Diabetes, the metabolic syndrome, and ischemic stroke: epidemiology and possible mechanisms

Limb Remote Ischemic Conditioning: Mechanisms, Anesthetics, and the Potential for Expanding Therapeutic Options

Novel and innovative approaches are essential in developing new treatments and improving clinical outcomes in patients with ischemic stroke. Remote ischemic conditioning (RIC) is a series of mechanical interruptions in blood flow of a distal organ, following end organ reperfusion, shown to significantly reduce infarct size through inhibition of oxidation and inflammation. Ischemia/reperfusion (I/R) is what ultimately leads to the irreversible brain damage and clinical picture seen in stroke patients. There have been several reports and reviews about the potential of RIC in acute ischemic stroke; however, the focus here is a comprehensive look at the differences in the three types of RIC (remote pre-, per-, and postconditioning). There are some limited uses of preconditioning in acute ischemic stroke due to the unpredictability of the ischemic event; however, it does provide the identification of biomarkers for clinical studies. Remote limb per- and postconditioning offer a more promising treatment during patient care as they can be harnessed during or after the initial ischemic insult. Though further research is needed, it is imperative to discuss the importance of preclinical data in understanding the methods and mechanisms involved in RIC. This understanding will facilitate translation to a clinically feasible paradigm for use in the hospital setting.

The Burden of Diabetes and the Chance of a Previous Stroke: Thrombolysis for Recurrent Stroke in Diabetics

BACKGROUND

Intravenous thrombolysis with recombinant tissue plasminogen activator is still not approved by the European Medicines Agency for patients with diabetes mellitus and previous stroke. We assessed functional benefit and potential risk of thrombolysis in patients with diabetes and previous stroke and the influence of age, preexisting diabetic damage, as well as acute and chronic hyperglycemia on outcome, symptomatic intracranial hemorrhage, and in-hospital mortality.

METHODS

We analyzed 527 consecutive patients treated with thrombolysis for acute stroke. Poor outcome was defined as deterioration of prestroke modified Rankin Scale (mRS) to 3 or greater at discharge. Symptomatic intracranial hemorrhage was defined according to the Safe Implementation of Thrombolysis in Stroke-Monitoring Study criteria.

RESULTS

Of the patients, 35.9% were diabetic and 33.2% had previous stroke. Of these patients, 14.4% were diabetics with previous stroke (index group). The rate of patients with poor functional outcome at discharge, symptomatic intracranial hemorrhage, or mortality did not differ between the index group and patients with either diabetes or previous stroke in 2 × 2 comparisons. Diabetics with first-ever stroke showed significantly more symptomatic intracranial hemorrhage (9.7%, P < .001) than the other groups, poorer functional recovery (P = .036), and the highest rate of mortality (12.4%, P < .001). Significant predictors for poor outcome were age (P < .001) and HbA1c (P = .013), for symptomatic intracranial hemorrhage HbA1c (P = .006) and for mortality acute hyperglycemia (P = .001) and age (P = .004).

CONCLUSION

Diabetics with previous stroke should not be withheld from intravenous thrombolysis. The risk of complications derives primarily from poor long-term metabolic control rather than from acute hyperglycemia or from previous stroke.

Stroke, Vascular Dementia, and Alzheimer's Disease: Molecular Links

Stroke is a brain disease that occurs when blood flow stops, resulting in reduced oxygen supply to neurons. Stroke occurs at any time and at any age, but increases after the age of 55. It is the second leading cause of death and the third leading cause of disability-adjusted, life-years. The pathophysiology of ischemic stroke is complex and recent molecular, cellular, and animal models and postmortem brain studies have revealed that multiple cellular changes have been implicated, including oxidative stress/mitochondrial dysfunction, inflammatory responses, micro RNA alterations, and marked changes in brain proteins. These cellular changes provide new information for developing therapeutic strategies for ischemic stroke treatment. Research also revealed that stroke increases with a number of modifiable factors and most strokes can be prevented and/or controlled through pharmacological or surgical interventions and lifestyle changes. Ischemic stroke is the major risk factor for vascular dementia and Alzheimer's disease. This review summarizes the latest research findings on stroke, including causal factors and molecular links between stroke and vascular disease/Alzheimer's disease.

Effect of natural products on diabetes associated neurological disorders

Diabetes mellitus, a metabolic disorder, is associated with neurological complications such as depression, anxiety, hypolocomotion, cognitive dysfunction, phobias, anorexia, stroke, pain, etc. Traditional system of medicine is long known for its efficient management of diabetes. The current review discusses the scope of some common medicinal herbs as well as secondary metabolites with a special focus on diabetes-mediated central nervous system complications. Literatures suggest that natural products reduce diabetes-mediated neurological complications partly by reducing oxidative stress and/or inflammation or apoptosis in certain brain regions. Natural products are known to modulate diabetes-mediated alterations in the level of acetylcholinesterase, choline acetyltransferase, monoamine oxidase, serotonin receptors, muscarinic receptors, insulin receptor, nerve growth factor, brain-derived neurotrophic factor, and neuropeptide in brain. Further, there are several natural products reported to manage diabetic complications with unknown mechanism. In conclusion, medicinal plants or their secondary metabolites have a wide scope and possess therapeutic potential to effectively manage neurological complications associated with chronic diabetes.

Thoracic extra-coronary calcification for the prediction of stroke: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Atherosclerosis is a systemic disease. We examined whether the cumulative burden of thoracic extra-coronary calcification (ECC) improves prediction of stroke, transient ischemic attack (TIA), and stroke mortality beyond traditional risk factors and coronary artery calcium (CAC).

METHODS

We followed a total of 6805 participants (mean age 62.1 ± 10.2 years, 47.2% male) from the Multi-Ethnic Study of Atherosclerosis (MESA) over a median of 12.1 years. The presence or absence of calcification at 4 thoracic ECC sites (mitral valve annulus, aortic valve, aortic root, and thoracic aorta) was determined from baseline cardiac-gated non-contrast CT scans. A multisite thoracic ECC score, ranging 0-4, was calculated by summing the 4 individual sites, which were treated as binary variables. Multivariable Cox proportional hazards regression models, controlled for traditional risk factors and CAC, were used to estimate hazard ratios for ischemic (primary endpoint) and hemorrhagic stroke, total stroke, TIA, and stroke mortality with increasing thoracic ECC.

RESULTS

With an increasing number of thoracic ECC sites, there was a significant (p < 0.05) multivariable adjusted step-wise increase in the risk for ischemic stroke (n = 184), total stroke (n = 235), and TIA (n = 85), but not hemorrhagic stroke (n = 32) and stroke mortality (n = 42). Thoracic ECC increased the c-statistic and net reclassification index beyond traditional risk factors and CAC, but the results were not significant (p > 0.10).

CONCLUSIONS

Although multisite thoracic ECC is independently associated with ischemic stroke, total stroke, and TIA, the incremental predictive value of thoracic ECC beyond traditional risk factors and CAC appears to be minimal.

