Higher leptin is associated with hypertension: the Multi-Ethnic Study of Atherosclerosis

The effects of physical exercise therapy on weight control: its regulation of adipocyte physiology and metabolic capacity

Factors associated with increased body mass, including dyslipidemia, hypertension, insulin resistance, vascular endothelial dysfunction and sleep disorders, may contribute to the exacerbation of cardiovascular disease. These health problems associated with obesity are caused by accumulated metabolism and physical and emotional stress. Lifestyle, especially exercise, is a major therapeutic strategy for the treatment and management of obesity-induced metabolic problems. Metabolic disease often co-occurs with abdominal obesity. Exercise is necessary for the treatment of obesity, diabetes and cardiovascular disease. A potential benefit of exercise is to promote fat burning and energy use increases both during exercise itself and in the post-exercise period. Exercise suppresses basal metabolic rate and also has many health benefits. Why should we exercise to lose weight? Does physical activity help lower blood pressure, blood cholesterol, and blood sugar? In this article, we review the positive effects of physical exercise on weight maintenance and weight loss, and the effectiveness of physical exercise on the treatment and prevention of metabolic syndrome.

Blood Pressure Correlates with Serum Leptin and Body Mass Index in Overweight Male Saudi Students

The precise association of serum leptin (Lep) with the body mass index (BMI) and blood pressure (BP) is not well known for understanding their involvement in health and disease. Hence, the present study was conducted to investigate the association of BP, BMI and serum Lep levels in young normal-weight (NW) and overweight (OW) male Saudi students. The NW (n: 198) and OW (n: 192) male subjects in the age range of 18-20 years were consulted. The BP was measured with a mercury sphygmomanometer. Leptin Human ELISA Kits were employed for the determination of the serum Lep levels. The mean ± SD values of BMI (kg/m²), Lep (ng/mL), systolic BP (SBP; mmHg), and diastolic BP (DBP; mmHg) all showed significant differences for young OW vs. NW subjects as: 27.52 ± 1.42 vs. 21.49 ± 2.03; 10.70 ± 4.67 vs. 4.68 ± 1.91; 121.37 ± 2.59 vs. 118.51 ± 1.54 and 81.44 ± 1.97 vs. 78.79 ± 1.44, respectively. All associations (among BMI, Lep, SBP and DBP) showed a positive linear and significant correlation, except the nonsignificant correlation of BMI and SBP for the NW group. Other variables showing significant variation for NW vs. OW subjects were: interleukin-6, high sensitivity C-reactive protein, apelin (APLN) and resistin. Serum APLN correlated significantly with Lep, BMI, SBP and DBP in lower and higher levels of BMI, with considerable progressive patterns in both the NW and OW groups and subgroups. The present study in young Saudi male students presents significant variations for BP and serum leptin levels, and a significant positive linear association among serum leptin, BMI and BP.

Impaired glucose metabolism reduces the neuroprotective action of adipocytokines in cognitively normal older adults with insulin resistance

Evidence suggests that aging-related dysfunctions of adipose tissue and metabolic disturbances increase the risk of diabetes and metabolic syndrome (MtbS), eventually leading to cognitive impairment and dementia. However, the neuroprotective role of adipocytokines in this process has not been specifically investigated. The present study aims to identify metabolic alterations that may prevent adipocytokines from exerting their neuroprotective action in normal ageing. We hypothesize that neuroprotection may occur under insulin resistance (IR) conditions as long as there are no other metabolic alterations that indirectly impair the action of adipocytokines, such as hyperglycemia. This hypothesis was tested in 239 cognitively normal older adults (149 females) aged 52 to 87 years (67.4 ± 5.9 yr). We assessed whether the homeostasis model assessment-estimated insulin resistance (HOMA-IR) and the presence of different components of MtbS moderated the association of plasma adipocytokines (i.e., adiponectin, leptin and the adiponectin to leptin [Ad/L] ratio) with cognitive functioning and cortical thickness. The results showed that HOMA-IR, circulating triglyceride and glucose levels moderated the neuroprotective effect of adipocytokines. In particular, elevated triglyceride levels reduced the beneficial effect of Ad/L ratio on cognitive functioning in insulin-sensitive individuals; whereas under high IR conditions, it was elevated glucose levels that weakened the association of the Ad/L ratio with cognitive functioning and with cortical thickness of prefrontal regions. Taken together, these findings suggest that the neuroprotective action of adipocytokines is conditioned not only by whether cognitively normal older adults are insulin-sensitive or not, but also by the circulating levels of triglycerides and glucose, respectively.

