Circulating ghrelin levels in obese women: a possible association with hypertension

OBJECTIVE: The orexigenic hormone ghrelin induces weight gain by stimulating food intake. Ghrelin has been shown to modulate sympathetic activity, to exert vasodilative effects and to counterreact with leptin on both food intake and blood pressure. Of these two hormones, ghrelin levels are decreased in obesity, whereas leptin levels are increased. In this cross-sectional study, differences in serum ghrelin and leptin levels were examined in normotensive and hypertensive obese women. MATERIAL AND METHODS: Sixty-one normotensive and hypertensive women were classified according to the body mass indices as follows: (a) 18 healthy subjects with BMI 21.5-27.5 kg/m(2); (b) 22 normotensive subjects with BMI 30-47 kg/m(2); (c) 21 hypertensive obese subjects (BMI 30-48 kg/m(2)) with systolic blood pressure > or =140 mmHg or diastolic blood pressure > or =90 mmHg. Anthropometric measurements including height, weight, BMI, waist and hip circumferences and blood pressure were recorded. The levels of ghrelin and leptin were determined in sera using the commercial ELISA kits. RESULTS: In normotensive obese subjects, ghrelin levels were significantly lower than in controls (0.21+/-0.13 vs 0.60+/-0.3 ng/mL), whereas hypertensive obese women had elevated ghrelin levels (0.64+/-0.36 ng/mL). Ghrelin concentration was decreased despite the presence of hypertension in the patients who had BMIs above 35 kg/m(2). Leptin levels were significantly higher in both normotensive and hypertensive obese groups (19.54+/-11.19 and 21.61+/-12.7 ng/mL, respectively) than in controls (7.61+/-3.3 ng/mL), and were not affected by the presence of hypertension in obese subjects. CONCLUSION: Ghrelin was positively associated with hypertension in obese women and this association was inversely influenced by the increase of BMI.     

The relation of serum leptin to body mass index and to serum cortisol in men with spinal cord injury

OBJECTIVE: To investigate the relations among serum leptin, body mass index (BMI), and various hormone levels in men with spinal cord injury (SCI). DESIGN: Cross-sectional. SETTING: University hospital that is a tertiary referral center. PARTICIPANTS: Forty-seven men with traumatic neurologically complete SCI and 47 age- and BMI-matched male controls. MAIN OUTCOME MEASURES: Baseline levels of various hormones were measured in subjects with SCI. Serum leptin and cortisol levels and BMI were measured in both groups. RESULTS: Serum leptin was significantly higher in the group with SCI than in the control group. A linear relation was found between serum leptin and BMI in both groups separately. A polynomial relation was found between serum leptin level and BMI in the group with SCI. A "J" phenomenon is noted at the lowest BMI. Serum cortisol correlated significantly with serum leptin level in the group with SCI. CONCLUSION: Sympathetic denervation, peripheral nerve palsy, recurrent infections, and possible central neurotransmitter alterations after SCI may contribute to the elevation of serum leptin level in men with SCI.     

Effect of a high saturated fat and no-starch diet on serum lipid subfractions in patients with documented atherosclerotic cardiovascular disease

OBJECTIVE: To determine whether a diet of high saturated fat and avoidance of starch (HSF-SA) results in weight loss without adverse effects on serum lipids in obese nondiabetic patients. PATIENTS AND METHODS: Twenty-three patients with atherosclerotic cardiovascular disease participated in a prospective 6-week trial at the Christiana Care Medical Center in Newark, Del, between August 2000 and September 2001. All patients were obese (mean +/- SD body mass index [BMI], 39.0+/-7.3 kg/m2) and had been treated with statins before entry in the trial. Fifteen obese patients with polycystic ovary syndrome (BMI, 36.1+/-9.7 kg/m2) and 8 obese patients with reactive hypoglycemia (BMI, 46.8+/-10 kg/m2) were monitored during an HSF-SA diet for 24 and 52 weeks, respectively, between 1997 and 2000. RESULTS: In patients with atherosclerotic cardiovascular disease, mean +/- SD total body weight (TBW) decreased 5.2%+/-2.5% (P<.001) as did body fat percentage (P=.02). Nuclear magnetic resonance spectroscopic analysis of lipids showed decreases in total triglycerides (P<.001), very low-density lipoprotein (VLDL) triglycerides (P<.001), VLDL size (P<.001), large VLDL concentration (P<.001), and medium VLDL concentration (P<.001). High-density lipoprotein (HDL) and LDL concentrations were unchanged, but HDL size (P=.01) and LDL size (P=.02) increased. Patients with polycystic ovary syndrome lost 14.3%+/-20.3% of TBW (P=.008) and patients with reactive hypoglycemia lost 19.9%+/-8.7% of TBW (P<.001) at 24 and 52 weeks, respectively, without adverse effects on serum lipids. CONCLUSION: An HSF-SA diet results in weight loss after 6 weeks without adverse effects on serum lipid levels verified by nuclear magnetic resonance, and further weight loss with a lipid-neutral effect may persist for up to 52 weeks.     