Phototherapy for treating foot ulcers in people with diabetes

BACKGROUND

Foot ulcers are a disabling complication of diabetes that affect 15% to 25% of people with diabetes at some time in their lives. Phototherapy is a relatively new, non-invasive, and pain-free treatment method, which promotes the ulcer repair process through multiple mechanisms such as increased cell growth and vascular activity. Phototherapy may be used as an alternative approach for the treatment of foot ulcers in people with diabetes, but the evidence for its effect compared with placebo or other treatments has not yet been established.

OBJECTIVES

To assess the effects of phototherapy for the treatment of foot ulcers in people with diabetes.

SEARCH METHODS

We searched the Cochrane Wounds Specialised Register (11 October 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 10), Ovid MEDLINE (11 October 2016), Ovid MEDLINE (In-Process & Other Non-Indexed Citations) (11 October 2016), Ovid Embase (11 October 2016), EBSCO CINAHL Plus (11 October 2016), and China National Knowledge Infrastructure (24 June 2017). We also searched clinical trials registries for ongoing and unpublished studies on 24 June 2017, and screened reference lists to identify additional studies. We used no restrictions with respect to language, date of publication, or study setting.

SELECTION CRITERIA

Randomised controlled trials or cluster randomised controlled trials that 1) compared phototherapy with sham phototherapy, no phototherapy, or other physical therapy modalities, 2) compared different forms of phototherapy, or 3) compared phototherapy of different output power, wavelength, power density, or dose range, in adults with diabetes and an open foot ulcer of any severity, in any setting.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, and 'Risk of bias' assessment. We combined the study outcomes when appropriate.

MAIN RESULTS

Eight trials with 316 participants met the inclusion criteria. Most of the included studies were single-centre studies that were carried out in clinics or hospitals with a sample size ranging from 14 to 84. We generally considered the included studies to be at unclear or high risk of bias, as they had one domain at high risk of bias, or three or more domains at unclear risk of bias.We did not identify any studies that reported valid data for time to complete wound healing. Meta-analysis of four studies including 116 participants indicated that participants receiving phototherapy may experience a greater proportion of wounds completely healed during follow-up compared with those receiving no phototherapy/placebo (64.5% for the phototherapy group versus 37.0% for the no phototherapy/placebo group; risk ratio 1.57, 95% confidence interval 1.08 to 2.28; low-quality evidence, downgraded for study limitations and imprecision). Two studies mentioned adverse events in the results; one study with 16 participants suggested that there were no device-related adverse events, and the other study with 14 participants suggested that there was no clear difference between phototherapy and placebo group.Four studies reported change in ulcer size, but primarily due to high heterogeneity, they were not combined. Results from individual trials (including 16 participants to 84 participants) generally suggested that after two to four weeks of treatment phototherapy may result in a greater reduction in ulcer size but the quality of the evidence was low due to unclear risk of bias in the original trial and small sample size. We based the analyses for quality of life and amputations on only one study each (28 participants and 23 participants respectively); both outcomes showed no clear difference between the phototherapy group and the no phototherapy/placebo group.

AUTHORS' CONCLUSIONS

This systematic review of randomised trials suggested that phototherapy, when compared to no phototherapy/placebo, may increase the proportion of wounds completely healed during follow-up and may reduce wound size in people with diabetes, but there was no evidence that phototherapy improves quality of life. Due to the small sample size and methodological flaws in the original trials, the quality of the evidence was low, which reduces our confidence in these results. Large, well-designed randomised controlled trials are needed to confirm whether phototherapy could be an effective option for the treatment of foot ulcers in people with diabetes.

Bronchiectasis and increased risk of ischemic stroke: a nationwide population-based cohort study

BACKGROUND

Bronchiectasis is characterized by permanent dilatation of the bronchial tree caused by recurrent airway infection and inflammation. The association of atherosclerosis and inflammation is well established. However, studies on the relationship between bronchiectasis and stroke are scant.

OBJECTIVE

We conducted a population-based cohort study to investigate the incidence and risk of ischemic stroke in patients with bronchiectasis.

METHODS

Data of 1,295 patients newly diagnosed as bronchiectasis between 2000 and 2008 were retrieved from the Taiwan National Health Insurance Research Database. A total of 6,475 controls without bronchiectasis at a ratio of 5:1 were randomly selected from the general population based on frequency-matched age and sex to the patients. All participants were followed up to the date of ischemic stroke development, censoring, or the end of 2010. The Cox proportional hazard model was used to identify the risk of ischemic stroke in patients with bronchiectasis compared with those without bronchiectasis.

RESULTS

The patients with bronchiectasis exhibited a higher incidence rate of ischemic stroke (9.18 vs 4.66 per 1,000 person-years) than the patients without bronchiectasis, with an adjusted hazard ratio of 1.74 (95% confidence interval =1.28-2.35). The patients with bronchiectasis and any comorbidities exhibited a 2.66-fold adjusted hazard ratio of ischemic stroke compared with those with neither bronchiectasis nor comorbidity (95% confidence interval =1.85-3.84). The patients with bronchiectasis carried a dose response of ischemic stroke according to the number of emergency visits and hospitalizations per year.

CONCLUSION

This study indicated that bronchiectasis is an independent risk factor of ischemic stroke.

Long-term excess risk of stroke in people with Type 2 diabetes in Sweden according to blood pressure level: a population-based case-control study

AIMS

To estimate the risk of stroke in people with Type 2 diabetes with different blood pressure levels compared with the risk in the general population in Sweden.

METHODS

This prospective case-control study included 408 076 people with Type 2 diabetes, aged ≥ 18 years, and free of prior stroke, registered in the Swedish National Diabetes Register 1998-2011. Age- and sex-matched control subjects (n = 1 913 507) without stroke from the general population were included. Stroke diagnoses were retrieved using International Classification of Disease codes from the Swedish patient and death registers. Cox hazard ratios and 95% confidence intervals (CIs) were estimated at six different blood pressure levels.

RESULTS

During a median follow-up of 4 years, 19 548 (4.8%) people with Type 2 diabetes and 61 690 (3.2%) without diabetes were diagnosed with stroke, corresponding to an adjusted hazard ratio of 1.43 (95% CI 1.41-1.46) for people with Type 2 diabetes as a group. Compared with people without diabetes, the risk of stroke for people with Type 2 diabetes with different blood pressure levels was significantly higher, starting at blood pressure levels > 130/80 mmHg. Hazard ratios for stroke were 1.20 (95% CI 1.16-1.24), 1.47 (95% CI 1.43-1.50), and 1.97 (95% CI 1.90-2.03) for blood pressure categories of 130-139/80-89 mmHg, 140-159/90-99 mmHg and ≥ 160/≥ 100 mmHg, respectively, after adjustment for age, sex, diabetes duration, being born in Sweden, maximum education level and baseline comorbidities.

CONCLUSIONS

People with Type 2 diabetes and blood pressure < 130/80 mmHg had a risk of stroke similar to that of the general population.

