Positive Association of High Leptin Level and Abdominal Aortic Calcification in Men - The Prospective MINOS Study

BACKGROUND

Severe abdominal aortic calcification (AAC) points to high cardiovascular risk and leptin stimulates arterial calcification; however, clinical data on their association are scarce. We studied the link between serum leptin and AAC severity and progression, and the effect of smoking and lipid levels, on this association in men. Methods and Results: At baseline, 548 community-dwelling men aged 50-85 years underwent blood collection and lateral lumbar spine radiography. In 448 men, X-ray was repeated after 3 and 7.5 years. AAC was assessed using Kauppila's semiquantitative score. In multivariable models, high leptin was associated with higher odds of severe AAC (odds ratio [OR]=1.71 per SD, 95% confidence interval [CI]: 1.22-2.40). The odds of severe AAC were the highest in men who had elevated leptin levels and either were ever-smokers (OR=9.22, 95% CI: 3.43-24.78) or had hypertriglyceridemia (vs. men without these characteristics). Higher leptin was associated with greater AAC progression (OR=1.34 per SD, 95% CI: 1.04-1.74). The risk of AAC progression was the highest in men who had elevated leptin levels and either were current smokers or had high low-density lipoprotein-cholesterol levels (OR=5.91, 95% CI: 2.46-14.16 vs. men without these characteristics). These links remained significant after adjustment for baseline AAC and in subgroups defined according to smoking and low-density lipoprotein-cholesterol levels.

CONCLUSIONS

In older men, high leptin levels are associated with greater severity and rapid progression of AAC independent of smoking, low-density lipoprotein-cholesterol or triglycerides.

Dose and timing of injections for effective cyclosporine A pretreatment before renal ischemia reperfusion in mice

Background

There is experimental evidence that lethal ischemia-reperfusion injury (IRI) is largely due to mitochondrial permeability transition pore (mPTP) opening, which can be prevented by cyclosporine A (CsA). The aim of our study is to show that a higher dose of CsA (10 mg/kg) injected just before ischemia or a lower dose of CsA (3 mg/kg) injected further in advance of ischemia (1 h) protects the kidneys and improves mitochondrial function.

Methods

All mice underwent a right unilateral nephrectomy followed by 30 min clamping of the left renal artery. Mice in the control group did not receive any pharmacological treatment. Mice in the three groups treated by CsA were injected at different times and with different doses, namely 3 mg/kg 1 h or 10 min before ischemia or 10 mg/kg 10 min before ischemia. After 24 h of reperfusion, the plasma creatinine level were measured, the histological score was assessed and mitochondria were isolated to calculate the calcium retention capacity (CRC) and level of oxidative phosphorylation.

Results

Mortality and renal function was significantly higher in the CsA 10 mg/kg-10 min and CsA 3mg/kg-1 h groups than in the CsA 3mg/kg-10 min group. Likewise, the CRC was significantly higher in the former two groups than in the latter, suggesting that the improved renal function was due to a longer delay in the opening of the mPTP. Oxidative phosphorylation levels were also higher 24 h after reperfusion in the protected groups.

Conclusions

Our results suggest that the protection afforded by CsA is likely limited by its availability. The dose and timing of the injections are therefore crucial to ensure that the treatment is effective, but these findings may prove challenging to apply in practice.

Fast therapeutic hypothermia prevents post-cardiac arrest syndrome through cyclophilin D-mediated mitochondrial permeability transition inhibition

The opening of the mitochondrial permeability transition pore (PTP), which is regulated by the matrix protein cyclophilin D (CypD), plays a key role in the pathophysiology of post-cardiac arrest (CA) syndrome. We hypothesized that therapeutic hypothermia could prevent post-CA syndrome through a CypD-mediated PTP inhibition in both heart and brain. In addition, we investigated whether specific pharmacological PTP inhibition would confer additive protection to cooling. Adult male New Zealand White rabbits underwent 15 min of CA followed by 120 min of reperfusion. Five groups (n = 10-15/group) were studied: control group (CA only), hypothermia group (HT, hypothermia at 32-34 °C induced by external cooling at reperfusion), NIM group (injection at reperfusion of 2.5 mg/kg NIM811, a specific CypD inhibitor), HT + NIM, and sham group. The following measurements were taken: hemodynamics, echocardiography, and cellular damage markers (including S100β protein and troponin Ic). Oxidative phosphorylation and PTP opening were assessed on mitochondria isolated from both brain and heart. Acetylation of CypD was measured by immunoprecipitation in both the cerebral cortex and myocardium. Hypothermia and NIM811 significantly prevented cardiovascular dysfunction, pupillary areflexia, and early tissue damage. Hypothermia and NIM811 preserved oxidative phosphorylation, limited PTP opening in both brain and heart mitochondria and prevented increase in CypD acetylation in brain. There were no additive beneficial effects in the combination of NIM811 and therapeutic hypothermia. In conclusion, therapeutic hypothermia limited post-CA syndrome by preventing mitochondrial permeability transition mainly through a CypD-dependent mechanism.

