Remdesivir, dexamethasone and angiotensin-converting enzyme inhibitors use and mortality outcomes in COVID-19 patients with concomitant troponin elevation

BACKGROUND

There are indications that viral myocarditis, demand ischemia, and renin-angiotensin-aldosterone system pathway activation play essential roles in troponin elevation in coronavirus disease 2019 (COVID-19) patients. Antiviral medications and steroids are used to treat viral myocarditis, but their effect in patients with elevated troponin, possibly from myocarditis, has not been studied.

AIM

To evaluate the effect of dexamethasone, remdesivir, and angiotensin-converting enzyme (ACE) inhibitors (ACEI) on mortality in COVID-19 patients with elevated troponin.

METHODS

Our retrospective observational study involved 1788 COVID-19 patients at seven hospitals in Southern California, United States. We did a backward selection Cox multivariate regression analysis to determine predictors of mortality in our study population. Additionally, we did a Kaplan Meier survival analysis in the subset of patients with elevated troponin, comparing survival in patients that received dexamethasone, remdesivir, and ACEI with those that did not.

RESULTS

The mean age was 66 years (range 20-110), troponin elevation was noted in 11.5% of the patients, and 29.9% expired. The patients' age [hazard ratio (HR) = 1.02, P < 0.001], intensive care unit admission (HR = 5.07, P < 0.001), and ventilator use (HR = 0.68, P = 0.02) were significantly associated with mortality. In the subset of patients with elevated troponin, there was no statistically significant difference in survival in those that received remdesivir (0.07), dexamethasone (P = 0.63), or ACEI (P = 0.8) and those that did not.

CONCLUSION

Although elevated troponin in COVID-19 patients has been associated with viral myocarditis and ACE II receptors, conventional viral myocarditis treatment, including antiviral and steroids, and ACEI did not show any effect on mortality in these patients.

Parameters affecting the in vitro maturation of human monocytes to macrophages

In vitro maturation of human monocytes to macrophages was characterized by morphological criteria, cell size and lysosomal enzymes activity. Purified populations of monocytes were maintained in culture at either adherent or nonadherent conditions and their maturation to macrophages was observed in both cases. The addition of external factors such as hydrocortisone and vitamin D3 inhibited monocyte maturation. In the absence of external factors, nonadherent monocytes were inhibited in their maturation for up to 10 days when plated at crowded cell concentrations. In addition, the presence of human serum in the culture media had a higher inhibitory activity than similar concentrations of fetal calf serum. Supernates from crowded macrophages were also inhibitory for monocyte maturation. We suggest the possibility that cell crowding, as well as soluble factors found in the serum and probably secreted by macrophages, participate in the regulation of monocyte development by inhibiting their maturation. Once released from this inhibitory signal or environment, the monocytes mature to macrophages.

The effect of estradiol on human myelomonocytic cells. 1. Enhancement of colony formation

Cyclic changes were observed in the content of blood monocytes during the menstrual cycle of normal women. Elevated blood monocytes were found during the ovulation period as well as in other conditions which are associated with increased blood estradiol (E2). To understand the possible association between E2 and monocytosis, we analysed the in vitro effect of E2 on the development of myelomonocytic colonies in culture. E2 in physiological concentrations was found to increase the number of colonies developed from peripheral blood mononuclear cells (PBM) of both females and males. The optimal concentration for the augmenting effect on males' PBM was lower than that for females. Mononuclear cells derived from cord blood, which yielded much higher numbers of colonies than adult PBM, also responded to the stimulatory effect of E2. Estrone and estriol were less effective than E2 in adult PBM. In contrast, progesterone, diethylstilbestrol and testosterone did not affect the number of colonies at the range of physiological concentrations tested. The anti-estrogen Tamoxifen did not inhibit the stimulatory effect of E2. The augmenting effect of E2 on monomyelocytic colony formation may explain at least in part the increase in blood monocyte content of women with high E2 as well as other phenomena of macrophage and granulocyte changes associated with the menstrual cycle.

Development of macrophage and granulocyte colonies from human peripheral blood

The presence of macrophage and granulocyte progenitor cells in the human peripheral blood enabled the establishment of colonies from this accessible tissue and obviated the need for bone marrow to achieve this task. We have developed a method of obtaining reproducible growth of macrophage/granulocyte colonies from human peripheral blood. Colonies of macrophages and granulocytes were obtained by plating peripheral blood mononuclear cells (PBM) in methylcellulose containing medium in the presence of medium conditioned by nonstimulated PBM (CM). At early stages of colony growth both macrophage and granulocyte colonies were detected while following 20-25 days in culture all colonies tested revealed monocyte-macrophage morphology. To obtain higher numbers of colonies, we tested different cell sources, different CM preparations and the effect of steroid hormones on colony development. We found that the mononuclear cells obtained from cord blood (CB) or from some patients with inflammatory bowel disease yielded much higher numbers of colonies than PBM from normal individuals. Colony development from these two sources did not depend on an external source of colony stimulating factor (CSF) but was augmented as a result of CSF supplementation. CM obtained from CB mononuclear cells as well as supernatants from some human monoblastic cell lines were similar in their CSF activity to CM from normal PBM and made possible the development of macrophage/granulocyte colonies. Higher numbers of colonies were induced by including physiological concentrations of estradiol in the culture medium, in the absence of external sources of CSF. The system described above enabled the analysis of cloned macrophages and their circulating progenitor cells as well as the assay of different preparations of CSF.