Effect of ramipril on kidney, lung and heart ACE2 in a diabetic mice model

SARS-CoV-2 Spike Protein Enhances Carboxypeptidase Activity of Angiotensin-Converting Enzyme 2

In this study, we investigated whether severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein may modify angiotensin-converting enzyme 2 (ACE2) activity in the plasma, heart, kidney, liver, lung, and six brain regions (amygdala, brain stem, cortex, hippocampus, hypothalamus, and striatum) of diabetic and hypertensive rats. We determine ACE2 activity in the plasma and lysates of heart, kidney, liver, lung, and six brain regions. MLN-4760 inhibits ACE2 activity in the plasma and all organs. On the other hand, soluble ACE2 (sACE2) activity increased in the plasma of diabetic rats, and there was no change in the plasma of hypertensive rats. ACE2 activity was augmented in the liver, brain stem, and striatum, while it decreased in the kidney, amygdala, cortex, and hippocampus of diabetic rats. ACE2 activity increased in the kidney, liver, and lung, while it decreased in the heart, amygdala, cortex, and hypothalamus of hypertensive rats. We measured the ACE2 content via enzyme-linked immunosorbent assay and found that ACE2 protein levels increased in the heart, while it decreased in the plasma, kidney, brain stem, cortex, hippocampus, hypothalamus, and striatum of diabetic rats. ACE2 protein levels decreased in the brain stem, cortex, hippocampus, and hypothalamus of hypertensive rats. Our data showed that the spike protein enhanced ACE2 activity in the liver and lungs of diabetic rats, as well as in the heart and three of the brain regions (cortex, hypothalamus, and striatum) of hypertensive rats.

Anisomeles indica Extracts and Their Constituents Suppress the Protein Expression of ACE2 and TMPRSS2 In Vivo and In Vitro

Coronavirus disease 2019 (COVID-19), stemming from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has had a profound global impact. This highly contagious pneumonia remains a significant ongoing threat. Uncertainties persist about the virus's effects on human health, underscoring the need for treatments and prevention. Current research highlights angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) as key targets against SARS-CoV-2. The virus relies on ACE2 to enter cells and TMPRSS2 to activate its spike protein. Inhibiting ACE2 and TMPRSS2 expression can help prevent and treat SARS-CoV-2 infections. Anisomeles indica (L.) Kuntze, a medicinal plant in traditional Chinese medicine, shows various promising pharmacological properties. In this study, ethanolic extracts of A. indica were examined both in vivo (250 and 500 μM) and in vitro (500 μM). Through Western blotting analysis, a significant reduction in the expression levels of ACE2 and TMPRSS2 proteins was observed in HepG2 (human hepatocellular carcinoma) cells and HEK 293T (human embryonic kidney) cell lines without inducing cellular damage. The principal constituents of A. indica, namely, ovatodiolide (5 and 10 μM), anisomlic acid (5 and 10 μM), and apigenin (12.5 and 25 μM), were also found to produce the same effect. Furthermore, immunohistochemical analysis of mouse liver, kidney, and lung tissues demonstrated a decrease in ACE2 and TMPRSS2 protein expression levels. Consequently, this article suggests that A. indica and its constituents have the potential to reduce ACE2 and TMPRSS2 protein expression levels, thus aiding in the prevention of SARS-CoV-2 infections.

Caution may be required in using l-theanine in diabetes mellitus: A study on the rats

BACKGROUND

The study aimed to identify the effects of l-theanine on kidney and heart tissues in diabetic rats. 24 male rats included in the study were divided into 4 groups (n = 6/group): SHAM, LTEA, DM and DM + LTEA. For 28 days, drinking water was given to SHAM and DM, and LTEA (200 mg/kg/day) to LTEA and DM + LTEA groups, intragastrically. DM was induced by 120 mg/kg nicotinamide (NA) + 60 mg/kg streptozotocin (STZ). The levels of cystatin C (CysC) and angiotensin-converting enzyme 2 (ACE2) were determined by ELISA kits, homocysteine, electrolytes and iron by an autoanalyzer, the ratio of oxidized/total reduced glutathione (GSSG/TGSH) by assay kits. The tissues were histopathologically analyzed.

RESULTS

LTEA alleviated histopathological degenerations. However, it decreased significantly serum iron and homocysteine levels (p < 0.05).

CONCLUSION

LTEA did not exhibit significant protective effects on kidney and heart tissues; it may have affected the homocysteine and iron metabolisms in diabetics.