乳腺癌患者血清抵抗素、脂联素和瘦素水平及其临床意义

目的了解乳腺癌患者血清中抵抗素、脂联素、瘦素及血脂变化及临床意义。方法测定90例乳腺癌患者（48例未绝经,42例已绝经）及50名健康对照者血清抵抗素、脂联素、瘦素、空腹血糖（FBG）及血脂。结果乳腺癌患者脂联素及高密度脂蛋白胆固醇（HDL-C）显著低于对照组（P〈0.01或P〈0.05）,抵抗素、瘦素、FBG及三酰甘油（TG）均明显增加（P〈0.01或P〈0.05）。但抵抗素、脂联素及瘦素在未绝经乳腺癌患者与健康对照组之间差异无统计学意义（P〉0.05）。有淋巴结转移的乳腺癌患者抵抗素、脂联素及瘦素水平与无淋巴结转移乳腺癌患者间差异有统计学意义（P〈0.01）。逐步回归分析,脂联素及HDL-C的降低,瘦素和抵抗素的升高将会增加罹患乳腺癌的风险。血清脂联素降低和瘦素的增加与乳腺癌患者淋巴结的转移呈现相关性。结论血清脂联素水平的降低和抵抗素及瘦素水平的升高是患乳腺癌的危险因素。血清中较低的脂联素和较高的瘦素水平是乳腺癌转移的危险因素。     

Leptin, leptin soluble receptor and coronary atherosclerosis

BACKGROUND: The adipose tissue-related hormone leptin plays an important role in the regulation of body weight. The associations of leptin and leptin soluble receptor (sOb-R) with coronary artery disease (CAD) are not clear. DESIGN: We measured leptin and sOb-R in 543 consecutive patients (379 men, 164 women) referred for coronary angiography for the evaluation of CAD. Coronary artery stenoses with lumen narrowing > or = 50% were considered significant. RESULTS: Serum leptin correlated significantly with body mass index (r(s) = 0.443), with insulin resistance as assessed by the homeostasis model for the assessment of insulin resistance (r(s) = 0.339), with serum triglycerides (r(s) = 0.181), with systolic as well as diastolic blood pressure (r(s) = 0.170 and r(s) = 0.133, respectively) and, inversely, with sOb-R (r(s) = -0.346; P < 0.01 for all correlations). Coronary angiography revealed significant coronary artery stenoses in 331 (61%) of our patients. Serum leptin was significantly lower in patients with significant coronary artery stenoses than in patients without such lesions (8.5 +/- 7.8 vs. 13.2 +/- 12.2 ng mL(-1); P < 0.001). Multivariate logistic regression analysis proved serum leptin inversely and independently associated with the presence of significant coronary artery stenoses (standardized adjusted odds ratio 0.746, 95% confidence interval 0.566-0.983, P = 0.038). In contrast to serum concentrations of leptin, serum concentrations of sOb-R did not significantly differ between patients with significant stenoses and those without such lesions (22.4 +/- 8.3 vs. 23.1 +/- 12.1 ng mL(-1); P = 0.655). CONCLUSIONS: Serum leptin but not sOb-R is significantly lower in patients with angiographically determined CAD. Despite its association with cardiovascular risk factors, leptin should not be simply regarded as a promoter of atherosclerosis.     

