A Xu

Protective roles of adiponectin in obesity- related fatty liver diseases: mechanisms and therapeutic implications Adiponectina e seu papel na proteção contra a doença hepática gordurosa na obesidade: mecanismos e implicações terapêuticas

Adiponectin is an insulin-sensitizing adipokine possessing multiple beneficial effects on obesity-related medical complications. This adipokine is secreted from adipocytes into the circulation as three oligomeric isoforms, including trimer, hexamer and the high molecular weight (HMW) oligomeric complex. Each oligomeric isoform of adiponectin possesses distinct biological properties and activates different signaling pathways in various target tissues. The hepato-protective activities have been demonstrated by many clinical and experimental studies. The decreased level of serum adiponectin represents an independent risk factor for nonalcoholic fatty liver disease (NAFLD) and liver dysfunctions in humans. In animals, elevation of circulating adiponectin by either pharmacological or genetic approaches leads to a significant alleviation of hepatomegaly, steatosis and necro-inflammation associated with various liver diseases. In adiponectin knockout mice, there is a pre-existing condition of hepatic steatosis and mitochondria dysfunction, which might contribute to the increased vulnerabilities of these mice to the secondary liver injuries induced by obesity and other conditions. This review aims to summarize recent advances on delineation of the structural, molecular and cellular mechanisms underlying the hepato-protective properties of adiponectin.

Skeletal muscle and plasma lipidomic signatures of insulin resistance and overweight/obesity in humans.

Alterations in lipids in muscle and plasma have been documented in insulin‐resistant people with obesity. Whether these lipid alterations are a reflection of insulin resistance or obesity remains unclear.

C-reactive protein as a predictor of hypertension in the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS) cohort

Inflammation contributes to the development of hypertension. Whether C-reactive protein (CRP) has a causal role in hypertension remains unknown. We studied the relationship between circulating CRP levels and hypertension. The role of single-nucleotide polymorphisms (SNPs) in the CRP gene as determinants of its plasma levels and the propensity to develop hypertension was investigated. Plasma CRP and genotypes of nine SNPs were determined in 1925 unrelated subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS-2) in 2000–2004. Among 1378 subjects normotensive in CRISPS-2, 1115 subjects had been followed up in CRISPS-3 after a median interval of 5.3 years, 236 of whom had developed hypertension. Plasma CRP was independently associated with the development of hypertension in CRISPS-3 (odds ratio per quartile=1.26, P=0.010). Six SNPs were associated with plasma CRP (all P<0.001). However, none of the SNPs was significantly associated with blood pressure, prevalent or incident hypertension, or change in blood pressure. In conclusion, plasma CRP predicts the development of hypertension. Genetic variants in the CRP gene are significantly associated with plasma CRP but not with hypertension. The future risk of hypertension is therefore more related to plasma CRP than SNPs in the CRP gene in this population.

Genetic variants associated with persistent central obesity and the metabolic syndrome in a 12-year longitudinal study

OBJECTIVE Central obesity predisposes to various cardiometabolic diseases and is a key component of the metabolic syndrome (MetS). We have previously demonstrated that three obesity-susceptible single nucleotide polymorphisms (SNPs), rs10938397 (GNPDA2), rs8050136 (FTO) and rs17782313 (MC4R), were associated with obesity and waist circumference in cross-sectional studies in the Chinese population. In this study, we investigate whether these SNPs could also predict the persistence of central obesity and MetS in subjects from the Hong Kong Cardiovascular Risk Factors Prevalence Study (CRISPS) cohort. DESIGN AND METHODS We genotyped these SNPs in i) 354 subjects with and 994 subjects without central obesity at both baseline and a 12-year follow-up, ii) 2214 subjects (816 cases and 1398 controls) in an MetS cross-sectional case-control study and iii) 225 subjects with and 1221 subjects without MetS at both baseline and the 12-year follow-up. RESULTS Both FTO rs8050136 (P(age, sex-adjusted)=0.019; odds ratio (OR) (95% confidence intervals (CI)): 1.35 (1.05, 1.73)) and GNPDA2 rs10938397 (P(age, sex-adjusted)=3 × 10(-3); OR (95% CI): 1.34 (1.11, 1.63)) were significantly associated with persistent central obesity. GNPDA2 rs10938397 was also significantly associated with MetS (P(age, sex-adjusted)=0.011, OR (95% CI): 1.20 (1.04, 1.38)) in the case-control study. However, none of these SNPs showed an individual association with persistent MetS. In the combined genetic risk analyses for persistent central obesity and persistent MetS, the combined genetic risk score of the three SNPs showed an OR of 1.25 (95% CI: 1.10, 1.42; P(age, sex-adjusted)=4.92 × 10(-3)) and 1.19 (95% CI: 1.03, 1.38; P(age, sex-adjusted)=0.019) for each additional risk allele respectively. CONCLUSION This study demonstrated that FTO and GNPDA2 variants predicted persistent central obesity in the Chinese population, further supporting their importance as obesity-susceptible genes.