Possible Preventative/Rehabilitative Role of Gliflozins in OSA and T2DM. A Systematic Literature Review-Based Hypothesis

Obstructive sleep apnoea (OSA) is characterized by frequent apnoea episodes during sleep due to upper airway obstruction. The present review summarizes current knowledge on inter-relationships between OSA and type 2 diabetes mellitus (T2DM) and suggests the former as a possible target for sodium-glucose co-transporter-2 inhibitors (SGLT-2i). Based on pathophysiological mechanisms underlying OSA onset and renal SGLT-2 effects, we suggest that SGLT-2i indications might expand beyond current ones, including glucose, lipids, uric acid, blood pressure, and body weight control as well as chronic heart failure and kidney disease prevention.

Adipocytokines and High Blood Pressure in Mexican Children

Given that adipocytokines may play an important role in the pathophysiology of high blood pressure (HBP) and because related reports in children are scarce and controversial, we evaluated the relationship of leptin, resistin, tumor necrosis factor-α, interleukin-6, adiponectin, and interferon-γ with HBP. Materials and Methods. A total of 129 (53.8%) girls and 111 (46.2%) boys, with average ages of 10.8 ± 0.9 and 10.6 ± 1.0 years, respectively, were enrolled in a cross-sectional study. HBP was defined by systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) between the 90th and 95th percentiles. A multivariate logistic regression backwards-stepwise analysis adjusted for body mass index, waist circumference, and triglyceride levels was performed to compute the association between adipocytokines and HBP. Results. Seventy-two (30.0%) participants showed HBP: 44 (61.1%) girls and 28 (38.9%) boys. Multivariate analysis showed that, irrespective of obesity, serum levels of adiponectin, but not those of other adipocytokines, are inversely associated with HBP (odds ratio 0.93; 95% CI 0.77 to 0.98, p = .04). Conclusions. Our results show that low serum adiponectin levels, but not those of other adipocytokines, are inversely associated with HBP; this association is independent of obesity.

Sex and Body Mass Index Modify the Association Between Leptin and Sodium Excretion: A Cross-sectional Study in an African Population

BACKGROUND

Renal sodium handling could be a potential mediator linking adipokines to hypertension. The aim of the study was to assess the relationship of leptin with urinary sodium excretion and proximal sodium reabsorption in humans.

METHODS

This cross-sectional study was conducted on participants of hypertensive families from the Seychelles Island. A split urine (daytime and nighttime) collection and plasma leptin were measured. Endogenous lithium clearance was used to assess proximal sodium reabsorption. Mixed multiple linear regression tests adjusted for confounding factors were used.

RESULTS

Three hundred and sixty-five participants (57% women) were included in this analysis. Leptin and adiponectin were higher in women (P < 0.001). Leptin was associated positively with daytime (coefficient [c]: 0.16, standard deviation (SD): 0.03, P < 0.001), nighttime urinary sodium excretion (c: 0.17, SD: 0.04), P < 0.01), daytime lithium clearance (c: 0.40, SD: 0.08, P < 0.001), and nighttime lithium clearance (c: 0.39, SD: 0.10, P < 0.001) after adjusting for sex. The association was lost or mitigated only when BMI was introduced in the model. When BMI was categorized in normal vs. overweight participant, leptin was associated with daytime and nighttime sodium excretion rates (c: 0.14, SD: 0.05, P = 0.011 and c: 0.22, SD: 0.07, P = 0.002, respectively) only in overweight participants.

CONCLUSION

Leptin is associated positively with daytime and nighttime sodium excretion and lithium clearance suggesting a natriuretic rather than a sodium retaining effect of leptin. Sex and body mass index (BMI) are major confounders in this association. These results highlight the importance of sex and obesity in our understanding of the relationships between leptin, blood pressure, and renal sodium handling.