Comparison of the Incidence of Major Bleeding With Rivaroxaban Use Among Nonvalvular Atrial Fibrillation Patients With Versus Without Diabetes Mellitus

Diabetes mellitus (DM) is a common co-morbidity in those with nonvalvular atrial fibrillation (NVAF). Most patients with DM and NVAF have a CHA₂DS₂-VASc score of ≥1 and should be considered for oral anticoagulation therapy for stroke prevention per treatment guidelines. The most important risk associated with anticoagulation is bleeding, which may be higher in those with NVAF plus DM. Our objective was to evaluate the incidence and characteristics of major bleeding (MB) in rivaroxaban users diagnosed with NVAF, further comparing those with DM versus those without DM, in a real-world clinical setting. Electronic medical records of >10 million patients from the Department of Defense Military Health System were queried to identify rivaroxaban users with NVAF over a 2.5-year period. Major bleeding-related hospitalization was identified by a validated case-finding algorithm. Patient characteristics, incidence and management of MB, and fatal outcomes were assessed by DM status. Of 44,793 rivaroxaban users with NVAF, 12,039 (26.9%) had DM, who were more likely men, younger, with more co-morbidity and higher CHA₂DS₂-VASc scores. Major bleeding incidence was higher among those with DM compared with those without, 3.68 (95% confidence interval [CI] 3.37 to 4.03) versus 2.51 (95% CI 2.34 to 2.69) per 100 person-years, and intracranial bleeding incidence was 0.19 (95% CI 0.13 to 0.28) versus 0.25 (95% CI 0.20 to 0.31) per 100 person-years. Fatal outcomes were rare for both cohorts, 0.09 per 100 person-years. In conclusion, in this post-marketing study of 44,793 rivaroxaban users with NVAF, patients with DM had more co-morbidities and higher incidence of MB compared with those without DM.

Role of prediabetes in stroke

Stroke is one of the leading causes of death and probably the greatest cause of adult disability worldwide. Diabetes mellitus (DM) is a state of accelerated aging of blood vessels. Patients with diabetes have increased risk of stroke. Hyperglycemia represents a risk factor for poor outcome following stroke, and probably is just a marker of poor outcome rather than a cause. Lowering of blood glucose levels has not been shown to improve prognosis. Also, prevention of stroke risk among patients with DM is not improved with therapy for reduction of glucose levels. On the other hand, prediabetes, a metabolic state between normal glucose metabolism and diabetes, is a risk factor for the development of DM type 2 and subsequently for stroke. Several methods are known to identify prediabetes patients, including fasting plasma glucose levels, 2-hour post load glucose levels, and glycosylated hemoglobin levels. In this text, we tried to summarize known data about diagnosis, epidemiology, risk factors, pathophysiology, and prevention of prediabetes in relation to DM and stroke.

Cerebral ischemic damage in diabetes: an inflammatory perspective

Stroke is one of the leading causes of death worldwide. A strong inflammatory response characterized by activation and release of cytokines, chemokines, adhesion molecules, and proteolytic enzymes contributes to brain damage following stroke. Stroke outcomes are worse among diabetics, resulting in increased mortality and disabilities. Diabetes involves chronic inflammation manifested by reactive oxygen species generation, expression of proinflammatory cytokines, and activation/expression of other inflammatory mediators. It appears that increased proinflammatory processes due to diabetes are further accelerated after cerebral ischemia, leading to increased ischemic damage. Hypoglycemia is an intrinsic side effect owing to glucose-lowering therapy in diabetics, and is known to induce proinflammatory changes as well as exacerbate cerebral damage in experimental stroke. Here, we present a review of available literature on the contribution of neuroinflammation to increased cerebral ischemic damage in diabetics. We also describe the role of hypoglycemia in neuroinflammation and cerebral ischemic damage in diabetics. Understanding the role of neuroinflammatory mechanisms in worsening stroke outcome in diabetics may help limit ischemic brain injury and improve clinical outcomes.

Obesity and stroke: Can we translate from rodents to patients?

Obesity is a risk factor for stroke and is consequently one of the most common co-morbidities found in patients. There is therefore an identified need to model co-morbidities preclinically to allow better translation from bench to bedside. In preclinical studies, both diet-induced and genetically obese rodents have worse stroke outcome, characterised by increased ischaemic damage and an altered inflammatory response. However, clinical studies have reported an 'obesity paradox' in stroke, characterised by reduced mortality and morbidity in obese patients. We discuss the potential reasons why the preclinical and clinical studies may not agree, and review the mechanisms identified in preclinical studies through which obesity may affects stroke outcome. We suggest inflammation plays a central role in this relationship, as obesity features increases in inflammatory mediators such as C-reactive protein and interleukin-6, and chronic inflammation has been linked to worse stroke risk and outcome.

Prediction of Outcome in Diabetic Acute Ischemic Stroke Patients: A Hospital-Based Pilot Study Report

BACKGROUND

Demographic and clinical characteristics are known to influence the outcome in acute ischemic stroke (AIS) patients.

PURPOSE

This study is aimed at evaluating short- and long-term outcomes in diabetic AIS patients. In addition, the study also evaluates the impact of diabetes on the performance of indigenously reported biomarker, inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) and known biomarkers, neuron-specific enolase (NSE) and glial-derived S-100 beta beta protein (S-100ββ).

METHODS

This study was performed on 29 diabetes and 75 non-diabetes AIS patients. Outcome of AIS patients was analyzed by using modified Rankin scale at discharge, then at 12 and 18 months after discharge. Based on the obtained scores, patients were classified as improved group (scales 1-3) and dependent/expired group (scales 3-6). Blood samples were collected during admission and at discharge/expired time. Levels of NSE, S100ββ, and ITIH4 were analyzed in all samples.

RESULTS

On discharge, frequencies of dependent/expired outcome were 4/29 (14%) and 19/75 (17%) in diabetic and non-diabetic AIS patients. However, follow-up outcome at 12 and 18 months showed higher dependent/expired cases of 43 and 41% among diabetic AIS patients compared to 27 and 21% in non-diabetic patients. Multivariate analysis revealed that diabetes is an independent risk factor for dependent/expired outcome in AIS patients (OR 0.484 (at discharge); 1.307 (at 12 months) and 1.675 (at 18 months)). NSE, S100ββ, and ITIH4 showed a differential expression in both the outcome groups of AIS patients, irrespective of diabetes.

CONCLUSION

Diabetes increases the risk of dependent/expired outcome in AIS patients. Also, serum NSE, S100ββ, and ITIH4 are independent biomarkers for prognosis of outcome in AIS patients, irrespective of diabetes.

Angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and the risk of major adverse cardiac events in patients with diabetes and prior stroke: a nationwide study

OBJECTIVE

Renin-angiotensin-aldosterone system blockers are the preferred antihypertensive medications in patients with diabetes and prior stroke. This study aimed to compare the effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) in terms of major adverse cardiac events (MACEs) in patients with diabetes who survived ischemic stroke.

