The number of risk factors not at target is associated with cardiovascular risk in a type 2 diabetic population with albuminuria in primary cardiovascular prevention. Post-hoc analysis of the NID-2 trial

Background

Nephropathy in Diabetes type 2 (NID-2) study is an open-label cluster randomized clinical trial that demonstrated that multifactorial intensive treatment reduces Major Adverse Cardiac Events (MACEs) and overall mortality versus standard of care in type 2 diabetic subjects with albuminuria and no history of cardiovascular disease. Aim of the present post-hoc analysis of NID- 2 study is to evaluate whether the number of risk factors on target associates with patient outcomes.

Methods

Intervention phase lasted four years and subsequent follow up for survival lasted 10 years. To the aim of this post-hoc analysis, the whole population has been divided into 3 risk groups: 0–1 risk factor (absent/low); 2–3 risk factors (intermediate); 4 risk factors (high). Primary endpoint was a composite of fatal and non-fatal MACEs, the secondary endpoint was all-cause death at the end of the follow-up phase.

Results

Absent/low risk group included 166 patients (52.4%), intermediate risk group 128 (40.4%) and high-risk group 23 (7.3%). Cox model showed a significant higher risk of MACE and death in the high-risk group after adjustment for confounding variables, including treatment arm (HR 1.91, 95% CI 1.04–3.52, P = 0.038 and 1.96, 95%CI 1.02–3.8, P = 0,045, respectively, vs absent/low risk group).

Conclusions

This post-hoc analysis of the NID-2 trial indicates that the increase in the number of risk factors at target correlates with better cardiovascular-free survival in patients with type 2 diabetes at high CV risk.

Clinical Trial Registration

ClinicalTrials.gov number, NCT00535925. https://clinicaltrials.gov/ct2/show/NCT00535925

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01674-7.

Moderate-intensity statin therapy seems ineffective in primary cardiovascular prevention in patients with type 2 diabetes complicated by nephropathy. A multicenter prospective 8 years follow up study

BACKGROUND

Although numerous studies and metanalysis have shown the beneficial effect of statin therapy in CVD secondary prevention, there is still controversy such the use of statins for primary CVD prevention in patients with DM. The purpose of this study was to evaluate the occurrence of total major adverse cardio-vascular events (MACE) in a cohort of patients with type 2 diabetes complicated by nephropathy treated with statins, in order to verify real life effect of statin on CVD primary prevention.

METHODS

We conducted an observational prospective multicenter study on 564 patients with type 2 diabetic nephropathy free of cardiovascular disease attending 21 national outpatient diabetes clinics and followed them up for 8 years. 169 of them were treated with statins (group A) while 395 were not on statins (group B).

RESULTS

Notably, none of the patients was treated with a high-intensity statin therapy according to last ADA position statement. Total MACE occurred in 32 patients from group A and in 68 patients from group B. Fatal MACE occurred in 13 patients from group A and in 30 from group B; nonfatal MACE occurred in 19 patients from group A and in 38 patients from group B. The analysis of the Kaplan-Meier survival curves showed a not statistically significant difference in the incidence of total (p 0.758), fatal (p 0.474) and nonfatal (p 0.812) MACE between the two groups. HbA1c only showed a significant difference in the incidence of MACE between the two groups (HR 1.201, CI 1.041-1.387, p 0.012).

CONCLUSIONS

These findings suggest that, in a real clinical setting, moderate-intensity statin treatment is ineffective in cardiovascular primary prevention for patients with diabetic nephropathy. Trial registration ClinicalTrials.gov Identifier NCT00535925. Date of registration: September 24, 2007, retrospectively registered.

Lack of effect of aspirin in primary CV prevention in type 2 diabetic patients with nephropathy: results from 8 years follow-up of NID-2 study

