Clinical correlates, heritability, and genetic linkage of circulating CD40 ligand in the Framingham Offspring Study

The association between impaired glucose tolerance and soluble CD40 ligand: a 15-year prospective cohort study

BACKGROUND AND AIMS

The aim of the present study was to assess soluble CD40 Ligand (sCD40L) levels in relation to impaired glucose tolerance (IGT) at population level.

METHODS

This study is part of a prospective, population-based cohort study, carried out from 1990 to 2008 in northern Finland. Study members, born in 1935 and living in the City of Oulu, underwent oral glucose tolerance test (OGTT) and measurement of plasma sCD40L at three different time points during the 15-year follow-up. The total number of study members who underwent OGTT was 768 at the baseline, 557 at the first and 467 at the second follow-up. SCD40L levels in patients with IGT were compared with those in subjects with normal glucose tolerance or impaired fasting glucose (non-IGT).

RESULTS

Geometric mean level of sCD40L was significantly higher in the IGT group compared with the non-IGT group at the baseline (0.42 vs. 0.27 ng/mL) and at the first follow-up (1.50 vs. 0.36 ng/mL) (repeated measures mixed models ANOVA, p < 0.05). At the second follow-up (age 72-73 years), however, the difference was not statistically significant (9.44 vs. 7.24 ng/mL). During the entire follow-up, the levels of sCD40L increased significantly both in IGT and non-IGT groups.

CONCLUSION

We found that plasma sCD40L level increases with age as well as there are elevated levels of plasma sCD40L in subjects with IGT compared with non-IGT. This may indicate an increased cardiovascular risk in older age and in subjects with IGT.

Change of coronary flow velocity during the cold pressor test is related to endothelial markers in subjects with chest pain and a normal coronary angiogram

BACKGROUND

Several studies demonstrated that endothelial or atherosclerotic biomarkers, including plasma free insulin-like growth factor-I(IGF-I), soluble CD40 ligand (sCD40L), adiponectin, and leptin have an influence on coronary endothelial function.

HYPOTHESIS

The aim of the present study was to investigate whether change of coronary flow velocity of the distal left anterior descending artery (LAD) during the cold pressor test (CPT) with transthoracic Doppler echocardiography (TTE) was associated with these biomarkers in subjects with chest pain and a normal coronary angiogram.

METHODS

In 190 subjects (mean age, 54±11 years; male:female, 113:77) with chest pain and a normal coronary angiogram, peak diastolic velocity (PDV) of the distal LAD during the CPT with TTE was assessed. Acetylcholine provocation test was performed in 58 subjects (mean age, 51±10 years) who were clinically suspected of vasospasm. CPT%PDV was defined as the percent change in PDV during the CPT. Associations between CPT%PDV and clinical parameters were analyzed.

RESULTS

According to multiple regression analysis, CPT%PDV was associated with plasma free IGF-I in the entire study population (β=0.295, P<0.001 in all subjects; β=0.341, P=0.001 in males; β=0.243, P=0.037 in females; β=0.303, P=0.002 in nonsmokers; and β=0.256, P=0.047 in smokers), and sCD40L in males (β=-0.269, P=0.008)and smokers (β=-0.261, P=0.046). Subjects with vasospasm to intracoronary acetylcholine had lower plasma free IGF-I(6.9±3.3 vs 8.9±3.4, P=0.026) and CPT%PDV (8.8±24.9 vs 52.7±26.0, P<0.001) than the others. Plasma adiponectin and leptin were not associated with CPT%PDV.

CONCLUSIONS

Change of coronary flow velocity assessed using the CPT with TTE may be related to endothelial markers, especially plasma free IGF-I.

