Autonomic cardiac function in children and adolescents with long COVID: a case-controlled study.

Although the mechanisms underlying the pathophysiology of long COVID condition are still debated, there is growing evidence that autonomic dysfunction may play a role in the long-term complications or persisting symptoms observed in a significant proportion of patients after SARS-CoV-2 infection. However, studies focused on autonomic dysfunction have primarily been conducted in adults, while autonomic function has not yet been investigated in pediatric subjects. In this study, for the first time, we assessed whether pediatric patients with long COVID present abnormalities in autonomic cardiac function. Fifty-six long COVID pediatric patients (mean age 10.3 ± 3.8 y) and 27 age-, sex-, and body surface area-matched healthy controls (mean age 10.4 ± 4.5y) underwent a standard 12-lead electrocardiography (ECG) and 24-h ECG Holter monitoring. Autonomic cardiac function was assessed by time-domain and frequency-domain heart rate variability parameters. A comprehensive echocardiographic study was also obtained by two-dimensional echocardiography and tissue Doppler imaging. Data analysis showed that pediatric patients with long COVID had significant changes in HRV variables compared to healthy controls: significantly lower r-MSSD (root mean square of successive RR interval differences, 47.4 ± 16.9 versus 60.4 ± 29.1, p = 0.02), significant higher values VLF (very low frequency, 2077.8 ± 1023.3 versus 494.3 ± 1015.5 ms, p = 0.000), LF (low frequency, 1340.3 ± 635.6 versus 354.6 ± 816.8 ms, p = 0.000), and HF (high frequency, 895.7 ± 575.8 versus 278.9 ± 616.7 ms, p = 0.000). No significant differences were observed between the two groups both in systolic and diastolic parameters by echocardiography.  Conclusion: These findings suggest that pediatric patients with long COVID have an imbalance of cardiac autonomic function toward a relative predominance of parasympathetic tone, as already reported in adult patients with long COVID. Further studies are needed to clarify the clinical significance of this autonomic dysfunction and demonstrate its role as a pathophysiological mechanism of long COVID, paving the way for effective therapeutic and preventive strategies. What is Known: • Long Covid in children has been described globally, but studies have mostly focused on collecting the temporal evolution of persisting symptoms. What is New: • Cardiac autonomic imbalance toward a relative predominance of parasympathetic tone is a mechanism underlying Long Covid in children, as also described in adults.

A local glucagon-like peptide 1 (GLP-1) system in human pancreatic islets.

AIMS/HYPOTHESIS: Glucagon-like peptide 1 (GLP-1) is a major incretin, mainly produced by the intestinal L cells, with beneficial actions on pancreatic beta cells. However, while in vivo only very small amounts of GLP-1 reach the pancreas in bioactive form, some observations indicate that GLP-1 may also be produced in the islets. We performed comprehensive morphological, functional and molecular studies to evaluate the presence and various features of a local GLP-1 system in human pancreatic islet cells, including those from type 2 diabetic patients. METHODS: The presence of insulin, glucagon, GLP-1, proconvertase (PC) 1/3 and PC2 was determined in human pancreas by immunohistochemistry with confocal microscopy. Islets were isolated from non-diabetic and type 2 diabetic donors. GLP-1 protein abundance was evaluated by immunoblotting and matrix-assisted laser desorption-ionisation-time of flight (MALDI-TOF) mass spectrometry. Single alpha and beta cell suspensions were obtained by enzymatic dissociation and FACS sorting. Glucagon and GLP-1 release were measured in response to nutrients. RESULTS: Confocal microscopy showed the presence of GLP-1-like and PC1/3 immunoreactivity in subsets of alpha cells, whereas GLP-1 was not observed in beta cells. The presence of GLP-1 in isolated islets was confirmed by immunoblotting, followed by mass spectrometry. Isolated islets and alpha (but not beta) cell fractions released GLP-1, which was regulated by glucose and arginine. PC1/3 (also known as PCSK1) gene expression was shown in alpha cells. GLP-1 release was significantly higher from type 2 diabetic than from non-diabetic isolated islets. CONCLUSIONS/INTERPRETATION: We have shown the presence of a functionally competent GLP-1 system in human pancreatic islets, which resides in alpha cells and might be modulated by type 2 diabetes.

Fasitibant prevents the bradykinin and interleukin 1ß synergism on prostaglandin E2 release and cyclooxygenase 2 expression in human fibroblast-like synoviocytes.

This study investigates the effect of the selective and potent B(2) receptor antagonist fasitibant (MEN16132) on the proinflammatory effect of bradykinin (BK) and its interaction with interleukin 1ß (IL-1ß) in human synoviocytes. PGE(2) content was detected in the surnatants and COX-2 and COX-1 gene and protein expression determined in the cells. Radioligand binding ([(3) H]BK) and BK-induced inositolphosphate experiments were performed. Incubation of synoviocytes with BK induced a sustained production of PGE(2) and transient COX-2 gene expression that were prevented by pretreatment with fasitibant (1 µM, 30 min preincubation). IL-1ß increased PGE(2) release and COX-2 expression more than BK alone. The combined treatment of cells with BK and IL-1ß induced an even increase of released PGE(2) and COX-2 gene and protein expression indicating a synergistic rather than an additive effect, not related to an increase of B(2) receptors density or its coupling. These potentiating effects of BK on PGE(2) production and increased COX-2 expression produced by IL-1ß were B(2)-receptor-mediated as fasitibant could prevent them. None of the treatments induced changes in the COX-1 expression. The synergistic PGE(2) production was abolished by the specific NF-kappaB inhibitor (BAY-117085), whereas specific inhibitors for the p38 (SB203580), JNK (SP600125), and ERK1/2 (PD98059) mitogen-activated protein kinases could prevent the prostanoid release. BK can potentiate the COX-2 gene expression and consequent prostanoid production induced by IL-1ß. The prevention of this synergism by fasitibant indicates BK B(2) receptor blockade as an alternative symptomatic therapy for osteoarthritis.

A novel ex vivo organotypic culture model of alkaptonuria-ochronosis.

OBJECTIVES: Alkaptonuria (AKU) is an orphan disease that has an estimated prevalence of 0.3/100,000. The disease is caused by the lack of activity of homogentisic acid oxidase (HGO), an enzyme involved in tyrosine and phenylalanine metabolism. To date, there is only one drug, the nitisinone, with orphan designation authorised by both Food and Drug Administration (FDA) and European Medical Agency (EMA) for AKU. A clinical trial on AKU patients using nitisinone has recently been completed but it needs further investigation for long-term therapy. In recent years our group has developed a series of AKU in vitro models using cell lines, primary chondrocytes and human plasma in order to test the efficacy of new substances, mainly antioxidant compounds, for AKU therapy. Herein, we report the optimisation of an ex vivo reproducible culture method exploiting cartilage slices in order to investigate the deposition of ochronotic pigment in this kind of connective tissue. METHODS: Human normal cartilage slices, obtained after surgery for prosthesis replacement, were cultured for several days in the presence of a sublethal concentration of homogentisic acid (HGA). RESULTS: After two months of incubation with HGA, the peculiar melanin-like ochronotic pigmentation can be observed into the cartilage tissue. CONCLUSIONS: This novel organo-typic ex vivo model could be extremely useful to investigate the efficacy of substances able to ameliorate the conditions of AKU patients. Moreover, it could be used for genetic and proteomic investigations to better define AKU pathophysiology.