Plasma zinc status and hyperinflammatory syndrome in hospitalized COVID-19 patients

Background SARS-CoV-2 is associated with significant mortality and morbidity in a subgroup of patients who develop cytokine releasing syndrome (CRS) and the related acute respiratory distress syndrome. Precedent evidence suggests that deficiency of the element zinc can be associated with similar complications as well as impaired antiviral response. Herein, beyond determining the zinc status, we explore the association between the plasma zinc concentration, the development of CRS, and the clinical outcomes in hospitalized COVID-19 patients. Methods We conducted a prospective, single-center, observational study in a tertiary university hospital (CUB-Hopital Erasme, Brussels). Hospitalized adult patients with PCR-confirmed SARS-CoV-2 infection were enrolled within 72 hours of hospital admission. We assessed the presence and severity of COVID-19-associated hyperinflammatory syndrome (cHIS), an additive six-point clinical scale that we independently validated in the current study. We defined the clinical outcomes as the length of hospitalization, the incidence of mechanical ventilation, and mortality. We recorded the outcomes with a follow-up of 90 days from hospital admission. Results One hundred and thirty-nine eligible patients were included between May 2020 and November 2020 (median age of 65 years [IQR, 54 to 77]). Our cohort's mean plasma zinc concentration was 56.2 mcg/dL (standard deviation [SD], 14.8). The absolute majority of patients (96%) were zinc deficient (<80mcg/dL). The mean plasma zinc concentration was lower in patients with CRS (cHIS ≧ 2)compared to those without CRS (-5 mcg/dL; 95% CI, -10.5 to 0.051; p = 0.048). We observed that the plasma zinc concentration is weakly but significantly correlated with the length of hospital stay (rho = -0.19; p = 0.022). However, the plasma zinc concentration was not significantly associated with the risk of mortality or morbidity. Conclusions Markedly, an absolute majority of hospitalized COVID-19 patients are zinc deficient. We found no significant association between zinc plasma concentration and cHIS. We find a weak (reverse) correlation between plasma zinc concentration and the length of hospital stay, but not with mortality or morbidity. As such, our findings do not support the role of zinc as a robust prognostic factor among hospitalized COVID-19 patients. We encourage further studies to explore the role of zinc as a biomarker for assessing the risk of developing a tissue-damaging CRS and predicting outcomes in patients diagnosed with COVID-19.

Considerations on the Influence of Zinc on Infectious Diseases in Children

Zinc modulates the human body defence against infections. Mild and medium deficiency in this mineral appears usually sub-clinically, being mistaken for other diseases, but the severe form can be fatal. The purpose of the study was to determine the plasma zinc concentration (PZC) for the most common infectious pathology in children. Zinc was measured in plasma using direct colorimetric assay based on the 5-Br-PAPS method (CV% 0.98-4.64%). In the paediatric patients, 0-3 years old, the PZC values were 15.20�1.37 μmol/L, with limits ranging between 13.05-20.6 μmol/L, the values falling within normal limits and proving the absence of zinc deficiency in the investigated population. During 3 years of follow up, 137 healthy children presented low values of plasma zinc concentration if they had acute lower respiratory infections, acute otitis media or giardiasis in past medical history. There were not found significant differences in case of children with viral or bacterial acute diarrheal diseases or viral exanthemas. In the present study, the children exposed to severe, complicated or chronic forms of infectious diseases were predisposed to low plasma zinc concentrations.

Zinc Intake, Zinc Bioavailability and Plasma Zinc in Obese Adolescents with Clinical Insulin Resistance Following Low Energy Diets

Background: Zinc has a critical role in metabolism and growth. This study aims to determine the effects of low-energy diets differing in macronutrient composition on zinc intake, estimated zinc bioavailability (phytate:zinc molar ratio) and plasma zinc concentration and associations between zinc status and cardiometabolic markers in obese adolescents with clinical insulin resistance (IR). Methods: Eighty-seven obese adolescents (10-17 years, body mass index z-score 2.3 ± 0.37) with clinical IR were randomized to a low-energy diet (6.0-8.0 MJ), which was either high carbohydrate or moderate carbohydrate with increased protein. Twenty-four-hour dietary recalls were collected at 6, 9 and 12 weeks. Plasma zinc concentration and cardiometabolic markers were assessed at baseline and 12 weeks. Results: Zinc intake did not differ between the 2 diet groups (p = 0.612). The high-carbohydrate group had a higher phytate intake (894 vs. 671 mg, p = 0.018) and phytate:zinc molar ratio (9.4 vs. 7.4, p = 0.009) than the increased-protein group. Plasma zinc concentration did not change from baseline in either of the diet groups, but correlated positively with zinc intake (r = 0.235, p = 0.042) and % energy from protein (r = 0.383, p = 0.001), and inversely with % energy from carbohydrate (r = -0.296, p = 0.010). Conclusions: Low energy diets for obese adolescents at risk of diabetes may need increased protein content to optimize zinc bioavailability.