Gut microbiota in hypertensive patients with versus without obstructive sleep apnea

Anthocyanins as natural bioactives with anti-hypertensive and atherosclerotic potential: Health benefits and recent advances

BACKGROUND

Hypertension is a highly prevalent chronic metabolic illness affecting individuals of all age groups. Furthermore, it is a significant risk factor for the development of atherosclerosis (AS), as a correlation between hypertension and AS has been observed. However, the effective treatments for either of these disorders appear to be uncommon.

METHODS

A systematic search of articles published in PubMed, Web of Science, ScienceDirect, Scopus, and Google Scholar databases over the last decade was performed using the following keywords: hypertension, AS, anthocyanins, antioxidants, gut microbes, health benefits, and bioactivity.

RESULTS

The available research indicates that anthocyanin consumption can achieve antioxidant effects by inducing the activation of intracellular nuclear factor erythroid 2-related factor (Nrf2) and the expression of antioxidant genes. Moreover, previous reports showed that anthocyanins can enhance the human body's ability to fight against inflammation and cancer through the inhibition of inflammatory factors and the regulation of related signaling pathways. They can also protect the blood vessels and nervous system by regulating the production and function of endothelial nitric oxide synthase (eNOS). Gut microorganisms play an important role in various chronic diseases. Our research has also investigated the role of anthocyanins in the metabolism of the gut microbiota, leading to significant breakthroughs. This study not only presents a unique strategy for reducing the risk of cardiovascular diseases (CVDs) without the need for medicine but also provides insights into the development and utilization of intestinal probiotic dietary supplements.

CONCLUSION

In this review, different in vitro and in vivo studies have shown that anthocyanins slow down the onset and progression of hypertension and AS through different mechanisms. In addition, gut microbial metabolites also play a crucial role in diseases through the gut-liver axis.

Association between obstructive sleep apnea and arrhythmia and heart rate variability among hypertensive patients

BACKGROUND

The relationship between obstructive sleep apnea (OSA) and the occurrence of arrhythmias and heart rate variability (HRV) in hypertensive patients is not elucidated. Our study investigates the association between OSA, arrhythmias, and HRV in hypertensive patients.

METHODS

We conducted a cross-sectional analysis involving hypertensive patients divided based on their apnea-hypopnea index (AHI) into two groups: the AHI ≤ 15 and the AHI > 15. All participants underwent polysomnography (PSG), 24-hour dynamic electrocardiography (DCG), cardiac Doppler ultrasound, and other relevant evaluations.

RESULTS

The AHI > 15 group showed a significantly higher prevalence of frequent atrial premature beats and atrial tachycardia (P = 0.030 and P = 0.035, respectively) than the AHI ≤ 15 group. Time-domain analysis indicated that the standard deviation of normal-to-normal R-R intervals (SDNN) and the standard deviation of every 5-minute normal-to-normal R-R intervals (SDANN) were significantly higher in the AHI > 15 group (P = 0.020 and P = 0.033, respectively). Frequency domain analysis revealed that the low-frequency (LF), high-frequency (HF) components, and the LF/HF ratio were also significantly elevated in the AHI > 15 group (P < 0.001, P = 0.031, and P = 0.028, respectively). Furthermore, left atrial diameter (LAD) was significantly larger in the AHI > 15 group (P < 0.001). Both univariate and multivariable linear regression analyses confirmed a significant association between PSG-derived independent variables and the dependent HRV parameters SDNN, LF, and LF/HF ratio (F = 8.929, P < 0.001; F = 14.832, P < 0.001; F = 5.917, P = 0.016, respectively).

CONCLUSIONS

Hypertensive patients with AHI > 15 are at an increased risk for atrial arrhythmias and left atrial dilation, with HRV significantly correlating with OSA severity.