The risk-to-benefit ratio for the use of low dose of aspirin in primary cardiovascular (CV) prevention in patients with diabetes mellitus remains to be clarified. We assessed the effect of aspirin on risk of CV events in type 2 diabetic patients with nephropathy, in order to verify the usefulness of Guidelines in clinical practice. We carried out a prospective multicentric study in 564 patients with type 2 diabetic nephropathy free of CV disease attending outpatient diabetes clinics . A total of 242 patients received antiplatelet treatment with aspirin 100 mg/day (group A), and 322 were not treated with antiplatelet drugs (group B). Primary end point was the occurrence of total major adverse cardio-vascular events (MACE). Secondary end points were the relative occurrence of fatal MACE. The average follow-up was 8 years. Total MACE occurred in 49 patients from group A and in 52 patients from group B. Fatal MACE occurred in 22 patients from group A and in 20 from group B; nonfatal MACE occurred in 27 patients from group A and in 32 patients from group B. Kaplan-Meier analysis did not show a statistically significant difference of cumulative MACE between the two groups. A not statistically significant difference in the incidence of both fatal (p = 0.225) and nonfatal CV events (p = 0.573) between the two groups was observed. These results were confirmed after adjustment for confounders (HR for MACE 1.11, 95 % CI 0.91-1.35). These findings suggest that low dose of aspirin is ineffective in primary prevention for patients with nephropathy.

Autonomic dysfunction is associated with brief episodes of atrial fibrillation in type 2 diabetes

BACKGROUND AND AIMS

This study aimed to investigate the relationship between asymptomatic episodes of atrial fibrillation (AF) and abnormalities of the autonomic nervous system in type 2 diabetic patients who did not have evidence of atrial fibrillation at baseline.

METHODS AND RESULTS

In a multicentric cross-sectional controlled study, 1992 patients with type 2 diabetes were screened. All underwent ambulatory ECG recording for 48-hour at 3, 6, 9, and 12months. Heart rate variability (HRV) was used as indicator of autonomic activity. One hundred seventy-six diabetics with silent atrial fibrillation episodes (SAFE group) and 288 without silent atrial fibrillation (non-SAFE group) were enrolled. These selected diabetics were matched on clinical and anthropometric data to 120 control subjects without diabetes of the control group. HRV analysis evidenced that LF/HF ratio was significantly higher in the SAFE group than in the non-SAFE group (P<0.05) in the whole period of HM analysis. AF absolute burdens were positively correlated with LF/HF ratio (r=0.31, P<0.001). Multiple regression analysis showed that LF/HF ratio was an independent determinant of AF episodes.

CONCLUSIONS

This study originally showed a strong relationship between autonomic dysfunction and silent atrial fibrillation in type 2 diabetes.

Peri-procedural tight glycemic control during early percutaneous coronary intervention is associated with a lower rate of in-stent restenosis in patients with acute ST-elevation myocardial infarction

OBJECTIVE

We examined the effects of peri-procedural intensive glycemic control (IGC) during early percutaneous coronary intervention (PCI) on restenosis rate in hyperglycemic patients with ST-segment elevation myocardial infarction (STEMI).

RESEARCH DESIGN AND METHODS

A total of 165 hyperglycemic patients (glucose ≥ 140 mg/dl) with first STEMI undergoing PCI were studied. Patients were randomized to IGC for almost 24 h after PCI (n = 82; glucose, 80-140 mg/dl) followed by multidose sc insulin during the hospital stay or conventional glycemic control (CGC; n = 83; glucose, 180-200 mg/dl) followed by conventional therapy. Coronary angiography was performed at study entry and at 6-month follow-up. Blood samples for glycemia, hemoglobin A1c, inflammatory markers (C-reactive protein and TNF-α), monocyte chemoattractant-protein-1, and oxidative stress (nitrotyrosine) were collected immediately before and 24 h, 30 and 180 d after PCI.

RESULTS

After insulin infusion, mean plasma glucose during the peri-procedural period was greater in the CGC group than in the IGC group (CGC, 191 ± 15 mg/dl; IGC, 145 ± 35 mg/dl; P < 0.001). After the insulin infusion period, the levels of markers of oxidative stress (nitrotyrosine), inflammation (C-reactive protein, TNF-α), and monocyte chemoattractant-protein-1 were significantly higher in CGC patients compared with IGC patients. Moreover, ICG during PCI reduces restenosis by half (48 and 24%) at 6 months. During follow-up, there was no difference in mortality rates, glucose, inflammatory and oxidative stress markers among the groups. In-stent restenosis was positively associated with mean plasma glucose levels as well as oxidative stress and inflammatory markers during the insulin infusion period.

CONCLUSIONS

In hyperglycemic patients with STEMI, optimal peri-procedural glycemic control by reducing oxidative stress and inflammation may improve the outcome after PCI.