High serum oxytocin is associated with metabolic syndrome in older men - The MINOS study

AIM

Oxytocin regulates food intake, carbohydrate and lipid metabolism, and urinary sodium excretion. We assessed the association between serum oxytocin levels and presence of metabolic syndrome (MetS) in older men.

METHODS

Cross-sectional study was performed in 540 volunteer men aged 50-85yrs from the MINOS cohort. Oxytocin was measured in fasting serum by radioimmunoassay (Oxytocin RIA, Phoenix Pharmaceuticals). MetS was diagnosed using the harmonized definition.

RESULTS

Serum oxytocin was higher in 166 men with MetS vs. controls (p<0.005). After adjustment for confounders including leptin, higher oxytocin was associated with higher odds of MetS (OR=1.38 per SD, 95%CI: 1.10-1.71, p<0.005). Men with serum oxytocin >0.74pg/mL (median) had higher odds of MetS vs. men with oxytocin ⩽0.74pg/mL (OR=2.06, 95%CI: 1.33-3.18, p<0.005). Higher oxytocin levels and low testosterone levels (total or free) were significantly associated with higher odds of MetS jointly and independently of each other. Men having oxytocin >0.74pg/mL and total testosterone <300ng/dL (<10.4nmol/L) had higher odds of MetS vs. men without these characteristics (OR=3.95, 95%CI: 1.65-9.46, p<0.005). Men having 25-hydroxycholecalciferol levels <30ng/mL and oxytocin >0.74pg/mL had higher odds of MetS vs. men without these characteristics (OR=2.86, 95%CI: 1.47-5.58, p<0.01). Men having oxytocin >0.74pg/mL and osteocalcin levels <14.6ng/mL (lowest quartile) had higher odds of MetS vs. men without these characteristics (OR=4.12, 95%CI: 2.07-8.20, p<0.001).

CONCLUSION

In older men, higher serum oxytocin levels are associated with higher odds of MetS regardless of potential confounders.

Has sclerostin a true endocrine metabolic action complementary to osteocalcin in older men?

The reported association between sclerostin and diabetes mellitus or abdominal fat may be biased by body size and bone mass. In older men, the association between serum sclerostin levels and metabolic syndrome lost significance after adjustment for bone mass. The association between sclerostin and energy metabolism needs further clarification.

INTRODUCTION

Sclerostin is associated with abdominal fat, but this relationship may be biased since both are associated with body size and bone mass. Osteocalcin is a bone-derived hormone regulating energy metabolism. We assessed the association between serum sclerostin and metabolic syndrome (MetS) accounting for whole body mineral content (BMC) and osteocalcin.

METHODS

We studied 694 men aged 51-85 who had serum osteocalcin and sclerostin measurements.

RESULTS

Sclerostin was higher in 216 men with MetS compared with those without MetS (p < 0.005). Average sclerostin level increased significantly across the increasing number of MetS components. In multivariable models, higher sclerostin was associated with higher odds of MetS (odds ratio (OR) = 1.24/1 standard deviation (SD) increase [95 % confidence interval (95 % CI), 1.01-1.51]; p < 0.05). After further adjustment for BMC, the association of MetS with sclerostin lost significance, whereas that with osteocalcin remained significant. Men who were simultaneously in the highest sclerostin quartile and the lowest osteocalcin quartile had higher odds of MetS (OR = 2.14 [95 % CI, 1.15-4.18]; p < 0.05) vs. men being in the three lower sclerostin quartiles and three upper osteocalcin quartiles. After adjustment for whole body BMC, the association lost significance.

CONCLUSIONS

Higher sclerostin level is associated with MetS severity; however, this association may be related to higher whole body BMC. The adjustment for BMC had no impact on the association between MetS and osteocalcin. Clinical cross-sectional studies do not elucidate the potential role of sclerostin in the regulation of energy metabolism and direct experimental approach is necessary.

