High-sensitivity C-reactive protein and impaired coronary vasoreactivity in young men with uncomplicated type 1 diabetes

Incremental effect of coronary obstruction on myocardial microvascular dysfunction in type 2 diabetes mellitus patients evaluated by first-pass perfusion CMR study

BACKGROUND

Type 2 diabetes mellitus (T2DM) frequently coexists with obstructive coronary artery disease (OCAD), which are at increased risk for cardiovascular morbidity and mortality. This study aimed to investigate the impact of coronary obstruction on myocardial microcirculation function in T2DM patients, and explore independent predictors of reduced coronary microvascular perfusion.

METHODS

Cardiac magnetic resonance (CMR) scanning was performed on 297 T2DM patients {188 patients without OCAD [T2DM(OCAD -)] and 109 with [T2DM(OCAD +)]} and 89 control subjects. CMR-derived perfusion parameters, including upslope, max signal intensity (MaxSI), and time to maximum signal intensity (TTM) in global and segmental (basal, mid-ventricular, and apical slices) were measured and compared among observed groups. According to the median of Gensini score (64), T2DM(OCAD +) patients were subdivided into two groups. Univariable and multivariable linear regression analyses were performed to identify independent predictors of microcirculation dysfunction.

RESULTS

T2DM(OCAD -) patients, when compared to control subjects, had reduced upslope and prolonged TTM in global and all of three slices (all P < 0.05). T2DM(OCAD +) patients showed a significantly more severe impairment of microvascular perfusion than T2DM(OCAD -) patients and control subjects with a more marked decline upslope and prolongation TTM in global and three slices (all P < 0.05). From control subjects, through T2DM(OCAD +) patients with Gensini score ≤ 64, to those patients with Gensini score > 64 group, the upslope declined and TTM prolonged progressively in global and mid-ventricular slice (all P < 0.05). The presence of OCAD was independently correlated with reduced global upslope (β =  - 0.104, P < 0.05) and global TTM (β = 0.105, P < 0.05) in patients with T2DM. Among T2DM(OCAD +) patients, Gensini score was associated with prolonged global TTM (r = 0.34, P < 0.001).

CONCLUSIONS

Coronary artery obstruction in the context of T2DM exacerbated myocardial microcirculation damage. The presence of OCAD and Gensini score were independent predictors of decreased microvascular function.

TRIAL REGISTRATION

Retrospectively registered.

Incremental prognostic value of coronary flow reserve determined by phase-contrast cine cardiovascular magnetic resonance of the coronary sinus in patients with diabetes mellitus

BACKGROUND

Although non-invasive assessment of coronary flow reserve (CFR) by cardiovascular magnetic resonance (CMR) provides prognostic information for patients with diabetes mellitus (DM), the incremental prognostic value of CMR-derived CFR remains unclear.

PURPOSE

To evaluate the incremental prognostic value of CMR-derived CFR for patients with DM who underwent stress CMR imaging.

MATERIALS AND METHODS

A total of 309 patients with type 2 DM [69 ± 9 years; 244 (78%) male] assessed between 2009 and 2019 were retrospectively reviewed. Coronary sinus blood flow (CSBF) was measured using phase contrast (PC) cine CMR. CFR was calculated as the CSBF during adenosine triphosphate infusion divided by that at rest. Major adverse cardiac events (MACE) were defined as death, acute coronary syndrome, hospitalization due to heart failure exacerbation, or sustained ventricular tachycardia. The incremental prognostic value of CFR over clinical and CMR variables was assessed by calculating the C-index and net reclassification improvement (NRI).

RESULTS

During a median follow-up of 3.8 years, 42 patients (14%) experienced MACE. The annualized event rate was significantly higher among patients with CFR < 2.0, regardless of the presence of late gadolinium enhancement (LGE) (1.4% vs. 9.8%, p = 0.011 in the LGE (-) group; 1.8% vs. 16.9%, p < 0.001 in the LGE (+) group). In addition, this trend was maintained in the subgroups stratified by presence or absence of ischemia (0.3% vs. 6.7%, p = 0.007 in the ischemia (-) group; 3.9% vs. 17.1%, p = 0.001 in the ischemia (+) group). Adding CFR to the risk model (age + gender + left ventricular ejection fraction + %LGE + %ischemia) resulted in a significant increase of the C-index from 0.838 to 0.870 (p = 0.038) and an NRI of 0.201 (0.004-0.368, p = 0.012).

CONCLUSION

PC cine CMR-derived CFR of the coronary sinus may be useful as a prognostic marker for DM patients, incremental to common clinical and CMR parameters. Due to the high prevalence of coronary microvascular dysfunction, the addition of CFR to conventional vasodilator stress CMR imaging may improve risk stratification for patients with DM.

