determine the benefits and harms of the type of statin therapy.

AUTHORS' CONCLUSIONS

Statins reduce death and major cardiovascular events by about 20% and probably make no difference to stroke or kidney failure in people with CKD not requiring dialysis. However, due to limited reporting, the effect of statins on elevated creatinine kinase or rhabdomyolysis is unclear. Statins have an important role in the primary prevention of cardiovascular events and death in people who have CKD and do not require dialysis. Editorial note: This is a living systematic review. We will search for new evidence every three months and update the review when we identify relevant new evidence. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

The Effect of Statins on Ocular Disorders: A Systematic Review of Randomized Controlled Trials

AIM

Statins have been established in the market not only due to their ability to lower plasma cholesterol levels but also due to their pleiotropic effects. In the literature, there is a controversy regarding the role of statins in ophthalmology. We aimed to systematically address the possible effect of statin therapy on ocular diseases and to identify if there is a beneficial relationship.

METHODS

We searched PubMed and Cochrane Library databases up to 31 December 2022 for studies evaluating the effect of statins on ocular diseases. We included all relevant Randomized Control Trials (RCTs) that have been conducted in the adult population. PROSPERO registration number: CRD42022364328.

RESULTS

Nineteen RCTs were finally considered eligible for this systematic review, with a total of 28,940 participants. Ten studies investigated the role of simvastatin, suggesting a lack of cataractogenic effect and a possible protective role in cataract formation, retinal vascular diseases, and especially diabetic retinopathy, age-related macular disease progression, and non-infectious uveitis. Four studies investigated lovastatin, showing no cataractogenic effect. Three studies examined atorvastatin, revealing conflicting results regarding diabetic retinopathy. Two studies examined rosuvastatin, indicating a possibly harmful effect on lenses and a significant protective effect on retinal microvasculature.

CONCLUSIONS

Based on our findings, we believe that statins have no cataractogenic effect. There are indications that statins may have a protective role against cataract formation, AMD, diabetic retinopathy progression, and non-infectious uveitis. However, our results were insufficient for any robust conclusion. Future RCTs, with large sample sizes, on the current topic are therefore recommended to provide more solid evidence.

Emerging Roles of microRNAs as Biomarkers and Therapeutic Targets for Diabetic Neuropathy

Diabetic neuropathy (DN) is the most prevalent chronic complication of diabetes mellitus. The exact pathophysiological mechanisms of DN are unclear; however, communication network dysfunction among axons, Schwann cells, and the microvascular endothelium likely play an important role in the development of DN. Mounting evidence suggests that microRNAs (miRNAs) act as messengers that facilitate intercellular communication and may contribute to the pathogenesis of DN. Deregulation of miRNAs is among the initial molecular alterations observed in diabetics. As such, miRNAs hold promise as biomarkers and therapeutic targets. In preclinical studies, miRNA-based treatment of DN has shown evidence of therapeutic potential. But this therapy has been hampered by miRNA instability, targeting specificity, and potential toxicities. Recent findings reveal that when packaged within extracellular vesicles, miRNAs are resistant to degradation, and their delivery efficiency and therapeutic potential is markedly enhanced. Here, we review the latest research progress on the roles of miRNAs as biomarkers and as potential clinical therapeutic targets in DN. We also discuss the promise of exosomal miRNAs as therapeutics and provide recommendations for future research on miRNA-based medicine.

REvisiting Lipids in REtinal Diseases: A Focused Review on Age-related Macular Degeneration and Diabetic Retinopathy

Dyslipidemia refers to an abnormal amount of lipid in the blood, and the total cholesterol level is defined as the sum of high-density lipoprotein cholesterol, low-density lipoprotein (LDL) cholesterol, and very-LDL cholesterol concentrations. In Korea, the westernization of lifestyle habits in recent years has caused an increase in the incidence of dyslipidemia, which is an important risk factor of cardiovascular disease (CVD). Several studies have been conducted on how dyslipidemia affects not only CVD, but also chorioretinal diseases such as age-related macular degeneration (AMD) and diabetic retinopathy. Recently, a pathological model of AMD was proposed under the assumption that AMD proceeds through a mechanism similar to that of atherosclerotic CVD. However, controversy remains regarding the relationship between chorioretinal diseases and lipid levels in the blood, and the effects of lipid-lowering agents. Herein, we summarize the role of lipids in chorioretinal diseases. In addition, the effects of lipid-lowering agents on the prevention and progression of chorioretinal diseases are presented.

Reporting quality and adherence of randomized controlled trials about statins and/or fibrates for diabetic retinopathy to the CONSORT checklist

BACKGROUND

A considerable amount of randomized controlled trials (RCTs) have been published on statins and/or fibrates for diabetic retinopathy, a clinical condition associated with high social and economic burden. Adherence to the CONSORT statement items is imperative to ensure transparency and reproducibility in clinical research. The aim of this study is to assess the reporting quality and the adherence to CONSORT of RCTs assessing statins and/or fibrates for diabetic retinopathy.

METHODS

We conducted a critical appraisal study at Discipline of Evidence-based Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp). A sensitive literature search was performed to identify all relevant RCTs, with no time or language limits. Two authors independently evaluated the reporting quality of the selected RCTs using the CONSORT statement as a standard.

RESULTS

Thirteen reports of RCTs were included in this study. The adherence of the reports to CONSORT items ranged from 24% to 68%. The median score was 11 (interquartile range (IQR) 8 to 13). When analyzed separately, the methods sections of the reports had a median of three items (IQR 2 to 4) judged adherent to the methods items of CONSORT (items 3 to 12). The most underreported items were those related to trial design, title and abstract, allocation concealment, implementation of the randomization sequence, and blinding. Other important items, such as the one related to the description of the inclusion criteria, also had low adherence.

CONCLUSIONS

The overall adherence to the CONSORT checklist items was poor, especially in the items related to the methods section. RCT reports on statins and/or fibrates for diabetic retinopathy must be optimized to avoid reporting biases and to improve transparency and reproducibility.

Effect of different types of statins on kidney function decline and proteinuria: a network meta-analysis

Previous studies showed that statins reduce the progression of kidney function decline and proteinuria, but whether specific types of statins are more beneficial than others remains unclear. We performed a network meta-analysis of randomized controlled trials (RCT) to investigate which statin most effectively reduces kidney function decline and proteinuria. We searched MEDLINE, Embase, Web of Science, and the Cochrane database until July 13, 2018, and included 43 RCTs (>110,000 patients). We performed a pairwise random-effects meta-analysis and a network meta-analysis according to a frequentist approach. We assessed network inconsistency, publication bias, and estimated for each statin the probability of being the best treatment. Considerable heterogeneity was present among the included studies. In pairwise meta-analyses, 1-year use of statins versus control reduced kidney function decline by 0.61 (95%-CI: 0.27; 0.95) mL/min/1.73 m² and proteinuria with a standardized mean difference of -0.58 (95%-CI:-0.88; -0.29). The network meta-analysis for the separate endpoints showed broad confidence intervals due to the small number available RCTs for each individual comparison. In conclusion, 1-year statin use versus control attenuated the progression of kidney function decline and proteinuria. Due to the imprecision of individual comparisons, results were inconclusive as to which statin performs best with regard to renal outcome.

Statins in ophthalmology

Statins, 3-hydroxy-3-methyl-gutaryl coenzyme A reductase inhibitors, are a class of lipid-lowering drugs with anti-inflammatory, immunomodulatory, and vascular effects. Statins are increasingly being used in the treatment of a variety of medical conditions. We examine the actions of statins on the eye and its associated ophthalmic disorders. Statins can be synthetic or nonsynthetic, and their differentiating derivations may contribute to their varying cholesterol-lowering and pleiotropic effects. There is conflicting evidence on the ocular therapeutic and adverse effects of the statins. Statins may play a role in reducing the burden of dry eye, corneal ulcer scarring, thyroid-associated orbitopathy, glaucoma, uveitis and other associated ocular inflammatory states, cataract, proliferative vitreoretinopathy, diabetic retinopathy, macular degeneration, and choroidal melanoma. Topical preparations of statins can be formulated, thereby extending the range of ocular diseases that may be amenable to treatment. Statins have a relatively safe side effect profile, but rare and serious adverse reactions have been reported with their usage in ophthalmology, including myopathies and rhabdomyolysis with acute renal failure.