Tight glycemic control may increase regenerative potential of myocardium during acute infarction

AIMS

We analyzed the effects of tight glycemic control on regenerative potential of myocardium during acute myocardial infarction.

PATIENTS AND METHODS

Seventy-five patients with their first acute myocardial infarction undergoing coronary bypass surgery were studied: 25 patients with glycemia below 140 mg/dl served as the control group; hyperglycemic patients (glucose>140 mg/dl) were randomized to intensive glycemic control (IGC; n=20; glucose goal, 80-140 mg/dl), conventional glycemic control (CGC; n=20; glucose goal, 180-200 mg/dl), or glucose-insulin-potassium (GIK; n=10; glucose goal, 180-200 mg/dl) for almost 3 d before surgery, using insulin infusion followed by sc insulin treatment. During surgery, myocyte precursor cells (MPC) (c-kit/MEFC2/GATA4-positive cells), oxidation of MPC DNA (c-kit/8-hydroxydeoxyguanosine-positive cells), senescent MPC (c-kit/p16INK4a-positive cells), and cycling cardiomyocytes (Ki-67-positive cells) were analyzed in biopsy specimens taken from the peri-infarcted area.

RESULTS AND DISCUSSION

Before surgery, plasma glucose reduction was greater in the IGC group than in the CGC and GIK groups (P<0.001 for both). IGC patients had higher MPC (P<0.01) and cycling myocytes (P<0.01), as well as less oxidized (P<0.01) and senescent MPC (P<0.01) in peri-infarcted specimens compared with both CGC and GIK patients. Tight glycemic control, by reducing senescent MPC, may increase regenerative potential of the ischemic myocardium.

Coronary artery disease is detectable by multi-slice computed tomography in most asymptomatic type 2 diabetic patients at high cardiovascular risk

OBJECTIVE

Non-invasive testing often does not identify coronary artery disease (CAD) in diabetic subjects. This study was designed in order to examine the prevalence of CAD in a cohort of asymptomatic type 2 diabetic patients at high cardiovascular risk and negative nuclear imaging, using multi-slice computed tomography (MSCT) angiography.

METHODS

In total, 770 type 2 diabetic patients were screened from January 2008 through July 2010. Of these, 132 Caucasians with diabetic nephropathy and asymptomatic for angina were eligible for a cross-sectional study. Patients underwent MSCT after ischaemia was excluded by myocardial Single Photon Emission Computed Tomography (SPECT) at rest and after dynamic exercise. When obstructive plaques were found (≥ 50% lumen narrowing), patients were sent to conventional coronary angiography (CCA).

RESULTS

Six subjects were not included in the analysis because of motion artefacts. MSCT was positive for CAD in 114 patients (90%). Within patients with positive MSCT, 60 (48% of all) showed one or more obstructive plaques. CCA confirmed significant stenosis (≥ 50%) in 48 of these 60 patients (80%). Some 21 (35%) showed stenosis ≥ 75% and were submitted to the revascularisation procedure.

CONCLUSION

MSCT seems to better identify CAD than myocardial SPECT in asymptomatic patients with type 2 diabetes and diabetic nephropathy.

Perspectives of nuclear diagnostic imaging in diabetic cardiomyopathy

Diabetic cardiomyopathy is a ventricular dysfunction in the absence of coronary artery disease, valvular or hypertensive heart disease. The mechanisms underlying diabetic cardiomyopathy may involve metabolic disturbances, myocardial fibrosis, small vessel disease, microcirculation abnormalities, cardiac autonomic neuropathy and insulin resistance. Diagnostic problems emerge because no specific disease pattern characterizes the disease and because there may be coexistence in diabetes of coronary artery disease and hypertension as independent but compounding causes of biochemical, anatomical and functional alterations impairing cardiac function. In this paper we will review the role of nuclear imaging today, concentrating on the diagnostic capabilities of radionuclide ventriculography, to study the effect of insulin resistance and, more extensively, gated-single photon emission computed tomography with Tc-99m labelled agents. A broad analysis will be dedicated to: 1) positron emission tomography using perfusion agents, with the potential to quantify resting and stress blood flow and coronary flow reserve; 2) radionuclide procedures evaluating aerobic and anaerobic cardiac metabolism; and 3) cardiac neurotransmission imaging, studying the autonomic neuropathy.