Adiponectin gene variants and the risk of coronary heart disease: a 16-year longitudinal study.

OBJECTIVE Circulating adiponectin levels have been shown to be associated with a risk of coronary heart disease (CHD). However, its primary role in protecting against the development of CHD remains controversial due to conflicting observations in prospective studies. To gain further insight into the primary role of adiponectin, our major objective was to investigate the relationship between single nucleotide polymorphisms (SNPs) of the adiponectin gene (ADIPOQ) and incident CHD in a population-based cohort with no CHD at baseline. DESIGN AND METHODS We conducted a 16-year longitudinal study in 2196 subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS). During 33 862 person-years of follow-up, 184 subjects developed CHD (cumulative incidence rate=5.4 per 1000 person-years). Nine ADIPOQ SNPs with potential functional relevance or shown to be associated with adiponectin levels and/or CHD were genotyped. RESULTS Among the nine ADIPOQ SNPs, +276G>T (rs1501299) was independently associated with incident CHD in men but not in women, even after adjustments for traditional cardiovascular risk factors (Padjusted=5.5×10(-3) to 0.023; hazard ratio=1.39-1.54). Furthermore, there was a significant association of the T allele of +276G>T with a lower adiponectin level (P=0.027; β (95% CI)=-0.05 (-0.10, -0.01). CONCLUSIONS This study demonstrated that +276G>T may be an independent predictor of CHD development. Our findings suggest that low adiponectin levels, as may be influenced by +276G>T, confer a higher risk of CHD, in keeping with a role of hypoadiponectinaemia in the development of CHD in the general population.

Obesity, adipokines and cancer: an update

Obesity causes dysfunction of adipose tissue, with resultant chronic inflammation and adverse interplay of various adipokines, sex steroids and endocrine hormones. All these drive tumourigenesis and explain the epidemiological link between obesity and cancer. Over the past decade, the associations among obesity, adipokines and cancer have been increasingly recognized. Adipokines and their respective signalling pathways have drawn much research attention in the field of oncology and cancer therapeutics. This review will discuss the recent advances in the understanding of the association of several adipokines with common obesity‐related cancers and the clinical therapeutic implications.

High level expression and purification of active recombinant human interleukin-15 in Pichia pastoris

Interleukin-15 (IL-15) is a pleiotropic cytokine and a member of the four α-helix bundle family of cytokines which include IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21. IL-15 exhibits a broad biological activity and induces the differentiation and proliferation of T, B and natural killer (NK) cells. In this study, a DNA fragment containing the mature human IL-15 sequence was cloned into pPICZaA vector, generating a fusion protein with the alpha factor signal sequence in the N-terminus and 6×His as well as c-Myc tags in the C-terminus. The resulting plasmid was integrated into the genome of Pichia pastoris strain X-33. Recombinant yeast transformants with high-level recombinant human IL-15 (rhIL-15) production were identified, which secrete as much as 75 mg/L rhIL-15 after 3 days of induction by methanol. The rhIL-15 was purified by Ni(+)-NTA affinity chromatography, followed by DEAE anion exchange, yielding over 95% highly purified rhIL-15. Mass spectrometry and MALDI-TOF-TOF analysis showed the purified rhIL-15 had larger molecular weights than expected, due to different degrees of N-linked glycosylation. The biological activity of the rhIL-15 proteins was measured by its ability to enhance cellular proliferation of CTLL-2 and NK cells. The results demonstrate that the experimental procedure we have reported here can produce a large amount of active recombinant human IL-15 from P. pastoris.