Statins and/or fibrates for diabetic retinopathy: a systematic review and meta-analysis

Evidence from observational studies have found a relationship between serum cholesterol and diabetic retinopathy (DR). Apart of the assumption that cholesterolemic control has benefits for patients with diabetes with or without retinopathy, the effects of lipid-lowering drugs have not been properly mapped and critically assessed so far. The objective of this study was to evaluate the effects of statins and/or fibrates on prevention and progression of DR. We conducted a Systematic review of randomized controlled trials (RCTs) following the Cochrane Handbook for Systematic Reviews of Interventions and reported in accordance to PRISMA Statement. GRADE approach was used to summarize the certainty of the evidence. Eight RCTs that fulfilled our eligibility criteria were included, assessing the effects of fibrates (n = 4), statins (n = 3) and fibrate plus statins (n = 1) for therapy (n = 8) or prevention (n = 4) of DR. Overall, the main concern regarding risk of bias assessment was due to incomplete outcome data because high rate of losses in five RCTs. Furthermore, the risk of reporting bias was rated unclear due the lack of previously published protocol in seven RCTs. Fibrates seemed to be associated with a 45% risk reduction of macular edema incidence (Relative Risk 0.55, 95% confidence interval of 0.38 to 0.81, 1309 participants, 2 RCTs, I² = 0%, low certainty of the evidence). The certainty of evidence for other outcomes was also very low or low, and we are uncertain regarding the effects of fibrates for DR. Overall, adverse events seemed to be similar between fibrate and placebo, but again based on the width of the confidence intervals, an important increase of adverse events cannot be rule out. The combination statin/fibrate did not seem to have benefit for visual acuity but is likely that further studies can modify this estimate since the current evidence is limited. Adverse events and quality of life were not measured or reported. Concluding, this study found eight RCTs, with limited methodological quality, that assessed the effects of fibrates and/or statins for DR. Based on these findings, we are uncertain about the effects of statins for DR. Fibrates seemed to reduce the incidence of macular edema (low certainty evidence) without increase adverse events (low to very low certainty evidence). Number of Protocol registration PROSPERO CRD42016029746.

Ameliorative effects of protodioscin on experimental diabetic nephropathy

BACKGROUND

Diabetic nephropathy is one of the most common and serious complications of diabetes mellitus.

HYPOTHESIS/PURPOSE

The present study aimed to investigate the effects of protodioscin on renal damage in high-fat diet-fed and streptozotocin-induced diabetic rats.

METHODS

After 4 weeks of feeding a high-fat diet, male Sprague-Dawley rats were injected 35 mg/kg streptozotocin intraperitoneally. The diabetic rats were divided into 4 groups, and treated orally with carboxymethylcellulose sodium, metformin, or protodioscin (20 or 40 mg/kg). After 12 weeks of treatment, blood, urine, and renal tissue were collected for biochemical and histological examination.

RESULTS

Protodioscin significantly reduced the levels of blood glucose, serum creatinine, and blood urea nitrogen, and also the excretion of urinary protein and albumin in diabetic rats. Histological examinations showed that protodioscin ameliorated the diabetes-induced glomerular and tubular pathological changes. Furthermore, protodioscin significantly reduced the renal concentrations of total cholesterol, triglycerides, free fatty acids, phospholipids, and TNF-α.

CONCLUSION

These results indicate that protodioscin has ameliorative effects on diabetic nephropathy.

Long-term effects of various types of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors on changes in glomerular filtration rate in Korea

Few long-term follow-up studies have compared the changes in renal function according to the type of statin used in Korea. We compared the long-term effects of statin intensity and type on the changes in the glomerular filtration rate (GFR). We extracted data of patients who took statin for the first time. We analyzed whether or not different statins affect the changes in GFR at 3 months after baseline and 4 years after. We included 3678 patients and analyzed the changes in GFR. The GFR decreased by 3.2% ± 0.4% on average 4 years after the first statin prescription, indicating statistically significant deterioration (from 83.5 ± 0.4 mL/min/1.73 m² to 79.9 0.4 mL/min/1.73 m², P < 0.001). When comparing the GFR among different statins, significant differences were observed between atorvastatin and fluvastatin (-5.3% ± 0.7% vs. 1.2% ± 2.2%, P < 0.05) and between atorvastatin and simvastatin (-5.3% ± 0.7% vs. -0.7% ± 0.8%, P < 0.05). In pitavastatin (odds ratio [OR]= 0.64, 95% confidence interval [CI]= 0.46-0.87, P < 0.005) and simvastatin (OR = 0.69, 95% CI = 0.53-0.91, P < 0.008), the GFR rate that decreased by < 60 mL/min/1.73 m² was significantly lower than that of atorvastatin. Regarding long-term statin intake, GFR changed with the type of statin. This work is the first in Korea to compare each statin in terms of changes in the GFR after the statin prescription.

Cardiovascular autonomic neuropathy in adolescents and young adults with type 1 and type 2 diabetes: The SEARCH for Diabetes in Youth Cohort Study

OBJECTIVE

To estimate the prevalence of and risk factors for cardiovascular autonomic neuropathy (CAN) in adolescents and young adults with type 1 and type 2 diabetes enrolled in the SEARCH for Diabetes in Youth Study.

METHODS

The study included 1646 subjects with type 1 diabetes (age 18 ± 4 years, diabetes duration 8 ± 2 years, HbA1c 9.1 ± 1.9%, 76% non-Hispanic Whites) and 252 with type 2 diabetes (age 22 ± 4 years, diabetes duration 8 ± 2 years, HbA1c 9.2 ± 3.0%, 45% non-Hispanic Blacks). Cross-sectional and longitudinal risk factors were assessed at baseline and follow-up visits. Area under the curve (AUC) was used to assess the longitudinal glycemic exposure and cardiovascular risk factors. CAN was assessed by time and frequency domain indices of heart rate variability (HRV). CAN was defined as the presence of ≥3 of 5 abnormal HRV indices.

RESULTS

The prevalence of CAN was 12% in adolescents and young adults with type 1 diabetes and 17% in those with type 2 diabetes. Poor long-term glycemic control (AUC HbA1c), high blood pressure, and elevated triglyceride levels were correlates of CAN in subjects with type 1 diabetes. In those with type 2 diabetes, CAN was associated with elevated triglycerides and increased urinary albumin excretion.

CONCLUSIONS

The prevalence of CAN in this multiethnic cohort of adolescents and young adults with type 1 and type 2 diabetes are comparable to those reported in adults with diabetes. Suboptimal glycemic control and elevated triglycerides were the modifiable risk factors associated with CAN.

'Statins in retinal disease'

Statins are known for their blood cholesterol-lowering effect and are widely used in patients with cardiovascular and metabolic diseases. Research over the past three decades shows that statins have diverse effects on different pathophysiological pathways involved in angiogenesis, inflammation, apoptosis, and anti-oxidation, leading to new therapeutic options. Recently, statins have attracted considerable attention for their immunomodulatory effect. Since immune reactivity has been implicated in a number of retinal diseases, such as uveitis, age-related macular degeneration (AMD) and diabetic retinopathy, there is now a growing body of evidence supporting the beneficial effects of statins in these retinopathies. This review evaluates the relationship between statins and the pathophysiological basis of these diseases, focusing on their potential role in treatment. A PubMed database search and literature review was conducted. Among AMD patients, there is inconsistent evidence regarding protection against development of early AMD or delaying disease progression; though they have been found to reduce the risk of developing choroidal neovascular membranes (CNV). In patients with retinal vein occlusion, there was no evidence to support a therapeutic benefit or a protective role with statins. In patients with diabetic retinopathy, statins demonstrate a reduction in disease progression and improved resolution of diabetic macular oedema (DMO). Among patients with uveitis, statins have a protective effect by reducing the likelihood of uveitis development.

Efficacy of statins in patients with diabetic nephropathy: a meta-analysis of randomized controlled trials

Background

The effects of statins in patients with diabetic nephropathy are controversial. With increasing interest in the potential therapeutic role of statins in diabetic nephropathy, it is essential to evaluate its real effects.

