๐ก Postural Orthostatic Tachycardia Syndrome (POTS) and post-acute COVID-19 syndrome (PACS) have been associated with autonomic dysfunction. This study aimed to investigate gastrointestinal symptoms and gut microbiota composition in POTS and PACS patients compared to controls. The study focused on understanding the relationship between clinical symptoms, microbiota diversity, and taxonomic abundance.
๐ Methods:
Fecal samples and 4-day food diaries were collected from POTS patients (n=27), PACS patients (n=32), and controls (n=39). DNA sequencing was conducted to analyze microbiota composition. Participants also completed irritable bowel syndrome-severity scoring system (IBS-SSS) and visual analog scale for IBS (VAS-IBS) assessments.
๐ Key Findings:
๐ Microbiota Diversity: POTS patients showed lower alpha diversity (richness and Shannon indices) compared to controls. PACS patients exhibited lower richness in alpha diversity compared to controls.
๐ Taxonomic Composition: Significant differences in taxonomic composition were observed between POTS patients and controls, affecting multiple levels, including MGS, species, genus, family, and order. PACS patients only showed differences in the abundance of the phyla ๐๐ด๐ค๐ฐ๐ฎ๐บ๐ค๐ฐ๐ต๐ข ๐ข๐ฏ๐ฅ ๐๐ช๐ณ๐ฎ๐ช๐ค๐ถ๐ต๐ฆ๐ด compared to controls.
๐ Clinical Correlations: Total IBS-SSS, fatigue, bloating, and flatulence correlated significantly with multiple microbiome variables in both POTS and PACS patients. The associations included alpha diversity, individual taxa abundances, and gene- or MGS-based functional group abundances.
๐ Microbiota and Autonomic Neuropathy: Autonomic neuropathy may lead to gastrointestinal dysmotility, impacting microbiota composition. Bidirectional crosstalk between microbiota and gastrointestinal function was evident, with correlations between gastrointestinal symptoms and bacteria composition.
๐ Comparison with Previous Studies: Comparisons with studies on diabetes suggest similarities in microbiota alterations due to autonomic neuropathy.
๐ Gut-Lung Axis in COVID-19: The gut-lung axis may explain the concomitant occurrence of fever, cough, fatigue, and gastrointestinal symptoms in COVID-19. Dysbiosis in COVID-19 patients may contribute to symptoms, and probiotics have shown symptom improvement.
๐ Limitations: Challenges in comparing microbiota composition across studies due to methodological differences and reliance on symptom criteria for diagnoses. The study’s cross-sectional design limits the determination of causality.
๐ POTS and, to a lesser extent, PACS are associated with differences in gut microbiota composition at various taxonomic levels and diversity indices. Clinical symptoms, including total IBS-SSS, fatigue, and bloating, correlate with microbiota variations, suggesting a bidirectional relationship. Microbiota alterations appear more pronounced in POTS than PACS, indicating potential disease-specific effects on gut microbiota. Understanding the gut-lung axis and bidirectional crosstalk between microbiota and gastrointestinal function provides insights into the complex interplay between autonomic dysfunction, microbiota, and clinical symptoms.
๐ Future Directions: Longitudinal studies are recommended to elucidate the temporal relationship between microbiota changes and symptoms.
Inclusion of larger and more diverse cohorts, along with standardized methodologies, would enhance the generalizability and comparability of findings.
Further exploration of the gut-lung axis in the context of COVID-19 and the impact of interventions like probiotics on symptom management.
Link to the article : http://tinyurl.com/5xupj3kx