Association between Mineralocorticoid Receptor Antagonist and Mortality in SARS-CoV-2 Patients: A Systematic Review and Meta-Analysis

Since the onset of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, various potential targeted therapies for SARS-CoV-2 infection have been proposed. The protective effects of mineralocorticoid receptor antagonists (MRA) against tissue fibrosis, pulmonary and systemic vasoconstriction, and inflammation have been implicated in potentially attenuating the severity of SARS-CoV-2 infection by inhibiting the deleterious effects of aldosterone. Furthermore, spironolactone, a type of MRA, has been suggested to have a beneficial effect on SARS-CoV-2 outcomes through its dual action as an MRA and antiandrogen, resulting in reduced transmembrane protease receptor serine type 2 (TMPRSS2)-related viral entry to host cells. In this study, we sought to investigate the association between MRA antagonist therapy and mortality in SARS-CoV-2 patients via systematic review and meta-analysis. The systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. MEDLINE and EMBASE databases were searched for studies that reported the incidence of mortality in patients on MRA with SARS-CoV-2 infection. Pooled odds ratio (OR) and 95% confidence interval (CI) of the outcome were obtained using the random-effects model. Five studies with a total of 1,388,178 subjects (80,903 subjects receiving MRA therapy) met the inclusion criteria. We included studies with all types of MRA therapy including spironolactone and canrenone and found no association between MRA therapy and mortality in SARS-CoV-2 infection (OR = 0.387, 95% CI: 0.134–1.117, p = 0.079).

Oral Lisinopril Raises Tissue Levels of ACE2, the SARS-CoV-2 Receptor, in Healthy Male and Female Mice

Angiotensin-converting enzyme 2 (ACE2) is the established cellular receptor for SARS-CoV-2. However, it is unclear whether ACE1 inhibitors (e.g., lisinopril) or angiotensin receptor blockers (e.g., losartan) alter tissue ACE2 expression. This study sought to determine whether lisinopril or losartan, as monotherapies or in combination, changes tissue levels of ACE2 in healthy male and female mice. Mice received lisinopril (10 mg/kg/day), losartan (10 mg/kg/day), or both for 21 days via drinking water. A control group received water without drug. The ACE2 protein index (ACE2 protein/total protein) was determined on the small intestine, lung, kidney, and brain. Oral lisinopril increased the ACE2 protein index across all tissues (p < 0.0001 vs. control). In contrast, the combination of lisinopril plus losartan did not increase ACE2 levels in any tissue (p = 0.89 vs. control) and even decreased tissue expression of the Ace2 gene (p < 0.001 vs. control). Tissue ACE2 remained elevated in the mice 21 days after cessation of lisinopril (p = 0.02). Plasma ACE2 did not correlate with the ACE2 protein index in any tissue. A sex difference was observed: kidney ACE2 levels were higher in male than in female mice (p < 0.0001). Oral lisinopril increases ACE2, the cellular receptor for SARS-CoV-2, in tissues that are relevant to the transmission and pathogenesis of COVID-19. Remarkably, the addition of losartan prevented lisinopril-induced increases in ACE2 across tissues. These results suggest that ACE inhibitors and angiotensin receptor blockers interact to determine tissue levels of ACE2.

Association of renin–angiotensin system blockers with COVID-19 diagnosis and prognosis in patients with hypertension: a population-based study

Background

The effect of renin–angiotensin system (RAS) blockade either by angiotensin-converting enzyme inhibitors (ACEis) or angiotensin-receptor blockers (ARBs) on coronavirus disease 2019 (COVID-19) susceptibility, mortality and severity is inadequately described. We examined the association between RAS blockade and COVID-19 diagnosis and prognosis in a large population-based cohort of patients with hypertension (HTN).

Methods

This is a cohort study using regional health records. We identified all individuals aged 18–95 years from 87 healthcare reference areas of the main health provider in Catalonia (Spain), with a history of HTN from primary care records. Data were linked to COVID-19 test results, hospital, pharmacy and mortality records from 1 March 2020 to 14 August 2020. We defined exposure to RAS blockers as the dispensation of ACEi/ARBs during the 3 months before COVID-19 diagnosis or 1 March 2020. Primary outcomes were: COVID-19 infection and severe progression in hospitalized patients with COVID-19 (the composite of need for invasive respiratory support or death). For both outcomes and for each exposure of interest (RAS blockade, ACEi or ARB) we estimated associations in age-, sex-, healthcare area- and propensity score-matched samples.

Results

From a cohort of 1 365 215 inhabitants we identified 305 972 patients with HTN history. Recent use of ACEi/ARBs in patients with HTN was associated with a lower 6-month cumulative incidence of COVID-19 diagnosis {3.78% [95% confidence interval (CI) 3.69–3.86%] versus 4.53% (95% CI 4.40–4.65%); P &lt; 0.001}. In the 12 344 patients with COVID-19 infection, the use of ACEi/ARBs was not associated with a higher risk of hospitalization with need for invasive respiratory support or death [OR = 0.91 (0.71–1.15); P = 0.426].

Conclusions

RAS blockade in patients with HTN is not associated with higher risk of COVID-19 infection or with a worse progression of the disease.