Heart Rate Variability and Inflammatory Stress Response in Young African American Men: Implications for Cardiovascular Risk

Effects of Probiotics on Inflammatory Biomarkers and Its Associations With Cardiac Autonomic Function in Women With Arterial Hypertension: A Secondary Analysis of a Randomized Clinical Trial

Preclinical evidence suggests that probiotic administration may exert an anti-inflammatory effect and reduce autonomic dysfunction and blood pressure. This study evaluated the effects of probiotic therapy on inflammatory biomarkers and characterized the correlations between inflammation and cardiac autonomic function in women with arterial hypertension. Women were randomized into probiotics (n = 20) or placebo (n = 20). The probiotic group received 109 CFU/day of Lactobacillus (L.) paracasei LPC-37, L. rhamnosus HN001, L. acidophilus NCFM, and Bifidobacterium lactis HN019, and the placebo group received polydextrose. Clinical, electrocardiogram, heart rate variability (HRV) analysis, and cytokine levels were assessed at baseline and after 8 weeks. Women who received probiotics for 8 weeks had increased serum levels of IL-17A (p = 0.02) and decreased INF-γ (p = 0.02) compared to baseline. Probiotic supplementation increased serum levels of IL-10 compared to the placebo group (p = 0.03). Probiotic or placebo administration did not change serum levels of TNFα and IL-6. Serum levels of IL-2 (p = 0.001, and p = 0.001) and IL-4 (p = 0.001, and p = 0.001) were reduced in women receiving placebo or probiotics, respectively. Correlations between HRV indices and inflammatory variables showed that INF-γ was positively correlated with heart rate (HR) and sympathetic HRV indices and negatively correlated with vagal HRV indices. IL-10 was negatively correlated with HR and sympathetic HRV indices. IL-6 was negatively correlated with parasympathetic HRV indices and positively correlated with SD2/SD1 ratio. Probiotic therapy has a discreet anti-inflammatory effect in hypertensive women, and pro-inflammatory cytokines were negatively correlated with vagal modulation and positively correlated with sympathetic modulation of HRV. The clinical trial was registered in the Brazilian Registry of Clinical Trials (ReBEC) with the identification RBR-9mj2dt.

The Interplay of Peer Victimization and Parasympathetic Nervous System Activity on Acute Inflammatory Stress Responses in Adolescence

This study examined the extent to which adolescent peer victimization predicted acute inflammatory responses to stress, and whether both resting parasympathetic nervous system (PNS) activity and PNS stress reactivity moderated this association. 83 adolescents (Mage = 14.89, SDage = 0.52, 48% female) reported their history of peer victimization and were exposed to a standardized social stress task before and after which dried blood spot samples were collected to assay inflammatory markers. Inflammatory responses to the stress task were assessed with a latent inflammatory change factor using the cytokines interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α). PNS functioning, indexed by high-frequency heart rate variability, was measured at rest and during the stressor. Contrary to hypotheses, analyses revealed no direct relation between peer victimization and acute inflammatory responses, and resting PNS activity did not moderate this association. However, peer victimization predicted stronger inflammatory responses among adolescents with weaker PNS reactivity to the stress task (b = 0.63, p = .02). This association was not observed among adolescents with stronger PNS reactivity, for whom a negative but non-significant trend was found. Weaker PNS reactivity may thus indicate victimized adolescents' vulnerability for acute inflammatory responses, whereas stronger PNS reactivity may indicate adolescents' resilience to a social stressor.

The Feasibility and Reliability of Upper Arm-Worn Apple Watch Heart Rate Monitoring for Surgeons During Surgery: Observational Study

BACKGROUND

Health care professionals, particularly those in surgical settings, face high stress levels, impacting their well-being. Traditional monitoring methods, like using Holter electrocardiogram monitors, are impractical in the operating room, limiting the assessment of physicians' health. Wrist-worn heart rate monitors, like the Apple Watch, offer promise but are restricted in surgeries due to sterility issues.

OBJECTIVE

This study aims to assess the feasibility and accuracy of using an upper arm-worn Apple Watch for heart rate monitoring during robotic-assisted surgeries, comparing its performance with that of a wrist-worn device to establish a reliable alternative monitoring site.

METHODS

This study used 2 identical Apple Watch Series 8 devices to monitor the heart rate of surgeons during robotic-assisted surgery. Heart rate data were collected from the wrist-worn and the upper arm-worn devices. Statistical analyses included calculating the mean difference and SD of difference between the 2 devices, constructing Bland-Altman plots, assessing accuracy based on mean absolute error and mean absolute percentage error, and calculating the intraclass correlation coefficient.

RESULTS

The mean absolute errors for the whole group and for participants A, B, C, and D were 3.63, 3.58, 2.70, 3.93, and 4.28, respectively, and the mean absolute percentage errors were 3.58%, 3.34%, 2.42%, 4.58%, and 4.00%, respectively. Bland-Altman plots and scatter plots showed no systematic error when comparing the heart rate measurements obtained from the upper arm-worn and the wrist-worn Apple Watches. The intraclass correlation coefficients for participants A, B, C, and D were 0.559, 0.651, 0.508, and 0.563, respectively, with a significance level of P<.001, indicating moderate reliability.

CONCLUSIONS

The findings of this study suggest that the upper arm is a viable alternative site for monitoring heart rate during surgery using an Apple Watch. The agreement and reliability between the measurements obtained from the upper arm-worn and the wrist-worn devices were good, with no systematic error and a high level of accuracy. These findings have important implications for improving data collection and management of the physical and mental demands of operating room staff during surgery, where wearing a watch on the wrist may not be feasible.

Inflammatory proteins are associated with mortality in a middle-aged diverse cohort

BACKGROUND

Recent data indicate a decline in overall longevity in the United States. Even prior to the COVID-19 pandemic, an increase in midlife mortality rates had been reported. Life expectancy disparities have persisted in the United States for racial and ethnic groups and for individuals living at low socioeconomic status. These continued trends in mortality indicate the importance of examining biomarkers of mortality at midlife in at-risk populations. Circulating levels of cytokines and inflammatory markers reflect systemic chronic inflammation, which is a well-known driver of many age-related diseases.

METHODS

In this study, we examined the relationship of nine different inflammatory proteins with mortality in a middle-aged socioeconomically diverse cohort of African-American and White men and women (n = 1122; mean age = 47.8 years).

RESULTS

We found significant differences in inflammatory-related protein serum levels between African-American and White middle-aged adults. E-selectin and fibrinogen were significantly higher in African-American adults. IFN-γ, TNF-α trimer, monocyte chemoattractant protein-1 (MCP-1), soluble receptor for advanced glycation end-products (sRAGE) and P-selectin were significantly higher in White participants compared to African-American participants. Higher levels of E-selectin, MCP-1 and P-selectin were associated with a higher mortality risk. Furthermore, there was a significant interaction between sex and IL-6 with mortality. IL-6 levels were associated with an increased risk of mortality, an association that was significantly greater in women than men. In addition, White participants with high levels of sRAGE had significantly higher survival probability than White participants with low levels of sRAGE, while African-American participants had similar survival probabilities across sRAGE levels.

CONCLUSIONS

These results suggest that circulating inflammatory markers can be utilized as indicators of midlife mortality risk in a socioeconomically diverse cohort of African-American and White individuals.