Antihypertensive agents acting on the renin-angiotensin system and the risk of sepsis

Impact of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on the mortality in sepsis: A meta-analysis

BACKGROUND

The effect of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) on the mortality of patients with sepsis is not well characterized.

AIM

To elucidate the association between prior ACEI or ARB exposure and mortality in sepsis.

METHODS

The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for all studies of premorbid ACEI or ARB use and sepsis mortality until November 30 2019. Two reviewers independently assessed, selected, and abstracted data from studies reporting ACEIs or ARBs, sepsis, and mortality. The primary extracted data consisted of premorbid ACEI or ARB exposure, mortality, and general patient data. Two reviewers independently assessed the risk of bias and quality of evidence.

RESULTS

A total of six studies comprising 281238 patients with sepsis, including 49799 cases with premorbid ACEI or ARB exposure were eligible for analysis. Premorbid ACEIs or ARBs exposure decreased the 30-d mortality in patients with sepsis. Moreover, the use of ACEIs or ARBs was associated with approximately a 6% decreased risk of 30-d mortality.

CONCLUSION

The results of this systematic review suggest that ACEI or ARB exposure prior to sepsis may be associated with reduced mortality. Further high-quality cohort studies and molecular mechanism experiments are required to confirm our results.

Role of the Renin Angiotensin Aldosterone System in the Pathogenesis of Sepsis-Induced Acute Kidney Injury: A Systematic Review

BACKGROUND

Sepsis is a life-threatening condition responsible for up to 20% of all global deaths. Kidneys are among the most common organs implicated, yet the pathogenesis of sepsis-induced acute kidney injury (S-AKI) is not completely understood, resulting in the treatment being nonspecific and responsive. In situations of stress, the renin angiotensin aldosterone system (RAAS) may play a role. This systematic review focuses on analyzing the impact of the RAAS on the development of S-AKI and discussing the use of RAAS antagonists as an emerging therapeutic option to minimize complications of sepsis.

METHODS

Studies were identified using electronic databases (Medline via PubMed, Google Scholar) published within the past decade, comprised from 2014 to 2023. The search strategy was conducted using the following keywords: sepsis, S-AKI, RAAS, Angiotensin II, and RAAS inhibitors. Studies on human and animal subjects were included if relevant to the keywords.

RESULTS

Our search identified 22 eligible references pertaining to the inclusion criteria. Treatment of sepsis with RAAS inhibitor medications is observed to decrease rates of S-AKI, reduce the severity of S-AKI, and offer an improved prognosis for septic patients.

CONCLUSION

The use of RAAS antagonists as a treatment after the onset of sepsis has promising findings, with evidence of decreased renal tissue damage and rates of S-AKI and improved survival outcomes.

REGISTRATION

INPLASY202360098.

Pocket ACEs: Discovering new function within an old player

Angiotensin-converting enzyme (ACE) is canonically known for its role in the renin-angiotensin system (RAS) where its conversion of angiotensin I (Ang I) to the bioactive peptide angiotensin II (Ang II) helps to regulate blood pressure, electrolyte, and volume homeostasis. Further studies on ACE have shown that its enzymatic activity is relatively non-specific and functions outside of the RAS axis. Of the multiple systems it has been implicated in, ACE has been found to play an important role in the development and modulation of hematopoiesis and the immune system, both through the RAS and independently of the RAS axis.

Early Lactate Clearance as a Determinant of Survival in Patients with Sepsis: Findings from a Low-resource Country

Background

Single lactate measurements have been reported to have prognostic significance, however, there is a lack of data in local literature from Pakistan. This study was done to determine prognostic role of lactate clearance in sepsis patients being managed in our lower-middle income country.

Methods

This prospective cohort study was conducted from September 2019-February 2020 at the Aga Khan University Hospital, Karachi. Patients were enrolled using consecutive sampling and categorized based on their lactate clearance status. Lactate clearance was defined as decrease by 10% or greater in repeat lactate from the initial measurement (or both initial and repeat levels <=2.0 mmol/L).

Results

A total 198 patients were included in the study, 51% (101) were male. Multi-organ dysfunction was reported in 18.6% (37), 47.7% (94) had single organ dysfunction, and 33.8% (67) had no organ dysfunction. Around 83% (165) were discharged and 17% (33) died. There were missing data for 25.8% (51) of the patients for the lactate clearance, whereas 55% (108) patients had early lactate clearance and 19.7% (39) had delayed lactate clearance.On univariate analysis, mortality rate was higher in patients with delayed lactate clearance (38.4% vs 16.6%) and patients were 3.12 times (OR = 3.12; [95% CI: 1.37-7.09]) more likely to die as compared with early lactate clearance. Patients with delayed lactate clearance had higher organ dysfunction (79.4% vs 60.1%) and were 2.56 (OR = 2.56; [95% CI: 1.07-6.13]) times likely to have organ dysfunction. On multivariate analysis, after adjusting for age and co-morbids, patients with delayed lactate clearance were 8 times more likely to die than patients with early lactate clearance [aOR = 7.67; 95% CI:1.11-53.26], however, there was no statistically significant association between delayed lactate clearance [aOR = 2.18; 95% CI: 0.87-5.49)] and organ dysfunction.

Conclusion

Lactate clearance is a better determinant of sepsis and septic shock effective management. Early lactate clearance is related to better outcomes in septic patients.