Effect of Sitagliptin on Coronary Flow Reserve Assessed by Magnetic Resonance Imaging in Type 2 Diabetic Patients With Coronary Artery Disease

BACKGROUND

The present study was conducted to assess the cardiovascular effects of dipeptidyl peptidase-4 inhibitors (DPP4i) on coronary flow reserve (CFR), left ventricular (LV) function and endothelial function of the peripheral artery by comparison with those of α-glucosidase inhibitors (αGI) in patients with type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD).Methods and Results:We randomly assigned 30 patients with T2DM and CAD to receive either sitagliptin or voglibose, and 28 patients (age 69±9 years, 75% male, hemoglobin A1c [HbA1c] 6.62±0.48%) completed the study (14 in each group). CFR and LV function, assessed by cardiac magnetic resonance imaging, and endothelial function, assessed by reactive hyperemia peripheral arterial tonometry (RH-PAT), were measured at baseline and 24 weeks after treatment. Clinical and laboratory parameters, including HbA1c level, plasma active glucagon-like peptide-1 concentrations, and biomarkers of inflammation, were unchanged in both groups after 24 weeks of treatment. CFR were unchanged in both the αGI group (3.01±0.98 at baseline and 3.06±0.8 after treatment, P=NS) and the DPP4i group (4.29±2.04 at baseline and 3.63±1.31 after treatment, P=NS), with no interaction effect. LV functional parameters and the reactive hyperemia index also remained unchanged after the 24-week treatment.

CONCLUSIONS

DPP4i did not improve CFR, LV function or endothelial function of the peripheral artery in patients with relatively well-controlled T2DM and CAD.

Human C-reactive protein accentuates macrophage activity in biobreeding diabetic rats

OBJECTIVE

Type 1 diabetes (T1DM) is a pro-inflammatory state characterized by high C-reactive protein (CRP) levels. However, there is a paucity of data examining the role of CRP in promoting the pro-inflammatory state of diabetes. Thus, we examined the pro-inflammatory effects of human CRP using spontaneously diabetic bio-breeding (BB) rats.

METHODS

Diabetic rats (n=9/group) were injected with Human serum albumin (huSA) or Human CRP (hCRP, 20 mg/kg body weight; i.p.) for 3 consecutive days. Blood and peritoneal macrophages (MØ) were obtained following euthanasia. Peritoneal macrophages were used for measuring superoxide anion release, NF-κB DNA binding activity, proinflammatory mediator secretion.

RESULTS

hCRP administration resulted in significantly increased superoxide anion production, along with increased release of cytokines/chemokines, and plasminogen activator inhibitor (PAI-1) and Tissue Factor (TF) activity in diabetic rats compared to huSA. hCRP-treated BB rat MØ showed significant induction of protein kinase C (PKC)-alpha, PKC-delta and p47 phox expression and NF-κB compared to huSA.

CONCLUSIONS

Thus, our data suggest that human CRP exacerbates in-vivo the pro-inflammatory, pro-oxidant and procoagulant states of diabetes predominantly via increased macrophage activity and this could have implications with respect to vascular complications and anti-inflammatory therapies.

Antisense to protein kinase C-alpha and p47phox attenuates the pro-inflammatory effects of human C-reactive protein in macrophages of biobreeding diabetic rats

OBJECTIVE

Type 1 diabetes mellitus (T1DM) is a pro-inflammatory state characterized by high C-reactive protein (CRP) levels. Previously, we showed that CRP accentuated a macrophage (MO) activity in spontaneously diabetic biobreeding (BB) rats and increased the MO activity of protein kinase C-alpha (PKC-α) and p47phox. In this report, we tested the effects of molecular inhibition of CRP effects on MO activity using antisense oligonucleotide (ASO) to both PKC-α and p47phox.

METHODS

Prior to administration of human C-reactive protein (hCRP) daily for 3 days, ASO or scrambled ASO to either PKC-α or p47phox was also delivered for 3 days and after killing on day 4, peritoneal MOs were isolated.

RESULTS

The increase in the levels of superoxide anion, interleukin (IL)-1, monocyte chemoattractant protein-1 (MCP-1), tumour necrosis factor-alpha (TNF-α) and IL-6 release in MOs with hCRP compared to human albumin was significantly attenuated by antisense to either PKC-α and p47phox (p < 0.01 vs. scrambled ASO; n = 5 per group).

CONCLUSION

Our novel data suggest that antisense to either PKC-α or p47phox attenuates the pro-inflammatory effects of human CRP on MOs in diabetic rats.

Association between coronary vascular dysfunction and cardiac mortality in patients with and without diabetes mellitus

BACKGROUND

Diabetes mellitus increases the risk of adverse cardiac outcomes and is considered a coronary artery disease (CAD) equivalent. We examined whether coronary vascular dysfunction, an early manifestation of CAD, accounts for increased risk among diabetics compared with nondiabetics.