Vitamin K deficiency and osteopenia in elderly women with Alzheimer's disease

OBJECTIVE: To analyze the relation between vitamin K status and bone mineral density (BMD) in women with Alzheimer's disease (AD). DESIGN: Cross-sectional study. SETTING: Outpatient departments of neurology and neuropsychiatry at a hospital in Japan. Participants One hundred women with AD (mean age, 79.8 y) and 100 age-matched community dwelling controls (mean age, 80.6 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Patients were divided into 2 groups according to the degree of dementia: the mild AD group was composed of patients with a score in Mini-Mental State Examination (MMSE) of 16 and above (n=42); patients in the severe AD group had MMSE scores below 15 (n=58). We assessed body mass index (BMI). BMD was measured by computed x-ray densitometry. Serum concentrations of vitamin K 1 , 25-hydroxyvitamin D (25[OH]D 3 ), intact parathyroid hormone (PTH), and Glu osteocalcin (OC) were measured. RESULTS: BMI was significantly lower in women with more severe AD. Metacarpal BMD ( P <.02) and serum concentrations of vitamin K 1 ( P <.03) and 25(OH)D 3 ( P <.001) were significantly lower in the severe AD group than in the mild AD group. Serum levels of intact PTH and Glu OC in severely demented patients were higher than those with mild dementia ( P <.001). Serum PTH concentration correlated negatively with serum 25(OH)D 3 level ( r =-.241, P =.016). Serum concentration of vitamin K 1 correlated positively with that of 25(OH)D 3 ( r =.423, P <.001) and MMSE score ( r =.353, P <.001), and negatively with Glu OC ( r =-.580, P <.001). CONCLUSIONS: In female AD patients, nutritional vitamin K 1 deficiency may reduce production of fully carboxylated OC, which in turn may cause reduced BMD. Lower BMIs in more severe AD may imply the presence of general malnutrition in such a patient group.     

慢性肾功能衰竭时瘦素与肿瘤坏死因子及内皮素的关系

目的 观察慢性肾功能衰竭患者血清瘦素(Leptin)水平及其与肿瘤坏死因子(TNF)及内皮素(ET)的关系。方法 应用放射免疫方法检测40例慢性肾功能衰竭患者及20例健康志愿者血清Leptin、TNF及ET水平,并对血清Leptin水平与TNF及ET之间的关系进行相关性分析。结果 慢性肾功能衰竭患者血清Leptin水平显著高于正常对照组[(19.25±4.89)μg／L比(5.57±1.69)μg／L,P<0.01],并与TNF及ET水平呈显著正相关(rTNF=0.829,rET=0.605;P均<0.01);而肾功能和血中总蛋白的含量与Leptin之间无相关性(P均>0.05)。结论 慢性肾功能衰竭患者血清TNF及ET水平异常升高和高瘦素血症明显相关。     

老年心力衰竭患者血清脂联素的测定

目的探讨脂联素与心力衰竭的关系。方法采用酶联免疫吸附试验（ELISA）及电化学发光法分别测定54例左心室射血指数（LVEF）〈40%的心力衰竭患者和18名正常对照者血清脂联素、氨基末端B型钠尿肽原（NT-proBNP）,并作统计分析。结果心力衰竭患者的体重指数（BMI）[（22.17±2.48）kg/m2]与对照组[（23.32±2.03）kg/m2]差异无统计学意义（P〉0.05）;LVEF（30.92%±8.75%）显著低于对照组（70.14%±9.33%,P〈0.01）;血清脂联素[（23.62±5.43）mg/L]及NT-proBNP[（592.00±153.00）pg/mL]显著高于对照组[（10.81±2.64）mg/L,（21.00±3.49）pg/mL,P〈0.01]。心力衰竭组脂联素与BMI、LVEF呈负相关（r=-0.41、-0.32,P〈0.05）;对照组脂联素与BMI呈负相关（r=-0.387,P〈0.05）;心力衰竭组脂联素与NT-proBNP呈正相关（r=0.49,P〈0.01）,对照组则无相关性（r=0.11,P〉0.05）。调整BMI、年龄后,脂联素与LVEF的负相关依然存在,与NT-proBNP的正相关依然存在。结论血清脂联素与心力衰竭发病密切,通过更大规模的临床病例研究将为脂联素检测成为临床心力衰竭诊断的重要指标提供强有力的证据。     

Plasma leptin concentrations in lean and obese human subjects and Prader-Willi syndrome: comparison of RIA and ELISA methods.