Genetic regulation of inflammation-mediated activation of haemostasis: family-based approaches in population studies

Blood coagulation and inflammation play a key role in atherosclerosis and thrombosis. Candidate gene and genome wide association studies have identified potential specific genes that might have a causal role in these pathogenic processes. The analysis of quantitative traits is more powerful as they are closer to direct gene action than disease phenotypes. Thus linkage-based studies on extended families might be useful both to estimate the heritability and to map the genetic loci responsible for the regulation of the trait. Family-based studies may estimate high heritability for thrombosis and quantitative traits regarding both platelet aggregation and blood coagulation. Some specific loci relevant to thrombosis have been identified, with some of them showing a direct pleiotropic effect on the risk of thrombosis. Haemostasis factors can be activated by inflammatory stimuli. Fibrinogen level is genetically correlated with C-reactive protein levels with a link for both traits on chromosomes 12 and 21. Genes related to prostanoid biosynthesis, involved both in inflammation and thrombosis, show high heritability levels in both enzyme expression and prostanoid production. Considering that few large family-based linkage studies have as yet been performed on haemostasis and inflammation-related traits, additional studies are highly needed. We are performing a family-based linkage study on large pedigrees (750 subjects from 23 families with juvenile myocardial infarction and 31 control families), to identify genes responsible for quantitative traits involved in the pathway progressively going from inflammation to haemostasis, cell activation, thrombus formation and cardiovascular events.

Effects of cranberry juice consumption on vascular function in patients with coronary artery disease

BACKGROUND

Cranberry juice contains polyphenolic compounds that could improve endothelial function and reduce cardiovascular disease risk.

OBJECTIVE

The objective was to examine the effects of cranberry juice on vascular function in subjects with coronary artery disease.

DESIGN

We completed an acute pilot study with no placebo (n = 15) and a chronic placebo-controlled crossover study (n = 44) that examined the effects of cranberry juice on vascular function in subjects with coronary artery disease.

RESULTS

In the chronic crossover study, subjects with coronary heart disease consumed a research preparation of double-strength cranberry juice (54% juice, 835 mg total polyphenols, and 94 mg anthocyanins) or a matched placebo beverage (480 mL/d) for 4 wk each with a 2-wk rest period between beverages. Beverage order was randomly assigned, and participants refrained from consuming other flavonoid-containing beverages during the study. Vascular function was measured before and after each beverage, with follow-up testing ≥12 h after consumption of the last beverage. Mean (±SD) carotid-femoral pulse wave velocity, a measure of central aortic stiffness, decreased after cranberry juice (8.3 ± 2.3 to 7.8 ± 2.2 m/s) in contrast with an increase after placebo (8.0 ± 2.0 to 8.4 ± 2.8 m/s) (P = 0.003). Brachial artery flow-mediated dilation, digital pulse amplitude tonometry, blood pressure, and carotid-radial pulse wave velocity did not change. In the uncontrolled pilot study, we observed improved brachial artery flow-mediated dilation (7.7 ± 2.9% to 8.7 ± 3.1%, P = 0.01) and digital pulse amplitude tonometry ratio (0.10 ± 0.12 to 0.23 ± 0.16, P = 0.001) 4 h after consumption of a single 480-mL portion of cranberry juice.

CONCLUSIONS

Chronic cranberry juice consumption reduced carotid femoral pulse wave velocity-a clinically relevant measure of arterial stiffness. The uncontrolled pilot study suggested an acute benefit; however, no chronic effect on measures of endothelial vasodilator function was found. This trial was registered at clinicaltrials.gov as NCT00553904.

Soluble CD40 ligand is elevated in type 1 diabetic nephropathy but not predictive of mortality, cardiovascular events or kidney function

