The negative effects of obesity on heart, especially the electrophysiology of the heart

Angiotensin II type 1a receptor knockout ameliorates high-fat diet-induced cardiac dysfunction by regulating glucose and lipid metabolism

Obesity-related cardiovascular diseases are associated with overactivation of the renin-angiotensin system (RAS). However, the underlying mechanisms remain elusive. In this study, we investigate the role of angiotensin II (Ang II) in high-fat diet (HFD)-induced cardiac dysfunction by focusing on cardiac glucose and lipid metabolism and energy supply. Ang II plays a role in cardiovascular regulation mainly by stimulating angiotensin II type 1 receptor (AT1R), among which AT1aR is the most important subtype in regulating the function of the cardiovascular system. AT1aR gene knockout (AT1aR ‒/‒) rats and wild-type (WT) rats are randomly divided into four groups and fed with either a normal diet (ND) or a HFD for 12 weeks. The myocardial lipid content, Ang II level and cardiac function are then evaluated. The expressions of a number of genes involved in glucose and fatty acid oxidation and mitochondrial dynamics are measured by quantitative polymerase chain reaction and western blot analysis. Our results demonstrate that AT1aR knockout improves HFD-induced insulin resistance and dyslipidemia as well as lipid deposition and left ventricular dysfunction compared with WT rats fed a HFD. In addition, after feeding with HFD, AT1aR ‒/‒ rats not only show further improvement in glucose and fatty acid oxidation but also have a reverse effect on increased mitochondrial fission proteins. In conclusion, AT1aR deficiency ameliorates HFD-induced cardiac dysfunction by enhancing glucose and fatty acid oxidation, regulating mitochondrial dynamics-related protein changes, and further promoting cardiac energy supply.

Obesity as a risk factor for cardiac arrhythmias

Obesity is global health problem with an estimated three billion people worldwide being classified as overweight or obese. In addition to being associated with a range of adverse health outcomes, obesity is linked to higher risks of atrial and ventricular arrhythmias, as well as sudden cardiac death. Obesity is a multifactorial disease that often co-exists with hypertension, diabetes, and sleep apnoea, which are also independent risk factors for cardiac arrhythmias. Nevertheless, compelling evidence suggests that increasing adiposity is an independent proarrhythmic risk factor and that weight loss can be a mitigating and preventative intervention to reduce arrhythmia incidence. This review briefly outlines the economic and social burden of obesity and summarises evidence for the direct and indirect effects of increasing adiposity on risk of atrial and ventricular arrhythmias. The paper also summarises the evidence for electrocardiographic changes indicative of obesity-related atrial and ventricular remodelling and how weight reduction and management of comorbidity might reduce arrhythmic burden.

The Main Anthocyanin Monomer from Lycium ruthenicum Murray Fruit Mediates Obesity via Modulating the Gut Microbiota and Improving the Intestinal Barrier

Anthocyanins have been shown to exert certain antiobesity properties, but the specific relationship between anthocyanin-induced beneficial effects and the gut microbiota remains unclear. Petunidin-3-O-[rhamnopyranosyl-(trans-p-coumaroyl)]-5-O-(β-D-glucopyranoside) (P3G) is the main anthocyanin monomer from the fruit of Lycium ruthenicum Murray. Therefore, in this study, we investigated the antiobesity and remodeling effects of P3G on gut microbiota through a high-fat diet (HFD)-induced obesity mouse model and a fecal microbiota transplantation experiment. P3G was found to reduce body weight gain, fat accumulation, and liver steatosis in HFD-induced obese mice. Moreover, supplementation with P3G alleviated the HFD-induced imbalance in gut microbiota composition, and transferring the P3G-regulated gut microbiota to recipient mice provided comparable protection against obesity. This is the first time evidence is provided that P3G has an antiobesity effect by changing the intestinal microbiota. Our present data highlight a link between P3G intervention and enhancement in gut barrier integrity. This may be a promising option for obesity prevention.

Impact of surgical weight loss on novel P-wave-related variables which are nominated as predictors of atrial arrhythmias

BACKGROUND

Bariatric surgery has been associated with reduced cardiovascular mortality and morbidity in obese patients. In this study, we aimed to evaluate the alterations of novel P-wave related atrial arrhythmia predictors in patients who achieved effective weight loss with bariatric surgery.