Immunoassays for circulating leptin are important research tools for examining the role and regulation of leptin expression in human obesity. However, uncertainty exists regarding the comparability between studies of reported plasma or serum leptin concentrations. The purpose of the present study was to directly compare plasma leptin concentrations by using two of the most widely reported immunoassay methods-namely, a commercially available radioimmunoassay (RIA) and a proprietary enzyme-linked immunosorbent assay (ELISA). Plasma leptin concentrations were measured in healthy lean and obese volunteers and in patients with Prader-Willi syndrome (PWS). Over a wide range of plasma concentrations (2 to 70 ng/mL), leptin measurements obtained with the RIA and ELISA methods were highly correlated (r = 0.957, P<.0001) and were essentially indistinguishable. Leptin levels measured by RIA and ELISA were highly correlated with body mass index (BMI) overall (r = 0.784, P<.0001 and r = 0.732, P<.0001, respectively) and in the lean and obese subgroups. When compared with the results in the lean individuals (mean +/- SEM, 11.6+/-3.2 ng/mL), plasma leptin was significantly higher in both the obese (35.5+/-4.0 ng/mL, P<.0001) and the PWS subjects (30.7+/-6.9 ng/mL, P<.05). However, after we controlled for differences in BMI, the leptin levels were similar in all three groups. In conclusion, we found that the RIA and ELISA used in the present study yield plasma leptin concentrations that are essentially indistinguishable. Our findings should facilitate comparisons of leptin levels measured by these two widely used immunoassays in previous and future studies that examine the role of leptin in body weight regulation.     

胃癌患者血清生长激素释放肽和瘦素的水平变化及临床意义

目的 探讨胃癌患者血清生长激素释放肽（Ghrelin）和瘦素（Leptin）水平的变化及意义。方法应用放射免疫分析法和酶联免疫吸附测定法（ELISA）测定32例胃癌患者血清中生长激素释放肽和瘦素水平的变化,并与12例正常健康人作比较。结果胃癌患者血清生长激素释放肽和瘦素水平均非常显著地高于正常人组（P〈0．01）,且两者呈正相关性。结论检测胃癌患者血清生长激素释放肽和瘦素水平的变化对疾病的预后观察具有重要的临床价值。     

Paraoxonase, total antioxidant activity and peroxide levels in marasmic children: relationships with leptin

OBJECTIVES: The aim of this study was to investigate the oxidant/antioxidant status, paraoxonase (PON) activity and leptin levels in children with marasmic malnutrition. DESIGN AND METHODS: Thirty marasmic children (age 14.4+/-10.3 months) and 28 control subjects were included. Plasma PON activity, total antioxidant activity (TAO), total peroxide (TPX) and leptin levels were measured. RESULTS: Malnourished children had significantly lower leptin (3.6+/-1.1 vs. 11.8+/-4.5 ng/mL, P<0.001), PON activity (66.4+/-28.6 vs. 221.3+/-31.6 IU/L, P<0.001) and TAO (1.44+/-0.12 vs. 2.45+/-0.61 mmol Trolox equiv/L, P<0.001); and higher TPX (15.6+/-6.4 vs. 5.9+/-1.9 micromol/L, P<0.001) values than in controls. Significant negative correlation was found between PON and TPX (P=0.040) and positive correlation between TAO and BMI (P=0.034) in patients. No significant correlation was found between leptin and oxidant/antioxidant parameters (P>0.05). CONCLUSIONS: Children with marasmic malnutrition had increased pro-oxidant and decreased antioxidant status. Extent of oxidative stress increases with malnutrition severity. Antioxidants could be given during nutritional rehabilitation.     

Plasma ghrelin levels in children with chronic renal failure on peritoneal dialysis.

OBJECTIVES: Malnutrition and loss of appetite represent a serious problem in children with chronic renal failure. Ghrelin is a newly described hormone involved in control of growth hormone secretion, stimulation of food intake, and regulation of energy balance. METHODS: Plasma ghrelin levels were compared between 12 children on automated peritoneal dialysis (APD) and 9 children on conservative treatment of chronic renal failure. Eight healthy children matched for age and body mass index (BMI) served as a control group. RESULTS: Plasma ghrelin levels were similar in children on APD (698.3 +/- 59.7 pg/mL) and children on conservative treatment (675.4 +/- 41.9 pg/mL) compared to healthy controls (700.1 +/- 24.7 pg/mL). There was no difference in plasma ghrelin levels in children with chronic renal failure regardless of the method of treatment (peritoneal dialysis vs conservative treatment). The plasma ghrelin index was similar in all three investigated groups: APD 40.2 +/- 8.7 vs conservative treatment 39.1 +/- 5.6 vs controls 41.0 +/- 7.8 (pg/mL)/BMI (kg/m2). Plasma ghrelin levels did not correlate with age, duration of dialysis treatment, height, weight, BMI, creatinine and urea levels, adequacy parameters, or nightly glucose load. CONCLUSION: Plasma ghrelin levels in children on APD were not different from levels in children on conservative treatment or healthy controls with comparable BMI. The persistent state of toxic influence of uremic end-products could be responsible for such a lack of correlation with anthropometrical parameters. Further studies on a larger group of children on APD are needed to clarify the effect of ghrelin on nutritional status in children with chronic renal failure.     

