No abstract

Human plasma contains at least three forms of adiponectin: a trimer, a hexamer, and a high-molecular-weight (HMW) multimer. We purified HMW adiponectin from human plasma using its affinity to gelatin and obtained monoclonal antibodies against it. On Western blot analysis, the reactivity of these monoclonal antibodies was shown to be restricted to a non-heat-denatured form of adiponectin molecules. On heating, the collagen-like domain of adiponectin molecules became denatured, and thus the trimer form could not be maintained. From these, monoclonal antibodies against HMW adiponectin were suggested to react with the intact trimer of adiponectin. With these monoclonal antibodies, we developed a sandwich ELISA system for quantifying adiponectin in human serum. Its specificity was verified by analysis of serum fractions separated by gel-filtration chromatography, and our ELISA system was found to be HMW adiponectinspecific. With this novel ELISA, the HMW adiponectin concentrations were 8.4 6 5.5 mg/ml (mean 6 SD) in healthy women and 6.2 6 3.6 mg/ml in healthy men. Also, serum with a lower HMW adiponectin concentration was shown to have a lower HMW ratio (i.e., HMW adiponectin/total adiponectin).-Nakano, Y., S. Tajima, A. Yoshimi, H. Akiyama, M. Tsushima, T. Tanioka, T. Negoro, M. Tomita, and T. Tobe. A novel enzyme-linked immunosorbent assay specific for high-molecular-weight adiponectin. Adiponectin is an adipocyte-specific secretory protein that is highly and specifically expressed in adipose tissue (1-3). Adiponectin includes a collagen-like domain, and in this domain, three adiponectin peptides form one stable trimer and the trimers further multimerize to form "bouquet" forms (Fig. 1). In human plasma, adiponectin was found to circulate as a trimer, a hexamer, and a highmolecular-weight (HMW) multimer, and we purified the HMW adiponectin of 420 kDa from human serum using gelatin-Cellulofine and previously reported it as the gelatin binding protein of 28 kDa (GBP28) in 1996 (4).Plasma adiponectin levels are reported to be decreased in obese individuals, to be negatively correlated with visceral fat accumulation, and to be significantly lower in type 2 diabetic patients with coronary artery disease (5-7). Adiponectin mRNA levels are significantly reduced in omental adipose tissue of obese patients with type 2 diabetes compared with lean and obese normoglycemic subjects, and although less pronounced, the levels are also reduced in subcutaneous adipose tissue of type 2 diabetic patients (8). Plasma adiponectin concentrations in patients with acute coronary syndrome, both acute myocardial infarction and unstable angina pectoris, are significantly lower than those in patients with stable angina pectoris and in controls, and a low adiponectin concentration is correlated independently with the development of an acute coronary disease (9). Plasma adiponectin levels are an inverse predictor of the cardiovascular outcome in patients with end-stage renal disease (10). Tietge et al. (11) reported that plasma adipon...

This paper described the Guideline for Diagnosis and Management of Hyperlipidemias for Prevention of Atherosclerosis proposed by The Japan Atherosclerosis Society (JAS) Guideline Investigating Committee (1,995-2,000) under the auspices of the JAS Board of Directors. 1) The guideline defines the diagnostic criteria for serum total cholesterol (Table 1), LDL-cholesterol (Table 1), triglycerides (Table 4) and HDL-cholesterol (Table 7). It also indicates the desirable range (Table 1), the initiation levels of management (Table 2) and the target levels of treatment (Table 2) for total and LDL-cholesterol. 2) Though both total and LDL-cholesterol are shown as atherogenic parameter in the guideline, the use of LDL-cholesterol, rather than total cholesterol, is encouraged in daily medical practice and lipid-related studies, because LDL-cholesterol is more closely related to atherosclerosis. 3) Elevated triglycerides and low HDL-cholesterol are included in the risk factors, since no sufficient data have been accumulated to formulate the guideline for these two lipid disorders. 4) Emphasis is laid on evaluation of risk factors of each subject before starting any kind of treatment (Table 2). 5) This guideline is applied solely for adults (age 20-64). Lipid abnormalities in children or the youth under age 19, and the elderly with an age over 65 have to be evaluated by their own standard. 6) This part of the guideline gives only the diagnostic aspects of hyperlipidemias. The part of management and treatment will follow in the second section of the guideline that will be published in future.

Atherosclerosis is a multifactorial disorder. Recent studies indicate that the plasma level of sphingomyelin, which yields ceramide, correlates with the risk of coronary heart disease. Therefore, ceramide, a well-known lipid causing apoptosis in various cell types, may contribute to atherogenesis. We examined the relationship between ceramide concentration and risk factors of atherosclerosis in normal human plasma using electrospray tandem mass spectrometry (LC-MS/MS). Major ceramides in human plasma were C24:0 and C24:1. The ceramide concentration showed a significant positive correlation with total cholesterol (TC) and triglycerides (TG). In addition, plasma ceramide level increased drastically at a high level of LDL cholesterol (more than 170 mg/dL). Our previous studies demonstrated that the sum of fragmented and conjugated apolipoprotein B-100 proteins (B-ox), which were products of a radical reaction of LDL as well as plasma, was a reliable index of atherosclerosis. B-ox showed a significant positive correlation with the plasma ceramide level. Based on these results, we propose that the ceramide level in human plasma is a risk factor at the early stages of atherosclerosis.