METHODS

The study included 58 patients who underwent bariatric surgery. We measured heart rate, PR, P wave (PW) max, PW min, Average P axis, P wave peak time (PWPT) in lead D2 and lead V1, terminal force in lead V1 (V1TF), and we estimated P wave dispersion (PWdis) interval both pre-operation and 6 months after operation.

RESULTS

Heart rate, PR, PW max, PW min, PWdis, Average P axis, PWPTD2, PWPTV1 and V1TF values, which were close to the upper limit in the pre-op period, showed statistically significant decreases at 6 months after the operation. The most prominent changes were observed in PW dis (51.15 ± 9.70 ms vs. 48.79 ± 9.50 ms, p = .010), PWPTD2 (55.75 ± 6.91 ms vs. 50.59 ± 7.67 ms, p < .001), PWPTV1 (54.10 ± 7.06 ms vs. 48.05 ± 7.64 ms, p < .001) and V1TF (25 [43.1%] vs. 12 [20.7%], p < .001).

CONCLUSIONS

The results of our study indicated that bariatric surgery has positive effects on the regression of ECG parameters which are predictors of atrial arrhythmias, particularly atrial fibrillation (AF).

Evaluation of Changes in Ventricular Repolarization Parameters in Morbidly Obese Patients Undergoing Bariatric Surgery

BACKGROUND

Weight loss after bariatric surgery has been associated with reduced cardiovascular mortality and overall mortality in obese patients. In this study, we aimed to analyze the changes between pre-operation and post-operation ventricular arrhythmia predictors in patients who underwent bariatric surgery.

MATERIALS AND METHODS

The study included 58 patients who underwent bariatric surgery. We measured QT max, QT min, QRS, JT, and Tp-e intervals, and we estimated Tp-e/QT max, Tp-e/QTc max, Tp-e/JT, Tp-e/JTc rates, QTc max, QTc min, cQTd, and JTc intervals both pre-op and 6 months post-op.

RESULTS

Heart rate, PR, QT max, QTc max, QTc min, cQTd, JTc, Tp-e, Tp-e/QT max, Tp-e/QTc max, Tp-e/JT, and Tp-e/JTc values, which were close to the upper limit in the pre-op period, showed statistically significant decreases at 6 months post-op.

CONCLUSION

The results of our study showed that bariatric surgery had positive effects on the regression of ventricular repolarization parameters and the possible development of ventricular arrhythmia.

Relationship Between Serum Amyloid A1 (SAA1) Gene Polymorphisms Studies with Obesity in the Saudi Population

PURPOSE

Limited studies have shown positive and negative associations of serum amylase A1 (SAA1) gene in childhood obesity, previously showed the relation with obesity in different ethnicity. The current study therefore investigated the impact of single nucleotide polymorphisms present in the SAA1 gene on subjects of Saudi obesity.

PARTICIPANTS AND METHODS

In this case-control study, we selected 140 subjects of Saudi population and categorized them into 83 cases of obesity and 57 healthy controls. Genotyping was performed with quantitative/real time-polymerase chain reaction in the SAA1 gene for rs11603089A/G, rs4638289A/T and rs7131332A/G polymorphisms.

RESULTS

In rs11603089 polymorphism, co-dominant model (AG vs AA+GG; OR-2.23 [95% CI:1.02-4.86]; p=0.04) and rs4638289 polymorphism, a disparity in significance was observed between the homozygous variant (TT vs AA; OR-16.8 [95% CI: 2.06-136.8]; p=0.0009), dominant model (AT+TT vs AA; OR-2.57 [95% CI: 1.28-5.19]; p=0.007), recessive model (TT vs AA+AT; OR-11.36 [95% CI: 1.45-89.06]; p=0.004) and allelic frequency for (T vs A: OR-2.35 [95% CI: 1.39-3.98]; p=0.001) between the obesity cases and control subjects. However, statistical correlations did not reveal the rs7131332A/G polymorphism either (p>0.05).

CONCLUSION

In conclusion, rs4638289 polymorphism was associated with risk allele and dominant model with obesity subjects. Further additional studies were warranted.