Plasma adiponectin levels are associated with coronary lesion complexity in men with coronary artery disease

Relation between plasma adiponectin, high-sensitivity C-reactive protein, and coronary plaque components in patients with acute coronary syndrome

The present study investigated the relation between plasma high-sensitivity C-reactive protein (hs-CRP) and adiponectin and coronary plaque components in patients with acute coronary syndrome (ACS). Previous studies showed a pivotal role of inflammation in the progression of atherosclerosis and the prognostic value of several biomarkers. However, relations among inflammatory biomarkers and plaque characteristics were unknown. Ninety-three culprit plaques (ACS n = 50, non-ACS n = 43) and 56 nonculprit plaques (ACS n = 28, non-ACS n = 28) were analyzed using Virtual Histology intravascular ultrasound to examine relations among plasma hs-CRP, adiponectin, and ratios of each coronary plaque component. Plasma adiponectin was significantly lower and plasma hs-CRP was significantly higher in patients with than without ACS. Culprit plaques in patients with ACS had greater amounts of necrotic core plaque than those in patients without ACS. There was an inverse relation between serum hs-CRP and adiponectin with regard to necrotic core ratio in both culprit and nonculprit lesions in patients with ACS, but not those without ACS. In conclusion, increased plasma hs-CRP and hypoadiponectinemia might be related to the progression of ACS.

Inflammation in atherosclerosis: from vascular biology to biomarker discovery and risk prediction

Recent investigations of atherosclerosis have focused on inflammation, providing new insight into mechanisms of disease. Inflammatory cytokines involved in vascular inflammation stimulate the generation of endothelial adhesion molecules, proteases, and other mediators, which may enter the circulation in soluble form. These primary cytokines also induce production of the messenger cytokine interleukin-6, which stimulates the liver to increase production of acute-phase reactants such as C-reactive protein. In addition, platelets and adipose tissue can generate inflammatory mediators relevant to atherothrombosis. Despite the irreplaceable utility of plasma lipid profiles in assessment of atherosclerotic risk, these profiles provide an incomplete picture. Indeed, many cardiovascular events occur in individuals with plasma cholesterol concentrations below the National Cholesterol Education Program thresholds of 200 mg/dL for total cholesterol and 130 mg/dL for low-density lipoprotein (LDL) cholesterol. The concept of the involvement of inflammation in atherosclerosis has spurred the discovery and adoption of inflammatory biomarkers for cardiovascular risk prediction. C-reactive protein is currently the best validated inflammatory biomarker; in addition, soluble CD40 ligand, adiponectin, interleukin 18, and matrix metalloproteinase 9 may provide additional information for cardiovascular risk stratification and prediction. This review retraces the biology of atherothrombosis and the evidence supporting the role of inflammatory biomarkers in predicting primary cardiovascular events in this biologic context.

Adiponectin, obesity and atherosclerosis

The circulating protein adiponectin has been the subject of immense interest ever since it was first discovered in the mid-1990s. The protein is uniquely produced and secreted by mature adipocytes and is believed to have important anti-inflammatory and anti-diabetic effects; low levels have been shown to be predictive of future type 2 diabetes and cardiovascular disease. This review discusses adiponectin in relation to obesity, inflammation, insulin resistance and atherosclerosis.

Low serum adiponectin is associated with high circulating oxidized low-density lipoprotein in patients with type 2 diabetes mellitus and coronary artery disease

Decrease in adiponectin level, a common feature in patients with type 2 diabetes mellitus, is considered to predict cardiovascular events. Elevated oxidized low-density lipoprotein (oxLDL), formed within the arterial wall, is commonly seen as part of the atherogenic profile. We investigated the association of adiponectin and oxLDL in 58 patients with type 2 diabetes mellitus and ischemic coronary artery disease. In addition to adiponectin, the serum lipid profile (including oxLDL), plasminogen activator inhibitor 1, high-sensitivity C-reactive protein, and whole-body glucose uptake determined by euglycemic-hyperinsulinemic clamp were evaluated. The average adiponectin level was 7.1 +/- 3.5 microg/mL and was higher in female than in male patients (P = .011). Adiponectin level correlated with whole-body glucose uptake (P = .037) and high-density lipoprotein (HDL) cholesterol concentration (P = .007) and was inversely associated with oxLDL (P = .005), triglycerides (P = .010), and plasminogen activator inhibitor 1 (P = .004). No association was found between adiponectin and high-sensitivity C-reactive protein or LDL cholesterol levels. In multiple linear regression analysis, adiponectin contributed to oxLDL concentration, whereas total cholesterol, LDL and HDL cholesterol, and triglycerides did not. In conclusion, our results suggest that low adiponectin concentration indicates increased oxidative state in the arterial wall, which further supports previous data on the role of adipose tissue in atherogenesis.