Methods

PubMed, EMBASE, Web of Science databases, Cochrane Central Register of Controlled Trials and China National Knowledge Infrastructure were systematically searched for randomized controlled trials (RCTs) of statins in patients with diabetic nephropathy.

Results

Fourteen trials with 2866 participants were included in our meta-analysis. Compared with placebo, albuminuria and urinary albumin excretion rates in the statin group were reduced by 0.46 [95 % confidence interval (CI),−0.68 to −0.25, P < 0.0001] and 1.68 (95 % CI, −3.23 to −0.12, P = 0.03), respectively. The reduction of albuminuria was greater in patients of type 2 diabetes mellitus with diabetic nephropathy [standardized mean difference (SMD), −0.56; 95 % CI, −0.80 to −0.32, P < 0.00001] and the decrease was significant during the 1 to 3 years period of statin therapy (SMD, −0.57; 95 % CI, −0.95 to −0.19, P = 0.003). Subgroup analysis demonstrated the effects of statins were much stronger in subjects with pathologic albuminuria: change of −0.71 (95 % CI, −1.09 to −0.33, P = 0.0003) for those with urinary protein excretion 30 to 300 mg/day, −0.37 (95 % CI, −0.67 to −0.06, P = 0.02) for those with excretion more than 300 mg/day and −0.29 (95 % CI, −0.78 to 0.21, P = 0.26) for those with excretion less than 30 mg/day. In contrast, statins did not significantly reduce estimated glomerular filtration rate, serum creatinine and blood urea nitrogen levels.

Conclusions

Statins decrease the albuminuria and urinary albumin excretion rates significantly. The efficacy of statins on renal function is time dependent and better in type 2 diabetic patients with nephropathy.

Failure to define the pathogenesis and treatment of human diabetic neuropathy

The clinical manifestations, underlying pathology and aetiology of human diabetic neuropathy are varied and complex. Much data has been generated from preclinical models to provide a conceptual framework for the cause and treatment of human diabetic neuropathy. Despite this there remains much debate and controversy on the pathophysiology of the condition. Furthermore, many of the interventions reaching phase III clinical trials have failed to prove effective. To date we have no evidence-based and effective treatment(s) for human diabetic neuropathy.

Wherefore Art Thou, O Treatment for Diabetic Neuropathy?

As of March 2016, we continue to advocate the diagnosis of diabetic neuropathy using a simple foot examination or monofilament, which identifies only those with severe neuropathy and hence risk of foot ulceration. Given the fact that the 5-year mortality rate of diabetic patients with foot ulceration is worse than that of most common cancers, surely we should be identifying patients at an earlier stage of neuropathy to prevent its progression to a stage with such a high mortality? Of course, we lament that there is no licensed treatment for diabetic neuropathy. Who is to blame? As researchers and carers, we have a duty of care to our patients with diabetic neuropathy. So, we have to look forward not backwards, and move away from our firmly entrenched views on the design and conduct of clinical trials for diabetic neuropathy. Relevant organizations such as Neurodiab, the American Diabetes Association and the Peripheral Nerve Society have to acknowledge that they cannot continue to endorse a bankrupt strategy. The FDA needs an open and self-critical dialogue with these organizations, to give pharmaceutical companies at least a fighting chance to deliver effective new therapies for diabetic neuropathy.

Burning through the pain: treatments for diabetic neuropathy

The rise in the global burden of diabetes is spurring an increase in the prevalence of its complications. Diabetic peripheral neuropathy (DPN) is a common and devastating complication of diabetes, with multiple clinical manifestations. The most common is a symmetrical length-dependent dysfunction and damage of peripheral nerves. The management of DPN rests on three tenets: intensive glycaemic control, even though the evidence of benefit is questionable in people with type 2 diabetes; pathogenetic therapies; and symptomatic treatment. A number of pathogenetic treatments have been evaluated in phase III clinical trials, including α-lipoic acid (stems reactive oxygen species formation), benfotiamine (prevents vascular damage) and aldose-reductase inhibitors (reduce flux through the polyol pathway), protein kinase C inhibitors (prevent hyperglycaemia-induced activation of protein kinase C), nerve growth factors (stimulate nerve regeneration) and Actovegin® (improves tissue glucose and oxygen uptake). However, none have gained US Food and Drug Administration or European Medicines Agency (EMA) approval, questioning the validity of current trial designs and the endpoints deployed to define efficacy. For painful diabetic neuropathy, clinical guidelines recommend: atypical analgesics for pain relief, including duloxetine and amitriptyline; the γ-aminobutyric acid analogues gabapentin and pregabalin; opioids, including Tapentadol; and topical agents such as lidocaine and capsaicin. No single effective treatment exists for painful DPN, highlighting a growing need for studies to evaluate more potent and targeted drugs, as well as combinations. A number of novel potential candidates, including erythropoietin analogues and angiotensin II type 2 receptor anatagonists are currently being evaluated in phase II clinical trials.

Interventions for Diabetic Retinopathy in Type 1 Diabetes: Systematic Review and Meta-Analysis

PURPOSE

To systematically review the effectiveness of systemic interventions for diabetic retinopathy (DR) in type 1 diabetes.

DESIGN

Systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE and Cochrane Library were searched for studies published from January 1990 to December 2014. Randomized controlled trials and controlled cohort studies reporting incidence or progression of DR following systemic intervention were included. Two reviewers selected studies, extracted data, and assessed risk of bias. For each intervention, pooled outcomes were reported as relative risk (RR) estimates with 95% confidence intervals (CI).

RESULTS

Twenty-four studies involving 9302 patients met inclusion criteria. Incident DR was reduced by intensive vs conventional insulin therapy (RR 0.43; 95% CI 0.23-0.83), insulin pumps vs multiple daily injections (RR 0.45; 95% CI 0.24-0.83), and angiotensin receptor blockade vs placebo (RR 0.65; 95% CI 0.49-0.85). The benefit of insulin pumps over multiple daily infections was independent of HbA1c. DR progression was reduced by intensive vs conventional insulin therapy (RR 0.63; 95% CI 0.43-0.92), angiotensin-converting enzyme inhibition vs placebo (RR 0.60; 95% CI 0.41-0.86), and islet cell transplantation vs medical therapy (RR 0.25; 95% CI 0.08-0.71).

CONCLUSIONS

Intensive insulin therapy, and specifically insulin pump therapy vs multiple daily injections, prevents DR in both adults and adolescents with type 1 diabetes. Antihypertensive agents provide protection in normotensive, normoalbuminuric adults. In patients with type 1 diabetes of longer duration, islet cell transplantation may be more effective than medical therapy. There is insufficient evidence for antilipid therapy or other systemic interventions.

Treating Diabetic Neuropathy: Present Strategies and Emerging Solutions

Diabetic peripheral neuropathies (DPN) are a heterogeneous group of disorders caused by neuronal dysfunction in patients with diabetes. They have differing clinical courses, distributions, fiber involvement (large or small), and pathophysiology. These complications are associated with increased morbidity, distress, and healthcare costs. Approximately 50% of patients with diabetes develop peripheral neuropathy, and the projected rise in the global burden of diabetes is spurring an increase in neuropathy. Distal symmetrical polyneuropathy (DSPN) with painful diabetic neuropathy, occurring in around 20% of diabetes patients, and diabetic autonomic neuropathy (DAN) are the most common manifestations of DPN. Optimal glucose control represents the only broadly accepted therapeutic option though evidence of its benefit in type 2 diabetes is unclear. A number of symptomatic treatments are recommended in clinical guidelines for the management of painful DPN, including antidepressants such as amitriptyline and duloxetine, the γ-aminobutyric acid analogues gabapentin and pregabalin, opioids, and topical agents such as capsaicin. However, monotherapy is frequently not effective in achieving complete resolution of pain in DPN. There is a growing need for head-to-head studies of different single-drug and combination pharmacotherapies. Due to the ubiquity of autonomic innervation in the body, DAN causes a plethora of symptoms and signs affecting cardiovascular, urogenital, gastrointestinal, pupillomotor, thermoregulatory, and sudomotor systems. The current treatment of DAN is largely symptomatic, and does not correct the underlying autonomic nerve deficit. A number of novel potential candidates, including erythropoietin analogues, angiotensin II receptor type 2 antagonists, and sodium channel blockers are currently being evaluated in phase II clinical trials.