Mechanisms of obesity-induced metabolic and vascular dysfunctions

Obesity has reached epidemic proportions and its prevalence is climbing. Obesity is characterized by hypertrophied adipocytes with a dysregulated adipokine secretion profile, increased recruitment of inflammatory cells, and impaired metabolic homeostasis that eventually results in the development of systemic insulin resistance, a phenotype of type 2 diabetes. Nitric oxide synthase (NOS) is an enzyme that converts L-arginine to nitric oxide (NO), which functions to maintain vascular and adipocyte homeostasis. Arginase is a ureohydrolase enzyme that competes with NOS for L-arginine. Arginase activity/expression is upregulated in obesity, which results in diminished bioavailability of NO, impairing both adipocyte and vascular endothelial cell function. Given the emerging role of NO in the regulation of adipocyte physiology and metabolic capacity, this review explores the interplay between arginase and NO, and their effect on the development of metabolic disorders, cardiovascular diseases, and mitochondrial dysfunction in obesity. A comprehensive understanding of the mechanisms involved in the development of obesity-induced metabolic and vascular dysfunction is necessary for the identification of more effective and tailored therapeutic avenues for their prevention and treatment.

Plasma leptin level is positively associated with blood pressure measures independent of gender and BMI

Background: Since the introduction of leptin, many studies suggest an important role for this hormone in obesity-related hypertension. However, in non-obese patients, there are controversial results regarding the possible role of leptin in essential hypertension especially in both sexes and different groups of body mass index (BMI). We aimed to evaluate the association of leptin and hypertension in both female and male gender.Materials and Methods: This cross-sectional study was conducted, recruiting 80 essential hypertensive patients and 80 healthy normotensive volunteers using convenience sampling method. Subjects without history of diabetes mellitus, hyperlipidemia, smoking, thyroid disease and insulin or corticosteroid use were included in two groups of normotensive and hypertensive subjects who were matched for age, sex and BMI. Systolic and diastolic blood pressure (SBP and DBP), weight and height were measured for all subjects and a blood sample was obtained for measurement of leptin, fasting blood sugar and lipid profiles.Results: Leptin was significantly higher in hypertensive patients as compared to normotensive subjects in all study population and both male and female subgroups (p < 0.001). Statistically significant correlation was also found between leptin and both SBP and DBP in above-mentioned subgroups. In comparison of controlled and uncontrolled hypertensive patients, leptin was significantly higher in uncontrolled hypertensive patients (p < 0.001).Conclusion: Comparing two groups of hypertensive and normotensive subjects, leptin is found to be positively correlated with hypertension in both genders. Leptin level also tends to be higher in uncontrolled hypertensive patients which may indicate a possible role for leptin in mechanism of uncontrolled hypertension.

Cancer and comorbidity: The role of leptin in breast cancer and associated pathologies

Obesity is an important risk factor for postmenopausal breast cancer and also a poor prognostic factor among cancer patients. Moreover, obesity is associated with a number of health disorders such as insulin resistance/type-2 diabetes mellitus, hypertension, and other cardiovascular diseases. Frequently, these health disorders exhibit as components/complications of the metabolic syndrome. Nevertheless, obesity-related diseases may coexist with postmenopausal breast cancer; and these comorbid conditions could be substantial. Therefore, it may be assumed that different diseases including breast cancer could originate from a common pathological background in excessive adipose tissue. Adipocyte-released hormone-like cytokine (or adipokine) leptin behaves differently in a normal healthy state and obesity. A growing body of evidence suggests an important role of leptin in our major obesity-related health issues such as insulin resistance, hypertension, and neoplasia. In this context, this review describes the relationships of the abovementioned pathologies with leptin.

The role of adipokines as prognostic factors of one-year mortality in hip fracture patients

This study investigated the impact of anthropometric parameters, adiponectin, leptin, homeostatic model assessment for insulin resistance (HOMA-IR), beta-isomerised C-terminal telopeptide of collagen type I (β-CTX), and routine biochemical tests on one-year mortality in hip fracture patients. We found that male patients with high adiponectin, leptin, and β-CTX levels had a 5-fold increase in all-cause one-year mortality.

INTRODUCTION

Several predictors of one-year hip fracture mortality have been identified including advanced age, male sex, low bone mineral density, and preexisting comorbidities. However, the impact of metabolic parameters on hip fracture mortality remains unknown. The aim of this study was to examine the effect of serum leptin and adiponectin levels, as well as other metabolic parameters on all-cause one-year hip fracture mortality.

METHODS

This prospective study included 236 patients of all ages with non-traumatic hip fractures. Anthropometric parameters, adiponectin, leptin, HOMA-IR, β-CTX, and routine biochemical tests were recorded at admission and correlated with one-year mortality by using multivariate Cox proportional hazard models.