Ubiquitous protective effects of cyclosporine A in preventing cardiac arrest-induced multiple organ failure

Opening of the mitochondrial permeability transition pore (mPTP) appears to be a pivotal event in myocardial ischemia-reperfusion (I/R) injury. Resuscitated cardiac arrest (CA) leads to the post-CA syndrome that encompasses, not only myocardial dysfunction, but also brain injury, failure of other organs (kidney, liver, or lung), and systemic response to I/R. We aimed to determine whether cyclosporine A (CsA) might prevent multiple organ failure following CA through a ubiquitous mPTP inhibition in each distant vital organ. Anesthetized New Zealand White rabbits were subjected to 15 min of CA and 120 min of reperfusion. At the onset of resuscitation, the rabbits received CsA, its non-immunosuppressive derivative NIM811, or vehicle (controls). Survival, hemodynamics, brain damage, organ injuries, and systemic I/R response were analyzed. Fresh mitochondria were isolated from the brain, heart, kidney, liver, and lung to assess both oxidative phosphorylation and permeability transition. CsA analogs significantly improved short-term survival and prevented multiple organ failure, including brain damage and myocardial dysfunction (P < 0.05 vs. controls). Susceptibility of mPTP opening was significantly increased in heart, brain, kidney, and liver mitochondria isolated from controls, while mitochondrial respiration was impaired (P < 0.05 vs. sham). CsA analogs prevented these mitochondrial dysfunctions (P < 0.05 vs. controls). These results suggest that CsA and NIM811 can prevent the post-CA syndrome through a ubiquitous mitochondrial protective effect at the level of each major distant organ.

Lower serum osteocalcin is associated with more severe metabolic syndrome in elderly men from the MINOS cohort

BACKGROUND

Bone has emerged as an endocrine organ regulating energy metabolism through secretion of osteocalcin. In epidemiological studies, presence of metabolic syndrome (MetS) was associated with lower osteocalcin level.

OBJECTIVES

We evaluated whether osteocalcin level was associated with MetS severity in men and whether it was more strongly associated with MetS compared with N-terminal propeptide of type I procollagen (PINP), bone-specific alkaline phosphatase (BAP), and C-terminal telopeptide of type I collagen (βCTX).

METHODS

We included 798 men aged 51-85 years for total osteocalcin measurement. Number of MetS criteria was used to define severity. We used polytomous logistic regression to assess the relationship between MetS severity and osteocalcin level.

RESULTS

Thirty percent of men had MetS. In patients with MetS, the higher the number of MetS traits were present, the lower was the average osteocalcin level (0-2 criteria: 551 men: 19.5±6.7 ng/ml, three criteria: 155 men: 19.3±7.4 ng/ml, four criteria: 72 men: 17.3±5.7 ng/ml, and five criteria: 20 men: 15.0±5.1 ng/ml; P for trend=0.002).In the polytomous logistic regression model, an increase in osteocalcin level of 10 ng/ml was associated with lower prevalence of severe MetS: three criteria (odds ratio (OR)=0.93 (0.70-1.24)), four criteria (OR=0.54 (0.34-0.84)), and five criteria (OR=0.28 (0.10-0.82)) in comparison with no MetS (P for trend=0.008).After adjustment, using stepwise analysis of the polytomous logistic regression model, we observed that osteocalcin, age, and apparent free testosterone entered in the model but not other bone markers (PINP, βCTX, and BAP).

CONCLUSION

In older Caucasian men, total osteocalcin level was associated with MetS severity. Osteocalcin was more strongly associated with MetS severity than other bone turnover markers.

Higher serum osteocalcin is associated with lower abdominal aortic calcification progression and longer 10-year survival in elderly men of the MINOS cohort

CONTEXT

Abdominal aortic calcification (AAC) is an indicator of cardiovascular risk, especially in the diseases characterized by insulin resistance such as type 2 diabetes. Osteocalcin is a bone-secreted hormone that favors insulin sensitivity and insulin secretion.

OBJECTIVES

We investigated whether total serum osteocalcin level at baseline is associated with AAC progression and 10-year all-cause mortality in elderly men.

DESIGN AND PARTICIPANTS

We assessed 774 men aged 51-85 years from the MINOS cohort who had osteocalcin measurement and lumbar spine radiographs at baseline. They were followed-up prospectively for 10 years. Among them, 615 patients had a follow-up radiograph at 3.5 or 7 years.