Treatment of painful diabetic neuropathy

Painful diabetic neuropathy (PDN) is a debilitating consequence of diabetes that may be present in as many as one in five patients with diabetes. The objective assessment of PDN is difficult, making it challenging to diagnose and assess in both clinical practice and clinical trials. No single treatment exists to prevent or reverse neuropathic changes or to provide total pain relief. Treatment of PDN is based on three major approaches: intensive glycaemic control and risk factor management, treatments based on pathogenetic mechanisms, and symptomatic pain management. Clinical guidelines recommend pain relief in PDN through the use of antidepressants such as amitriptyline and duloxetine, the γ-aminobutyric acid analogues gabapentin and pregabalin, opioids and topical agents such as capsaicin. Of these medications, duloxetine and pregabalin were approved by the US Food and Drug Administration (FDA) in 2004 and tapentadol extended release was approved in 2012 for the treatment of PDN. Proposed pathogenetic treatments include α-lipoic acid (stems reactive oxygen species formation), benfotiamine (prevents vascular damage in diabetes) and aldose-reductase inhibitors (reduces flux through the polyol pathway). There is a growing need for studies to evaluate the most potent drugs or combinations for the management of PDN to maximize pain relief and improve quality of life. A number of agents are potential candidates for future use in PDN therapy, including Nav 1.7 antagonists, N-type calcium channel blockers, NGF antibodies and angiotensin II type 2 receptor antagonists.

Lipid mediators in diabetic nephropathy

The implications of lipid lowering drugs in the treatment of diabetic nephropathy have been considered. At the same time, the clinical efficacy of lipid lowering drugs has resulted in improvement in the cardiovascular functions of chronic kidney disease (CKD) patients with or without diabetes, but no remarkable improvement has been observed in the kidney outcome. Earlier lipid mediators have been shown to cause accumulative effects in diabetic nephropathy (DN). Here, we attempt to analyze the involvement of lipid mediators in DN. The hyperglycemia-induced overproduction of diacyglycerol (DAG) is one of the causes for the activation of protein kinase C (PKCs), which is responsible for the activation of pathways, including the production of VEGF, TGFβ1, PAI-1, NADPH oxidases, and NFҟB signaling, accelerating the development of DN. Additionally, current studies on the role of ceramide are one of the major fields of study in DN. Researchers have reported excessive ceramide formation in the pathobiological conditions of DN. There is less report on the effect of lipid lowering drugs on the reduction of PKC activation and ceramide synthesis. Regulating PKC activation and ceramide biosynthesis could be a protective measure in the therapeutic potential of DN. Lipid lowering drugs also upregulate anti-fibrotic microRNAs, which could hint at the effects of lipid lowering drugs in DN.

Risks and benefits of statin use in young people with type 1 diabetes

Cardiovascular disease (CVD) is the primary cause of mortality in patients with type 1 diabetes (T1D). Despite advances in the management of microvascular complications of T1D, there is a lack of similar progress in reduction of macrovascular complications. Dyslipidemia is one of the major contributory factors for macrovascular complications in T1D, but the literature suggests significant under-treatment of this risk factor in children and adolescents with diabetes. Statins have shown to be both effective and safe in young people with familial hypercholesterolemia and adults with diabetes mellitus, but the role for statins in children and adolescent with T1D remains unclear and controversial. In this review, we will summarize the risks and benefits of statin use in young people with T1D.

HMG CoA reductase inhibitors (statins) for people with chronic kidney disease not requiring dialysis

BACKGROUND

Cardiovascular disease (CVD) is the most frequent cause of death in people with early stages of chronic kidney disease (CKD), for whom the absolute risk of cardiovascular events is similar to people who have existing coronary artery disease. This is an update of a review published in 2009, and includes evidence from 27 new studies (25,068 participants) in addition to the 26 studies (20,324 participants) assessed previously; and excludes three previously included studies (107 participants). This updated review includes 50 studies (45,285 participants); of these 38 (37,274 participants) were meta-analysed.

OBJECTIVES

To evaluate the benefits (such as reductions in all-cause and cardiovascular mortality, major cardiovascular events, MI and stroke; and slow progression of CKD to end-stage kidney disease (ESKD)) and harms (muscle and liver dysfunction, withdrawal, and cancer) of statins compared with placebo, no treatment, standard care or another statin in adults with CKD who were not on dialysis.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 5 June 2012 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs that compared the effects of statins with placebo, no treatment, standard care, or other statins, on mortality, cardiovascular events, kidney function, toxicity, and lipid levels in adults with CKD not on dialysis were the focus of our literature searches.

DATA COLLECTION AND ANALYSIS

Two or more authors independently extracted data and assessed study risk of bias. Treatment effects were expressed as mean difference (MD) for continuous outcomes (lipids, creatinine clearance and proteinuria) and risk ratio (RR) for dichotomous outcomes (major cardiovascular events, all-cause mortality, cardiovascular mortality, fatal or non-fatal myocardial infarction (MI), fatal or non-fatal stroke, ESKD, elevated liver enzymes, rhabdomyolysis, cancer and withdrawal rates) with 95% confidence intervals (CI).

MAIN RESULTS

We included 50 studies (45,285 participants): 47 studies (39,820 participants) compared statins with placebo or no treatment and three studies (5547 participants) compared two different statin regimens in adults with CKD who were not yet on dialysis. We were able to meta-analyse 38 studies (37,274 participants).The risk of bias in the included studies was high. Seven studies comparing statins with placebo or no treatment had lower risk of bias overall; and were conducted according to published protocols, outcomes were adjudicated by a committee, specified outcomes were reported, and analyses were conducted using intention-to-treat methods. In placebo or no treatment controlled studies, adverse events were reported in 32 studies (68%) and systematically evaluated in 16 studies (34%).Compared with placebo, statin therapy consistently prevented major cardiovascular events (13 studies, 36,033 participants; RR 0.72, 95% CI 0.66 to 0.79), all-cause mortality (10 studies, 28,276 participants; RR 0.79, 95% CI 0.69 to 0.91), cardiovascular death (7 studies, 19,059 participants; RR 0.77, 95% CI 0.69 to 0.87) and MI (8 studies, 9018 participants; RR 0.55, 95% CI 0.42 to 0.72). Statins had uncertain effects on stroke (5 studies, 8658 participants; RR 0.62, 95% CI 0.35 to 1.12).Potential harms from statin therapy were limited by lack of systematic reporting and were uncertain in analyses that had few events: elevated creatine kinase (7 studies, 4514 participants; RR 0.84, 95% CI 0.20 to 3.48), liver function abnormalities (7 studies, RR 0.76, 95% CI 0.39 to 1.50), withdrawal due to adverse events (13 studies, 4219 participants; RR 1.16, 95% CI 0.84 to 1.60), and cancer (2 studies, 5581 participants; RR 1.03, 95% CI 0.82 to 130).Statins had uncertain effects on progression of CKD. Data for relative effects of intensive cholesterol lowering in people with early stages of kidney disease were sparse. Statins clearly reduced risks of death, major cardiovascular events, and MI in people with CKD who did not have CVD at baseline (primary prevention).

AUTHORS' CONCLUSIONS

Statins consistently lower death and major cardiovascular events by 20% in people with CKD not requiring dialysis. Statin-related effects on stroke and kidney function were found to be uncertain and adverse effects of treatment are incompletely understood. Statins have an important role in primary prevention of cardiovascular events and mortality in people who have CKD.

Simvastatin alleviates hyperpermeability of glomerular endothelial cells in early-stage diabetic nephropathy by inhibition of RhoA/ROCK1

Background

Endothelial dysfunction is an early sign of diabetic cardiovascular disease and may contribute to progressive diabetic nephropathy (DN). There is increasing evidence that dysfunction of the endothelial tight junction is a crucial step in the development of endothelial hyperpermeability, but it is unknown whether this occurs in glomerular endothelial cells (GEnCs) during the progression of DN. We examined tight junction dysfunction of GEnCs during early-stage DN and the potential underlying mechanisms. We also examined the effect of simvastatin (3-Hydroxy-3-methylglutaryl CoA reductase inhibitor) on dysfunction of the tight junctions of cultured GEnCs and in db/db mice with early-stage DN.