RESULTS

The median patient age was 82 (75-87) years, and one-year mortality rate was 28.4%. In univariate analysis, adiponectin, age, β-CTX, and renal function were associated with mortality. However, in a multivariate model, male gender, high β-CTX, adiponectin, and leptin were independently associated with increased mortality. Thus, we constructed a nomogram that included all the latter variables in addition to age. The nomogram predicted mortality with a sensitivity of 74.8% (66.0-82.3) and specificity of 74.4% (57.9-87.0), and had an area under the curve of 0.784. Patients that scored <9.2 had a mortality of 10.1%, while those with >9.2 had a mortality of 49.2% (relative risk 5.4, 95% CI 2.8-10.2, P < 0.001).

CONCLUSION

Male patients with high adiponectin, leptin, and β-CTX levels have a 5-fold increase in all-cause one-year mortality after hip fracture.

Alamandine reduces leptin expression through the c-Src/p38 MAP kinase pathway in adipose tissue

Objective

Obesity is associated with an increased risk of diabetes mellitus, hypertension, and renal dysfunction. Angiotensin 1–7 and alamandine are heptameric renin angiotensin system peptide hormones. Further, alamandine levels increase with renal dysfunction. In the cardiovascular system, angiotensin 1–7 and alamandine produce similar improvements and counterbalance angiotensin II in regulating vascular function. We aimed to determine whether the effect of alamandine on leptin expression and secretion in adipocytes was similar to that of angiotensin 1–7.

Approach and results

We studied isolated peri-renal visceral adipose tissue and peri-renal isolated visceral adipocytes from male Wistar rats. Angiotensin II from 0.01 to 10nM had no effect on leptin expression. Angiotensin 1–7 (1 nM) increased leptin secretion and expression, whereas alamandine (1 nM) decreased leptin secretion and expression in adipose tissue and isolated adipocytes and reduced blood leptin levels in vivo. These effects were mediated by Gq, c-Src, p38 mitogen-activated protein, and IκB activation. Additionally, alamandine induced nitric oxide expression via inducible nitric oxidase synthase and plasminogen activator inhibitor 1 expression in adipose tissue and isolated adipocytes.

Conclusions

Angiotensin 1–7 and alamandine produced opposing effects on leptin expression and secretion in adipose tissue. This result suggests that the action of Mas (angiotensin 1–7 receptor) and Mas-related G-protein coupled receptor D in adipocytes exhibited opposing actions similar to angiotensin II type 1 and type 2 receptors.

Association of adipokines with blood pressure, arterial elasticity and cardiac markers in dialysis patients: cross-sectional analysis of baseline data from a cohort study

Background

Adipokines are a set of cytokines secreted by white adipose tissue that have been suggested to be involved in the development of cardiovascular diseases. We aimed to evaluate the cross-sectional associations of a panel of representative adipokines with cardiovascular measures in a cohort of hemodialysis patients.

Methods

We measured plasma adiponectin, resistin, plasminogen activator inhibitor-1 (PAI-1), leptin, monocyte chemotactic protein 1 (MCP-1) and adipsin levels in 366 dialysis patients and 60 healthy controls. The associations of these adipokines with systolic blood pressure (assessed by ambulatory blood pressure monitoring), pulse wave velocity (PWV) and cardiac markers (BNP, NT-proBNP, Troponin I, Troponin T) in these patients were determined by general linear models with stepwise adjustment for covariates.

Results

In unadjusted comparison with controls, dialysis patients showed increased adiponectin, resistin, MCP-1 and adipsin levels, decreased PAI-1 concentrations (all p <0.001) and similar leptin levels (p = 0.82). On adjustment for body mass index and diabetes, however, the PAI-1 level was comparable between group (p = 0.06), whereas leptin levels became significantly higher in the patients(p <0.001). Higher adiponectin, lower PAI-1 and leptin levels were associated with higher systolic blood pressure, even after extensive adjustment (all p ≤ 0.01). Adiponectin was also consistently and inversely associated with PWV in fully adjusted models (p = 0.003). Resistin, PAI-1, leptin and adipsin showed negative associations with one or more circulating cardiac markers (all p ≤ 0.02).

Conclusions

We found significant associations between adipokines and cardiovascular measures. Our data suggest the possible involvement of adipokines in cardiovascular modulation in dialysis patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-017-0185-3) contains supplementary material, which is available to authorized users.