METHODS

We conducted an observational, nationwide, propensity score-matched cohort study using Taiwan's National Health Insurance Research Database. Patients aged at least 20 years with type 2 diabetes who initiated ACEI (n = 15,959) or ARB (n = 23,929) use within 90 days after discharge for first ischemic stroke between January 2000 and December 2011 were allocated to ACEI and ARB groups, respectively. The primary outcomes were MACEs (myocardial infarction, ischemic stroke, and cardiovascular mortality). The secondary outcomes were hospitalization for acute kidney injury and hyperkalemia. Intention-to-treat and as-treated models were used.

RESULTS

Intention-to-treat analysis showed no significant difference between the ACEI and ARB groups in the outcomes of MACEs [hazard ratio (HR), 0.99; 95% confidence interval (CI), 0.95-1.04], including ischemic stroke (HR, 1.01; 95% CI, 0.97-1.06), myocardial infarction (HR, 1.06; 95% CI, 0.95-1.18), and cardiovascular mortality (HR, 0.98; 95% CI, 0.91-1.06). As-treated analysis produced similar results. Additionally, the groups showed no difference in the risk of hospitalization for acute kidney injury or hyperkalemia.

CONCLUSION

Our study supports the hypothesis that the risks of MACEs and two additional secondary outcomes in patients with diabetes who survived ischemic stroke did not differ according to ACEI versus ARB use.

The association between comorbid anxiety disorders and the risk of stroke among patients with diabetes: An 11-year population-based retrospective cohort study

BACKGROUND

Diabetes and anxiety disorders are independent risk factors for stroke. However, it remains unclear whether the risk of stroke is higher among diabetic patients with comorbid anxiety than without comorbid anxiety. Therefore, the purpose of this study was to investigate the association between comorbid anxiety and the risk of stroke among patients with diabetes.

METHODS

This is a retrospective cohort study. We used the National Health Insurance Research Database in Taiwan to identify a diabetes cohort with a new diagnosis of an anxiety disorder but without a history of stroke. The enrollment period was 2001-2006 with up to 11 years of follow-up data. Comorbid anxiety was defined by both a clinical diagnosis of the DSM-IV (ICD-9-CM) and prescriptions for anxiolytic medications. Propensity score matching was performed to balance the selected confounders between the anxiety-exposed group and anxiety non-exposed group. Cox-propositional hazard regression models were used to evaluate the association between comorbid anxiety and the risk of stroke.

RESULTS

Among patients with diabetes (N=40,846), an estimated 5.8% (N=2374) of patients had comorbid anxiety disorders. Diabetic patients with comorbid anxiety were significantly associated with a higher risk of stroke compared to patients without comorbid anxiety (hazard ratio: 1.33, 95% confidence interval: 1.02-1.72).

LIMITATIONS

The severity of anxiety or diabetes could not be measured from the claims data. Residual confounding may still exist.

CONCLUSION

A significantly elevated risk of stroke was observed in association with comorbid anxiety among patients with diabetes. Psychiatrists should consider routine screening for anxiety disorders to prevent a stroke event among patients with diabetes.

Stroke and Risks of Development and Progression of Kidney Diseases and End-Stage Renal Disease: A Nationwide Population-Based Cohort Study

BACKGROUND

There is little information about the association between stroke and kidney diseases. We aimed to investigate the impact of stroke on long-term renal outcomes.

METHODS

In this large population-based retrospective cohort study, we identified 100,353 subjects registered in the National Health Insurance Research Database of Taiwan from January 1, 2000, through December 31, 2012, including 33,451 stroke patients and 66,902 age-, sex- and Charlson's comorbidity index score-matched controls.

RESULTS

The incidence rate of chronic kidney disease (CKD) was higher in the stroke than in the control cohort (17.5 vs. 9.06 per 1000 person-years). After multivariate adjustment, the risk of developing CKD was significantly higher in patients with stroke (adjusted hazard ratio [aHR] 1.43, 95% confidence interval [CI] 1.36-1.50, P<0.001). Subgroup analysis showed that stroke patients <50 years (aHR 1.61, P<0.001) and those with concomitant diabetes mellitus (aHR 2.12, P<0.001), hyperlipidemia (aHR 1.53, P<0.001) or gout (aHR 1.84, P<0.001) were at higher risk of incident CKD. Additionally, the risks of progression to advanced CKD and end-stage renal disease (ESRD) were significantly higher for stroke patients (aHRs, 1.22 and 1.30; P = 0.04 and P = 0.008, respectively), independent of age, sex, comorbidities and long-term medications.

CONCLUSIONS

Stroke is associated with higher risks for incident CKD, decline in renal function and ESRD. Younger stroke patients, as well as those with concomitant diabetes mellitus, hyperlipidemia or gout are at greater risk for kidney diseases.

Cardiometabolic risk factors predict cerebrovascular health in older adults: results from the Brain in Motion study

Aging and physical inactivity are associated with an increased risk of developing metabolic syndrome (MetS). With the rising prevalence of MetS, it is important to determine the extent to which it affects cerebrovascular health. The primary purpose of this report is to examine the impact of MetS on cerebrovascular health (resting cerebral blood flow (CBF) peak velocity (V¯P), cerebrovascular conductance (CVC), and CBF responses to hypercapnia) in healthy older adults with normal cognition. A secondary goal was to examine the influence of apolipoprotein E (APOE) ε4 expression on these indices. In a sample of 258 healthy men and women older than 53 years, 29.1% met criteria for MetS. MetS, sex, and age were found to be significant predictors of CVC, and V¯P, MetS, and APOE status were significant predictors of V¯P-reactivity, and CVC-reactivity was best predicted by MetS status. After controlling for these factors, participants with MetS demonstrated lower cerebrovascular measures (CVC, V¯P, CVC-reactivity, and V¯P-reactivity) compared to participants without MetS. APOE ε4 carriers had higher V¯P-reactivity than noncarriers. These results provide evidence that cardiometabolic and vascular risk factors clustered together as the MetS predict measures of cerebrovascular health indices in older adults. Higher V¯P-reactivity in APOE ε4 carriers suggests vascular compensation for deleterious effects of this known risk allele for Alzheimer's disease and stroke.

Diabetes is associated with cerebrovascular but not Alzheimer's disease neuropathology

INTRODUCTION

The relationship of diabetes to specific neuropathologic causes of dementia is incompletely understood.

METHODS

We used logistic regression to evaluate the association between diabetes and infarcts, Braak neurofibrillary tangle stage, and neuritic plaque score in 2365 autopsied persons. In a subset of >1300 persons with available cognitive data, we examined the association between diabetes and cognition using Poisson regression.

RESULTS

Diabetes increased odds of brain infarcts (odds ratio [OR] = 1.57, P < .0001), specifically lacunes (OR = 1.71, P < .0001), but not Alzheimer's disease neuropathology. Diabetes plus infarcts was associated with lower cognitive scores at end of life than infarcts or diabetes alone, and diabetes plus high level of Alzheimer's neuropathologic changes was associated with lower mini-mental state examination scores than the pathology alone.