Soluble CD40 ligand (sCD40L) derived from platelets mediates atherothrombosis, leading to proinflammatory and proatherosclerotic responses. We investigated the predictive value of plasma sCD40L for all-cause mortality, cardiovascular mortality and morbidity, progression towards end-stage renal disease (ESRD) and rate of decline in glomerular filtration rate (GFR) in patients with type 1 diabetes (T1DM) and nephropathy. The study was a prospective, observational follow-up study of 443 T1DM patients with diabetic nephropathy (274 men; age 42.1 ± 10.5 years [mean ± SD], duration of diabetes 28.3 ± 8.9 years, GFR 76 ± 33 ml/min/1.73 m2) and a control group of 421 patients with longstanding type 1 diabetes and persistent normoalbuminuria (232 men; age 45.4 ± 11.5 years, duration of diabetes 27.7 ± 10.1 years) at baseline. sCD40L was measured by ELISA. Plasma sCD40L levels were higher in patients with diabetic nephropathy compared to normoalbuminuric patients (median (range) 1.54 (0.02-13.38) vs. 1.30 (0.04-20.65) µg/L, respectively p = 0.004). The patients were followed for 8.1 (0.0-12.9) years (median (range)). Among normoalbuminuric patients, sCD40L levels did not predict all-cause mortality (p = 0.33) or combined fatal and non-fatal cardiovascular disease (CVD) (p = 0.27). Similarly, among patients with diabetic nephropathy, the covariate adjusted sCD40L levels did not predict all-cause mortality (p = 0.86) or risk of fatal and non-fatal CVD (p = 0.08). Furthermore, high levels of sCD40L did not predict development of ESRD (p = 0.85) nor rate of decline in GFR (p = 0.69). Plasma sCD40L is elevated in T1DM nephropathy but is not a predictor of all-cause mortality, cardiovascular mortality and morbidity or deterioration of kidney function

Effects of Concord grape juice on ambulatory blood pressure in prehypertension and stage 1 hypertension

BACKGROUND

Consumption of flavonoid-containing foods may be useful for the management of hypertension.

OBJECTIVE

We investigated whether 100% Concord grape juice lowers blood pressure in patients with prehypertension and stage 1 hypertension.

DESIGN

We conducted a double-blind crossover study to compare the effects of grape juice (7 mL · kg⁻¹ · d⁻¹) and matched placebo beverage on 24-h ambulatory blood pressure, stress-induced changes in blood pressure, and biochemical profile. Participants consumed each beverage for 8 wk with a 4-wk rest period between beverages. They ceased consumption of grapes and other flavonoid-containing beverages throughout the study.

RESULTS

We enrolled 64 otherwise healthy patients taking no antihypertensive medications (31% women, 42% black, age 43 ± 12 y). Baseline mean (± SD) cuff blood pressure was 138 ± 7 (systolic)/82 ± 7 (diastolic) mm Hg. No effects on the primary endpoint of 24-h mean systolic blood pressure, diastolic blood pressure, or stress-induced changes in blood pressure were observed. A secondary endpoint was nocturnal dip in systolic pressure. At baseline, nocturnal pressure was 8.3 ± 7.1% lower at night than during daytime. The mean nocturnal dip increased 1.4 percentage points after grape juice and decreased 2.3 percentage points after placebo (P = 0.005). Fasting blood glucose was 91 ± 10 mg/dL at baseline for the entire cohort. Glucose decreased 2 mg/dL after consumption of grape juice and increased 1 mg/dL after consuming the placebo (P = 0.03).

CONCLUSIONS

We observed no effect of grape juice on ambulatory blood pressure in this cohort of relatively healthy individuals with modestly elevated blood pressure. Secondary analyses suggested favorable effects on nocturnal dip and glucose homeostasis that may merit further investigation. This trial was registered at clinicaltrials.gov as NCT00302809.

Influence of glycaemic control on platelet bound CD40-CD40L system, P-selectin and soluble CD40 ligand in Type 2 diabetes

AIMS

Type 2 diabetes is a potent cardiovascular risk factor, associated with proinflammatory and prothrombotic processes. The purpose of this study was to investigate whether platelet-bound CD40-CD40L signalling, P-selectin expression and soluble CD40L were increased in patients with diabetes mellitus and can be normalized by improving glycaemic control.