Serum asymmetric dimethylarginine and nitric oxide levels in obese postmenopausal women

Background: It has been reported that estrogen deficiency after menopause might cause a decrement in nitric oxide (NO) bioavailability by increasing the level of asymmetric dimethylarginine (ADMA), a major endogenous nitric oxide synthase inhibitor, thus leading to abnormalities in endothelial function. Because NO plays an important role on feeding behavior, ADMA may be involved in the pathogenesis of obesity, too. This cross‐sectional study aimed to evaluate the relations of ADMA and NO with the obesity‐linked peptides, such as ghrelin, leptin, and adiponectin in postmenopausal women free of hormone replacement therapy. Methods: Adiponectin, ghrelin, leptin, ADMA, and NO_x (total nitrite/nitrate) were measured in 22 obese (BMI: 30–47 kg/m²) and 19 normal weight (BMI: 21.5–26 kg/m²) postmenopausal women.Anthropometric measurements (height, weight, BMI, waist, and hip circumferences) were recorded. Statistics were made by the Mann–Whitney U‐test. Results: Ghrelin and adiponectin levels were significantly lower (P<0.001), whereas ADMA and leptin levels were higher in obese women than in normal weight controls (P<0.01 and 0.001, respectively). BMI was correlated negatively with adiponectin and ghrelin and positively with ADMA and leptin levels. No correlation existed between ADMA and NO. Conclusion: Estrogen deficiency alone may not cause an increase in ADMA levels unless the women are prone to disturbances in energy homeostasis. In spite of the high ADMA levels, the unaltered NO levels in plasma may be owing to ongoing inflammatory conditions. J. Clin. Lab. Anal. 25:174–178, 2011. © 2011 Wiley‐Liss, Inc.     

The concentration of adiponectin in breast milk is related to maternal hormonal and inflammatory status during 6 months of lactation

Abstract Background: Varying concentrations of adiponectin are present in human breast milk. This study aimed to determine the relationship between milk adiponectin concentration and the hormonal and inflammatory status of breast-feeding women. Methods: Blood and breast milk samples were collected from 157 breast-feeding women enrolled at 1-180 post-partum lactation days. The milk and serum adiponectin concentrations were measured by radioimmunoassays. The serum oestradiol, prolactin, thyroxine, triiodothyronine, cortisol and insulin concentrations were measured by the chemiluminescent immunometric method. The leptin, resistin and ghrelin concentrations were measured by the immunometric methods. Results: The milk, but not serum, adiponectin concentration increased during the 180-day lactation period and displayed a positive correlation (r=0.748; p<0.001) to the lactation day. The milk adiponectin concentration was positively correlated to the maternal serum ghrelin concentration (r=0.299; p<0.001) and inversely to the maternal serum oestradiol (r=-0.366; p<0.001), prolactin (r=-0.444; p<0.001), thyroxine (r=-0.355; p<0.001), triiodothyronine (r=-0.291; p<0.001), cortisol (r=-0.537; p<0.001), and C-reactive protein (r=-0.483; p<0.001) concentrations. The milk adiponectin concentration was positively correlated to the milk leptin (r=0.344; p<0.001) and ghrelin (r=0.458; p<0.001) concentrations, and inversely to milk resistin concentration (r=-0.518; p<0.001). The serum adiponectin concentration in breastfed infants was positively correlated (r=0.711; p<0.001) to the adiponectin concentration in the consumed breast milk. Conclusions: The adiponectin concentration in breast milk increases over time during lactation and is affected by the maternal hormonal and inflammatory status.     

