Circulating haematopoietic stem cells and long-term outcomes of COVID-19

BACKGROUND AND AIMS

An acute depletion of circulating haematopoietic stem/progenitor cells (HSPCs) occurs during COVID-19, especially among patients with a poorer disease course. We herein examined whether HSPCs levels at hospital admission for COVID-19 predict 1-year mortality and the long-COVID syndrome.

MATERIALS AND METHODS

Patients hospitalized for COVID-19 in an infectious disease ward were consecutively enrolled. Circulating HSPC levels were assessed by flow cytometry as cells expressing CD34 and/or CD133. Follow-up was performed for 12 months after hospitalization through the review of electronic medical records and demographic local registers.

RESULTS

The study included 100 patients, 36 of whom reported symptoms of long-COVID and 20 died during follow-up. The reduction of 1-SD of HSPCs was associated with a 3- to 5-fold increase in the risk of 1-year mortality. Age, admission hyperglycaemia, C-reactive protein peak, liver enzymes, the need of high-flow oxygen and/or invasive ventilation were predictors of mortality at univariate analysis. Among pre-existing comorbidities, coronary heart disease and chronic kidney disease, but not diabetes, were associated with 1-year mortality. In multivariate analyses, HSPCs remained significantly associated with 1-year mortality independently of confounders. The development of pneumonia an in-hospital treatment with glucocorticoids and convalescent plasma were associated with long-COVID symptoms at follow-up. HSPCs, diabetes and other comorbidities were not predictors of long-COVID.

CONCLUSIONS

In a cohort of patients hospitalized for COVID-19, lower HSPC levels at the time of admission were independent predictors of 1-year mortality. However, COVID-19 severity, but not HSPC level, was significantly associated with the development of long-COVID symptoms.

Sphingosine 1-phosphate signaling axis mediates neuropeptide S-induced invasive phenotype of endometriotic cells

Endometriosis is a chronic gynecological syndrome characterized by endometrial cell invasion of the extra-uterine milieu, pelvic pain and infertility. Treatment relies on either symptomatic drugs or hormonal therapies, even though the mechanism involved in the onset of endometriosis is yet to be elucidated. The signaling of sphingolipid sphingosine 1-phosphate (S1P) is profoundly dysregulated in endometriosis. Indeed, sphingosine kinase (SK)1, one of the two isoenzymes responsible for S1P biosynthesis, and S1P1, S1P3 and S1P5, three of its five specific receptors, are more highly expressed in endometriotic lesions compared to healthy endometrium. Recently, missense coding variants of the gene encoding the receptor 1 for neuropeptide S (NPS) have been robustly associated with endometriosis in humans. This study aimed to characterize the biological effect of NPS in endometriotic epithelial cells and the possible involvement of the S1P signaling axis in its action. NPS was found to potently induce cell invasion and actin cytoskeletal remodeling. Of note, the NPS-induced invasive phenotype was dependent on SK1 and SK2 as well as on S1P1 and S1P3, given that the biological action of the neuropeptide was fully prevented when one of the two biosynthetic enzymes or one of the two selective receptors was inhibited or silenced. Furthermore, the RhoA/Rho kinase pathway, downstream to S1P receptor signaling, was found to be critically implicated in invasion and cytoskeletal remodeling elicited by NPS. These findings provide new information to the understanding of the molecular mechanisms implicated in endometriosis pathogenesis, establishing the rationale for non-hormonal therapeutic targets for its treatment.

Distinguishable DNA methylation defines a cardiac-specific epigenetic clock

BACKGROUND

The present study investigates whether epigenetic differences emerge in the heart of patients undergoing cardiac surgery for an aortic valvular replacement (AVR) or coronary artery bypass graft (CABG). An algorithm is also established to determine how the pathophysiological condition might influence the human biological cardiac age.

RESULTS

Blood samples and cardiac auricles were collected from patients who underwent cardiac procedures: 94 AVR and 289 CABG. The CpGs from three independent blood-derived biological clocks were selected to design a new blood- and the first cardiac-specific clocks. Specifically, 31 CpGs from six age-related genes, ELOVL2, EDARADD, ITGA2B, ASPA, PDE4C, and FHL2, were used to construct the tissue-tailored clocks. The best-fitting variables were combined to define new cardiac- and blood-tailored clocks validated through neural network analysis and elastic regression. In addition, telomere length (TL) was measured by qPCR. These new methods revealed a similarity between chronological and biological age in the blood and heart; the average TL was significantly higher in the heart than in the blood. In addition, the cardiac clock discriminated well between AVR and CABG and was sensitive to cardiovascular risk factors such as obesity and smoking. Moreover, the cardiac-specific clock identified an AVR patient's subgroup whose accelerated bioage correlated with the altered ventricular parameters, including left ventricular diastolic and systolic volume.

CONCLUSION

This study reports on applying a method to evaluate the cardiac biological age revealing epigenetic features that separate subgroups of AVR and CABG.