DISCUSSION

This study supports the conclusions that diabetes increases the risk of cerebrovascular but not Alzheimer's disease pathology, and at least some of diabetes' relationship to cognitive impairment may be modified by neuropathology.

[Imaging in syndrome complex diabetes mellitus: Current standards and future perspectives]

CLINICAL/METHODICAL ISSUE

Diabetes mellitus is a highly prevalent multisystemic disorder with numerous potential complications and substantial socioeconomic consequences. In many cases, the patient history, physical examination and laboratory tests are not sufficient for a comprehensive evaluation of complicating disorders.

STANDARD RADIOLOGICAL METHODS

Imaging modalities, such as sonography, computed tomography (CT) and magnetic resonance imaging (MRI) are of major significance in the evaluation of complicating disorders of diabetes according to current guidelines. Examples include assessment of coronary artery disease, peripheral artery disease, stroke and diabetic foot syndrome.

METHODICAL INNOVATIONS

Technical developments allow a substantial reduction in radiation dose and scan time in CT and MRI, respectively and could therefore justify a broader application in this patient population.

PERFORMANCE

In the future CT and MRI could also be used for the early detection of diabetic complications. Furthermore, they could also be used for risk stratification, e.g. measurement of hepatic fat content and evaluation of atherosclerosis in whole body MRI.

ACHIEVEMENTS

Prior to widespread application of advanced imaging techniques in this patient population, improved outcomes with respect to survival, quality of life and cost-effectiveness need to be demonstrated.

PRACTICAL RECOMMENDATIONS

Diagnostic imaging modalities for the evaluation of the syndrome complex of diabetic disorders should be used according to the current guidelines but the use is predicted to increase given the high potential in this population.

How fisetin reduces the impact of age and disease on CNS function

It is becoming increasingly clear that neurological diseases are multi-factorial involving disruptions in multiple cellular systems. Thus, while each disease has its own initiating mechanisms and pathologies, certain common pathways appear to be involved in most, if not all, neurological diseases. Thus, it is unlikely that modulating only a single factor will be effective at either preventing disease development or slowing disease progression. A better approach is to identify small (< 900 daltons) molecules that have multiple biological activities relevant to the maintenance of brain function. We have identified an orally active, novel neuroprotective and cognition-enhancing molecule, the flavonoid fisetin. Fisetin not only has direct antioxidant activity but it can also increase the intracellular levels of glutathione, the major intracellular antioxidant. Fisetin can also activate key neurotrophic factor signaling pathways. In addition, it has anti-inflammatory activity and inhibits the activity of lipoxygenases, thereby reducing the production of pro-inflammatory eicosanoids and their by-products. This wide range of actions suggests that fisetin has the ability to reduce the impact of age-related neurological diseases on brain function.

The interactive effect of diabetes and central obesity on stroke: a prospective cohort study of inner Mongolians

Background

The relationship between central obesity and stroke is inconsistent in diabetic and non-diabetic populations. This indicates an interaction between diabetes and central obesity on stroke risk. The present study aimed to examine the interaction in a cohort of Inner Mongolians.

Methods

In this prospective cohort study, we assessed the interaction between diabetes and central obesity on stroke incidence between June 2003 and July 2012. At baseline, 2,589 adults were recruited and examined from Inner Mongolia, China. Participants were categorized into four subgroups according to presence of diabetes and/or central obesity. Both additive and multiplicative interactions were evaluated using Cox proportional-hazard models.

Results

121 stroke events were recorded during the follow-up period. The cumulative incidence of stroke was highest for participants with both diabetes and central obesity (log-rank test, P = 0.042). The multivariable-adjusted risk for stroke was significantly higher in participants with both conditions (HR = 3.02, 95% CI 1.24-7.33, P = 0.015) compared to those with neither diabetes nor central obesity. Attributable proportion due to the interaction between diabetes and central obesity was 0.571 (95% CI 0.017-1.125). The multiplicative interactive effect between diabetes and central obesity on stroke was also statistically significant (HR = 2.67, 95% CI 1.14-6.26, P = 0.024).

Conclusions

The participants who were both diabetic and centrally obese had significantly higher risk for incident stroke than the combination of individuals who individually had either condition among Mongolian population. This study suggests that central obesity and diabetes act synergistically to increase the risk of stroke.

Hyperglycemia / hypoglycemia-induced mitochondrial dysfunction and cerebral ischemic damage in diabetics

Enhancement of ischemic brain damage is one of the most serious complications of diabetes. Studies from various in vivo and in vitro models of cerebral ischemia have led to an understanding of the role of mitochondria and complex interrelated mitochondrial biochemical pathways leading to the aggravation of ischemic neuronal damage. Advancements in the elucidation of the mechanisms of ischemic brain damage in diabetic subjects have revealed a number of key mitochondrial targets that have been hypothesized to participate in enhancement of brain damage. The present review initially discusses the neurobiology of ischemic neuronal injury, with special emphasis on the central role of mitochondria in mediating its pathogenesis and therapeutic targets. Later it further details the potential role of various biochemical mediators and second messengers causing widespread ischemic brain damage among diabetics via mitochondrial pathways. The present review discusses preclinical data which validates the significance of mitochondrial mechanisms in mediating the aggravation of ischemic cerebral injury in diabetes. Exploitation of these targets may provide effective therapeutic agents for the management of diabetes-related aggravation of ischemic neuronal damage.

Metabolic syndrome, platelet activation and the development of transient ischemic attack or thromboembolic stroke

Stroke is the second most common cause of mortality in the world today, where transient ischemic attack (TIA) is a period of focal ischemia, the symptoms of which resemble a thromboembolic stroke. Contrary to stroke, TIA symptoms typically last less than one hour and necrosis is absent. Stroke is often preceded by TIA, making it an important predictor of future ischemic events. The causal role of atherosclerosis in the development of TIA is well established, however, research indicates that the atherosclerotic process begins years earlier with the development of metabolic syndrome, which affects approximately 45% of the adult population worldwide. Metabolic syndrome is present if three or more of the following is present: increased waist circumference, increased triglycerides, decreased HDL, increased fasting glucose and hypertension. This syndrome causes systemic inflammation that activates the coagulation system and may cause the formation of pathological thrombi. The role of platelets in stroke has been studied and platelet activation pathways identified. ADP and thromboxane A(2) are the most common activators of platelets in normal physiology. Several pharmacological treatments have been employed to prevent the activation of platelets, the most common of which include aspirin and P2Y(12)-inhibitors. Although treatment is administered strokes and subsequent TIAs are very common in individuals that suffered an initial event. This indicates that research needs to be done in order to elucidate new therapeutic targets, but also to better treat ischemic events to not only decrease the amount of recurring events but also decrease stroke mortality worldwide.