Progress in the oral treatment of type 2 diabetes: update on DPP-IV inhibitors

Glucagon-like peptide-1 (GLP-1) is a gut hormone that plays an important role in regulating glucose homeostasis by both its pancreatic and extrapancreatic activity. Defects of GLP-1 characterize type 2 diabetes as a primary or perhaps consequent phenomenon, resulting in inappropriately low insulin secretion after oral ingestion of nutrients. The discovery that cleavage by the ubiquitous enzyme dipeptidyl peptidase-IV (DPP-IV) is the primary route of GLP-1 metabolism formed the rationale behind the proposal to prevent degradation of endogenously released GLP-1 by DPP-IV inhibition as a novel approach to the management of type 2 diabetes. Enhanced insulin secretion as well as delayed gastric emptying, reduced glucagon secretion, and inhibited apoptosis of beta cells resulting from blockade of incretin degradation, have been proposed as the major actions of DPP-IV inhibitors as antidiabetic agents. Clinical studies to date indicate that DPP-IV inhibitors effectively ameliorate islet dysfunction and improve glucose control in patients with type 2 diabetes. They appear to have excellent therapeutic effectiveness as monotherapy in patients inadequately controlled with diet and exercise and as add-on therapy in combination with metformin, thiazolidinediones, and insulin. Their pharmacokinetic and pharmacodynamic profiles support once-daily dosing, with relatively few adverse effects.

Management of cardiovascular risk factors in advanced type 2 diabetic nephropathy: a comparative analysis in nephrology, diabetology and primary care settings

OBJECTIVES

Advanced diabetic nephropathy (DN) is characterized by a marked development of cardiovascular and renal disease. These patients are frequently managed by different health professionals with the consequence that the quality of care may differ substantially. To compare the management of cardiovascular risk factors in patients with type 2 DN and an estimated glomerular filtration rate (GFR) of 15-60 ml/min per 1.73 m2 followed in nephrology, diabetology and primary care.

METHODS

This multicentre cross-sectional study verified the control of blood pressure (BP), total cholesterol, triglycerides, glycosylated haemoglobin A1c (HbA1c) and haemoglobin in patients exclusively followed in either nephrology (n = 266), diabetology (n = 246) or primary care (n = 195) of the same metropolitan area for at least 1 year.

RESULTS

Primary care patients were older and had a greater prevalence of previous cardiovascular events. The GFR was lower in nephrology than in diabetology and primary care (33 +/- 13 versus 47 +/- 9 and 40 +/- 12 ml/min per 1.73 m2, P < 0.0001). The prevalence of BP target (< 130/80 mmHg) was similarly low in nephrology, diabetology and primary care (14, 13 and 10%, P = 0.421) probably because of insufficient prescription of diuretics and low-salt diet. Whereas the prevalence of the triglycerides target was similar, that of total cholesterol (< 200 mg/dl) was larger in diabetology (63%) than in nephrology and primary care (59 and 46%, P = 0.003) because of greater statin prescription in hypercholesterolemic individuals (70, 50 and 41%, respectively, P = 0.002). The attainment of HbA1c less than 7% was less frequent in diabetology (32%) than in nephrology and primary care (61 and 46%, P = 0.0003) despite a more frequent prescription of insulin/oral agents in diabetology. The control of anaemia was better in diabetology. Multivariate analysis adjusted for the patient case-mix and physician-level clustering confirmed these differences except for anaemia.

CONCLUSION

Patients with advanced DN, despite the worst renal and cardiovascular prognosis, are at high risk of being under-treated independently of the type of clinical setting.

Adapting the GLP-1-signaling system to the treatment of type 2 diabetes

Glucagon-like peptide-1 (GLP-1) may contribute to the decreased incretin effect characterizing type 2 diabetes. Multiple actions other than insulin secretion stimulation give to GLP-1 a highly desirable profile for an antidiabetic agent. To overcome the need for continuous infusion of the native compound, which is rapidly degraded by dimethyl-peptidyl-peptidase-IV (DPP-IV), analogues with low affinity for this protease have been developed. A second major strategy is represented by DPP-IV inhibitors that act to increase endogenous GLP-1. On the basis of the promising results in clinical trials, the incretin-based therapy may offer an useful option for diabetes management.

