Synergistic Effects Of Obesity Research Articles

The synergistic effect of obesity and dyslipidemia on hypertension: results from the STEPS survey

BackgroundObesity and dyslipidemia are important risk factors for hypertension (HTN). When these two conditions coexist, they may interact in a synergistic manner and increase the risk of developing HTN and its associated complications. The aim of this study was to investigate the synergistic effect of general and central obesity with dyslipidemia on the risk of HTN.MethodData from 40,387 individuals aged 25 to 64 years were obtained from a repeated cross-sectional study examining risk factors for non-communicable diseases (STEPS) in 2007, 2011 and 2016. Body mass index (BMI) was calculated as a measure of general obesity and waist circumference (WC) as a measure of central obesity. Dyslipidemia was defined as the presence of at least one of the lipid abnormalities. Hypertension was defined as systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg or current use of antihypertensive medication. To analyze the synergistic effect between obesity and dyslipidemia and HTN, the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (SI) were calculated. A weighted logistic regression model was performed to estimate the odds ratios (ORs) for the risk of HTN.ResultsThe results showed an association between obesity, dyslipidemia and hypertension. The interaction between obesity and dyslipidemia significantly influences the risk of hypertension. In hypertensive patients, the presence of general obesity increased from 14.55% without dyslipidemia to 64.36% with dyslipidemia, while central obesity increased from 13.27 to 58.88%. This interaction is quantified by RERI and AP values of 0.15 and 0.06 for general obesity and 0.24 and 0.09 for central obesity, respectively. The corresponding SI of 1.11 and 1.16 indicate a synergistic effect. The OR also show that the risk of hypertension is increased in the presence of obesity and dyslipidemia.ConclusionObesity and dyslipidemia are risk factors for HTN. In addition, dyslipidemia with central obesity increases the risk of HTN and has a synergistic interaction effect on HTN. Therefore, the coexistence of obesity and lipid abnormalities has many clinical implications and should be appropriately monitored and evaluated in the management of HTN.

The association between obesity and vitamin D deficiency modifies the progression of kidney disease after ischemia/reperfusion injury.

Acute kidney injury (AKI) alters renal hemodynamics, leading to tubular injury, activating pathways of inflammation, proliferation, and cell death. The initial damage caused to renal tissue after an ischemia/reperfusion (I/R) injury exerts an important role in the pathogenesis of the course of AKI, as well as in the predisposition to chronic kidney disease. Vitamin D deficiency has been considered a risk factor for kidney disease and it is associated with tubulointerstitial damage, contributing to the progression of kidney disease. Obesity is directly related to diabetes mellitus and hypertension, the main metabolic disorders responsible for the progression of kidney disease. Furthermore, the expansion of adipose tissue is described as an important factor for increased secretion of pro-inflammatory cytokines and their respective influence on the progression of kidney disease. We aimed to investigate the influence of vitamin D deficiency and obesity on the progression of renal disease in a murine model of renal I/R. Male Wistar rats underwent renal I/R surgery on day 45 and followed until day 90 of the protocol. We allocated the animals to four groups according to each diet received: standard (SD), vitamin D-depleted (VDD), high fat (HFD), or high fat vitamin D-depleted (HFDV). At the end of 90 days, we observed almost undetectable levels of vitamin D in the VDD and HFDV groups. In addition, HFD and HFDV groups presented alterations in the anthropometric and metabolic profile. The combination of vitamin D deficiency and obesity contributed to alterations of functional and hemodynamic parameters observed in the HFDV group. Moreover, this combination favored the exacerbation of the inflammatory process and the renal expression of extracellular matrix proteins and phenotypic alteration markers, resulting in an enlargement of the tubulointerstitial compartment. All these changes were associated with an increased renal expression of transforming growth factor β and reduced expression of the vitamin D receptor. Our results show that the synergistic effect of obesity and vitamin D deficiency exacerbated the hemodynamic and morphological changes present in the evolution of renal disease induced by I/R.

Obesity and contraceptive use: impact on cardiovascular risk.