Modeling the impact of growth and leptin deficits on the neuronal regulation of blood pressure

The risk of hypertension is increased by intrauterine growth restriction (IUGR) and preterm birth. In the search for modifiable etiologies for this life-threatening cardiovascular morbidity, a number of pathways have been investigated, including excessive glucocorticoid exposure, nutritional deficiency and aberration in sex hormone levels. As a neurotrophic hormone that is intimately involved in the cardiovascular regulation and whose levels are influenced by glucocorticoids, nutritional status and sex hormones, leptin has emerged as a putative etiologic and thus a therapeutic agent. As a product of maternal and late fetal adipocytes and the placenta, circulating leptin typically surges late in gestation and declines after delivery until the infant consumes sufficient leptin-containing breast milk or accrues sufficient leptin-secreting adipose tissue to reestablish the circulating levels. The leptin deficiency seen in IUGR infants is a multifactorial manifestation of placental insufficiency, exaggerated glucocorticoid exposure and fetal adipose deficit. The preterm infant suffers from the same cascade of events, including separation from the placenta, antenatal steroid exposure and persistently underdeveloped adipose depots. Preterm infants remain leptin deficient beyond term gestation, rendering them susceptible to neurodevelopmental impairment and subsequent cardiovascular dysregulation. This pathologic pathway is efficiently modeled by placing neonatal mice into atypically large litters, thereby recapitulating the perinatal growth restriction-adult hypertension phenotype. In this model, neonatal leptin supplementation restores the physiologic leptin surge, attenuates the leptin-triggered sympathetic activation in adulthood and prevents leptin- or stress-evoked hypertension. Further pathway interrogation and clinical translation are needed to fully test the therapeutic potential of perinatal leptin supplementation.

Neonatal growth restriction-related leptin deficiency enhances leptin-triggered sympathetic activation and central angiotensin II receptor-dependent stress-evoked hypertension

BACKGROUND

Neonatal growth restriction (nGR) leads to leptin deficiency and increases the risk of hypertension. Previous studies have shown nGR-related hypertension is normalized by neonatal leptin (nLep) and exacerbated by psychological stress. With recent studies linking leptin and angiotensin signaling, we hypothesized that nGR-induced nLep deficiency increases adult leptin sensitivity; leading to leptin- or stress-induced hypertension, through a pathway involving central angiotensin II type 1 receptors.

METHODS

We randomized mice with incipient nGR, by virtue of their presence in large litters, to vehicle or physiologic nLep supplementation (80 ng/g/d). Adult caloric intake and arterial pressure were monitored at baseline, during intracerebroventricular losartan infusion and during systemic leptin administration.

RESULTS

nGR increased leptin-triggered renal sympathetic activation and hypertension with increased leptin receptor expression in the arcuate nucleus of the hypothalamus; all of those nGR-associated phenotypes were normalized by nLep. nGR mice also had stress-related hyperphagia and hypertension, but only the stress hypertension was blocked by central losartan infusion.

CONCLUSION

nGR leads to stress hypertension through a pathway that involves central angiotensin II receptors, and nGR-associated leptin deficiency increases leptin-triggered hypertension in adulthood. These data suggest potential roles for preservation of neonatal growth and nLep supplementation in the prevention of nGR-related hypertension.

Differences in various biochemical and clinical parameters with respect to family history of Non Communicable Diseases in fourth year MBBS students of Karachi, Pakistan

Objective:

To observe the differences of various biochemical and clinical parameters with respect to Family History (FH) of Non-communicable Diseases (NCDs) in fourth year Bachelor of Medicine, Bachelor of Surgery (MBBS) students.

Methods:

This observational study was conducted at Baqai Institute of Diabetology & Endocrinology from December 2013 to January 2014. Total 50 medical students from Dow University of Health Sciences (DUHS) participated in the study. Statistical Package for Social Sciences (SPSS) version 13 was used to analyze the data. For cross tabulation and mean comparison z-test and t test were applied.

Results:

Out of 50 subjects, there were 26 (52%) females. Mean age of the study population was 21.56 ± 0.90 years. Mean serum cholesterol levels with positive FH of NCDs was significantly higher than negative FH of NCDs (p=0.005). Mean value of low density lipoprotein (LDL) of positive family history of NCDs was found higher than those with negative FH (p=0.006) being statistically significant. The insulin levels in subjects with positive FH of NCDs were higher than subjects with negative FH of NCDs (p=0.685). However, serum leptin and plasma renin showed no significant difference with the negative FH of NCDs being higher compared to positive FH of NCDs (p=0.068) and (p=0.884) respectively. However, Waist circumference, Body mass index and central obesity in subjects with positive FH of NCDs shows increasing trend but no statistically significant difference (p > 0.05) was observed.