MAIN OUTCOME MEASURES

Serum total osteocalcin was measured with an immunoradiometric assay on morning fasting serum collected at baseline. Kauppila's AAC score was assessed from lumbar spine radiographs. AAC progression rate was calculated as the difference between AAC on the last available radiograph and AAC at baseline divided by the follow-up time. Death status was collected over 10 years.

RESULTS

In multivariate analysis, higher baseline total osteocalcin was associated with lower AAC progression rate (odds ratio = 0.74 [0.57-0.97] per 10 ng/mL variation; P = 0.029). At the 10-year follow-up, there were 599 men alive (77%), 181 dead (23%), and 2 lost to follow-up. Higher osteocalcin was associated with lower 10-year all-cause mortality (hazard ratio = 0.62 [0.44-0.86] per 10 ng/mL variation; P = 0.005).

CONCLUSION

Higher baseline total osteocalcin concentrations were associated with lower AAC progression rate and lower mortality. These data suggest that osteocalcin level might be an independent indicator of cardiovascular risk and global health in elderly Caucasian men.

GFR estimation in adolescents and young adults

The performance of creatinine-based equations to obtain the estimated GFR in adolescents and young adults is poorly understood. We assessed creatinine-based GFR estimating equations in a cross-section of 751 adolescents and young adults (1054 measurements), using inulin clearance (measured GFR [mGFR]) as the reference method. We evaluated the following: Cockcroft-Gault, four-variable Modified Diet in Renal Disease, and the Chronic Kidney Disease Epidemiology Collaboration equations for adult participants, as well as the Schwartz 2009 and Schwartz-Lyon equations for pediatric age groups. Participants ranged in age from 10 to 26 years (mean 16.8 years); we divided the population into four groups according to age (10-12 years, 13-17 years, 18-21 years, and 21-25 years). Evaluation of the agreement between these formulas and mGFR (e.g., correlation, Bland-Altman plots, bias, and accuracy) showed that there was a good correlation between mGFR and both pediatric formulas in all age groups, whereas the adult formulas substantially overestimated mGFR. In conclusion, we recommend the use of pediatric equations to estimate GFR from childhood to early adulthood.

Serum level of the phosphaturic factor FGF23 is associated with abdominal aortic calcification in men: the STRAMBO study

CONTEXT

Calcification inhibitor deficiencies, mineral imbalance, and phenotypic transformation of vascular cells to osteogenic cells initiate and sustain vascular calcification. Fibroblast growth factor-23 (FGF23) is a key molecule regulating mineral homeostasis.

OBJECTIVE

Our objective was to assess the association of serum FGF23 levels with mineral metabolism parameters and abdominal aortic calcification (AAC) in men.

DESIGN

This was a cross-sectional analysis in the STRAMBO cohort.

SETTING

Men holding a private health insurance cover with Mutuelle de Travailleurs de la Région Lyonnaise were included in the study.

PARTICIPANTS

Participants included male volunteers aged 20-87 (n = 1130).

INTERVENTIONS

Nonfasting blood collection was done. AAC was semiquantitatively assessed from vertebral fracture assessment scans obtained using dual-energy x-ray absorptiometry.

MAIN OUTCOME MEASURES

We evaluated the association between FGF23 concentration and AAC severity in men.

RESULTS

In 350 men aged 60 yr or younger, FGF23 levels decreased with age (r = -0.21; P < 0.001) but were not associated with any other parameter. In 780 men aged over 60 yr, serum FGF23 correlated with age (r = 0.37; P < 0.001) and, after adjustment for confounders, with glomerular filtration rate (r = -0.31; P < 0.001) and PTH levels (r = 0.25; P < 0.001). After adjustment for confounders, self-reported ischemic heart disease, diabetes mellitus as well as higher concentrations of C-reactive protein and osteoprotegerin were all associated with higher FGF23 levels. After adjustment for confounders, subjects in the highest FGF23 quartile had higher prevalence of severe AAC compared with the three lower quartiles combined (odds ratio = 1.88; 95% confidence interval = 1.22-2.85; P < 0.005).

CONCLUSIONS

In healthy older men, circulating FGF23 is associated with parameters of mineral metabolism, including bone metabolism-regulating cytokines, and with severe AAC independent of traditional risk factors.