Decreased Insulin Sensitivity and Impaired Fibrinolytic Activity in Type 2 Diabetes Patients and Nondiabetics with Ischemic Stroke

We analyzed (a) insulin sensitivity (IS), (b) plasma insulin (PI), and (c) plasminogen activator inhibitor-1 (PAI-1) in type 2 diabetes (T2D) patients with (group A) and without (group B) atherothrombotic ischemic stroke (ATIS), nondiabetics with ATIS (group C), and healthy controls (group D). IS was determined by minimal model (Si). Si was lower in A versus B (1.18 ± 0.67 versus 2.82 ± 0.61 min-1/mU/L × 104; P < 0.001) and in C versus D (3.18 ± 0.93 versus 6.13 ± 1.69 min-1/mU/L × 104; P < 0.001). PI and PAI-1 were higher in A versus B (PI: 19.61 ± 4.08 versus 14.91 ± 1.66 mU/L; P < 0.001, PAI-1: 7.75 ± 1.04 versus 4.57 ± 0.72 mU/L; P < 0.001) and in C versus D (PI: 15.14 ± 2.20 versus 7.58 ± 2.05 mU/L; P < 0.001, PAI-1: 4.78 ± 0.98 versus 3.49 ± 1.04 mU/L; P < 0.001). Si correlated with PAI-1 in T2D patients and nondiabetics, albeit stronger in T2D. Binary logistic regression identified insulin, PAI-1, and Si as independent predictors for ATIS in T2D patients and nondiabetics. The results imply that insulin resistance and fasting hyperinsulinemia might exert their atherogenic impact through the impaired fibrinolysis.

Progress on diabetic cerebrovascular diseases

Diabetic cerebrovascular diseases are defined as cerebral vascular diseases induced by diabetes with sugar, fat and a series of nutrient substance metabolic disorders, resulting in intracranial large and small vessel diseases. About 20%-40% patients with type 2 diabetes suffer from cerebral blood vessel diseases. Diabetic cerebrovascular diseases are the main causes of death in patients with diabetes mellitus. The major clinical manifestations are asymptomatic cerebral atherosclerosis, stroke, cerebral small vessel disease and acute cerebral vascular disease. The pathogenesis, clinical characteristics, treatment and prognosis of diabetic cerebrovascular disease are obviously different from non-diabetic cerebral vascular diseases. This paper will focus on the diabetic cerebrovascular disease, including its latest research progress. Diabetic cerebral large vascular disease and diabetic cerebral small vessel disease will be reviewed here.

Ischemic stroke in prediabetic patients

To describe the clinical characteristics of first-ever ischemic stroke (IS) patients with prediabetes, and to compare them with diabetes mellitus (DM) and non-DM patient characteristics. Retrospective analysis of a prospective series of first-ever acute IS patients. Patients were classified as non-DM (HbA1c during admission <5.7% and no previous evidence of 2 or more fasting glucose >126 mg/dL), prediabetes (HbA1c from 5.7 to 6.4%), and DM (previous DM diagnosis or HbA1c ≥6.5% independently of current blood glucose). Demographic and clinical characteristics were compared between the three groups, along with outcome data [early neurological deterioration (END), 3-month poor outcome, 3-month mortality, outcome after rtPA treatment]. No demographic differences were observed. Prediabetic patients had more arterial hypertension (p = 0.006) and higher waist circumference (p < 0.0001) than non-DM patients, and DM patients had more hypercholesterolemia (p < 0.0001), body mass index (p = 0.017), and coronary artery disease (p = 0.005) than prediabetics. There were differences in TOAST subtype distribution (p < 0.0001). There were no differences in rtPA treatment success rate between groups. Multivariate analysis adjusted by age and stroke severity showed that DM but not prediabetes is an independent factor associated with END and 3-month poor outcome. Prediabetic patients with IS exhibit an "intermediate" vascular risk factor profile between that of non-DM and DM patients. In contrast to DM patients, IS prognosis in patients with prediabetes is similar to non-DM patients.

Comparison of carotid and cerebrovascular stenosis between diabetic and nondiabetic patients using digital subtraction angiography

BACKGROUND

The aim of our study was to evaluate the differences of prevalence and manifestation of extracranial and intracranial artery stenosis between patients with and without type 2 diabetes using digital subtraction angiography.

METHODS

A retrospective study was conducted by analyzing clinical and lifestyle data collected from 1137 patients enrolled in the Nanjing Stroke Registry Program between June 2004 and March 2011. Vascular risk factors were analyzed, and carotid and cerebrovascular artery stenoses were measured in 383 patients with type 2 diabetes mellitus and 754 nondiabetic patients by digital subtraction angiography.

RESULTS

In all, 1069 stenoses were found among 383 diabetic patients and 1990 among 754 nondiabetic patients. No statistical differences were observed for the distribution of stenosis in intracranial-extracranial vessels between diabetic and nondiabetic patients (P=.210). There was no difference in the distribution of stenosis in the anterior and posterior circulation vessels between these 2 groups (P=.628). Among diabetic patients with stenosis, a single stenosis was found in 116 (30.29%) and multiple stenoses were found in 267 (69.71%). In their nondiabetic counterparts, a single stenosis was found in 249 (33.02%) and multiple stenoses were found in 505 (66.98%). Compared with nondiabetic patients, the diabetic patients have a tendency of a higher incidence of multiple stenosis. Nonobstructive stenosis occurs more often in diabetic than in nondiabetic patients (P=.002).

CONCLUSIONS

This retrospective study suggests that diabetes be associated with higher incidence of nonobstructive stenosis and that there be no significant difference observed in the extent and distribution of the extra- and intracranial artery stenoses between diabetic and nondiabetic patients.

Abnormal Ca2+ spark/STOC coupling in cerebral artery smooth muscle cells of obese type 2 diabetic mice

Diabetes is a major risk factor for stroke. However, the molecular mechanisms involved in cerebral artery dysfunction found in the diabetic patients are not completely elucidated. In cerebral artery smooth muscle cells (CASMCs), spontaneous and local increases of intracellular Ca2+ due to the opening of ryanodine receptors (Ca2+ sparks) activate large conductance Ca2+-activated K+ (BK) channels that generate spontaneous transient outward currents (STOCs). STOCs have a key participation in the control of vascular myogenic tone and blood pressure. Our goal was to investigate whether alterations in Ca(2+) spark and STOC activities, measured by confocal microscopy and patch-clamp technique, respectively, occur in isolated CASMCs of an experimental model of type-2 diabetes (db/db mouse). We found that mean Ca(2+) spark amplitude, duration, size and rate-of-rise were significantly smaller in Fluo-3 loaded db/db compared to control CASMCs, with a subsequent decrease in the total amount of Ca(2+) released through Ca(2+) sparks in db/db CASMCs, though Ca(2+) spark frequency remained. Interestingly, the frequency of large-amplitude Ca(2+) sparks was also significantly reduced in db/db cells. In addition, the frequency and amplitude of STOCs were markedly reduced at all voltages tested (from -50 to 0 mV) in db/db CASMCs. The latter correlates with decreased BK channel β1/α subunit ratio found in db/db vascular tissues. Taken together, Ca(2+) spark alterations lead to inappropriate BK channels activation in CASMCs of db/db mice and this condition is aggravated by the decrease in the BK β1 subunit/α subunit ratio which underlies the significant reduction of Ca(2+) spark/STOC coupling in CASMCs of diabetic animals.