Serum leptin levels in rheumatoid arthritis and relationship with disease activity

OBJECTIVES: This study was performed to evaluate serum leptin levels in rheumatoid arthritis (RA) patients and investigate the correlation with serum tumor necrosis factor alpha (TNF-alpha) levels and clinical and laboratory parameters of disease activity. METHODS: Fifty patients with RA and 34 control subjects were included. Disease activity score 28 (DAS28) was calculated for each patient. Laboratory activity was assessed by examining erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Immunoradiometric assay was used for measuring serum leptin levels (ng/mL). Serum TNF-alpha levels (pg/mL) were measured by sandwich enzyme-linked immunosorbent assay method in 41 of 50 RA patients and in 24 control subjects. RESULTS: Age, sex and body mass index (BMI) did not show a statistically significant difference between RA and control subjects (P > 0.05). Serum leptin levels were higher in RA (P = 0.000). In RA patients, there were no correlations between serum leptin levels and disease duration, swollen and tender joint counts, DAS28, CRP, ESR, serum TNF-alpha levels, oral glucocorticoid and methotrexate usage (P > 0.05). There was no statistically significant serum leptin level difference between patients with high disease activity and mild and low disease activity (P = 0.892). Serum leptin levels positively correlated with BMI in both patient and control groups (P < 0.05). In both groups, mean serum leptin levels were higher in women than men. CONCLUSIONS: Even though serum leptin levels were found to be significantly higher in RA patients than in control subjects in this study, there was no correlation between serum leptin levels and TNF-alpha levels, clinical and laboratory parameters of disease activity. However serum leptin levels positively correlated with BMI in both patient and control groups. In RA, circulating leptin levels do not seem to reflect disease activity.     

阻塞性睡眠呼吸暂停低通气综合征患者血清瘦素水平的研究

目的 探讨阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者血清瘦素水平以及口腔矫治器治疗对患者血清瘦素水平的影响。方法 对22例经过多导睡眠监测确诊的OSAHS患者行口腔矫治器治疗。采用放射免疫测定法测定22例OSAHS患者治疗前、治疗后以及22例年龄、体质指数相近的单纯打鼾患者（对照组）的血清瘦素水平，分析瘦素与呼吸暂停低通气指数（AHI）、体质指数的关系，以及治疗前、治疗后血清瘦素水平的变化。结果 OSAHS患者血清瘦素水平与AHI呈正相关（r=0．469，P〈0．05），与夜间最低动脉血氧饱和度呈负相关（r=-0．787，P〈0．01）。治疗前OSAHS患者的血清瘦素水平明显高于对照组。口腔矫治器治疗后患者AHI及最低血氧饱和度明显改善，且血清瘦素水平较治疗前明显降低。结论 OSAHS患者血清瘦素水平增高，且瘦素水平与睡眠呼吸暂停的程度有密切联系；口腔矫治器治疗有效者血清瘦素水平下降。呼吸暂停有可能是导致OSAHS患者体内瘦素水平增高的重要因素。     

Relationships between serum adiponectin, leptin, resistin, visfatin levels and bone mineral density, and bone biochemical markers in Chinese men

BACKGROUND: Adiponectin, leptin, resistin, and visfatin, as the main circulating peptides secreted by adipose tissue, are potential contributors to bone metabolism. We investigated whether these serum adipocytokines levels are associated with BMD and bone turnover biochemical markers in 232 Chinese men (20-80 y). METHODS: Serum adiponectin, leptin, resistin, and visfatin levels were determined by ELISA. RESULTS: Leptin had a positively correlation with fat mass, and remained significant after adjustment for age and BMI. There was a significant negative weak correlation between adiponectin and fat mass, and disappear after adjustment for age and BMI. Resistin and visfatin were not significantly correlated with fat mass. In the multiple linear stepwise regression analysis, lean mass and adiponectin, but not leptin, resistin and visfatin, were independent predictors of BMD. The significant positive correlations between adiponectin and bone-specific alkaline phosphatase (BAP), bone cross-linked N-telopeptides of type collagen (NTX) were found, and remained significant after adjustment for age and fat mass. CONCLUSIONS: Adiponectin was an independent predictor of BMD in Chinese men, and positively correlated with bone turnover biochemical markers. It suggested that adiponectin exert a negative effect on bone mass in men.     