METHODS

Soluble (s) CD40L, platelet surface expression of CD40L, CD40 and P-selectin (CD62P) on platelets were measured by flow cytometry in 71 patients with Type 2 diabetes mellitus and 37 healthy volunteers. In addition, the relationship of HbA1c to CD40-CD40L and P-selectin expression was determined in a longitudinal follow-up.

RESULTS

In patients with Type 2 diabetes, platelet membrane CD40 expression (Type 2 diabetes 3.1+/-0.61 vs. controls 2.5+/-0.85 mean fluorescence intensity; P=0.001), platelet-bound CD40L (1.2+/-0.32 vs. 1.1+/-0.14; P=0.034) as well as surface expression of CD62P (0.66+/-0.19 vs. 0.57+/-0.12; P=0.007) were higher than in control subjects. Plasma sCD40L values (3.2+/-1.70 vs. 1.8+/-0.50 ng/ml; P<0.001) were also significantly increased in Type 2 diabetes. After improving glycaemic control in patients with initial HbA1c>8.5% (n=15), platelet P-selectin and CD40-CD40L expression decreased significantly by 54.0%, 36.22% and 16.26%, respectively 1 year later.

CONCLUSIONS

Type 2 diabetes is associated with up-regulation of the platelet-bound CD40-CD40L system, platelet hyperactivity (enhanced P-selectin expression) and increased sCD40L levels. Improved glycaemic control, however, does help to correct abnormal platelet activation via down-regulation of CD40-CD40L system and P-selectin expression.

Soluble CD40 ligand levels in essential hypertensive men: evidence of a possible role of insulin resistance

BACKGROUND

Elevated levels of the proinflammatory cytokine soluble CD40 ligand (sCD40L) were reported in subjects with diabetes, impaired glucose tolerance, metabolic syndrome (MS), obesity, and insulin resistance. Metabolic abnormalities might also account for increased sCD40L in subjects with essential hypertension.

METHODS

Several metabolic and vascular correlates of sCD40L levels have been investigated in 90 nondiabetic never-treated essential hypertensive men.

RESULTS

Median sCD40L level was 8.7 ng/ml (interquartile range: 4.9-11.7). On the basis of sCD40L, subjects were divided by tertiles (thresholds at 6.6 and 11.0 ng/ml). The three groups did not differ for age, body mass index (BMI), smokers, blood pressure (BP), prevalence of nondippers, lipids and lipoproteins, renal function, and albuminuria. Carotid intima-media thickness (IMT: 0.79 +/- 0.22, 0.83 +/- 0.29, and 0.85 +/- 0.30 mm) and percentage of subjects with wall thickening (IMT >0.9 to <1.3 mm: 23, 27, and 27%, respectively) were superimposable in the three groups. No differences were observed in high-sensitivity C-reactive protein (hs-CRP) and no correlation emerged between sCD40L and hs-CRP. An increase through sCD40L tertiles emerged for basal insulin (11.2 +/- 5.6, 14.7 +/- 7.7, and 16.8 +/- 13.5 microU/ml, P = 0.10) and fasting glucose (95 +/- 11, 103 +/- 16, and 105 +/- 14 mg/dl, P = 0.028). Consistently, along with the increase in sCD40L, a worsening in insulin sensitivity was observed, which was expressed as homeostasis model assessment for insulin sensitivity (HOMA%S: 99 +/- 52, 77 +/- 43, and 72 +/- 35, P < 0.05), composite insulin sensitivity index (ISIcomp; Matsuda index: 5.11 +/- 2.65, 3.61 +/- 1.98, and 3.28 +/- 1.87, P = 0.025), or oral glucose insulin sensitivity (OGIS) index (OGIS: 421 +/- 67, 386 +/- 90, and 362 +/- 72, P = 0.004).

CONCLUSIONS

In newly diagnosed hypertensive men, sCD40L levels are inversely related to insulin sensitivity, with no correlation with BP, other cardiovascular risk factors, or the degree of subclinical atherosclerosis.