Conclusion:

In our study of various biochemical and clinical parameters with respect to FH of NCDs, Serum Cholesterol and LDL levels were observed higher and statistically significant.

BMI, body fat mass and plasma leptin level in relation to cardiovascular diseases risk factors among adolescents in Taitung

BACKGROUND

To investigate the risk factors associated with cardiovascular diseases and its relation to BMI, body fat mass and plasma leptin level among adolescents in Taitung, Taiwan.

METHODS

A cross-sectional Taitung Children Heart Study for 500 young adolescents between ages 13 and 15 was conducted. Gender-specific regression models were used to determine the associations between BMI, percentage of body fat mass, plasma leptin level and seven CVDs risk factors (systolic and diastolic blood pressure, mean arterial pressure, triglycerides, total cholesterol, HDL-cholesterol and LDL-cholesterol) before and after adjusting for weight status and age.

RESULTS

After adjusting for weight status and age, BMI was positively associated with systolic BP, triglycerides, LDL-cholesterol levels but negatively associated with HDL-cholesterol level in boys while positively associated with systolic and diastolic BP, mean arterial pressure, and LDL-cholesterol level in girls. The percentage of body fat mass was positively associated with triglycerides, total cholesterol, and LDL-cholesterol in boys while positively associated with systolic BP, total cholesterol, and LDL-cholesterol in girls. Plasma leptin was positively associated with triglycerides, total cholesterol and LDL-cholesterol in boys but no statistically significant associations with CVDs risk factors in girls. A strong relationship between the percentage of body fat mass and plasma leptin appeared among all participants (r=0.59, p<0.01).

CONCLUSIONS

BMI, body fat mass and plasma leptin level may be used to identify certain CVDs risk factors among Taitung adolescents. Future researches could consider measuring body fat mass in the relationship of CVDs risk factors instead of plasma leptin among young adolescents.

Chronic Kidney Disease and Fibrosis: The Role of Uremic Retention Solutes

Chronic kidney disease (CKD) is a major global health concern, and the uremic state is highly associated with fibrogenesis in several organs and tissues. Fibrosis is characterized by excessive production and deposition of extracellular matrix proteins with a detrimental impact on organ function. Another key feature of CKD is the retention and subsequent accumulation of solutes that are normally cleared by the healthy kidney. Several of these uremic retention solutes, including indoxyl sulfate and p-cresyl sulfate, have been suggested to be CKD-specific triggers for the development and perpetuation of fibrosis. The purpose of this brief review is to gather and discuss the current body of evidence linking uremic retention solutes to the fibrotic response during CKD, with a special emphasis on the pathophysiological mechanisms in the kidney.

Leptin receptor gene polymorphisms and risk of hypertension: a meta-analysis

OBJECTIVE

To assess the relationship between the polymorphisms of leptin receptor gene and hypertension.

METHODS

Meta analysis was conducted by using RevMan 5.3. Relevant literatures were retrieved by searching PubMed using the keywords "Hypertension", "Leptin Receptor", "OB Receptor", "LEPR Protein".

RESULTS

Fifteen studies with a total of 5955 patients with hypertension and 3830 healthy controls were included in this meta-analysis. The results showed that Gln223Arg gene polymorphism was significantly higher in hypertension patients than in control (OR=1.36, 95% CI=1.23-1.51, P<0.00001). However, no statistically significant difference was found in Lys109Arg polymorphism between hypertension patients and control (OR=0.99, 95% CI=0.85-1.16, P=0.91).

CONCLUSION

Gln223Arg, but not Lys109Arg gene polymorphism, is higher in hypertension patients, suggesting that patients with Gln223Arg allele carry a higher risk to develop hypertension.

Leptin and incident cardiovascular disease: the Multi-ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

Higher serum leptin levels have been associated with a modestly higher incidence of cardiovascular disease in studies involving mostly Caucasian men. We aimed to assess the hypothesis that higher baseline levels of serum leptin are associated with higher risk of future cardiovascular disease in a diverse cohort.

METHODS

The Multi-Ethnic Study of Atherosclerosis (MESA) is a modern, community-based, ethnically-diverse, and sex-balanced prospective cohort study of US adults free from cardiovascular disease. Serum leptin was measured in an ancillary study in 2002-2005. This analysis included 1905 MESA participants with baseline leptin and incident cardiovascular event data. Leptin levels were modeled as a log-transformed continuous variable and multivariable-adjusted Cox regression was performed for the primary outcome of hard cardiovascular disease, including coronary heart disease and stroke.