Pathophysiological significance of adiponectin

Adipose tissue, which classically has been considered as an energy-storing organ, is now viewed as a massive source of bioactive substances such as leptin, tumor necrosis factor (TNF)-alpha, and adiponectin. Adiponectin was discovered to be the most abundant adipose-specific transcript. Its function had been unclear, but epidemiological and clinical studies have demonstrated that serum levels of adiponectin are inversely associated with body weight, especially abdominal visceral fat accumulation. In addition, adiponectin was inversely related to cardiovascular risk factors, such as insulin resistance, blood pressure, and low-density lipoprotein (LDL) cholesterol and triglyceride levels, and was positively related to high-density lipoprotein (HDL) cholesterol levels. Moreover, low adiponectin concentration is associated with a high incidence of cardiovascular disease (CVD), diabetes, some kinds of cancer, and other various diseases. These associations suggest the clinical significance of adiponectin, and a number of investigations are now being conducted to clarify the biological functions of adiponectin. Recent studies have revealed that adiponectin exhibits antiinflammatory, antiatherogenic, and antidiabetic properties. In addition, adiponectin has been thought to be a key molecule in "metabolic syndrome," which is an epidemiological target for preventing cardiovascular disease. Various functions of adiponectin may possibly serve to prevent and treat obesity-related diseases and CVD. Furthermore, enhancement of adiponectin secretion or action may become a promising therapeutic target.

Adiponectin and the metabolic syndrome: mechanisms mediating risk for metabolic and cardiovascular disease

PURPOSE OF REVIEW

Adiponectin is secreted exclusively by adipocytes, aggregates in multimeric forms, and circulates at high concentrations in blood. This review summarizes recent studies highlighting cellular effects of adiponectin and its role in human lipid metabolism and atherosclerosis.

RECENT FINDINGS

Adiponectin is an important autocrine/paracrine factor in adipose tissue that modulates differentiation of preadipocytes and favors formation of mature adipocytes. It also functions as an endocrine factor, influencing whole-body metabolism via effects on target organs. Adiponectin multimers exert differential biologic effects, with the high-molecular-weight multimer associated with favorable metabolic effects (i.e. greater insulin sensitivity, reduced visceral adipose mass, reduced plasma triglycerides, and increased HDL-cholesterol). Adiponectin influences plasma lipoprotein levels by altering the levels and activity of key enzymes (lipoprotein lipase and hepatic lipase) responsible for the catabolism of triglyceride-rich lipoproteins and HDL. It thus influences atherosclerosis by affecting the balance of atherogenic and antiatherogenic lipoproteins in plasma, and by modulating cellular processes involved in foam cell formation.

SUMMARY

Recent studies emphasize the role played by adiponectin in the homeostasis of adipose tissue and in the pathogenesis of the metabolic syndrome, type 2 diabetes, and atherosclerosis. These pleiotropic effects make it an attractive therapeutic target for obesity-related conditions.

Relationship of Serum Adiponectin Level to Adverse Cardiovascular Events in Patients Who Undergo Percutaneous Coronary Intervention

BACKGROUND

Hypoadiponectinemia has been reported to indicate an increased risk of cardiovascular disease, so the present study investigated the significance of serum adiponectin (APN) levels for predicting clinical outcomes after percutaneous coronary intervention (PCI).

METHODS AND RESULTS

The APN levels were evaluated in 184 consecutive patients who underwent PCI. The patients were divided into Group A [the lowest quartile of APN levels (APN < or =4.5 microg/ml), n=46] and Group B [the upper 3 quartiles of APN levels (APN >4.5 microg/ml), n=138]. During a mean follow-up period of 27.3 months, the rate of major adverse cardiac and cerebrovascular events (MACCE: death from any cause, re-infarction, repeat coronary revascularization, hospitalization because of congestive heart failure, and cerebral infarction) was higher in Group A (58.7%) than in Group B (37.0%, p=0.0101). Moreover, when the APN levels were calculated by adjusting for sex, age, body mass index, and triglyceride levels, patients in the lowest quartile of residual APN levels had a higher risk of MACCE (p=0.0405). Multiple logistic analyses showed that hypoadiponectinemia (APN < or =4.5 microg/ml) was independently correlated with MACCE. Kaplan-Meier analysis demonstrated a higher MACCE rate in Group A than in Group B (Log-rank chi(2)=7.89, p=0.0050).

CONCLUSION

The APN level may be helpful for predicting clinical outcomes after PCI.

Effects of Plasma Adiponectin Levels on the Number and Function of Endothelial Progenitor Cells in Patients With Coronary Artery Disease

BACKGROUND

It is not known whether plasma adiponectin levels are associated with the number and function of endothelial progenitor cells (EPCs) in patients with coronary artery disease (CAD).

METHODS AND RESULTS

Plasma levels of adiponectin were measured in 70 patients undergoing coronary angiography. The numbers of colony-forming units (CFUs) of EPCs and senescent EPCs, determined by acidic beta-galactosidase staining, were counted. The angiogenic growth factors in the culture medium were also measured. There was a significant positive correlation between adiponectin level and CFUs (r=0.257, p<0.05) but not with the occurrence of senescent EPCs. Next, patients were divided into a high adiponectin group (high ADP: > or =6.17 microg/ml, n=36) and low adiponectin group (low ADP: <6.17 microg/ml, n=34). The number of diseased coronary arteries was less in the high ADP group than that in the low ADP patients (1.7+/-0.8 vs 2.1+/-0.7, p<0.05). No significant differences between the 2 groups were demonstrated in angiogenic growth factors secreted from EPCs.

CONCLUSIONS

The results suggest that plasma adiponectin levels are associated with the number of EPCs in patients with CAD.