Association of bone microarchitecture with parathyroid hormone concentration and calcium intake in men: the STRAMBO study

OBJECTVIE: In the elderly, vitamin D deficit, low calcium intake, and impaired bone microarchitecture are associated with higher risk of hip fracture. We assessed the association of bone microarchitecture with calcium intake and serum concentrations of 25-hydroxycholecalciferol (25OHD) and parathyroid hormone (PTH) in men.

DESIGN

Cross-sectional analysis was performed in 1064 men aged 20-87 years not taking vitamin D or calcium supplements.

METHODS

Daily calcium intake was assessed using a food frequency questionnaire. Bone microarchitecture was assessed at distal radius and tibia by high-resolution peripheral quantitative computed tomography. We measured serum and urinary levels of biochemical bone turnover markers (BTMs). Statistical models were adjusted for age, weight, height, and glomerular filtration rate.

RESULTS

In 500 men aged <65 years, lower 25OHD levels and low calcium intake were associated with lower trabecular volumetric bone mineral density (Dtrab) at the distal tibia, due to lower trabecular number (Tb.N). Low calcium intake was associated with lower cortical thickness (Ct.Th). Higher PTH level was associated with higher BTM levels. In 563 men aged ≥65 years, the highest PTH quartile was associated with lower Ct.Th (tibia), lower Dtrab (both sites), and lower Tb.N (radius) compared with the lowest quartile. Low calcium intake was associated with lower Tb.N and more heterogenous trabecular distribution. BTM positively correlated with the PTH concentration.

CONCLUSION

In older men, elevated PTH concentration is associated with high bone turnover, poor trabecular microarchitecture (radius and tibia), and, at the distal tibia, lower Ct.Th. Low calcium intake is associated with lower Tb.N and more heterogenous trabecular distribution.

Men with metabolic syndrome have lower bone mineral density but lower fracture risk--the MINOS study

Data on the association of the metabolic syndrome (MetS) with bone mineral density (BMD) and fracture risk in men are inconsistent. We studied the association between MetS and bone status in 762 older men followed up for 10 years. After adjustment for age, body mass index, height, physical activity, smoking, alcohol intake, and serum 25-hydroxycholecalciferol D and 17beta-estradiol levels, men with MetS had lower BMD at the hip, whole body, and distal forearm (2.2% to 3.2%, 0.24 to 0.27 SD, p < .05 to .005). This difference was related to abdominal obesity (assessed by waist circumference, waist-hip ratio, or central fat mass) but not other MetS components. Men with MetS had lower bone mineral content (3.1% to 4.5%, 0.22 to 0.29 SD, p < .05 to 0.001), whereas differences in bone size were milder. Men with MetS had a lower incidence of vertebral and peripheral fractures (6.7% versus 12.0%, p < .05). After adjustment for confounders, MetS was associated with a lower fracture incidence [odds ratio (OR) = 0.33, 95% confidence interval (CI) 0.15-0.76, p < .01]. Among the MetS components, hypertriglyceridemia was most predictive of the lower fracture risk (OR = 0.25, 95%CI 0.10-0.62, p < .005). Lower fracture risk in men with MetS cannot be explained by differences in bone size, rate of bone turnover rate and bone loss, or history of falls or fractures. Thus older men with MetS have a lower BMD related to the abdominal obesity and a lower risk of fracture related to hypertriglyceridemia. MetS probably is not a meaningful concept in the context of bone metabolism. Analysis of its association with bone-related variables may obscure the pathophysiologic links of its components with bone status.

Interleukin-17 increases the effects of IL-1 beta on muscle cells: arguments for the role of T cells in the pathogenesis of myositis

We studied the production of interleukin (IL)-6 and CCL20/macrophage inflammatory protein-3 alpha (MIP-3 alpha) by human myoblasts and muscle samples in response to IL-17 alone or in combination with IL-1 beta. Both IL-17 and IL-1 beta induced IL-6 production by normal myoblasts and muscle samples. IL-17 had no effect on CCL20 production by myoblasts. Combination of IL-17 and IL-1 beta further increased IL-6 and CCL20 production by muscle samples but not that of CK. IL-17 induced also HLA class I, C-Fos, nuclear factor kappa B (NF-kappa B) and C-Jun expression by myoblasts but not that of HLA class II, CD40, vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1). Finally, immunostaining of dermatomyositis (DM) and polymyositis (PM) muscle biopsies showed IL-17 and CCL20 expression. Our study shows that low levels of cytokines produced by T cells (IL-17) and monocytes (IL-1 beta) can act in combination on skeletal myoblasts and muscle tissue.