Increased activity of the ubiquitin-proteasome system in patients with symptomatic carotid disease is associated with enhanced inflammation and may destabilize the atherosclerotic plaque: effects of rosiglitazone treatment

OBJECTIVES

We evaluated ubiquitin-proteasome activity in carotid plaques of asymptomatic and symptomatic patients and the effect of rosiglitazone, a peroxisome proliferator-activated receptor-gamma activator, in symptomatic plaques.

BACKGROUND

The role of the ubiquitin-proteasome system, the major pathway for non-lysosomal intracellular protein degradation in eucaryotic cells, in the progression of atherosclerotic plaque to instability is unclear.

METHODS

Plaques were obtained from 40 symptomatic and 38 asymptomatic patients undergoing carotid endarterectomy. Symptomatic patients received 8 mg rosiglitazone (n = 20) or placebo (n = 20) for 4 months before scheduled endarterectomy. Plaques were analyzed for macrophages (CD68), T-lymphocytes (CD3), inflammatory cells (HLA-DR), ubiquitin-proteasome activity, nuclear factor kappa B (NFkB), inhibitory kappa B (IkB)-beta, nitrotyrosine, matrix metalloproteinase (MMP)-9, and collagen content (immunohistochemistry and enzyme-linked immunosorbent assay).

RESULTS

Compared with asymptomatic plaques, symptomatic plaques had more macrophages, T-lymphocytes, and HLA-DR+ cells (p < 0.001); more ubiquitin-proteasome activity and NFkB (p < 0.001); and more markers of oxidative stress (nitrotyrosine and O2- production) and MMP-9 (p < 0.01) along with a lesser collagen content and IkB-beta levels (p < 0.001). Compared with placebo-treated plaques, rosiglitazone-treated symptomatic plaques presented fewer inflammatory cells (p < 0.01); less ubiquitin, proteasome 20S, and NFkB (p < 0.01); less nitrotyrosine and O2- production (p<0.01); and greater collagen content (p<0.01), indicating a more stable plaque phenotype.

CONCLUSIONS

Ubiquitin-proteasome overactivity is associated with enhanced inflammatory reaction in symptomatic plaques. The inhibition of ubiquitin-proteasome activity in lesions of symptomatic patients by rosiglitazone is associated with plaque stabilization, possibly by down-regulating NFkB-mediated inflammatory pathways.

Cardiovascular risk factors and disease management in type 2 diabetic patients with diabetic nephropathy

OBJECTIVE

The purpose of this study was to assess the prevalence of cardiorenal risk factors, their management in a routine clinical setting, and the actual achievement of international guideline targets in a large cohort of type 2 diabetic patients with diabetic nephropathy.

RESEARCH DESIGN AND METHODS

A multicentric cross-sectional study was performed in the Campania region in Italy to evaluate cardiorenal risk factors and their management in light of international guidelines. Overall, 28,550 diabetic patients were screened in the 21 participating centers; 847 (348 male and 449 female) patients with type 2 diabetes and a clinical diagnosis of diabetic nephropathy were recruited.

RESULTS

Of these subjects, 749 had microalbuminuria and 98 had macroalbuminuria. Targets for blood pressure, HbA(1c), LDL cholesterol, HDL cholesterol, and triglycerides were reached in, respectively, 17.5, 32.3, 30.7, 47, and 55.2% of the patients. Chronic renal failure (glomerular filtration rate <60 ml/min) was revealed in 41% and anemia in 23.8% of the patients.

CONCLUSIONS

This is the first study to investigate a large cohort of type 2 diabetic patients with early and moderate diabetic nephropathy strictu sensu. Notably, impaired renal function can be often diagnosed in these patients even in the presence of microalbuminuria. Thus, clinical diagnosis of diabetic nephopathy allows us to identify a group of patients at very high cardiorenal risk, for whom care is really difficult. We suggest that a correct diagnosis of diabetic nephropathy should always be made and that sodium intake and anemia should be routinely evaluated in these patients.