Methods

We assessed the expression of occludin and ZO-1, two major components of the tight junction complex, in cultured rat GEnCs treated with high glucose and in 12 week-old db/db mice with early-stage DN. We also investigated activation of RhoA/ROCK1 signaling, GEnC permeability, and renal function of the mice.

Results

High glucose suppresses occludin expression and disrupts occludin/ZO-1 translocation in GEnCs. These changes were associated with increased permeability to albumin and activation of RhoA/ROCK1 signaling. Occludin and ZO-1 dysregulation also occurred in the glomeruli of mice with early-stage DN, and these abnormalities were accompanied by albuminuria and activation of RhoA/ROCK1 in isolated glomeruli. Simvastatin prevented high glucose or hyperglycemia-induced dysregulation of occludin and ZO-1 by inhibition of RhoA/ROCK1 signaling in cultured GEnCs and in db/db mice with early-stage DN.

Conclusion

Our results indicate that activation of RhoA/ROCK1 by high glucose disrupts the expression and translocation of occludin/ZO-1 and that simvastatin alleviates occludin/ZO-1 dysregulation and albuminuria by suppressing RhoA/ROCK1 signaling during early-stage DN. These results suggest a potential therapeutic strategy for preventing the onset of albuminuria in early-stage DN.

Impaired endothelium-dependent skin microvascular function during high-dose atorvastatin treatment in patients with type 1 diabetes

AIMS

The present study investigated the effects of lipid-lowering therapy with atorvastatin on skin microvascular function in patients with type 1 diabetes and dyslipidaemia.

METHODS

Twenty patients received daily treatment with atorvastatin 80 mg or placebo during 2 months in a randomised, double-blind, cross-over study. Forearm skin microcirculation was investigated with laser Doppler perfusion imaging during iontophoresis of acetylcholine and sodium nitroprusside to assess endothelium-dependent and endothelium-independent microvascular reactivity, respectively. Various biochemical markers of endothelial function were also investigated.

RESULTS

Endothelium-dependent microvascular reactivity decreased during atorvastatin (p < 0.001), showing a significant treatment effect compared with placebo (p = 0.04). Atorvastatin treatment was also associated with increased haemoglobin A1C levels from 7.45% to 7.77% (p = 0.008).

CONCLUSIONS

The present study shows impaired endothelium-dependent skin microvascular function during high-dose atorvastatin treatment in patients with type 1 diabetes, thus implicating a risk for deterioration of microvascular function during such therapy in these patients.

Clinical profile of long-term survivors and nonsurvivors with type 2 diabetes

OBJECTIVE

To compare clinical profile of long-term survivors and nonsurvivors with type 2 diabetes (T2DM).

RESEARCH DESIGN AND METHODS

After conducting a retrospective survey of >200,000 case records, we identified T2DM survivors (>40 years of duration) and age at diagnosis and sex-matched T2DM nonsurvivors. Prevalence of complications and causes of death were analyzed. Retinopathy was diagnosed by retinal photography. Microalbuminuria and macroalbuminuria, peripheral vascular disease based on ankle-brachial index <0.9, coronary artery disease based on history of myocardial infarction or coronary revascularization, and neuropathy based on vibration perception threshold >20 V were compared in both groups.

RESULTS

The mean duration of diabetes of survivors (n = 238) was 43.7 ± 3.9 years, and that of the nonsurvivors (n = 307), at time of death, was 22.4 ± 11.0 years (P < 0.001). Nonsurvivors had significantly higher systolic and diastolic blood pressures, plasma glucose, HbA1c, serum cholesterol, LDL cholesterol, and triglycerides and lower HDL cholesterol compared with long-term survivors (P < 0.001 for all parameters except systolic blood pressure, which was P = 0.027). Myocardial infarction (46.4%) and renal failure (16.6%) were the most common causes of death. Prevalence of most complications was higher among survivors because of longer duration and older age, as follows, for survivors versus nonsurvivors: retinopathy, 76 vs. 62%; microalbuminuria, 39.1 vs. 27.3%; macroalbuminuria, 8.4 vs. 23.7%; neuropathy, 86.5 vs. 63.5%; peripheral vascular disease, 23.1 vs. 11.4%; and coronary artery disease, 44.5 vs. 40.7%.

CONCLUSIONS

Long-term survivors with T2DM had better glycemic and blood pressure control and more favorable lipid profiles.

Association of statin use with peripheral neuropathy in the U.S. population 40 years of age or older

BACKGROUND

Peripheral neuropathy is a serious complication of diabetes and several conditions that may lead to the loss of lower extremity function and even amputations. Since the introduction of statins, their use has increased markedly. Recent reports suggest a role for statins in the development of peripheral neuropathy. The aims of the present study were to assess the association between statin use and peripheral neuropathy, and to determine whether this association varied by diabetes status.

METHODS

Data from the lower extremity examination supplement of the 1999-2004 National Health and Nutrition Examination Survey were used.

RESULTS

The overall prevalence of statin use was 15% and the prevalence of peripheral neuropathy was 14.9%. The prevalence of peripheral neuropathy was significantly higher among those who used statins compared with those who did not (23.5% vs 13.5%, respectively; P < 0.01). Multivariate logistic regression revealed that statin use (adjusted odds ratio 1.3; 95% confidence interval 1.1-1.6; Wald P = 0.04) was significantly associated with peripheral neuropathy, controlling for diabetes status, age, gender, race, height, weight, blood lead levels, poverty, glycohemoglobin, use of vitamin B12 , alcohol abuse, hypertension, and non-high-density lipoprotein-cholesterol. Diabetes status, age, gender, height, weight, blood lead levels, poverty, and glycohemoglobin were also significantly associated with peripheral neuropathy. We found no effect modification between statin use and diabetes status, race, gender, age, vitamin B12 , blood lead levels, or alcohol abuse.

CONCLUSIONS

In the present cross-sectional study, we found a modest association between peripheral neuropathy and statin use. Prospective studies are required to determine the causal direction.

Benefits and harms of statin therapy for persons with chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

Statins have uncertain benefits in persons with chronic kidney disease (CKD) because individual trials may have insufficient power to determine whether treatment effects differ with severity of CKD.

PURPOSE

To summarize the benefits and harms of statin therapy for adults with CKD and examine whether effects of statins vary by stage of kidney disease.

DATA SOURCES

Cochrane and EMBASE databases (inception to February 2012).

STUDY SELECTION

Randomized trials comparing the effects of statins with placebo, no treatment, or another statin on mortality and cardiovascular outcomes.

DATA EXTRACTION

Two independent reviewers extracted data and assessed risk of bias.

DATA SYNTHESIS

Eighty trials comprising 51099 participants compared statin with placebo or no treatment. Treatment effects varied with stage of CKD. Moderate- to high-quality evidence indicated that statins reduced all-cause mortality (relative risk [RR], 0.81 [95% CI, 0.74 to 0.88]), cardiovascular mortality (RR, 0.78 [CI, 0.68 to 0.89]), and cardiovascular events (RR, 0.76 [CI, 0.73 to 0.80]) in persons not receiving dialysis. Moderate- to high-quality evidence indicated that statins had little or no effect on all-cause mortality (RR, 0.96 [CI, 0.88 to 1.04]), cardiovascular mortality (RR, 0.94 [CI, 0.82 to 1.07]), or cardiovascular events (RR, 0.95 [CI, 0.87 to 1.03]) in persons receiving dialysis. Effects of statins in kidney transplant recipients were uncertain. Statins had little or no effect on cancer, myalgia, liver function, or withdrawal from treatment, although adverse events were evaluated systematically in fewer than half of the trials.

LIMITATION

There was a reliance on post hoc subgroup data for earlier stages of CKD.

CONCLUSION

Statins decrease mortality and cardiovascular events in persons with early stages of CKD, have little or no effect in persons receiving dialysis, and have uncertain effects in kidney transplant recipients.