Sleep apnoea, gut dysbiosis and cognitive dysfunction

Sleep disorders are becoming increasingly common, and their distinct effects on physical and mental health require elaborate investigation. Gut dysbiosis (GD) has been reported in sleep-related disorders, but sleep apnoea is of particular significance because of its higher prevalence and chronicity. Cumulative evidence has suggested a link between sleep apnoea and GD. This review highlights the gut-brain communication axis that is mediated via commensal microbes and various microbiota-derived metabolites (e.g. short-chain fatty acids, lipopolysaccharide and trimethyl amine N-oxide), neurotransmitters (e.g. γ-aminobutyric acid, serotonin, glutamate and dopamine), immune cells and inflammatory mediators, as well as the vagus nerve and hypothalamic-pituitary-adrenal axis. This review also discusses the pathological role underpinning GD and altered gut bacterial populations in sleep apnoea and its related comorbid conditions, particularly cognitive dysfunction. In addition, the review examines the preclinical and clinical evidence, which suggests that prebiotics and probiotics may potentially be beneficial in sleep apnoea and its comorbidities through restoration of eubiosis or gut microbial homeostasis that regulates neural, metabolic and immune responses, as well as physiological barrier integrity via the gut-brain axis.

The effects of obstructive sleep apnea on blood pressure variability and load in patients with hypertension

BACKGROUND

Hypertension frequently coexists with obstructive sleep apnea (OSA), and their interplay substantially impacts the prognosis of affected individuals. Investigating the influence of OSA on blood pressure variability (BPV) and blood pressure load (BPL) in hypertensive patients has become a focal point of clinical research.

METHODS

This cross-sectional study recruited hypertensive patients (n = 265) without discrimination and classified them into four groups based on their apnea-hypopnea index (AHI): control group (n = 40), AHI < 5; mild group (n = 74), 5 ≤ AHI ≤ 15; moderate group (n = 68), 15 < AHI ≤ 30; severe group (n = 83), AHI > 30. All participants underwent comprehensive assessments, including polysomnography (PSG) monitoring, 24-h ambulatory blood pressure (ABP) monitoring, cardiac Doppler ultrasound, and additional examinations when indicated.

RESULTS

BPV and BPL exhibited significant elevations in the moderate and severe OSA groups compared to the control and mild OSA groups (P < 0.05). Moreover, interventricular septum thickness and left ventricular end-diastolic volume (LVEDV) demonstrated higher values in the moderate and severe OSA groups (P < 0.05). Multiple stepwise regression analysis identified noteworthy risk factors for elevated BPV in hypertensive patients with OSA, including AHI, maximum apnea time, total times of oxygen reduction, and mean time of apnea.

CONCLUSION

Hypertensive patients with moderate to severe OSA exhibited substantially increased BPV and BPL. Moreover, BPV was correlated with AHI, maximum apnea time, total times of oxygen reduction, and mean time of apnea in hypertensive patients with OSA.

Association of Tumor Necrosis Factor-Alpha, Interleukin-1β, Interleukin-8, and Interferon-γ with Obstructive Sleep Apnea in Both Children and Adults: A Meta-Analysis of 102 Articles

Background: Cytokines may have a significant impact on sleep regulation. In this meta-analysis, we present the serum/plasma levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-8, IL-1β, and interferon-gamma (IFN-γ) in both children and adults with obstructive sleep apnea (OSA) in comparison to controls. Methods: Four electronic databases were systematically searched (PubMed, Web of Science, Scopus, and Cochrane Library) through 19 October 2023, without any restrictions on language, date, age, and sex. We used Review Manager version 5.3 to perform meta-analysis and presented the data as standardized mean difference (SMD) and 95% confidence interval (CI) values to evaluate the relationships between the levels of cytokines and OSA. Results: A total of 102 articles (150 independent studies) were included in the meta-analysis. The pooled SMDs in adults were 1.42 (95%CI: 1.11, 1.73; p < 0.00001), 0.85 (95%CI: 0.40, 1.31; p = 0.0002), 0.69 (95%CI: 0.22, 1.16; p = 0.004), and 0.39 (95%CI: -0.37, 1.16; p = 0.31) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. The pooled SMDs in children were 0.84 (95%CI: 0.35, 1.33; p = 0.0008), 0.60 (95%CI: 0.46, 0.74; p < 0.00001), 0.25 (95%CI: -0.44, 0.93; p = 0.49), and 3.70 (95%CI: 0.75, 6.65; p = 0.01) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. Conclusions: The levels of proinflammatory cytokines of TNF-α, IL-8, and IL-1β in adults, and TNF-α, IL-8, and IFN-γ in children with OSA, are significantly higher than those in controls.

