ABSTRACT
BACKGROUND AND AIMS: There is incomplete information on the impact of a third dose of the SARS-CoV-2 vaccine in advance chronic kidney disease (CKD). The aim of the present analysis was to evaluate the kinetics of humoral response in the CKD spectrum (KT, HD, PD and ND-CKD) 6 months after completing the initial vaccine schedule. Some patients of each group received a third dose before 6 months, providing a pragmatic insight into real-world responses to different vaccine schedules in patients with advanced CKD not on dialysis, on dialysis or in KT recipients. METHOD: The SENCOVAC study describes the humoral response and safety of different SARS-CoV-2 vaccines in a real-world setting in 3687 CKD patients: 787 kidney transplant (KT), 319 peritoneal dialysis (PD), 2297 haemodialysis (HD) and 284 non-dialysis-CKD (ND-CKD) patients. Anti-Spike antibodies were assessed in an efficacy analysis at 28 days (n = 1755), 3 months (n = 1386), and 6 months (n = 1018, of whom 628 had received a third vaccine dose). Adverse events (AEs) were registered during follow-up, including SARS-CoV-2 infections in the safety analysis. RESULTS: Among the patients included in the efficacy analysis, KT recipients presented lower anti-Spike antibody titers than other CKD cohorts at 28 days and 3 months (P < .001 for all). A total of 943 patients [249 (26%) KT, 108 (11%) PD, 511 (54%) HD and 75 (8%) ND-CKD] had negative baseline anti-Spike antibodies. Again, at 28 days or 3 months, KT recipients developed lower anti-Spike antibody titers than PD (P < .001), HD (P < .001) and ND-CKD (P< .001) patients. At 6 months, patients that had received a third vaccine dose had higher anti-Spike antibody titers than those without the third dose [1837 (507-9726) UI/mL versus 80 (19-409) ml/UI;P < .001] and this was evident in all CKD cohorts. Anti-Spike titers after the third dose were higher in patients boosted with mRNA-1273 than with BNT162b2 [1710 (322-9615) versus 472 (34-2094);P < .001). At 6 months, in patients that had received a third dose, a positive humoral response (anti-Spike antibodies > 36 UI/mL) was achieved in 584 (93%): 94 (80%) of 118 KT recipients, 20 (100%) of 20 patients on PD, 436 (96%) of 455 patients on HD and 34 (97%) of 35 patients with ND-CKD (Fig. 1). Among patients without humoral response 3 months after completing the initial vaccination schedule, 72 (69%) seroconverted after the third dose (62% KT, 76% HD, 100% NDCKD, all PD patients had a positive humoral response at 3 months). Independent predictors of a positive humoral response at 6 months were not-KT (HR for KT 0.26, P = .011), third dose (HR 22.9, P < .001), initial mRNA-1273 (HT 1.78, P = .017) and humoral response at 3 months (HR 26.2, P < .001). Breakthrough SARS-CoV-2 infections occurred in 1.1% of patients, and mortality was 14.6%, none after the third dose. CONCLUSION: In the CKD spectrum, anti-Spike antibody titers continued to decrease from 3 to 6 months after complete vaccination, and KT recipients presented higher rates of negative humoral response at 6 months. A third dose of mRNA vaccine increased anti-Spike antibody titers but was still insufficient to spur a humoral immune response in at least 38% of KT recipients and 24% of patients on HD that lacked anti-SARS-CoV-2 antibodies 3 months post-initial vaccination. New strategies are urgently needed to protect CKD patients that remain negative for anti-SARS-CoV- 2 antibodies, given the high mortality of breakthrough SARS-CoV-2 infections. (Figure Presented).
ABSTRACT
BACKGROUND AND AIMS: Angiotensin converting enzyme 2 (ACE2) is one of the components of the renin-angiotensin system (RAS) that mainly degrades angiotensin II to angiotensin-(1-7). ACE2 is predominantly expressed in the kidney and the heart, but it has been evidenced in type 2 alveolar lung cells, where it acts as a receptor for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this context, a controversy arose as to whether the use of RAS blockers could increase ACE2 lung expression and the risk infection by COVID-19. This study aimed to investigate the effect of an ACE inhibitor (Ramipril) on ACE2 expression in experimental diabetes. METHOD: 12 weeks old diabetic db/db mice (n=7) were given ramipril (8 mg/Kg/day) during 8 weeks or the respective vehicle. db/m (n=7) vehicle-treated non-diabetic mice were included as controls. ACE2 mRNA expression and enzymatic activity were studied in kidney, heart and lung samples of these animals to identify if the diabetic condition or treatment with ramipril modulated ACE2 expression. RESULTS: In vehicle-treated diabetic db/db animals, ACE2 mRNA expression was significantly increased in the kidney (p<0.001) and ramipril treatment reversed this effect (p=0.026). In the heart, ACE2 expression decreased in db/db when compared to db/m littermates (p=0.035) and ramipril had no effect. We found no differences in ACE2 gene expression in the lung. Besides, ACE2 enzymatic activity was increased in the kidney (29%) and also in the lung (16%) of db/db mice when compared to controls. Ramipril treatment decreased ACE2 activity a 19% in the lung and had no effect in the kidney when compared to untreated db/db (see figure). In the heart, ACE2 activity tended to decrease in db/db mice (29%) when compared to db/m and ramipril increased ACE2 activity (18%) but did not exceed the cardiac ACE2 activity of the db/ m. CONCLUSION: ACE2 is increased in the kidney and the lung, and decreased in the heart of diabetic mice. Ramipril treatment restores ACE2 levels. The results suggest that ACE inhibitors do not increase ACE2 expression and the activity decrease exerted in the lung may be protective against COVID-19 infection.