The ubiquitin-proteasome system and inflammatory activity in diabetic atherosclerotic plaques: effects of rosiglitazone treatment

The role of ubiquitin-proteasome system in the accelerated atherosclerotic progression of diabetic patients is unclear. We evaluated ubiquitin-proteasome activity in carotid plaques of asymptomatic diabetic and nondiabetic patients, as well as the effect of rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)-gamma activator, in diabetic plaques. Plaques were obtained from 46 type 2 diabetic and 30 nondiabetic patients undergoing carotid endarterectomy. Diabetic patients received 8 mg rosiglitazone (n = 23) or placebo (n = 23) for 4 months before scheduled endarterectomy. Plaques were analyzed for macrophages (CD68), T-cells (CD3), inflammatory cells (HLA-DR), ubiquitin, proteasome 20S activity, nuclear factor (NF)-kappaB, inhibitor of kappaB (IkappaB)-beta, tumor necrosis factor (TNF)-alpha, nitrotyrosine, matrix metalloproteinase (MMP)-9, and collagen content (immunohistochemistry and enzyme-linked immunosorbent assay). Compared with nondiabetic plaques, diabetic plaques had more macrophages, T-cells, and HLA-DR+ cells (P < 0.001); more ubiquitin, proteasome 20S activity (TNF-alpha), and NF-kappaB (P < 0.001); and more markers of oxidative stress (nitrotyrosine and O2(-) production) and MMP-9 (P < 0.01), along with a lesser collagen content and IkappaB-beta levels (P < 0.001). Compared with placebo-treated plaques, rosiglitazone-treated diabetic plaques presented less inflammatory cells (P < 0.01); less ubiquitin, proteasome 20S, TNF-alpha, and NF-kappaB (P < 0.01); less nitrotyrosine and superoxide anion production (P < 0.01); and greater collagen content (P < 0.01), indicating a more stable plaque phenotype. Similar findings were obtained in circulating monocytes obtained from the two groups of diabetic patients and cultured in the presence or absence of rosiglitazone (7.0 micromol/l). Ubiquitin-proteasome over-activity is associated with enhanced inflammatory reaction and NF-kappaB expression in diabetic plaques. The inhibition of ubiquitin-proteasome activity in atherosclerotic lesions of diabetic patients by rosiglitazone is associated with morphological and compositional characteristics of a potential stable plaque phenotype, possibly by downregulating NF-kappaB-mediated inflammatory pathways.

Increased vascular endothelial growth factor expression but impaired vascular endothelial growth factor receptor signaling in the myocardium of type 2 diabetic patients with chronic coronary heart disease

OBJECTIVES

The aim of the present study was to evaluate the expression and the activity of vascular endothelial growth factor (VEGF) in the hearts of diabetic patients with chronic coronary heart disease (CHD).

BACKGROUND

Diabetes is characterized by a decreased collateral vessel formation in response to coronary ischemic events, although the role of VEGF in human diabetic macroangiopathy has not been fully investigated.

METHODS

Biopsies of left ventricular (LV) myocardium were obtained from 10 patients with type 2 diabetes and 10 non-diabetic patients with chronic CHD, all undergoing surgical coronary revascularization. Right ventricle myocardial samples taken from normal hearts were used as control specimens. Vascular endothelial growth factor and VEGF-receptors (flt-1 and flk-1) were evaluated by Western blot, reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time RT-PCR. Akt and endothelial nitric oxide synthase (eNOS) protein expression and their phosphorylated forms were also evaluated by Western blot.

RESULTS

Vascular endothelial growth factor, flt-1, and flk-1 messenger ribonucleic acid (mRNA) and protein expressions were increased in non-diabetic patients with CHD compared with control subjects. Remarkably, in diabetic patients, VEGF mRNA and protein levels were significantly higher, whereas flt-1, flk-1 mRNA, and protein were lower when compared with non-diabetic patients. Interestingly, phospho-flk-1 was reduced in diabetic patients compared with non-diabetic patients. As a consequence, Akt phosphorylation, eNOS protein and its phosphorylated form were significantly higher in the samples from non-diabetic patients compared with diabetic patients.

CONCLUSIONS

Chronic CHD in diabetic patients is characterized by an increased VEGF myocardial expression and a decreased expression of its receptors along with a down-regulation of its signal transduction. The latter could be partially responsible for the reduced neoangiogenesis in diabetic patients with ischemic cardiomyopathy.

Effects of insulin on left ventricular function during dynamic exercise in overweight and obese subjects

AIMS

We designed this study in order to determine the effect of insulin on cardiac function in overweight and obese subjects during exercise.