METHODS AND RESULTS

A total of 2783 consecutive patients (1172 diabetics and 1611 nondiabetics) underwent quantification of coronary flow reserve (CFR; CFR=stress divided by rest myocardial blood flow) by positron emission tomography and were followed up for a median of 1.4 years (quartile 1-3, 0.7-3.2 years). The primary end point was cardiac death. Impaired CFR (below the median) was associated with an adjusted 3.2- and 4.9-fold increase in the rate of cardiac death for diabetics and nondiabetics, respectively (P=0.0004). Addition of CFR to clinical and imaging risk models improved risk discrimination for both diabetics and nondiabetics (c index, 0.77-0.79, P=0.04; 0.82-0.85, P=0.03, respectively). Diabetic patients without known CAD with impaired CFR experienced a rate of cardiac death comparable to that for nondiabetic patients with known CAD (2.8%/y versus 2.0%/y; P=0.33). Conversely, diabetics without known CAD and preserved CFR had very low annualized cardiac mortality, which was similar to patients without known CAD or diabetes mellitus and normal stress perfusion and systolic function (0.3%/y versus 0.5%/y; P=0.65).

CONCLUSIONS

Coronary vasodilator dysfunction is a powerful, independent correlate of cardiac mortality among both diabetics and nondiabetics and provides meaningful incremental risk stratification. Among diabetic patients without CAD, those with impaired CFR have event rates comparable to those of patients with prior CAD, whereas those with preserved CFR have event rates comparable to those of nondiabetics.

Cross-sectional associations of C-reactive protein with vascular risk factors and vascular complications in the DCCT/EDIC cohort

OBJECTIVE

To determine the relationships between C-reactive protein (CRP) levels and features of Type 1 diabetes.

RESEARCH DESIGN AND METHODS

Serum CRP was measured by nephelometry in a cross-sectional study of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) cohort (n=983) and nondiabetic subjects (n=71).

RESULTS

CRP levels [geometric mean (95% CI)] were higher in diabetic than in control subjects, 1.6 (1.5-1.7) vs. 1.2 (1.1-1.5) mg/l, P=.019. CRP was higher in diabetic women (n=438) than in men (n=545) [2.0 (1.8-2.3) vs. 1.3 (1.2-1.5), P<.001]. Diabetic subjects formerly in the DCCT intensive treatment group had higher CRP levels than those who were randomized to the conventional treatment group [1.8 (1.6-1.9), n=479 vs. 1.5 (1.3-1.6), n=456, P=.010], attributable to greater BMI in the prior intensive group. In diabetes, CRP correlated with HbA(1c) (r=0.13, P<.0001) and with insulin resistance traits: BMI (r=0.34, P<.0001), waist-to-hip ratio (WHR; males: r=0.35, P<.0001; females: r=0.22, P<.0001), diastolic blood pressure (r=0.07, P=.025), triglycerides (r=0.19, P<.0001), apoB (r=0.22, P<.0001), LDL particle concentration (r=0.26, P<.0001), and LDL particle size (r=-0.22, P<.0001). CRP was not associated with complications. Significant independent predictors of CRP in diabetes were gender, BMI, WHR, concurrent HbA(1c), and oral contraceptive pill use.

CONCLUSIONS

CRP was elevated relative to nondiabetic subjects, and in diabetes was higher in females. Elevated CRP in Type 1 diabetes was associated with poor glycemic control, larger body habitus, and other factors that comprise the insulin resistance syndrome. Nevertheless, CRP levels were not associated with complications. Longitudinal studies are warranted.

Increased toll-like receptor (TLR) 2 and TLR4 expression in monocytes from patients with type 1 diabetes: further evidence of a proinflammatory state

CONTEXT

Type 1 diabetes (T1DM) is associated with increased cardiovascular mortality. It is a pro-inflammatory state as evidenced by increased circulating biomarkers and monocyte activity. The toll-like receptors (TLRs) are pattern recognition receptors, expressed abundantly on monocytes. TLR2 and TLR4 are important in atherosclerosis. However, there is a paucity of data examining TLR2 and TLR4 expression in T1DM and examining its contribution to the proinflammatory state.

OBJECTIVE

Thus, we examined TLR2 and TLR4 expression in monocytes from T1DM patients compared with controls (n = 31 per group).

SETTING

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

PATIENTS

Healthy controls (n = 31) and T1DM patients (n = 31) were included in the study.