Obesity and oestrogen containing contraceptive products are well-known independent cardiovascular risk factors. However, a significant number of obese women continue to receive prescriptions of hormonal products that contain oestrogens for their contraception. We have conducted a narrative review to discuss the latest evidence, ongoing research, and controversial issues on the synergistic effect of obesity and contraceptive use, in terms of cardiovascular risk. There is compelling evidence of an interplay between obesity and contraception in increasing cardiovascular risk. Women who present both obesity and use of combined oral contraceptives (COCs) have a greater risk (between 12 and 24 times) to develop venous thromboembolism than non-obese non-COC users. Data here discussed offer new insights to increase clinicians' awareness on the cardiovascular risk in the clinical management of obese women. The synergistic effect of obesity and COCs on deep venous thrombosis risk must be considered when prescribing hormonal contraception. Progestin-only products are a safer alternative to COCs in patients with overweight or obesity. Obese women taking contraceptives should be viewed as an 'at risk' population, and as such, they should receive advice to change their lifestyle, avoiding other cardiovascular risk factors, as a form of primary prevention. This indication should be extended to young women, as data show that COCs should be avoided in obese women of any age.

The effects of obesity on skeletal muscle contractile function.

Obesity can cause a decline in contractile function of skeletal muscle, thereby reducing mobility and promoting obesity-associated health risks. We reviewed the literature to establish the current state-of-knowledge of how obesity affects skeletal muscle contraction and relaxation. At a cellular level, the dominant effects of obesity are disrupted calcium signalling and 5'-adenosine monophosphate-activated protein kinase (AMPK) activity. As a result, there is a shift from slow to fast muscle fibre types. Decreased AMPK activity promotes the class II histone deacetylase (HDAC)-mediated inhibition of the myocyte enhancer factor 2 (MEF2). MEF2 promotes slow fibre type expression, and its activity is stimulated by the calcium-dependent phosphatase calcineurin. Obesity-induced attenuation of calcium signalling via its effects on calcineurin, as well as on adiponectin and actinin affects excitation-contraction coupling and excitation-transcription coupling in the myocyte. These molecular changes affect muscle contractile function and phenotype, and thereby in vivo and in vitro muscle performance. In vivo, obesity can increase the absolute force and power produced by increasing the demand on weight-supporting muscle. However, when normalised to body mass, muscle performance of obese individuals is reduced. Isolated muscle preparations show that obesity often leads to a decrease in force produced per muscle cross-sectional area, and power produced per muscle mass. Obesity and ageing have similar physiological consequences. The synergistic effects of obesity and ageing on muscle function may exacerbate morbidity and mortality. Important future research directions include determining: the relationship between time course of weight gain and changes in muscle function; the relative effects of weight gain and high-fat diet feeding per se; the effects of obesity on muscle function during ageing; and if the effects of obesity on muscle function are reversible.

Obesity in Aging Exacerbates Neuroinflammation, Dysregulating Synaptic Function-Related Genes and Altering Eicosanoid Synthesis in the Mouse Hippocampus: Potential Role in Impaired Synaptic Plasticity and Cognitive Decline.

There is strong evidence that obesity has deleterious effects on cognitive function of older adults. Previous preclinical studies demonstrate that obesity in aging is associated with a heightened state of systemic inflammation, which exacerbates blood-brain barrier disruption, promoting neuroinflammation and oxidative stress. To test the hypothesis that synergistic effects of obesity and aging on inflammatory processes exert deleterious effects on hippocampal function, young and aged C57BL/6 mice were rendered obese by chronic feeding of a high-fat diet followed by assessment of learning and memory function, measurement of hippocampal long-term potentiation (LTP), assessment of changes in hippocampal expression of genes relevant for synaptic function and determination of synaptic density. Because there is increasing evidence that altered production of lipid mediators modulate LTP, neuroinflammation and neurovascular coupling responses, the effects of obesity on hippocampal levels of relevant eicosanoid mediators were also assessed. We found that aging exacerbates obesity-induced microglia activation, which is associated with deficits in hippocampal-dependent learning and memory tests, impaired LTP, decreased synaptic density, and dysregulation of genes involved in regulation of synaptic plasticity. Obesity in aging also resulted in an altered hippocampal eicosanoid profile, including decreases in vasodilator and pro-LTP epoxy-eicosatrienoic acids (EETs). Collectively, our results taken together with previous findings suggest that obesity in aging promotes hippocampal inflammation, which in turn may contribute to synaptic dysfunction and cognitive impairment.