METHODS AND RESULTS

The cardiac function of 62 normal glucose tolerant subjects, aged 30-40 and divided into normal weight (group 1, n=22, BMI 20-24.9 kg/m(2)), overweight (group 2, n=20, BMI 25-29.9 kg/m(2)), and obesity (group 3, n=20, BMI 30-35 kg/m(2)) was evaluated at rest and during dynamic exercise through angiocardioscintigraphy, when on hyperinsulinaemic euglycaemic clamp (test A) and when on normal saline infusion (test B). Left ventricular function at rest was statistically greater (P<0.05) in both tests in overweight and obese subjects compared with normal weight controls, with no statistical difference (P=0.057) within groups between insulin and normal saline infusion. During exercise, cardiac function improved in all the subjects in both tests. The increase was lower in overweight and obese patients, even if statistically significant only in obese vs. control subjects in both tests (P<0.05). Insulin sensitivity showed a significant correlation (P< or =0.001) with left ventricular ejection fraction (LVEF) at rest and with change in LVEF during clamp.

CONCLUSION

Our findings suggest a metabolic pathogenesis for the impaired LV function in obesity.

Glucose metabolism and coronary heart disease in patients with normal glucose tolerance

CONTEXT

Several investigations as well as prospective studies have shown a significant correlation between glucose metabolism and atherosclerosis in patients without diabetes, but differences in parameters of glucose metabolism among the various degrees of coronary disease in such patients have not been specifically evaluated.

OBJECTIVE

To investigate glucose metabolism in patients with normal glucose tolerance (NGT) and coronary heart disease (CHD).

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study of 234 men (mean [SD] age, 56.2 [6.1] years) with NGT and suspected CHD who were admitted from January 1 through June 30, 2001, to an academic medical center in Italy for coronary angiography.

MAIN OUTCOME MEASURES

Correlation of glucose metabolic factors and extent of atherosclerosis determined by coronary angiography. Factors included levels of fasting and postload glucose and insulin, glycosylated hemoglobin (HbA1c), and lipids, as well as insulin resistance measured by homeostasis model assessment (HOMA-IR).

RESULTS

Patients were divided into 4 groups based on coronary angiography: no significant stenosis (n = 42), 1-vessel disease (n = 72), 2-vessel disease (n = 64), and 3-vessel disease (n = 56). Simple correlation analysis showed that the factors correlated with the extent of atherosclerosis were levels of postload glucose (r = 0.667), HbA1c (r = 0.561), postload insulin (r = 0.221), and fasting insulin (r = 0.297), as well as HOMA-IR (r = 0.278) (P<.001 for all). Multiple stepwise regression analysis suggested that the factors independently associated with the number of stenosed coronary arteries were levels of postload plasma glucose (r = 0.572), HbA1c (r = 0.413), postload insulin (r = 0.267), and fasting insulin (r = 0.174), as well as HOMA-IR (r = 0.250) (P<.001 for all). Similar results were obtained after grouping patients by Duke Myocardial Jeopardy Score.

CONCLUSIONS

For patients with NGT and different extents of atherosclerotic disease, postload glycemia and HbA1c level are not equally distributed but are significantly higher in those with more severe disease. This suggests that the glycemic milieu correlates with the cardiovascular risk according to a linear model.

Increased vascular endothelial growth factor mRNA expression in the heart of streptozotocin-induced diabetic rats

The aim of the present study was to evaluate vascular endothelial growth factor (VEGF), fms-like tyrosine kinase 1 (flt-1), and fetal liver kinase (flk-1) expression in the heart of experimental diabetic rats. Ten young adult male Wistar rats (5 streptozotocin [STZ]-induced diabetic rats, without insulin treatment, and 5 controls) were studied. Ninety days after the induction of diabetes, semiquantitative reverse transcription (RT)-polymerase chain reaction (PCR) coamplification of VEGF/glyceraldehyde 3-phosphate dehydrogenase (GAPDH) transcription was performed. RT-PCR was also performed for VEGF receptors flk-1 and flt-1. VEGF mRNA expression, at 234 bp, was detectable in the heart of the rats and was significantly higher in those with diabetes. Densitometric analysis of PCR products showed that VEGF mRNA levels were meanly 4.8-fold higher in STZ-induced diabetic rats than controls (VEGF/GAPDH densitometric ratio, 3.46 +/- 0.20 v 0.74 +/- 0.10, P <.001). No significant difference was found in flt-1 and flk-1 amplification products between STZ-induced diabetic rats and controls (flt-1/GAPDH densitometric ratio, 0.58 +/- 0.01 v 0.64 +/- 0.05, P>.1; flk-1/GAPDH densitometric ratio, 0.66 +/- 0.10 v 0.7 +/- 0.06, P >.2). The increase in VEGF mRNA expression observed in this experimental diabetic model is in contrast with the typical impairment in collateral vessels of diabetic hearts. This apparent discrepancy might be explained by a resistance of cardiac tissue to VEGF. The lack of mRNA flt-1 and flk-1 overexpression in diabetic hearts could be one of the mechanisms for this resistance.