Recent advances in the treatment of atherogenic dyslipidemia in type 2 diabetes mellitus

Despite best treatment efforts reducing low-density lipoprotein cholesterol, a substantial number of type 2 diabetes mellitus patients still experience progression of cardiovascular risk. Even with intensification of statin therapy, a substantial residual cardiovascular risk remains and atherogenic dyslipidemia is an important driver of this so-called residual risk. Besides statin therapy, new strategies evaluate the role of intensive combination lipid treatment for the entire type 2 diabetic population. The results from the ACCORD (Action to Control Cardiovascular Risk in Diabetes) Lipid trial suggest that there is a lipid-related modifiable component to cardiovascular residual risk in statin-treated type 2 diabetic patients, and that further research should address patients with triglycerides above 204 mg/dl and high-density lipoprotein cholesterol below 34 mg/dl. Based on their respective lipid-modifying activity, the combination of a fibrate and statin is a logical approach to improving achievement of lipid targets in statin-treated patients with a glomerular filtration rate of >60 ml/min/1.73 m(2) and with residual atherogenic dyslipidemia. The link between dyslipidemia treatment and diabetic retinopathy, nephropathy and neuropathy is an emerging new field and microvascular complications are targets for new treatments.

Long-term diabetic complications may be ameliorated by targeting Rho kinase

This review addresses the roles of Rho/Rho-kinase (ROCK) pathway in the pathogenesis of diabetes complications. Diabetes can cause many serious complications and can result in physical disability or even increased mortality. However, there are not many effective ways to treat these complications. The small guanosine-5'-triphosphate-binding protein Rho and its downstream target Rho-kinase mediate important cellular functions, such as cell morphology, motility, secretion, proliferation, and gene expression. Recently, the Rho/Rho-kinase pathway has attracted a great deal of attention in diabetes-related research. These studies have provided evidence that the activity and gene expression of Rho-kinase are upregulated in some tissues in animal models of type 1 or type 2 diabetes and in cell lines cultured with high concentrations of glucose. Inhibitors of Rho-kinase could prevent or ameliorate the pathological changes in diabetic complications. The inhibitory effects of statins on the Rho/Rho-kinase signalling pathway may also play a role in the prevention of diabetic complications. However, the precise molecular mechanism by which the Rho/Roh-kinase pathway participates in the development or progression of diabetic complications has not been extensively investigated. This article evaluates the relationship between Rho/Roh-kinase activation and diabetic complications, as well as the roles of Roh-kinase inhibitors and statins in the complications of diabetes, with the objective of providing a novel target for the treatment of long-term diabetic complications.

RhoA/Rho kinase pathway contributes to the pathogenesis of thermal hyperalgesia in diabetic mice

Diabetic neuropathy is one of the most common complications of diabetes and causes various problems in daily life. Several investigations have noted that many factors in the spinal cord are involved in the symptoms of painful diabetic neuropathy, and there are very few effective therapeutic regimens. In the present study, we sought to elucidate the role of the RhoA/Rho kinase (ROCK) pathway in thermal hyperalgesia in diabetic mice. The intracellular localization of RhoA and the expression of eNOS were measured by western blotting. Thermal hyperalgesia was assessed by the tail-flick test and mechanical allodynia was assessed by automated von Frey filament test in streptozotocin(STZ)-induced diabetic mice. The spinal cord of STZ-treated diabetic mice showed increased membrane-bound RhoA compared to non-diabetic control. Treatment with the RhoA inhibitor exoenzyme C3, Clostridium botulinum, and the ROCK inhibitor Y27632 attenuated thermal hyperalgesia and mechanical allodynia in diabetic mice. Moreover, daily treatment with simvastatin attenuated all of those changes in diabetic mice. The expression of eNOS and NO metabolite contents in the spinal cord was decreased in diabetic mice, and these changes were normalized by treatment with simvastatin. The present results show that HMG-CoA reductase inhibitors have an inhibitory effect on thermal hyperalgesia in diabetic mice, which is mediated by an increase in NO production through the inhibition of RhoA/ROCK pathways. These results suggest that ROCK inhibitors and HMG-CoA inhibitors may be attractive compounds to relieve the symptoms of painful diabetic neuropathies.

Reviewing statin therapy in diabetes--towards the best practise

Statin therapy is considered critical both in primary and secondary prevention of cardiovascular disease in diabetes. Cholesterol Treatment Trialists' Collaborators meta-analysis of 14 randomised trials of statins in 18686 people with diabetes provides the latest and largest evidence showing a significant 21% reduction in major vascular events per mmol/l reduction in LDL cholesterol. Importantly, the risk reduction was similar in both types of diabetes. Growing evidence supports the view that statin therapy reduces microvascular complications as well. This review updates the current knowledge of statin therapy in preventing micro- and macrovascular complications in both type 1 and type 2 diabetes.

Fluvastatin attenuates diabetes-induced cardiac sympathetic neuropathy in association with a decrease in oxidative stress

BACKGROUND

Increased oxidative stress might contribute to diabetic (DM) neuropathy, so the effects of long-term treatment with fluvastatin (FL) on myocardial oxidative stress and cardiac sympathetic neural function were investigated in diabetic rats.

METHODS AND RESULTS

FL (10 mg . kg(-1) . day(-1), DM-FL) or vehicle (DM-VE) was orally administered for 2 weeks to streptozotocin-induced DM rats. Cardiac oxidative stress was determined by myocardial 8-iso-prostaglandin F(2alpha) (PGF(2alpha)) and NADPH oxidase subunit p22(phox) mRNA expression. Sympathetic neural function was quantified by autoradiography using (131)I- and (125)I-metaiodobenzylguanidine (MIBG). FL did not affect plasma glucose levels but remarkably decreased PGF(2alpha) levels compared with DM-VE rats (13.8+/-9.2 vs 175.0+/-93.9 ng/g tissue), although PGF(2alpha) levels were below the detection limit in non-DM rats. FL significantly reduced myocardial p22(phox) mRNA expression. Cardiac (131)I-MIBG uptake was lower in DM-VE rats than in non-DM rats, but the decrease was attenuated in DM-FL rats (1.31+/-0.08, 1.88+/-0.22, and 1.58+/-0.18 %kg dose/g, respectively, P<0.01). Cardiac MIBG clearance was not affected by the induction of DM or by FL, indicating that the reduced MIBG uptake in DM rats might result from impaired neural function.

CONCLUSIONS

FL ameliorates cardiac sympathetic neural dysfunction in DM rats in association with attenuation of increased myocardial oxidative stress.

Elevated triglycerides correlate with progression of diabetic neuropathy

OBJECTIVE

To evaluate mechanisms underlying diabetic neuropathy progression using indexes of sural nerve morphometry obtained from two identical randomized, placebo-controlled clinical trials.

RESEARCH DESIGN AND METHODS

Sural nerve myelinated fiber density (MFD), nerve conduction velocities (NCVs), vibration perception thresholds, clinical symptom scores, and a visual analog scale for pain were analyzed in participants with diabetic neuropathy. A loss of > or =500 fibers/mm(2) in sural nerve MFD over 52 weeks was defined as progressing diabetic neuropathy, and a MFD loss of < or =100 fibers/mm(2) during the same time interval as nonprogressing diabetic neuropathy. The progressing and nonprogressing cohorts were matched for baseline characteristics using an O'Brien rank-sum and baseline MFD.

RESULTS

At 52 weeks, the progressing cohort demonstrated a 25% decrease (P < 0.0001) from baseline in MFD, while the nonprogressing cohort remained unchanged. MFD was not affected by active drug treatment (P = 0.87), diabetes duration (P = 0.48), age (P = 0.11), or BMI (P = 0.30). Among all variables tested, elevated triglycerides and decreased peroneal motor NCV at baseline significantly correlated with loss of MFD at 52 weeks (P = 0.04).

CONCLUSIONS

In this cohort of participants with mild to moderate diabetic neuropathy, elevated triglycerides correlated with MFD loss independent of disease duration, age, diabetes control, or other variables. These data support the evolving concept that hyperlipidemia is instrumental in the progression of diabetic neuropathy.

HMG CoA reductase inhibitors (statins) for people with chronic kidney disease not requiring dialysis

BACKGROUND

Dyslipidaemia occurs frequently in chronic kidney disease (CKD) patients and contributes both to cardiovascular disease and worsening renal function. Statins are widely used in non-dialysis dependent CKD patients (pre-dialysis) even though evidence favouring their use is lacking.

