Obesity: Heart Rate Variability during standardized psychosocial stress induction

Age-related variations in heart rate variability profiles among patients with schizophrenia and major depressive disorder

Patients with psychiatric disorders exhibit general autonomic dysregulation and elevated cardiovascular risks, which could be indexed by heart rate variability (HRV). However, HRV is susceptible to age and other patient-specific factors. This study aimed to investigate the HRV profile and age-related variations, as well as the potential influence of sex, BMI, and HR on HRV in psychiatric populations. There were 571 consecutive patients diagnosed with schizophrenia (SZ) (N = 282) or major depressive disorder (MDD) (N = 289) recruited and classified as adolescent (11-21 years) and adult (> 21 years) groups. HRV indices were measured with 3-minute resting ECG recordings. Compared to adolescent subjects, all time-domain and nonlinear HRV indices were notably reduced in adults, while frequency-domain HRV was comparable. Between SZ and MDD groups, only HTI differed significantly. Age and psychiatric disorders exhibited complex interaction effects on HRV. Stratified by age stage, MDD patients exhibited slightly higher HRV in adolescence but slightly lower HRV in adulthood. In logistic regression analysis, HTI and SD2 were significantly distinctive between adolescents and adults in MDD group, while pNN50 was distinctive in SZ group. Moreover, female subjects demonstrated lower time-domain HRV, LF/HF and SD2 than males. HR exhibited inverse relationship with three domain HRV. No significant effect of BMI was observed. In psychiatric populations, compared to adolescents, adults decreased in time-domain and nonlinear HRV, but not in frequency-domain HRV. Age and psychotic disorders exhibited complex interaction effects on HRV. Sex and HR also emerged as important influencing factors of HRV.

Contribution of physiological dynamics in predicting major depressive disorder severity

This study aimed to explore the physiological dynamics of cognitive stress in patients with Major Depressive Disorder (MDD) and design a multiparametric model for objectively measuring severity of depression. Physiological signal recordings from 40 MDD patients and 40 healthy controls were collected in a baseline stage, in a stress-inducing stage using two cognitive tests, and in the recovery period. Several features were extracted from electrocardiography, photoplethysmography, electrodermal activity, respiration, and temperature. Differences between values of these features under different conditions were used as indexes of autonomic reactivity and recovery. Finally, a linear model was designed to assess MDD severity, using the Beck Depression Inventory scores as the outcome variable. The performance of this model was assessed using the MDD condition as the response variable. General physiological hyporeactivity and poor recovery from stress predict depression severity across all physiological signals except for respiration. The model to predict depression severity included gender, body mass index, cognitive scores, and mean heart rate recovery, and achieved an accuracy of 78%, a sensitivity of 97% and a specificity of 59%. There is an observed correlation between the behavior of the autonomic nervous system, assessed through physiological signals analysis, and depression severity. Our findings demonstrated that decreased autonomic reactivity and recovery are linked with an increased level of depression. Quantifying the stress response together with a cognitive evaluation and personalization variables may facilitate a more precise diagnosis and monitoring of depression, enabling the tailoring of therapeutic interventions to individual patient needs.

Nonlinear relationship between body mass index and serum uric acid: An observational and Mendelian randomization study among Chinese adults

BACKGROUND AND AIMS

Conflicting evidence exists on the relationship between body mass index (BMI) and serum uric acid (SUA), and importantly, the causal role of BMI in SUA remains unclear. We aimed to evaluate the BMI-SUA relationship and its causality among Chinese adults using observational and Mendelian randomization (MR) analyses.

METHODS AND RESULTS

Study included 6641 adults from East China. A genetic risk score based on 14 BMI-associated East Asian variants was formulated. One-sample MR and non-linear MR analyses assessed the causal link between BMI_GRS and SUA levels. Mean BMI levels were 24.8 (SD 3.4) and 24.3 (SD 3.6) kg/m2 in men and women, respectively. Spline models revealed gender-specific BMI-SUA associations: a reverse J-shape for men and a J-shape for women (P-values for nonlinearity <0.05). In men, BMI showed a positive correlation with SUA levels when BMI was below 29.6 kg/m2 (beta coefficient 19.1 [95 % CI 15.1, 23.0] μmol/L per 1-SD increase in BMI), while in women, BMI exhibited a negative correlation with SUA levels when the BMI was less than 21.7 kg/m2 (beta coefficient -12.9 [95 % CI -21.6, -4.1] μmol/L) and a positive correlation when BMI exceeded 21.7 kg/m2 (beta coefficient 13.3 [95 % CI 10.9, 15.8] μmol/L). Furthermore, MR analysis suggested non-linear BMI-SUA link in women but not men.

CONCLUSION

Our study indicates a non-linear correlation between BMI and SUA in both genders. It is noteworthy that in women, this correlation may have a causal nature. Nevertheless, further longitudinal investigations are required to authenticate our findings.

The relationship between self-reported chronic stress, physiological stress axis dysregulation and medically-unexplained symptoms

The positive feedback model of medically-unexplained symptoms posits that chronic stress affects the activity of the physiological stress axes, which in turn generates medically-unexplained symptoms. As a first step to empirically test its model assumptions, we investigated potential associations between chronic stress, physiological stress axis activity and medically-unexplained in a cross-sectional study. One hundred-ninety-nine healthy individuals provided self-reports on chronic stress and medically-unexplained symptoms, resting heart rate/variability (HR/HRV; e.g., root mean square of successive differences/RMSSD, low frequency/LF power), cortisol awakening response (CAR) and diurnal cortisol. Significant positive contributors to medically-unexplained symptoms were the chronic stress scales 'lack of social appreciation' and 'chronic worries', as well as CAR and LF HRV; diurnal cortisol was a negative contributor. Mediation analyses showed that the impact of neural indicators associated with physiological stress axis activity (HR/HRV) related to medically-unexplained symptoms, which was mediated by chronic stress, whereas the mediation effect as suggested by the positive feedback model was not significant. These cross-sectional findings do not support the positive feedback model. Longitudinal studies are required to conclude about potential mechanistic and causal relationships in the model. Nevertheless, our mediation analyses give first indication that the constitution of physiological stress axes may play a major role in how stressors are perceived and which kind of health-consequences (e.g., medically-unexplained symptoms) this may have.

Oral Ionic Liquid for Transdermal Delivery and Obesity Treatment

Obesity is currently a prerequisite for more than 70% of adults, including chronic obesity and long-term obesity. With the increase of diabetes patients in the world, it is urgent to develop effective oral drugs to replace insulin. However, the gastrointestinal tract is a main obstacle to oral drug preparations. Here, a highly effective oral drug was developed, mainly formulated as an ionic liquid (IL) prepared by l-(-)-carnitine and geranic acid. Density functional theory (DFT) calculations showed that l-(-)-carnitine and geranic acid can exist stably through hydrogen bonding. IL can significantly enhance the transdermal transport of drugs. In vitro study of intestinal permeability showed that particles formed by IL can prevent the absorption of intestinal fat. Compared with the control group, oral administration of IL (10 mL kg^-1) significantly reduced blood glucose, white adipose tissue in the liver and epididymis, and the expression of SREBP-1c and ACC in IL. Therefore, these results and high-throughput sequencing analysis showed that IL can effectively reduce the intestinal absorption of adipose tissue to reduce blood glucose. IL has good biocompatibility and stability. Therefore, IL has a certain application value in the field of oral drug-delivery carriers, which provides an effective means for the treatment of diabetes and is a potential tool to solve the epidemic of obesity.