Soluble leptin receptors and serum leptin in end-stage renal disease: relationship with inflammation and body composition

BACKGROUND: Elevated serum leptin (S-leptin) levels have been reported in patients with end-stage renal disease (ESRD). Apart from the decreased glomerular filtration rate (GFR), body composition and inflammation may affect leptin levels in ESRD. Leptin circulates both free of and bound to soluble leptin receptors (sOB-R), which are the main determinants of leptin activity and have not been described in ESRD until now. DESIGN: To analyze the association between S-leptin, sOB-R, and inflammation and body composition, we studied 149 (62% males) normal weight (BMI 24.7 +/- 0.4 kg m(-2)) ESRD patients (51 +/- 1 years old) shortly before the start of dialysis (GFR 7.0 +/- 0.2 mL min(-1)). sOB-R and plasma interleukin-6 (IL-6; n= 113) levels were evaluated using ELISA, S-leptin using RIA, and body composition was assessed by X-ray absorptiometry (n = 139). Forty-one healthy subjects age (51 +/- 1 years), BMI (23.6 +/- 0.5 kg m(-2)) and gender-matched (59% males) were used as controls. RESULTS: Median S-leptin was higher in the ESRD patients (10.0 ng mL(-1)) compared with the controls (3.9 ng mL(-1)) (P < 0.001). The median sOB-R did not differ significantly between the ESRD patients (44 U mL-1) and the controls (37 U mL-1). Thus, the sOB-R/S-leptin ratio was lower in the ESRD patients (9.5 +/- 1.2 vs. 12.3 +/- 1.8; P < 0.01) than the controls. A negative correlation was observed between S-leptin and sOB-R (Rho = -0.42; P < 0.0001) in the ESRD patients, a positive correlation was observed between lean body mass and the sOB-R/S-leptin ratio (Rho = 0.33, P = 0.0001) whereas fat mass was negatively correlated to both sOB-R (Rho = -0.26, P = 0.002), and the sOB-R/S-leptin ratio (Rho = -0.62, P < 0.0001). Positive correlations were observed between IL-6 and S-leptin (Rho = 0.19; P < 0.05) and weak but significant body fat mass (Rho = 0.20; P < 0.05), respectively. CONCLUSIONS: This study demonstrates that despite markedly elevated S-leptin levels in the ESRD patients, sOB-R did not differ from the controls. In view of the anorexigenic and pro-atherogenic effects of leptin, further elucidation of the consequences of free bioactive leptin in the development of complications such as malnutrition and cardiovascular disease in ESRD patients is required.     

Wavelet analysis of skin blood oscillations in persons with spinal cord injury and able-bodied subjects

OBJECTIVE: To assess the blood oscillations in the skin over the ischial tuberosity (high-risk area for pressure ulcer) using spectral analysis of laser Doppler flowmetry signals based on wavelet transform. DESIGN: Wavelet analysis of skin blood oscillations in persons with spinal cord injury (SCI) and able-bodied subjects. SETTING: Seating and body support interface laboratory. PARTICIPANTS: Ten men were recruited for this study, of whom 5 were able-bodied subjects (age, 31.2+/-3.3 y) and 5 were persons with SCI (age, 37.2+/-7.3 y). INTERVENTIONS: External pressure of 16.0 kPa (120 mmHg) was applied to the ischial tuberosity via 1 specifically designed pneumatic indentor. The loading duration was 30 minutes. MAIN OUTCOME MEASURES: Skin blood flow was monitored for 10 minutes prior to loading and 20 minutes after the prescribed loading period. With spectral analysis based on wavelet transform, 5 frequency intervals were identified (.01-.02, .02-.06, .06-.15, .15-.40, .40-2.0 Hz) corresponding to endothelial related metabolic, neurogenic, myogenic, respiratory, and cardiac activities, respectively. RESULTS: The relative amplitude of the metabolic component for persons with SCI was significantly lower (F=5.26, P=.032) during the resting conditions as compared with able-bodied subjects. During the postloading period, the response of oscillatory activities was evidently lower in the skin over the ischial tuberosity for persons with SCI when compared with able-bodied subjects. In addition, the relative amplitude of the neurogenic component (.02-.06 Hz) during postloading was significantly lower for persons with SCI (F=5.44, P=.029). CONCLUSIONS: These findings suggest that the contributions of endothelial related metabolic and neurogenic activities to the blood perfusion regulation become relatively less for persons with SCI during the resting and postloading periods, respectively.