ABSTRACT
BACKGROUND AND AIMS Replication of the enveloped SARS-COV2 virus can alter lipidomic composition and metabolism of infected cells [1]. These alterations commonly result in a decline in HDL, total cholesterol and LDL, and an increase in triglyceride levels in COVID-19 patients. Furthermore, the ‘cytokine storm’ subsequent to release of inflammatory cytokines can severely impair lipid homeostasis. Importantly, decreased HDL-cholesterol correlates with severity of COVID-19 infection and represents a significant prognostic factor in predicting poor clinical outcomes [2]. Similarly, it has been observed that COVID-19 patients’ recovery is accompanied by a rise in serum HDL levels. Pharmacological intervention that aims to restore ApoA-1 or functional HDL particles may have beneficial roles for clinical outcome of COVID-19 patients and has recently been approved for compassionate use [3]. SARS-CoV 2 spike proteins S1 and S2 can bind free cholesterol and HDL-bound cholesterol, facilitating virus entry by binding the ACE2 co-receptor Scavenger Receptor-BI (SR-BI) [4]. When activated at the trans-membrane level, SR-BI signalling culminates in Ser1173-eNOS phosphorylation with both anti-inflammatory and anti-apoptotic effect. We hypothesized that SARS-COV2 binding promoted SR-BI internalization, so that it could not exert its essential protective function. Therefore, the aim of this study is to evaluate the effects of CER-001, a mimetic HDL, in antagonizing this process. METHOD Endothelial and tubular (RPTEC) cells were exposed to S1, S2 and S1 + S2 (50–250 nM) with or without CER-001 (CER-001 50–500 ug/mL) and cholesterol (10–50 uM). Apoptosis tests (MTT and AnnV/PI) were performed. Internalization of SR-BI, ACE2 with S1 and activation of eNOS was evaluated by FACS analysis. SR-BI and ACE2 expression were evaluated on kidney biopsies from COVID-19 patients. RESULTS At concentrations used, the exposition of S1, S2 and S1 + S2 in the presence of CER-001 and cholesterol did not induce apoptosis of endothelial cells and RPTEC. Endothelial and tubular cells stimulated by S1, in presence of cholesterol, showed an increased intracellular level of SR-BI and ACE-2, with significantly reduced eNOS phosphorylation compared to baseline (P < 0.05). The treatment with CER-001 reversed trans-membrane SR-BI levels and eNOS phosphorylation to baseline values. The detection of S1 spike protein by endothelial cells immunohistochemistry revealed an increased level in S1-exposed cells with cholesterol and reduced S1 intracellular positive staining in CER-001-exposed cells (P < 0.05). Interestingly, S1-exposed cells without cholesterol appeared not to be capable of mediating S1 spike protein internalization. Consistent with in vitro results, analysis of renal biopsies from COVID-19 patients with proteinuria showed increased SR-BI and ACE-2 cytoplasmic signals and reduced expression at the apical domain of injured tubules. CONCLUSION Our data confirmed the key role of lipid profile in SARS-COV2 infection, evaluating the molecular signalling involved in HDL metabolism and inflammatory processes, and could offer new therapeutic strategies for COVID-19 patients.