RESULTS

The median follow-up was 7.6 years (25th-75th 7.1-8.3) with 7051 and 6738 person-years of follow-up in women and men. A hard cardiovascular disease event occurred in 47 women and 63 men. The age- and ethnicity-adjusted hazard ratio estimates for a 1 standard deviation increase in ln(leptin) were 1.16 in women (95% CI 0.78-1.73, p = 0.46) and 0.91 (95% CI 0.69-1.20, p = 0.51) in men. Pooling sexes, and adjusting for sex in addition to age and ethnicity, estimates were 0.98 (95% CI 0.78-1.23, p = 0.89). With additional adjustment for cardiovascular risk factors, the results remained nonsignificant: 0.87 (95% CI 0.68-1.11, p = 0.26).

CONCLUSION

In conclusion, in a modern, US prospective cohort study of multi-ethnic women and men of multi-ethnic backgrounds, leptin levels are not associated with incident cardiovascular events.

Leptin differentially increases sympathetic nerve activity and its baroreflex regulation in female rats: role of oestrogen

Obesity and hypertension are commonly associated, and activation of the sympathetic nervous system is considered to be a major contributor, at least in part due to the central actions of leptin. However, while leptin increases sympathetic nerve activity (SNA) in males, whether leptin is equally effective in females is unknown. Here, we show that intracerebroventricular (i.c.v.) leptin increases lumbar (LSNA) and renal (RSNA) SNA and baroreflex control of LSNA and RSNA in α-chloralose anaesthetized female rats, but only during pro-oestrus. In contrast, i.c.v. leptin increased basal and baroreflex control of splanchnic SNA (SSNA) and heart rate (HR) in rats in both the pro-oestrus and dioestrus states. The effects of leptin on basal LSNA, RSNA, SSNA and HR were similar in males and pro-oestrus females; however, i.c.v. leptin increased mean arterial pressure (MAP) only in males. Leptin did not alter LSNA or HR in ovariectomized rats, but its effects were normalized with 4 days of oestrogen treatment. Bilateral nanoinjection of SHU9119 into the paraventricular nucleus of the hypothalamus (PVN), to block α-melanocyte-stimulating hormone (α-MSH) type 3 and 4 receptors, decreased LSNA in leptin-treated pro-oestrus but not dioestrus rats. Unlike leptin, i.c.v. insulin infusion increased basal and baroreflex control of LSNA and HR similarly in pro-oestrus and dioestrus rats; these responses did not differ from those in male rats. We conclude that, in female rats, leptin's stimulatory effects on SNA are differentially enhanced by oestrogen, at least in part via an increase in α-MSH activity in the PVN. These data further suggest that the actions of leptin and insulin to increase the activity of various sympathetic nerves occur via different neuronal pathways or cellular mechanisms. These results may explain the poor correlation in females of SNA with adiposity, or of MAP with leptin.

Obesity-induced increases in sympathetic nerve activity: sex matters

Abundant evidence obtained largely from male human and animal subjects indicates that obesity increases sympathetic nerve activity (SNA), which contributes to hypertension development. However, recent studies that included women reported that the strong relationships between muscle SNA and waist circumference or body mass index (BMI) found in men are not present in overweight and obese women. A similar sex difference in the association between adiposity and hypertension development has been identified in animal models of obesity. In this brief review, we consider two possible mechanisms for this sex difference. First, visceral adiposity, leptin, insulin, and angiotensin II have been identified as potential culprits in obesity-induced sympathoexcitation in males. We explore if these factors wield the same impact in females. Second, we consider if sex differences in vascular reactivity to sympathetic activation contribute. Our survey of the literature suggests that premenopausal females may be able to resist obesity-induced sympathoexcitation and hypertension in part due to differences in adipose disposition as well as its muted inflammatory response and reduced production of pressor versus depressor components of the renin-angiotensin system. In addition, vascular responsiveness to increased SNA may be reduced. However, more importantly, we identify the urgent need for further study, not only of sex differences per se, but also of the mechanisms that may mediate these differences. This information is required not only to refine treatment options for obese premenopausal women but also to potentially reveal new therapeutic avenues in obese men and women.