OBJECTIVES

To evaluate the benefits and harms of statins in CKD patients who were not receiving renal replacement therapy.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, CENTRAL (in The Cochrane Library), and hand-searched reference lists of textbooks, articles and scientific proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing statins with placebo, no treatment or other statins in adult pre-dialysis CKD patients.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Results were expressed as mean difference (MD) for continuous outcomes (lipids, creatinine clearance and proteinuria) and risk ratio (RR) for dichotomous outcomes (all-cause mortality, cardiovascular mortality, fatal and non-fatal cardiovascular events, elevated liver enzymes, rhabdomyolysis and withdrawal rates) with 95% confidence intervals (CI).

MAIN RESULTS

Twenty six studies (25,017 participants) comparing statins with placebo were identified. Total cholesterol decreased significantly with statins (18 studies, 1677 patients: MD -41.48 mg/dL, 95% CI -49.97 to -33.99). Similarly, LDL cholesterol decreased significantly with statins (16 studies, 1605 patients: MD -42.38 mg/dL, 95% CI -50.71 to -34.05). Statins decreased both the risk of all-cause (21 RCTs, 18,781 patients, RR 0.81, 95% CI 0.74, 0.89) and cardiovascular deaths (20 studies, 18,746 patients: RR 0.80, 95% CI 0.70 to 0.90). Statins decreased 24-hour urinary protein excretion (6 studies, 311 patients: MD -0.73 g/24 h, 95% CI -0.95 to -0.52), but there was no significant improvement in creatinine clearance - a surrogate marker of renal function (11 studies, 548 patients: MD 1.48 mL/min, 95% CI -2.32 to 5.28).The incidence of rhabdomyolysis, elevated liver enzymes and withdrawal rates due to adverse events (well known complications of statins use), were not significantly different between patients receiving statins and placebo.

AUTHORS' CONCLUSIONS

Statins significantly reduced the risk of all-cause and cardiovascular mortality in CKD patients who are not receiving renal replacement therapy. They do not impact on the decline in renal function as measured by creatinine clearance, but may reduce protein excretion in urine. Statins appear to be safe in this population. Guidelines recommendations on hyperlipidaemia management in CKD patients could therefore be followed targeting higher proportions of patients receiving a statin, with appropriate monitoring of adverse events.

Renal agenesis and unilateral nephrectomy: what are the risks of living with a single kidney?

The long-term outlook for patients with unilateral renal agenesis or following unilateral nephrectomy in childhood is controversial. Animal studies suggest that the resultant compensatory increase in glomerular filtration might lead to progressive damage to the remaining renal tissue and may generate hypertension. Human studies addressing these concerns are limited in number and are difficult to interpret because they are small, retrospective, or cross sectional with significant variations in duration and completeness of follow-up. The published studies suggest that renal function remains stable for several decades in the majority of subjects. The clinical significance of mild-grade proteinuria and hypertension seen in some patients is unknown. Longitudinal studies are needed to understand the long-term effect and significance of the several pathophysiological changes observed in the solitary kidney.

Management of painful diabetic neuropathy

The commonest cause of peripheral neuropathy is diabetes and pain occurs in approximately 30% of diabetic patients with neuropathy. It is extremely distressing for the patient and poses significant difficulties in management, as no treatment to date provides total relief and the side effects of therapy limit dose titration. Understanding the pathogenesis of diabetic neuropathy may lead to the development of new treatments for preventing nerve damage. Furthermore, a better understanding of the mechanisms that modulate pain may lead to more effective relief of painful symptoms. This review provides an update on the assessment and treatment of painful diabetic neuropathy.

Interactions between microvascular and macrovascular disease in diabetes: pathophysiology and therapeutic implications

Convention partitions the complications of diabetes into two main subtypes. First are the diabetes-specific microvascular complications of retinopathy, nephropathy and neuropathy; second are the atherothrombotic macrovascular complications that account for the majority of premature deaths. Pathological interactions between microvascular and macrovascular complications, for example, nephropathy and macrovascular disease, are common. Similar mechanisms and shared risk factors drive the development and progression of both small and large vessel disease. This concept has therapeutic implications. Mounting evidence points to the need for multifactorial strategies to prevent vascular complications in subjects with diabetes and/or the metabolic syndrome. We advocate a combined therapeutic approach that addresses small and large vessel disease. Preferential use should be made of drug regimens that (i) maximize vascular protection, (ii) reduce the risk of iatrogenic vascular damage and (iii) minimize the increasing problem of polypharmacy.

Concomitant reduction of low-density lipoprotein-cholesterol and biomarkers of inflammation with low-dose simvastatin therapy in patients with type 1 diabetes

CONTEXT

Cardiovascular disease is a major cause of mortality in type 1 diabetes (TIDM). TIDM is a proinflammatory state. Whereas there is consensus on lipid management in type 2 diabetes, there is a lack of data in type 1 diabetes. In addition to benefits on the lipid profile, statin therapy is antiinflammatory.

OBJECTIVE

There are scant data on statin therapy in T1DM. Thus, we tested the effect of simvastatin, compared with placebo, on biomarkers of inflammation and monocyte function in TIDM patients.

DESIGN

This was a double-blind, randomized, placebo-controlled study of T1DM patients, randomized to placebo or simvastatin, 20 mg/d for 3 months.

SETTING

The study was conducted at the University of California, Davis, Medical Center.

PARTICIPANTS

Participants included patients with T1DM.

METHODS AND RESULTS

Analytes measured at baseline and 3 months included liver function tests, creatinine, hemoglobin AIC, high-sensitivity C-reactive protein, soluble CD40 ligand, monocyte O(2)(-), cytokines, nuclear factor-kappaB. Simvastatin therapy resulted in significant reduction in low-density lipoprotein and non-high-density lipoprotein cholesterol, high-sensitivity C-reactive protein (18% reduction, P < 0.001) and soluble CD40 ligand (22% reduction, P < 0.05), compared with placebo. Simvastatin therapy significantly inhibited lipopolysaccharide-activated monocyte release of O(2)(-) (P < 0.0005), IL-8 (P < 0.03), and TNF (P < 0.02). Simvastatin therapy significantly inhibited monocyte IL-6 release, compared with baseline (P = 0.02). Simvastatin therapy also significantly reduced monocytic nuclear factor-kappaB p65 activity, compared with placebo (P < 0.01).

CONCLUSIONS

This study demonstrates that simvastatin (20 mg/d) is safe in T1DM patients and has concomitant benefits on the lipid profile and biomarkers of inflammation. These novel findings could have implications for developing policy guidelines for statin therapy in forestalling vascular complications in young T1DM.

Diabetic Painful Neuropathy

Diabetic painful neuropathy (DPN) is one of the most common causes of neuropathic pain. The management of DPN consists of excluding other causes of painful peripheral neuropathy, maximising diabetic control and using medications to alleviate pain. The precise relationship between glycaemic control and the development and severity of DPN remains controversial. In this context, drugs such as aldose reductase inhibitors, ACE inhibitors, lipid-lowering agents and alpha-lipoic acid (thioctic acid) may have a useful role to play. There is also evidence that a successful pancreatic transplant may improve symptoms over time, but the mainstay of management continues to be symptomatic control of pain with drugs. Evidence from placebo-controlled studies has shown that opioids, antiepileptic and antidepressant drugs together with capsaicin are effective for alleviating DPN. Tramadol and oxycodone have been shown to be effective in studies of limited duration but their adverse effects, such as constipation and physical dependency, may limit their usefulness as a first-line treatment for DPN. Of the antidepressant drugs, the tricyclic antidepressants have been shown to be effective for alleviating DPN. These medications are widely used but their anticholinergic and sedative properties may not be well tolerated by patients. There is also good evidence that the serotonin-noradrenaline reuptake inhibitor antidepressant drugs venlafaxine and duloxetine are effective for treating DPN. However, venlafaxine may cause cardiac dysrhythmias, and patients using this medication require careful cardiac monitoring. Duloxetine appears to be less cardiotoxic and is licensed in the US and EU for alleviating DPN. The gabapentinoid group of drugs, gabapentin and pregabalin, appear to be the most evidence-based of the antiepileptic drugs for treating DPN. Large placebo-controlled studies have been performed with both of these agents. For many patients, it is still unclear what advantages pregabalin has over gabapentin for DPN. Until better evidence emerges, the potential availability of less expensive generic formulations of gabapentin, together with greater experience with its use, favour gabapentin as the main antiepileptic drug for alleviating DPN. Topiramate, lamotrigine, sodium valproate and oxcarbazepine have been shown to be effective in smaller studies but do not have the same evidence base as the gabapentinoid group of drugs. Of the newer antiepileptic drugs, lacosamide appears to be the most promising for alleviating DPN. Capsaicin has the best evidence base of all the topical agents, but local anaesthetic patches may also have a useful therapeutic role. It is not possible to nominate a single drug as the first-line treatment for DPN and there is evidence that a low-dose combination of two or more drugs rather than a single agent may provide better symptomatic relief with fewer adverse effects. Further studies are necessary to clarify the best combination(s) of treatment for DPN.