ABSTRACT
BACKGROUND AND AIMS COVID-19 infection in solid organ transplant recipients (SOT) is associated with increased morbidity and mortality due to comorbidities and immunosuppression state (Chaudhry ZS et al, 2020). Although vaccines represent the greatest hope to control COVID-19 pandemic, several studies showed the low immunogenicity of a two-dose mRNA COVID-19 vaccine regimen in SOT as compared with general population (Boyarsky BJ et al, 2021). Based on this evidence, on September 2021, the Italian Medicine Agency (AIFA) authorized a third vaccine administration as additional primary dose to immunocompromised patients. The aim of this study is to evaluate the seroconversion rate after the third dose of BNT162b2 (Pfizer-BioNTech) SARS-CoV-2 mRNA vaccine in kidney transplant recipients (KTRs) and to investigate the baseline factors associated with the absence of the antibody response. METHOD we performed a prospective and observational study on a monocentric cohort of 329 consecutive Caucasian KTRs given three doses of the BNT162b2 COVID-19 vaccine. Key exclusion criteria were a previous history of COVID-19 infection and transplantation or having underwent chemotherapy treatment within the last year. Antibody response against the spike protein was tested on blood sample collected before the administration of vaccine (T0), at 15 and 90 days after the second dose (T2 and T3, respectively) and one month after the third dose (T5). The level of antibodies was assessed using the Roche Elecsys anti–SARS-CoV-2 S enzyme immunoassay (positive cut-off ≥ 0.8 U/mL). A total of 22 patients were excluded from the analysis because categorized as SARS-CoV-2-pre-immunized according to the antibodies’ baseline status (T0) above the positivity cut-off. The Local Ethics Committees approved the study protocol and written informed consent was obtained before enrolment. RESULTS The study population of 307 KTRs was 57.10 ± 13.10 years, with a predominance of male sex (64.2%). Median time from transplantation to vaccine was 10 [IQR 5–17] years. Blood analysis at baseline revealed mean eGFR assessed by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation to be 56.95 ± 23.04 mL/min/1.73 m2. The standard immunosuppressive regimen consisted of glucocorticoids in all patients, calcineurin inhibitors (88.6% of patients), antimetabolites (73.3% of patients) and mTOR inhibitors (in 15.6% of patients). The first two doses were administered 21 days apart, and the third dose was administrated 172 ± 4 days after the second dose. In our cohort, 43.3% patients (133/307) responded to the vaccine at T2. The proportion of responders increased to 68.4% (186/272) at T3 (median antibody level: 5.2 [0.40–74.07]). One month after the third dose, a positive antibody titer was detected in 251 of 307 patients (81.8%) (median antibody titre: 1137.50 [9.32–4189.75]). The response curve starting at T2 and increasing at T3 makes apparent that there is a distinctive kinetic of humoral response in immunocompromised patients compared to immunocompetent individuals (Walsh EE et al., 2020). A multivariate analysis showed that the negative response to the third primary dose was associated with antimetabolite immunosuppressants (P = .001), lower estimated glomerular filtration rate (P < .001) and female sex (P = .04) (Figure 1). No serious adverse events were reported. Neither denovo DSAs nor change in proteinuria were reported after vaccination.FIGURE 1: Univariate and multivariate analysis of factors associated with vaccine response one month after third dose of SARS-CoV-2 mRNA vaccine. The limitation of this study is the absence of assays for cellular immune response. CONCLUSION Although the exact threshold of antibody titer for protection against SARS-CoV-2 infection remains unclear, the ability of the additional mRNA COVID-19 vaccine dose to increase both immune response (Figure 2A) and the prevalence of seroconversion rate (Figure 2B) associated with the acceptable safety profile s pports its use after an initial 2-dose mRNA COVID-19 primary vaccine series in immunocompromised patients.FIGURE 2: Antibody Response. Panel A shows the anti-SARS-CoV-2 antibody titers at different timepoints T0, T2, T3 and T5. Panel B shows prevalence of responders and noresponders at different timepoints T0, T2, T3 and T5.
ABSTRACT
Kidney transplant recipients (KTRs) have been considered as patients at higher risk of SARS-CoV-2-related disease severity, thus COVID-19 vaccination was highly recommended. However, possible interferences of different immunosuppression with development of both humoral and T cell-mediated immune response to COVID-19 vaccination have not been determined. Here we evaluated the association between mTOR-inhibitors (mTOR-I) and immune response to mRNA BNT162b2 (Pfizer-BioNTech) vaccine in KTR. To this aim 132 consecutive KTR vaccinated against COVID-19 in the early 2021 were enrolled, and humoral and T cell-mediated immune response were assessed after 4-5 weeks. Patients treated with mTOR-I showed significantly higher anti-SARS-CoV-2 IgG titer (p = .003) and higher percentages of anti-SARS-CoV-2 S1/RBD Ig (p = .024), than those without. Moreover, SARS-CoV-2-specific T cell-derived IFNγ release was significantly increased in patients treated with mTOR-I (p < .001), than in those without. Multivariate analysis confirmed that therapy with mTOR-I gained better humoral (p = .005) and T cell-mediated immune response (p = .005) in KTR. The presence of mTOR-I is associated with a better immune response to COVID-19 vaccine in KTR compared to therapy without mTOR-I, not only by increasing vaccine-induced antibodies but also by stimulating anti-SARS-CoV-2 T cell response. These finding are consistent with a potential beneficial role of mTOR-I as modulators of immune response to COVID-19 vaccine in KTR.