RESULTS

TLR2 and TLR4 surface expression and mRNA were significantly increased in T1DM monocytes compared with controls. Downstream targets of TLR, nuclear factor kappaB, myeloid differentiation factor 88, Trif, and phosphorylated IL-1 receptor-associated kinase were significantly up-regulated in T1DM. Finally, the release of IL-1beta and TNF-alpha was significantly increased in monocytes from T1DM compared with controls and correlated with TLR2 and TLR4 expression (P < 0.005). In addition, TLR2 and TLR4 expression was significantly correlated to glycosylated hemoglobin, carboxymethyllysine, and nuclear factor kappaB (P < 0.02).

CONCLUSION

Thus, we make the novel observation that TLR2 and TLR4 expression and signaling are increased in T1DM and contribute to the proinflammatory state.

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

CONTEXT

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

OBJECTIVE

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

DESIGN

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

SETTING

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

PARTICIPANTS

Participants included patients with T1DM.

METHODS AND RESULTS

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

CONCLUSIONS

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

Liver steatosis coexists with myocardial insulin resistance and coronary dysfunction in patients with type 2 diabetes

Nonalcoholic fatty liver (NAFL) is a common comorbidity in patients with type 2 diabetes and links to the risk of coronary syndromes. The aim was to determine the manifestations of metabolic syndrome in different organs in patients with liver steatosis. We studied 55 type 2 diabetic patients with coronary artery disease using positron emission tomography. Myocardial perfusion was measured with [15O]H2O and myocardial and skeletal muscle glucose uptake with 2-deoxy-2-[18F]fluoro-D-glucose during hyperinsulinemic euglycemia. Liver fat content was determined by magnetic resonance proton spectroscopy. Patients were divided on the basis of their median (8%) into two groups with low (4.6 +/- 2.0%) and high (17.4 +/- 8.0%) liver fat content. The groups were well matched for age, BMI, and fasting plasma glucose. In addition to insulin resistance at the whole body level (P = 0.012) and muscle (P = 0.002), the high liver fat group had lower insulin-stimulated myocardial glucose uptake (P = 0.040) and glucose extraction rate (P = 0.0006) compared with the low liver fat group. In multiple regression analysis, liver fat content was the most significant explanatory variable for myocardial insulin resistance. In addition, the high liver fat group had increased concentrations of high sensitivity C-reactive protein, soluble forms of E-selectin, vascular adhesion protein-1, and intercellular adhesion molecule-1 (P < 0.05) and lower coronary flow reserve (P = 0.02) compared with the low liver fat group. In conclusion, in patients with type 2 diabetes and coronary artery disease, liver fat content is a novel independent indicator of myocardial insulin resistance and reduced coronary functional capacity. Further studies will reveal the effect of hepatic fat reduction on myocardial metabolism and coronary function.

High-sensitivity C-reactive protein as cardiovascular risk marker in patients with diabetes mellitus

C-reactive protein (CRP) is a liver-derived pattern recognition molecule that is increased in inflammatory states. It rapidly increases within hours after tissue injury, and it is suggested that it is part of the innate immune system and contributes to host defense. Since cardiovascular disease is at least in part an inflammatory process, CRP has been investigated in the context of arteriosclerosis and subsequent vascular disorders. Based on multiple epidemiological and intervention studies, minor CRP elevation [high-sensitivity CRP (hsCRP)] has been shown to be associated with future major cardiovascular risk (hsCRP:<1 mg/L=low risk; 1-3 mg/L=intermediate risk; 3-10 mg/L=high risk; >10 mg/L=unspecific elevation). It is recommended by the American Heart Association that patients at intermediate or high risk of coronary heart disease may benefit from measurement of hsCRP with regard to their individual risk prediction. Elevation of hsCRP is associated with increased risk of type 2 diabetes development in patients with all levels of metabolic syndrome. In type 1 and type 2 diabetes mellitus, hemoglobin A1c significantly correlates with hsCRP levels and future cardiovascular risk. Also, hsCRP levels increase with the stage of beta-cell dysfunction and insulin resistance. Non-diabetes drugs that have been shown to reduce hsCRP concentrations include aspirin, statins, cyclooxygenase-2 inhibitors, and fibrates. Recent intervention studies have also demonstrated the distinct efficacy of different anti-diabetes treatments on a variety of cardiovascular risk markers. Intensive insulin therapy may reduce inflammation, but this effect may be influenced by the degree of weight gain. Treatment with peroxisome proliferator-activated receptor gamma has lead to substantial reduction of hsCRP and other cardiovascular risk markers in several comparator studies. Since this effect was shown to be independent of the degree of glycemic improvement, it can be regarded as a classspecific effect. Whether these findings translate into a reduction of overall cardiovascular mortality will soon be shown by the currently running thiazolidinedione outcome studies. Positive results in these trials will further strengthen the value and acceptance of hsCRP, which is recommended as a predictive laboratory marker for cardiovascular disease risk also in patients with diabetes mellitus.