Obesity in aging exacerbates neuroinflammation and alters eicosanoid profiles in the mouse hippocampus: potential role in impaired synaptic plasticity and cognitive decline

There is strong evidence that obesity has deleterious effects on cognitive function of older adults. Previous preclinical studies demonstrate that obesity in aging is associated with a heightened state of systemic inflammation, which exacerbates blood brain barrier disruption, promoting neuroinflammation and oxidative stress. To test the hypothesis that synergistic effects of obesity and aging on inflammatory processes exert deleterious effects on hippocampal function, young and aged C57BL/6 mice were rendered obese by chronic feeding of a high fat diet followed by measurement of long‐term potentiation (LTP) in acute hippocampal slices, assessment of changes in hippocampal expression of genes relevant for synaptic function and determination of synaptic spine density. Because there is increasing evidence that altered production of lipid mediators modulate LTP, neuroinflammation and neurovascular coupling responses, the effects of obesity on hippocampal levels of relevant eicosanoid mediators were also assessed. We found that aging exacerbates obesity‐induced microglia activation, which is associated with deficits in hippocampal‐dependent learning and memory tests, impaired LTP, decreased synaptic density and dysregulation of genes involved in regulation of synaptic plasticity. Obesity in aging also resulted in an altered hippocampal eicosanoid profile, including decreases in vasodilator and pro‐LTP epoxy‐eicosatrienoic acids (EETs). Collectively, our results taken together with previous findings suggest that obesity in aging promotes hippocampal inflammation, which in turn may contribute to synaptic dysfunction and cognitive impairment.Support or Funding InformationThis work was supported by grants from the American Heart Association, the National Center for Complementary and Alternative Medicine, and the National Institute on AgingThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Synergistic effect of obesity and lipid ingestion in suppressing the growth hormone response to exercise in children

Diet plays an important role in modulating exercise responses, including activation of the growth hormone (GH)/insulin-like growth factor-I (IGF-1) axis. Obesity and fat ingestion were separately shown to reduce exercise GH responses, but their combined effect, especially important in children, has not been studied. We therefore measured the GH response to exercise [30-min intermittent cycling, ten 2-min bouts at ~80% maximal aerobic capacity (Vo(2max)), separated by 1-min rest], started 45 min after ingestion of a high-fat meal (HFM) in 16 healthy [controls; body mass index percentile (BMI%ile) 51 ± 7], and 19 obese (Ob, BMI%ile 97 ± 0.4) children. Samples were drawn at baseline (premeal), and at start, peak, and 30 min postexercise. In the Ob group, a marked ~75% suppression of the GH response (ng/ml) to exercise was observed (2.4 ± 0.6 vs. 10.6 ± 2.1, P < 0.001). This level of suppression was also significantly greater compared with age-, fitness-, and BMI-matched historical controls that had performed identical exercise in fasting conditions. Our data indicate that the reduction in the GH response to exercise, already present in obese children vs. healthy controls, is considerably amplified by ingestion of fat nutrients shortly before exercise, implying a potentially downstream negative impact on growth factor homeostasis and long-term modulation of physiological growth.

Short-term ethinylestradiol treatment suppresses inferior caval vein thrombosis in obese mice

Obesity and oral estrogens are independent risk factors for venous thrombosis, and their combined effect is stronger than the sum of the isolated factors. It was the objective of this study to investigate the interaction between obesity and estrogens at the level of venous thrombotic tendency, coagulation and inflammation in a mouse model. Female C57Bl/6J mice were fed a standard fat diet (SFD) or a high fat diet (HFD) to induce nutritional obesity. After 14 weeks, while maintaining their diet, mice were orally treated eight days with 1 microg ethinylestradiol or vehicle (n=25 per group), and subsequently subjected to an inferior caval vein (ICV) thrombosis model. The ICV thrombosis model resulted in an increased thrombus weight in vehicle-treated HFD mice (3.0 +/- 0.7 mg) compared to vehicle-treated SFD mice (1.4 +/- 0.4 mg; p=0.064). Surprisingly, estrogens reduced thrombus weight, which was significant for the HFD group (0.8 +/- 0.5 mg; p=0.013). As compared to SFD feeding, HFD feeding significantly increased plasma levels of coagulation factor VIII, combined factor II/VII/X (p < 0.001), and plasminogen activator inhibitor-1 (p=0.009), causing a prothrombotic shift of the coagulation profile. Estrogens had no significant effects on this profile with either diet, whereas serum amyloid A and hepatic inflammatory cytokines were minimally affected. The synergistic effect of obesity and estrogens on the venous thrombotic risk in women could not be translated into the mouse context. Short-term ethinylestradiol administration in a mouse ICV thrombosis model counteracts the prothrombotic phenotype associated with nutritionally induced obesity, despite a comparable activated plasma coagulation profile in estrogen-treated and untreated obese mice.