Cardiovascular Risk Factors Predicting the Development of Distal Symmetrical Polyneuropathy in People with Type 1 Diabetes: A 9-Year Follow-up Study

The aim of the article was to use prospectively collected data on people with type 1 diabetes to examine which routinely collected clinical measures predict the development of peripheral neuropathy in people with type 1 diabetes. Within the Newcastle Diabetes Services, structured data collection at an annual review has been collected since 1985. This includes metabolic measures, cardiovascular risk factors, and markers of complications. From 1990 data collection was standardized and computerized. For this study, all people with type 1 diabetes in the database in both 1992 and 2001 were ascertained. Data were extracted for a diagnosis of peripheral neuropathy (based on neuropathic symptoms, absence of pinprick sensation, and abnormal biothesiometer measurements and/or monofilament sensation) and for the other metabolic and cardiovascular risk measures, as well as markers of other microvascular complications. Associations with the development of neuropathy were sought. Eighteen of 404 people already had peripheral neuropathy in 1992, and 38 others developed neuropathy during follow-up. People who developed neuropathy were older (47 +/- 14 [SD] versus 36 +/- 11 years; P = 0.000), had longer-duration of diabetes (27 +/- 13 versus 18 +/- 10 years; P = 0.001), higher baseline serum cholesterol (5.8 +/- 1.3 versus 5.2 +/- 1.2 mmol/L, P = 0.017), and higher systolic (139 +/- 18 versus 129 +/- 20 mmHg; P = 0.003) and diastolic BP (82 +/- 12 versus 76 +/- 11 mmHg; P = 0.009) than those who remained free of neuropathy. We found no significant difference for BMI and glycated hemoglobin. The multivariate model showed that diastolic BP, duration of diabetes, serum cholesterol, and history of callus/ulcers on the feet predicted the development of peripheral neuropathy. Neuropathy developed in 11.4% of people with type 1 diabetes over a 9-year follow-up, and was predicted by factors normally associated with cardiovascular rather than microvascular disease.

Statins for improving renal outcomes: a meta-analysis

Statins frequently are used to prevent cardiovascular events. Several recent studies suggest that statins also may have renal benefits, although this is controversial. This systematic review and meta-analysis were performed to assess the effect of statins on change in kidney function and urinary protein excretion. Medline, EMBASE, the Cochrane Central Register of Controlled Trials, conference proceedings, and the authors' personal files were searched. Published or unpublished randomized, controlled trials or crossover trials of statins that reported assessment of kidney function or proteinuria were included, and studies of individuals with ESRD were excluded. Data were extracted for study design, subject characteristics, type of statin and dose, baseline/change in cholesterol levels, and outcomes (change in measured or estimated GFR [eGFR] and/or urinary protein excretion). Weighted mean differences were calculated for the change in GFR between statin and control groups using a random-effects model. A random-effects model also was used to calculate the standardized mean difference for the change in urinary protein excretion between groups. Twenty-seven eligible studies with 39,704 participants (21 with data for eGFR and 20 for proteinuria or albuminuria) were identified. Overall, the change in the weighted mean differences for eGFR was statistically significant (1.22 ml/min per yr slower in statin recipients; 95% confidence interval [CI] 0.44 to 2.00). In subgroup analysis, the benefit of statin therapy was statistically significant in studies of participants with cardiovascular disease (0.93 ml/min per yr slower than control subjects; 95% CI 0.10 to 1.76) but was NS for studies of participants with diabetic or hypertensive kidney disease or glomerulonephritis. The standardized mean difference for the reduction in albuminuria or proteinuria as a result of statin therapy was statistically significant (0.58 units of SD greater in statin recipients; 95% CI 0.17 to 0.98). Statin therapy seems to reduce proteinuria modestly and results in a small reduction in the rate of kidney function loss, especially in populations with cardiovascular disease.

Serum lipids and the progression of nephropathy in type 1 diabetes

OBJECTIVE

Dyslipidemia contributes to the progression of microvascular disease in diabetes. However, different lipid variables may be important at different stages of nephropathy. This study examines the pattern of dyslipidemia associated with the progression of nephropathy in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

A total of 152 patients with type 1 diabetes were recruited in order to represent various phases of nephropathy. Patients were followed for 8-9 years, during which time they received standard care. Renal progression was defined a priori as a doubling in albumin excretion (in patients with normo- or microalbuminuria) or a decline in creatinine clearance (in those with macroalbuminuria). A panel of lipid variables was determined and correlated with indexes of progression.

RESULTS

In patients with normoalbuminuria (n = 66), progression was associated with male sex (P < 0.05), borderline albuminuria (P = 0.02), and LDL-free cholesterol (P = 0.02). In patients with microalbuminuria (n = 51), progression was independently associated with triglyceride content of VLDL and intermediate-density lipoprotein (both P < 0.05). In patients with macroalbuminuria (n = 36), a significant decline in the renal function (>3 ml x min(-1) x year(-1)) was independently associated with poor glycemic control, hypertension, and LDL size (P < 0.05). When all patients with progressive nephropathy were analyzed together, only LDL cholesterol was predictive on multivariate analysis (P < 0.05), which masked the importance of triglyceride enrichment in microalbuminuria.

CONCLUSIONS

Lipid variables are associated with progression of diabetic kidney disease, but the relationship is not the same at all stages. This finding has implications for the design of renoprotective strategies and the interpretation of clinical trials in type 1 diabetes.

Adjuvant strategies for prevention of glomerulosclerosis

The glomerulosclerosis which frequently complicates diabetes and severe hypertension is mediated primarily by increased mesangial production and activation of transforming growth factor-beta (TGF-beta), which acts on mesangial cells to boost their production of matrix proteins while suppressing extracellular proteolytic activity. Hyperglycemia and glomerular hypertension work in various complementary ways to stimulate superoxide production via NADPH oxidase in mesangial cells; the resulting oxidant stress results in the induction and activation of TFG-beta. Nitric oxide, generated by glomerular capillaries and by mesangial cells themselves, functions physiologically to oppose mesangial TGF-beta overproduction; however, NO bioactivity is compromised by oxidant stress. In addition to low-protein diets and drugs that suppress angiotensin II activity, a variety of other agents and measures may have potential for impeding the process of glomerulosclerosis. These include vitamin E, which blunts the rise in mesangial diacylglycerol levels induced by hyperglycemia; statins and (possibly) policosanol, which down-regulate NADPH oxidase activity by diminishing isoprenylation of Rac1; lipoic acid, whose potent antioxidant activity antagonizes the impact of oxidant stress on TGF-beta expression; pyridoxamine, which inhibits production of advanced glycation endproducts; arginine, high-dose folate, vitamin C, and salt restriction, which may support glomerular production of nitric oxide; and estrogen and soy isoflavones, which may induce nitric oxide synthase in glomerular capillaries while also interfering with TGF-beta signaling. Further research along these lines may enable the development of complex nutraceuticals which have important clinical utility for controlling and preventing glomerulosclerosis and renal failure. Most of these measures may likewise reduce risk for left ventricular hypertrophy in hypertensives, inasmuch as the signaling mechanisms which mediate this disorder appear similar to those involved in glomerulosclerosis.