[Analysis of gut target microbiota and species difference in patients with obstructive sleep apnea based on 16S rRNA sequencing]

OBJECTIVE

To explore the difference in gut microbiota composition between patients with obstructive sleep apnea (OSA) and healthy individuals and the role of gut microbiota in the pathogenesis of OSA.

METHODS

Thirty-nine patients with OSA admitted to our hospital between May and December, 2022 and 20 healthy individuals were enrolled in this study. Stool samples were collected from all the participants for analysis of microbiome composition using 16S rRNA high- throughput sequencing analysis. The alpha diversity, beta diversity, and species difference were determined between the two groups and marker species analysis and metabolic pathway function prediction analysis were performed.

RESULTS

The species diversity (Shannon and Simpson) indexes, richness (observed species) and evenness (Pielou) of gut microbiota were significantly lower in OSA patients than in the healthy individuals (P < 0.05). The OSA patients had also a significantly lowered community diversity (P < 0.05) with different gut microbial communities from those of the healthy individuals shown by increased relative abundance of potentially pathogenic bacteria such as Pseudomonas and Monocytogenes (P < 0.05). LEfSe analysis showed that the abundance of 23 species of gut microbiota differed significantly between the two groups and the OSA patients had significant increases in the abundance of Pseudomonas, Meganomonas, and Fusobacterium (P < 0.05). The differential marker flora affected host homeostasis. Random Forest and ROC curve analyses confirmed that Pseudomonas could be used as important biomarkers for a differential diagnosis. Metabolic pathway function prediction analysis showed that biosynthesis function had the greatest contribution to maintaining gut microbiota homeostasis, and Pseudomonas affected the occurrence and progression of OSA by participating in aromatic bioamine degradation and ketogluconic acid metabolic pathway.

CONCLUSION

OSA patients have obvious gut microbiota disturbances, and Pseudomonas may affect the development of OSA by participating in substance metabolism to serve as the potential target gut bacteria for OSA treatment.

Causality Investigation between Gut Microbiota, Derived Metabolites, and Obstructive Sleep Apnea: A Bidirectional Mendelian Randomization Study

Various studies have highlighted the important associations between obstructive sleep apnea (OSA) and gut microbiota and related metabolites. Nevertheless, the establishment of causal relationships between these associations remains to be determined. Multiple mendelian randomization (MR) analyses were performed to genetically predict the causative impact of 196 gut microbiota and 83 metabolites on OSA. Two-sample MR was used to assess the potential association, and causality was evaluated using inverse variance weighted (IVW), MR-Egger, and weighted median (WM) methods. Multivariable MR (MVMR) was employed to ascertain the causal independence between gut microbiota and the metabolites linked to OSA. Additionally, Cochran's Q test, the MR Egger intercept test and the MR Steiger test were used for the sensitivity analyses. The analysis of the 196 gut microbiota revealed that genus_Ruminococcaceae (UCG009) (PIVW = 0.010) and genus_Subdoligranulum (PIVW = 0.041) were associated with an increased risk of OSA onset. Conversely, Family_Ruminococcaceae (PIVW = 0.030), genus_Coprococcus2 (PWM = 0.025), genus_Eggerthella (PIVW = 0.011), and genus_Eubacterium (xylanophilum_group) (PIVW = 0.001) were negatively related to the risk of OSA. Among the 83 metabolites evaluated, 3-dehydrocarnitine, epiandrosterone sulfate, and leucine were determined to be potential independent risk factors associated with OSA. Moreover, the reverse MR analysis demonstrated a suggestive association between OSA exposure and six microbiota taxa. This study offers compelling evidence regarding the potential beneficial or detrimental causative impact of the gut microbiota and its associated metabolites on OSA risk, thereby providing new insights into the mechanisms of gut microbiome-mediated OSA development.

Analysis of gut microbiotal diversity in healthy young adults in Sunan County, Gansu Province, China

Objective

To examine gut microbiotal diversity in the Han Chinese and Yugur populations of Sunan County, Gansu Province, living in the same environmental conditions, and to analyze possible causes of differences in diversity.