The disparity in long-term survival after a first stroke in patients with and without diabetes persists: the Northern Sweden MONICA study

BACKGROUND

Diabetes is an established risk factor for stroke. Compared to nondiabetic patients, diabetic patients also have an increased risk of new vascular events and death after stroke. We analyzed how differences in long-term survival between diabetic and nondiabetic stroke patients have changed over time, and if differences varied with respect to sex and age.

METHODS

This population-based study included 12,375 first-ever stroke patients, 25-74 years old, who were registered in the Northern Sweden MONICA Stroke Registry 1985-2005. Uniform diagnostic criteria for stroke case ascertainment were used throughout the study period. The diagnosis of diabetes was based on medical records or diabetes diagnosed during the acute stroke event. Patients were separated into four cohorts according to year of stroke and followed for survival until August 30, 2008.

RESULTS

The diabetes prevalence at stroke onset was 21%, similar in men and women, and remained stable throughout the study period. The diabetic patients were an average of 2 years older, more often nonsmokers and more likely to have antihypertensive treatment, antithrombotics, atrial fibrillation, and a history of myocardial infarction or transient ischemic attack than the nondiabetic patients. The total follow-up time was 86,086 patient-years during which a total of 1,930 (75.7%) of the diabetic patients and 5,744 (58.5%) of the nondiabetic patients died (p < 0.001). Median survival was 60 months (95% CI: 57-64) in diabetic patients and 117 months (113-120) in the nondiabetic patients. Survival improved significantly in both groups (p < 0.001). A Cox regression, adjusting for possible confounders (age, sex, antihypertensive medication, antithrombotics or other thrombolytic agents, history of myocardial infarction, type of stroke, diabetes, cohort and the diabetes-by-sex, diabetes-by-age and diabetes-by-cohort interactions), showed a hazard ratio of 1.67 (1.58-1.76) comparing survival in diabetic versus nondiabetic patients. The reduced survival in diabetic stroke patients was more pronounced in women (p = 0.02) and younger patients (p < 0.001). There was a tendency that the difference in survival decreased between the earlier cohorts and the 2000-2005 cohort, but the test for interaction did not reach statistical significance (p = 0.08).

CONCLUSION

Long-term survival after a first stroke has improved in both diabetic and nondiabetic patients. Survival is markedly lower in diabetics, especially in women and younger patients, and the disparity persisted over 24 years. Decreasing the disparity in stroke survival is a challenge for stroke and diabetes care. New treatment methods in combination with intense secondary prevention in diabetic patients, especially in younger women, are needed.

Epigenetic manifestation of metabolic syndrome and dietary management

SIGNIFICANCE

Metabolic syndrome constitutes a group of disorders such as insulin resistance, hypertension, and hypertriglyceridemia, predisposing an individual to risk factors such as cardiovascular disease, diabetes, obesity, and dyslipidemia. A majority of these diseases are influenced by the environmental factors, nutrient uptake, and genetic profile of an individual that together dysregulate gene function. These genetic and nongenetic factors are reported to introduce epigenetic cues that modulate the gene function which is inherited by the offspring.

RECENT ADVANCES

Considering the epigenetic modulation of the metabolic disorders, nutrigenomics has been distinctly categorized as a branch that deals with modulatory effect of nutrients on metabolic disorders and disease progression by supplementing the individuals with key nutrient-enriched diets which are derived from plant and animal sources.

CRITICAL ISSUES

Nutritional components of the diet regulate the metabolic health of an individual either by controlling the expression of some key genes related to metabolic pathways or by modulating the epigenetic events on such genes. The present article discusses various metabolic disorders in detail and the effect of nutrients on the specific genes causing those disorders. We also highlight the molecular mechanisms of some metabolic disorders through epigenetic modifications and possible therapeutic interventions.

FUTURE DIRECTIONS

With the advent of high-throughput technologies and epigenetic modulation of the metabolic disorders, an altered epigenetic code that is programmed due to improper nutrients can be reverted back by supplementing the diet with various plant-derived compounds. The implication of small molecular drugs is also of utmost significance for challenging the metabolic disorders.

The diagnosis and management of cerebrovascular disease in diabetes

Cerebrovascular disease is a leading cause of morbidity and mortality in diabetes. Compared with nondiabetic patients, diabetic patients have at least twice the risk for stroke, earlier onset of symptoms, and worse functional outcomes. Approximately 20 % of diabetic patients will die from stroke, making it one of the leading causes of death in this population. Effective strategies for primary and secondary prevention of stroke have been developed in research cohorts that included both diabetic and nondiabetic patients. Nevertheless, prevention in diabetes has some specific considerations. In this paper, we summarize evidence to guide the diagnosis and management of stroke in diabetic patients. We propose that diabetic stroke patients should have a robust risk assessment to target interventions, like other patients with cerebrovascular disease, but with special attention to glycemic control and lifestyle modification.

Mechanisms of brain aging regulation by insulin: implications for neurodegeneration in late-onset Alzheimer's disease

Insulin and IGF seem to be important players in modulating brain aging. Neurons share more similarities with islet cells than any other human cell type. Insulin and insulin receptors are diffusely found in the brain, especially so in the hippocampus. Caloric restriction decreases insulin resistance, and it is the only proven mechanism to expand lifespan. Conversely, insulin resistance increases with age, obesity, and sedentarism, all of which have been shown to be risk factors for late-onset Alzheimer's disease (AD). Hyperphagia and obesity potentiate the production of oxidative reactive species (ROS), and chronic hyperglycemia accelerates the formation of advanced glucose end products (AGEs) in (pre)diabetes—both mechanisms favoring a neurodegenerative milieu. Prolonged high cerebral insulin concentrations cause microvascular endothelium proliferation, chronic hypoperfusion, and energy deficit, triggering β-amyloid oligomerization and tau hyperphosphorylation. Insulin-degrading enzyme (IDE) seems to be the main mechanism in clearing β-amyloid from the brain. Hyperinsulinemic states may deviate IDE utilization towards insulin processing, decreasing β-amyloid degradation.