Irbesartan reduces the albumin excretion rate in microalbuminuric type 2 diabetic patients independently of hypertension: a randomized double-blind placebo-controlled crossover study

OBJECTIVE

ACE inhibitors delay the progression from incipient to overt diabetic nephropathy and reduce albumin excretion rate (AER), independently of blood pressure. Angiotensin II type 1 receptor antagonists produce similar effects on microalbuminuria and mean arterial pressure. The aim of this study was to evaluate the effect of irbesartan on microalbuminuria and blood pressure in hypertensive and normotensive type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

Sixty-four microalbuminuric hypertensive (group 1) and 60 microalbuminuric normotensive (group 2) type 2 diabetic male patients, matched for age, BMI, HbA(1c), and diabetes duration, were enrolled. Each group was divided into two subgroups receiving either irbesartan (150 mg b.i.d. orally) or placebo for 60 days. After 15 days of washout, irbesartan was given to the subgroups who had received the placebo, and vice versa, in a randomized double-blind crossover study.

RESULTS

In microalbuminuric hypertensive type 2 diabetic subjects, irbesartan reduced 24-h mean systolic and diastolic pressure and AER. In microalbuminuric normotensive type 2 diabetic patients, irbesartan reduced AER.

CONCLUSIONS

These results indicate the beneficial effects of irbesartan on AER in type 2 diabetic subjects, independently of its antihypertensive effects.

Effects of insulin-glucose infusion on left ventricular function at rest and during dynamic exercise in healthy subjects and noninsulin dependent diabetic patients: a radionuclide ventriculographic study

OBJECTIVES

The aim of this study was to evaluate: 1) the effects of insulin administration on left ventricular ejection fraction (LVEF) during exercise, and 2) the eventual impairment of the cardiovascular response to insulin in noninsulin dependent diabetes mellitus.

BACKGROUND

Insulin influences the cardiovascular system, but its effect on left ventricular function has yet to be established.

METHODS

The effects of normal saline (test A) and insulin-glucose (insulin = 1.7 mU x kg(-1) x min(-1); glucose = 6 mg x kg(-1)min(-1)) (test B) infusions on systolic and diastolic functions at rest and during dynamic exercise were examined by radionuclide ventriculography. Twenty-two noninsulin-dependent diabetic patients and 22 gender, age and body mass index matched healthy subjects were investigated.

RESULTS

Both groups had normal scintigraphic parameters at rest and during dynamic exercise. Rest- and stress-LVEF as well as rest- and stress-peak filling rate were significantly (p < 0.001) lower in diabetic than in healthy subjects, both in test A and B. Rest-LVEF was significantly higher during test B than it was in test A only in diabetic subjects (p < 0.01). Stress-LVEF was significantly higher (p < 0.05) during test B than it was in test A, in both groups. Insulin-glucose infusion did not modify rest- and stress-peak filling rate in either group. No difference in left ventricular end diastolic volume and in mean blood pressure was found between test A and B at rest and during exercise in either group. A significant linear correlation between LVEF and the index of insulin sensitivity was found in diabetic patients.

CONCLUSIONS

In both normal and diabetic humans, insulin induces a very important rise in LVEF after submaximal work. However, the rise is significantly lower in diabetic than in nondiabetic subjects. The increase in exercise-LVEF on insulin is likely due to an enhancement of ventricular contractility. Insulin resistance could justify the lower angioscintigraphic indexes in diabetic subjects.

Molecular analysis of a case of IgA2 deficiency

A family with two members with selective IgA2 deficiency was analysed by direct gene analysis with different probes for the IgCH region. No gross gene deletions or rearrangements were detected. Genetic analysis based on serological and molecular markers did not rule out linkage with the IgCH region. However, a defect of other genes not linked to the Ig heavy chain region and controlling the expression of IgA may be possible as well.