High‐level expression, purification and characterization of active human C1q and tumour necrosis factor‐related protein‐1 in Escherichia coli

C1q and tumour necrosis factor‐related proteins (CTRPs) are a family of adiponectin paralogues. CTRP1 plays important biological functions in diabetes, obesity and hypertension. To further explore the physiological roles of human CTRP1 and its mechanisms of action, hCTRP1 gene was expressed in Escherichia coli. In the E. coli expression system, a large amount of soluble thioredoxin (Trx)‐hCTRP1 fusion protein could be produced using the expression plasmid pET32a (+) and induction with IPTG at 18°C, which accounts about 20% of the total soluble bacterial proteins. The recombinant Trx‐hCTRP1 fusion protein was purified to an approx. 95% purity using Ni‐NTA affinity chromatography and Superdex G‐75 column with a yield of about 28‐mg protein from 1‐l bacterial cultures. The purified recombinant Trx‐hCTRP1 was shown to be active under in vivo and in vitro assay conditions.

Lbps 02-06 Plasma Level of Fibroblast Growth Factor 21 Is Independently Related to Blood Pressure:

Objective: Fibroblast growth factor 21 (FGF21) plays an important role in glucose and lipid metabolism. Elevated blood FGF21 level is associated with obesity, diabetes and atherosclerosis. We therefore investigated its relationship with blood pressure. Design and Method: We measured FGF21 in the plasma of 1921 participants (891 men, 1030 women; 52 ± 12 years) taken at the start of the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS) using an enzyme-linked immunosorbent assay (Antibody & Immunoassay Services, University of Hong Kong). The log of FGF21 level was analysed for relationship with systolic and diastolic blood pressure (BP) at baseline and at the 5-year follow-up. Results: Plasma FGF21 level was 224.3 ± 7.4 in men and 214.1 ± 7.1 pg/ml in women. It correlated significantly (p < 0.001) with age (r = 0.30), waist circumference (r = 0.31), systolic BP (r = 0.32), diastolic BP (r = 0.22), triglyceride (r = 0.41), HDL-C (r = -0.27), fasting blood glucose (r = 0.27) and hsCRP (r = 0.27). In multivariate analysis, FGF21 was related to systolic and diastolic blood pressure at baseline (&bgr; = 0.076, p < 0.001 and &bgr; = 0.074, p = 0.001 respectively) and to diastolic blood pressure at follow-up (&bgr; = 0.06, p = 0.025). Conclusions: FGF21 level in blood is related to systolic and diastolic blood pressure, independent of age, obesity, lipids and blood glucose. FGF21 is related to the components of the metabolic syndrome and may have a pathophysiological role in hypertension. Support from the Hong Kong Research Grant Council (HKU2/CRF/12R) is gratefully acknowledged.

Plasma Fibrinogen Level as a Predictor of Cardiovascular Diseases, Independent of Diabetes, in a Population-Based 16-Year Prospective Study in Hong Kong

1395-P Does Functional Decline in Older Adults Hasten the Onset of Diabetes? The Health and Retirement Study 1998-2010 BARBARA H. BARDENHEIER, EDWARD GREGG, XIAOHUI ZHUO, YILING J. CHENG, LINDA GEISS, Atlanta, GA Prospective studies have associated diabetes with a high risk of incident disability among older adults. However, the converse association could also occur, with functional decline hastening the onset of diabetes, particularly in those at high risk. 13,134 adults aged over 50 years who entered the longitudinal Health and Retirement Study between 1992 and 2006 with no disability or diabetes were followed to 2010 to determine if those who became disabled would subsequently develop diabetes. Mobility disability was assessed by self-reported diffi culty walking one block; walking several blocks; climbing one fl ight of stairs; stooping, crouching, or kneeling; and pushing or pulling a large object. Participants were classifi ed by disability: none, mild (diffi culty with stooping and walking several blocks or diffi culty with > 2 mobility measures other than climbing), moderate (diffi culty with climbing or diffi culty with > 3 mobility measures), and severe (diffi culty with > 4 mobility measures). 1,955 (14.9%) participants developed diabetes, 8,228 (62.6%) reported incident disability, and 2,482 (18.9%) died by 2010. Among those who did not develop disability, diabetes incidence was 8.67 per 1,000; among those who developed disability and remained disabled at least 50% of the reporting period, diabetes incidence was 13.5 per 1,000. In a generalized estimating equation controlling for body mass index, age, sex, race/ethnicity, net wealth, and year of report, we found a statistically signifi cant dose-response relationship between incident disability and later incident diabetes: severe vs. none (OR: 2.18, 95%CI: 1.82, 2.61); moderate vs. none (OR: 1.50, 95%CI: 1.25, 1.80); mild vs. none (OR: 1.40, 95%CI: 1.26, 1.56). We found those who become mildly disabled are at increased risk of developing diabetes within a few years. These fi ndings raise the question of whether approaches to delay functional decline, an almost ubiquitous aspect of aging, may reduce the risk of diabetes.