Methods

We selected 28 people, ages 18-45 years old, all of whom were third-generation pure Yugur or Han Chinese from Sunan County. Fresh fecal samples were collected, and total bacterial deoxyribonucleic acid (DNA) was extracted. We performed 16S ribosomal ribonucleic acid (16S rRNA) high-throughput sequencing (HTS) and bioinformatics to study the relationships among between gut microbiota structure, genetics, and dietary habits in Yugur and Han Chinese subjects.

Results

We found 350 differential operational taxonomic units (OTUs) in Han Chinese and Yugur gut microbiota, proving that gut microbiota differed between the two populations. That were less abundant among Yugurs than Han Chinese were Prevotella_9 and Alloprevotella. That were more abundant among Yugurs than Han Chinese were Anaerostipes and Christensenellaceae_R-7_group. And they were significantly associated with a high-calorie diet In addition. we found differences in predicted gut microbiota structural functions (The main functions were metabolic and genetic information) between the two populations.

Conclusion

Yugur subjects demonstrated differences in gut microbiotal structure from Han Chinese subjects, and this difference influenced by dietary and may be influenced by genetic influences. This finding will provide a fundamental basis for further study of the relationships among gut microbiota, dietary factors, and disease in Sunan County.

Is the Gut Microbiome Implicated in the Excess Risk of Hypertension Associated with Obstructive Sleep Apnea? A Contemporary Review

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder and an established risk factor for cardiovascular diseases, including hypertension. The pathogenesis of elevated blood pressure (BP) in OSA is multifactorial, including sympathetic overdrive, vascular aberrations, oxidative stress, inflammation, and metabolic dysregulation. Among the mechanisms potentially involved in OSA-induced hypertension, the role of the gut microbiome is gaining increasing attention. Perturbations in the diversity, composition, and function of the gut microbiota have been causally linked to numerous disorders, and robust evidence has identified gut dysbiosis as a determinant of BP elevation in various populations. In this brief review, we summarize the current body of literature on the implications of altered gut microbiota for hypertension risk in OSA. Data from both preclinical models of OSA and patient populations are presented, and potential mechanistic pathways are highlighted, along with therapeutic considerations. Available evidence suggests that gut dysbiosis may promote the development of hypertension in OSA and may thus be a target for interventions aimed at attenuating the adverse consequences of OSA in relation to cardiovascular risk.

Gut microbiota in hypertensive patients with versus without obstructive sleep apnea

We investigated the alteration of gut microbiota and the associated metabolic risks in hypertensive patients with obstructive sleep apnea (OSA) comorbidity. Fecal and blood samples were collected from 52 hypertensive patients, who were divided into three groups: A (controls, apnea-hypopnea index[AHI] < 5, n = 15), B (mild OSA, 5 < AHI < 20, n = 17), and C (moderate-to-severe OSA, AHI > 20, n = 20). The composition of the gut microbiota was studied through 16s RNA sequencing of variable regions 3-4. Analysis of the results revealed that group C had a significant higher concentration of total cholesterol, low-density lipoprotein, and IL-1β compared with group A. The Shannon index showed that bacterial biodiversity was lower in OSA patients. At the phylum level, the ratio of Firmicutes to Bacteroidetes (F/B) was significantly higher in group C than in groups A and B. At the genus level, the relative abundance of short-chain fatty acids (SCFA)-producing bacteria (e.g., Bacteroides and Prevotella) was lower while the number of inflammation-related bacteria (e.g., Lactobacillus) was increased in patients with OSA. We found that the IL-1β level was negatively correlated with Bacteroidetes. The area under the receiver operating characteristic curve was .672 for F/B ratio in determining hypertensive patients with OSA. In patients with hypertension, OSA was associated with worse gut dysbiosis, as evidenced by decreased levels of short-chain fatty acids-producing bacteria and increased number of inflammation-related bacteria. The differences in gut microbiota discriminate hypertensive patients with OSA from those without and may result in an enhanced inflammatory response and increase the risk of metabolic diseases.