Influence of depressive mood on the association of CRP and obesity in 3205 middle aged healthy men

We studied concentrations of C-reactive proteins (CRP) in a population-based sample of 3204 men aged 45–74 years. Obesity was identified in 726 (23%) men (body mass index (BMI) >30 kg/m 2). Stratification of the sample into three levels of depressive mood revealed a significant association between increased CRP in the obese sample with highest level of depression in comparison to the low level obese depression group ( p=.013). The obesity × depression interaction was significant ( p=.021). Multivariate analysis confirmed this effect after adjusting for possible confounding variables (age, high blood pressure, smoking, physical inactivity, low social class, and low alcohol intake) ( p=.008). In the non-obese sample, there was no association between depressive mood and concentrations of CRP. These findings suggest a possible synergistic effect of obesity and depressive mood on chronic low level inflammation which may play a crucial role in the pathogenesis of atherosclerosis.

Effects of Obesity and Gender on Insulin Receptor Expression in Liver of SHHF/Mcc‐FACP Rats

In SHHF/Mcc-FAcp rats (formerly SHR/Mcc-cp), obesity and male gender synergistically modulate hyperinsulinemia, insulin resistance and predisposition to diabetes. Our previous studies showed gender and obesity modulate hepatic cell surface insulin binding and insulin clearance additively. Hepatic insulin receptors (IR) bind insulin as a first step in insulin clearance through internalization and degradation. We hypothesize that the synergistic effects of obesity and gender on hepatic insulin binding and clearance result from interaction of these two factors on hepatic IR expression. To address IR expression in SHHF/Mcc-FAcp rats, we quantitated IR protein levels in detergent-solubilized liver homogenates by Western blotting and IR mRNA levels by a solution hybridization/RNase protection assay. Obesity reduced total hepatic IR content in males and females, 50% and 68% respectively. Male gender reduced IR protein content 24% in lean, but had no effect on IR protein content in obese rats. Neither gender nor obesity affected hepatic IR mRNA content. Thus, obesity appears to affect hepatic IR protein content and cell surface binding through post-transcriptional mechanisms; similarly, male gender in lean rats reduces IR protein levels and cell surface binding through mechanisms not involving changes in mRNA levels. In obese rats, the synergistic effects of male gender appears to involve changes in IR trafficking and consequently cell surface insulin binding and processing.

Obesity Hypertension

Obesity and hypertension are two major risk factors for the cardiovascular system. Whereas arterial hypertension increases afterload to the left ventricle, obesity produces an increase in stroke volume and increases preload. As a result of this double burden, the heart adapts with eccentric left ventricular hypertrophy. Contractility becomes impaired early in the course of obesity hypertension, and ventricular ectopy is observed. As a consequence, the obese hypertensive patient is at a high risk for congestive heart failure and sudden death. Despite the synergistic effects of obesity and hypertension on the heart, patients appear to be relatively protected from nephrosclerosis and coronary artery disease. These epidemiologic observations are supported by the pathophysiologic changes that take place in obesity hypertension. At any given level of arterial pressure, cardiac output and renal blood flow are elevated in obese hypertensive patients, whereas systemic and renal vascular resistance are decreased when compared to lean hypertensive patients. Because total peripheral resistance is considered the hemodynamic hallmark of arterial hypertension, systemic vascular complications may be less pronounced in obesity hypertension. Weight loss decreases preload, afterload to the left ventricle, and the sympathetic drive to the heart. Protecting the heart from these hypertrophic stimuli should be a major goal of preventive cardiology.