Impaired vascular responses of insulin-resistant rats after mild subarachnoid hemorrhage

Insulin resistance (IR) impairs cerebrovascular responses to several stimuli in Zucker obese (ZO) rats. However, cerebral artery responses after subarachnoid hemorrhage (SAH) have not been described in IR. We hypothesized that IR worsens vascular reactions after a mild SAH. Hemolyzed blood (300 μl) or saline was infused (10 μl/min) into the cisterna magna of 11-13-wk-old ZO (n = 25) and Zucker lean (ZL) rats (n = 25). One day later, dilator responses of the basilar artery (BA) and its side branch (BA-Br) to acetylcholine (ACh, 10(-6) M), cromakalim (10(-7) M, 10(-6) M), and sodium nitroprusside (10(-7) M) were recorded with intravital videomicroscopy. The baseline diameter of the BA was increased both in the ZO and ZL rats 24 h after the hemolysate injection. Saline-injected ZO animals showed reduced dilation to ACh (BA = 9 ± 3 vs. 22 ± 4%; and BA-Br = 23 ± 5 vs. 37 ± 7%) compared with ZL rats. Hemolysate injection blunted the response to ACh in both the ZO (BA = 4 ± 2%; and BA-Br = 12 ± 3%) and ZL (BA = 7 ± 2%; and BA-Br = 11 ± 3%) rats. Cromakalim (10(-6) M)-induced dilation was significantly reduced in the hemolysate-injected ZO animals compared with the saline control (BA = 13 ± 3 vs. 26 ± 5%; and BA-Br = 28 ± 8 vs. 44 ± 9%) and in the hemolysate-injected ZL rats compared with their saline control (BA = 24 ± 4 vs. 32 ± 4%; but not BA-Br = 39 ± 6 vs. 59 ± 9%). No significant difference in sodium nitroprusside reactivity was observed. Western blot analysis of the BA showed a lower baseline level of neuronal nitric oxide synthase expression and an enhanced cyclooxygenase-2 level in the hemolysate-injected ZO animals. In summary, cerebrovascular reactivity to both endothelium-dependent and -independent stimuli is severely compromised by SAH in IR animals.

Metabolic syndrome and cerebral vasomotor reactivity

BACKGROUND AND PURPOSE

Metabolic syndrome has been proposed as a risk factor for stroke and transient ischaemic attack. One pathophysiological mechanism could be impairment of endothelial function. Thus, we hypothesized that cerebral vasomotor reactivity would be decreased in patients with metabolic syndrome, compared to patients without metabolic syndrome.

METHODS

In this retrospective analysis, 83 consecutive patients (aged 59.19 ± 15.98; 33 women) underwent Doppler examination for carotid artery disease including bi-hemispherical vasomotor reactivity assessment using transcranial Doppler monitoring. Vasomotor reactivity data were analyzed from the hemisphere with no or low-grade carotid stenosis (<40%). Cerebral vasomotor reactivity was calculated as percent increase in mean flow velocity per mmHg pCO(2) during 2 min of 5% CO(2) inhalation delivered by anesthesia mask (normal if ≥ 2%/mmHg). Univariate and multivariable linear regression models were used to determine factors, including metabolic syndrome, that were independently associated with pathologic vasomotor reactivity.

RESULTS

After adjusting for the presence of contralateral carotid stenosis and ipsilateral stroke in the multivariable model, metabolic syndrome was independently associated with lower vasomotor reactivity values (2.27 ± 1.24% vs. 2.68 ± 1.37; ß = -0.258, P = 0.033). In this model, there was no association of cerebral vasomotor reactivity with age, gender, race, cardiac disease, current statin therapy, or small vessel disease.

CONCLUSIONS

Our findings suggest that impaired cerebral vasomotor reactivity may be a mediator of stroke in patients with metabolic syndrome, a syndrome affecting a significant and growing proportion of the population. A prospective longitudinal study is warranted to study the cerebral haemodynamic effect of metabolic syndrome.

Neuroprotective properties of GLP-1: theoretical and practical applications

In the past few years, the development of pharmaceutical agents that enhance the physiological effects of glucagon-like peptide-1 (GLP-1), either through GLP-1 receptor agonism (GLP-1 agonists) or by inhibiting GLP-1 degradation (dipeptidylpeptidase-4 inhibitors) has broadened the range of treatment options for individuals with type 2 diabetes. It has been recognized for some time that GLP-1 also has extra-pancreatic effects, notably targeting the brain, where it regulates appetite and satiety, as well as peripheral functions highly controlled by the autonomic nervous system, such as gastric emptying. Furthermore, data are beginning to emerge that indicate a potential role for GLP-1 in neuroprotection. The increased risk of Alzheimer's disease, Parkinson's disease and stroke in people with type 2 diabetes suggests that shared mechanisms/pathways of cell death, possibly related to insulin dysregulation, may underlie all of these disorders. Although the disease anatomy varies with each disorder, a wide range of genetic and environmental triggers result in activation of similar biochemical pathways in all of them, suggesting a complex network of biochemical events that feed in to a final common path towards cellular dysfunction and death. This article summarizes the evidence for neuronal activity of GLP-1 and examines the limited data that currently exist on the therapeutic potential of GLP-1 in specific neurological and neurodegenerative conditions, namely Alzheimer's disease, Parkinson's disease, Huntingdon's disease, stroke and peripheral sensory neuropathy.

Basal C-peptide Level as a Surrogate Marker of Subclinical Atherosclerosis in Type 2 Diabetic Patients

BACKGROUND

Recent studies have revealed that C-peptide induces smooth muscle cell proliferation and causes human atherosclerotic lesions in diabetic patients. The present study was designed to examine whether the basal C-peptide levels correlate with cardiovascular risk in type 2 diabetes mellitus (T2DM) patients.

METHODS

Data was obtained from 467 patients with T2DM from two institutions who were followed for four years. The medical findings of all patients were reviewed, and patients with creatinine >1.4 mg/dL, any inflammation or infection, hepatitis, or type 1 DM were excluded. The relationships between basal C-peptide and other clinical values were statistically analyzed.

RESULTS

A simple correlation was found between basal C-peptide and components of metabolic syndrome (MS). Statistically basal C-peptide levels were significantly higher than the three different MS criteria used in the present study, the Adult Treatment Panel III (ATP III) of the National Cholesterol Education Program's (NCEP's), World Health Organization (WHO), and the International Diabetes Federation (IDF) criteria (NCEP-ATP III, P=0.001; IDF, P<0.001; WHO, P=0.029). The multiple regression analysis between intima-media thickness (IMT) and clinical values showed that basal C-peptide significantly correlated with IMT (P=0.043), while the analysis between the 10-year coronary heart disease risk by the United Kingdom Prospective Diabetes Study risk engine and clinical values showed that basal C-peptide did not correlate with IMT (P=0.226).

CONCLUSION

Basal C-peptide is related to cardiovascular predictors (IMT) of T2DM, suggesting that basal C-peptide does provide a further indication of cardiovascular disease.

Treatment of specific macrovascular beds in patients with diabetes mellitus

In 2007, over 23 million people had diabetes in the United States and death from cardiovascular disease is estimated to occur in 80% of those Americans. Risk factor reduction is the most important therapy for primary and secondary prevention of macrovascular disease in patients with and without diabetes mellitus. Despite this, presentation and response to therapy is often different for patients with diabetes compared to their non-diabetic counterparts. This paper will review the current targets for therapy of cardiovascular disease, peripheral vascular disease, and cerebrovascular disease in patients with diabetes.