Hypertension in children with obesity

The prevalence of obesity related hypertension has dramatically increased in children with the parallel increase in pediatric obesity. This pediatric health problem may adversely affect cardiovascular health in adult life. The pathogenesis of hypertension in obese children is not widely understood. We therefore undertake this review to raise public awareness. Early childhood parameters like birth weight and postnatal weight gain may play important roles in risk for obesity and obesity related hypertension later in childhood and adult life. Further information is required to confirm this origin of hypertension so that appropriate measures are taken in the peri-natal period. The role of sympathetic nervous system has now been well established as one of the principle mechanisms involved in obesity related hypertension. The Renin-Angiotensin system, insulin resistance due to obesity and as a part of metabolic syndrome along with imbalance in adipokines such as leptin and adiponectin, cause activation of the sympathetic system, vasoconstriction, endothelial dysfunction and sodium reabsorption among other perturbations. Multi-step interventions targeting these various mechanisms are required to break the cycle of obesity and metabolic syndrome. Vitamin D deficiency, sleep apnea due to airway obstruction and hyperuricemia may also play a significant role and should not be ignored in its early stages. Obesity is a risk factor for other co-morbid conditions like chronic kidney disease and fatty liver which further accentuate the risk of hypertension. Increased awareness is required to prevent, diagnose and treat obesity related hypertension among the pediatric population.

Leptin levels and nutritional status of indigenous Tepehuán and Mestizo subjects in Durango, Mexico

The aim of this study was to assess differences in nutritional status and their association with circulating leptin levels in the indigenous Tepehuán people of Mezquital Durango and Mestizo populations of Durango City, Mexico. A group of 128 volunteers aged 18 through 59 years were recruited for the study: 60 indigenous Tepehuán from Mezquital and 68 Mestizo individuals from Durango City. The classification of nutritional status was through body mass index (BMI). Clinical evaluations, including anthropometry and lipid profiles, were performed to ascertain the health of the participants. Circulating leptin levels were determined in blood samples after at 08 hours of fasting. The healthy subjects were classified according to BMI: 32 Tepehuán and 30 Mestizo subjects were of normal weight (NW), and 28 Tepehuán and 38 Mestizo subjects were overweight or obese (OW/O). Both NW and OW/O Tepehuán subjects showed lower leptin concentrations than the comparable Mestizo subjects. Statistical analysis showed a negative Pearson's correlation (r = -0.5; P < 0.05) between BMI and leptin levels in NW Tepehuán subjects, but no significant correlation was found in other groups. The differences found in Tepehuán compared with Mestizo subjects might be explained by poor nutritional status, which leads to scarce adipose tissue and low levels of leptin synthesis. Leptin concentration and its relationship to BMI are associated with ethnicity.

Immunometabolism in obese asthmatics: are we there yet?

Obesity is now recognised as a worldwide epidemic. The recent International Association for the Study of Obesity/International Obesity Taskforce (IASO/IOTF) analysis estimates that approximately 1.0 billion adults are currently overweight and a further 475 million are obese. Obesity has huge psychosocial impact with obese children and adolescents facing discrimination and stigmatization in many areas of their lives leading to body dissatisfaction, low self-esteem and depression. Indeed, obesity is recognised as an important risk factor for the development of several chronic diseases such as hypertension, cancer, asthma and metabolic syndrome. Chronic low grade systemic inflammation is considered as a hallmark of obesity and may possibly explain the link between obesity and chronic disease, in particular the increased incidence, prevalence and severity of asthma in obese individuals. There is now strong evidence for infiltration of immune and inflammatory cells into adipose tissue that drives systemic inflammation and subsequent end organ damage. In addition to adipocytes, the key adipose tissue resident immune cells are macrophages and mast cells. Immunometabolism, as an emerging field of investigation, explores the pivotal role of these immune cells in translating immunological changes to metabolic effects in obesity. Abundance of free fatty acids, along with other inflammatory cytokines shift the balance of metabolic homeostasis to pro-inflammatory status by influencing the development of inflammatory cell lineage, which, further exhibits distinct functional phenotypes. There is emerging evidence for macrophage activation and functional polarization of an anti-inflammatory M₂ phenotype towards a pro-inflammatory M₁ phenotype of macrophages in obese adipose tissue. Similarly, studies in both obese humans and murine models reveal the pathognomic presence of an increased number of mast cells in visceral adipose tissue. These suggest a possible contribution of mast cells to the unique metabolome of obese asthma. This review examines proposed multilevel interactions between metabolic and immune systems in obese asthmatics that underlie the negative effects of obesity and may offer significant therapeutic promise.