Angiotensin II Receptor Blocker Associated With Less Outcome Risk in Patients With Acute Kidney Disease

Objective: The aim of this study was to explore the respective use of angiotensin-converting-enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs) on the outcomes of patients who could be weaned from dialysis-requiring acute kidney injury (AKI-D). Methods: This case-control study enrolled 41,731 patients who were weaned from AKI-D for at least 7 days from Taiwan's National Health Insurance Administration. We further grouped AKI-D patients according to ACEi and ARB use to evaluate subsequent risks of all-cause mortality and re-dialysis. The outcomes included the all-cause mortality and new-onset of end-stage kidney disease (ESKD; re-dialysis) following withdraw from AKI-D. Results: A total of 17,141 (41.1%) patients surviving AKI-D could be weaned from dialysis for at least 7 days. The overall events of mortality were 366 (48.9%) in ACEi users, 659 (52.1%) in ARB users, and 6,261 (41.3%) in ACEi/ARB nonusers, during a mean follow-up period of 1.01 years after weaning from AKI-D. In regard to all-cause of mortality, pre-dialysis ARB users had lower incidence than ACEi users [hazard ratio (HR 0.82), p = 0.017]. Compared with ACEi/ARB nonusers, continuing ARB users had a significantly low risk of long-term all-cause mortality (adjusted hazard ratio 0.51, p = 0.013) after propensity score matching. However, new users of ACEi at the acute kidney disease (AKD) period had a higher risk of re-dialysis after weaning than ACEi/ARB nonusers (aHR 1.82, p < 0.001), whereas neither ACEi nor ARB users confronted significantly increased risks of hyperkalemia after weaning. Conclusions: Compared with patients without ACEi/ARB, those continuing to use ARB before the event and after weaning had low all-cause mortality, while new users of ACEi at AKD had increased risk of re-dialysis. AKI-D patients continuing to use ACEi or ARB did not have higher risk of hyperkalemia. Future prospective randomized trials are expected to confirm these findings.

Angiotensin-Converting Enzyme Inhibitor and Angiotensin Receptor Blocker Use Associated with Reduced Mortality and Other Disease Outcomes in US Veterans with COVID-19

Objective

To determine the association between angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) use and coronavirus disease 2019 (COVID-19) severity and outcomes in US veterans.

Patients and Methods

We retrospectively examined 27,556 adult US veterans who tested positive for COVID-19 between March to November 2020. Logistic regression and Cox proportional hazards models using propensity score (PS) for weight, adjustment, and matching were used to examine the odds of an event within 60 days following a COVID-19–positive case date and time to death, respectively, according to ACEI and/or ARB prescription within 6 months prior to the COVID-19–positive case date.

Results

The overlap PS weighted logistic regression model showed lower odds of an intensive care unit (ICU) admission (odds ratio [OR] 95% CI 0.77, 0.61–0.98) and death within 60 days (0.87, 0.79–0.97) with an ACEI or ARB prescription. Veterans with an ARB-only prescription also had lower odds of an ICU admission (0.64, 0.44–0.92). The overlap PS weighted model similarly showed a lower risk of time to all-cause mortality in veterans with an ACEI or ARB prescription (HR [95% CI]: 0.87, 0.79–0.97) and an ARB only prescription (0.78, 0.67–0.91). Veterans with an ACEI prescription had higher odds of experiencing a septic event within 60 days after the COVID-19–positive case date (1.22, 1.02–1.46).

Conclusion

In this study of a national cohort of US veterans, we found that the use of an ACEI/ARB in patients with COVID-19 was not associated with increased mortality and other worse outcomes. Future studies should examine underlying pathways and further confirm the relationship of ACEI prescription with sepsis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40265-021-01639-2.

Effects of Renin-Angiotensin-Aldosterone System Inhibitors on Long-Term Major Adverse Cardiovascular Events in Sepsis Survivors

Background Sepsis is known to increase morbidity and duration of hospital stay and is a common cause of mortality worldwide. Renin-angiotensin-aldosterone system inhibitors (RAASis) are commonly used to treat hypertension but are usually discontinued during hospitalization for sepsis because of concerns about renal hypoperfusion. The aim of our study was to investigate whether RAASis should be continued after discharge in sepsis survivors and to identify the effects on the clinical outcomes. Methods and Results A total of 9188 sepsis survivors aged 20 years and older who were discharged from January 1, 2012 to December 31, 2019 were included in our analyses. We further divided sepsis survivors into RAASi users and nonusers. These groups were matched by propensity scores before the outcomes of interest, including all-cause mortality and major adverse cardiac events (MACE), were examined. After propensity score matching, 3106 RAASi users and 3106 RAASi nonusers were included in our analyses. Compared with RAASi nonusers, RAASi users had lower risks of all-cause mortality (hazard ratio [HR], 0.68; 95% CI, 0.62-0.75), MACEs (HR, 0.87; 95% CI, 0.81-0.94), ischemic stroke (HR, 0.85; 95% CI, 0.76-0.96), myocardial infarction (HR, 0.74; 95% CI, 0.61-0.90), and hospitalization for heart failure (HR, 0.84; 95% CI, 0.77-0.92). Subgroup analyses stratified by admission to the ICU and the use of inotropes showed similar results. Conclusions In our study, we found that RAASi users had reduced risks of all-cause mortality and MACEs. These findings suggested a beneficial effect of RAASi use by sepsis survivors after discharge.

Antihypertensive Medications Prior to Shock Onset Do Not Impact Initial Vasopressor Requirements in Patients With Shock

Purpose: The effect of the use of antihypertensive agents in patients prior to the development of shock is unclear. The purpose of this study was to determine the impact of antihypertensive agents on vasopressor dose and duration in shock. Materials and Methods: This retrospective, single-center study included patients with shock who received at least one vasopressor for at least 24 hours after shock onset from January 1 to June 30, 2017. Patients taking an antihypertensive agent(s) were compared to those who were not. The primary outcome was the number of vasopressor-free hours at 72 hours. Secondary outcomes included maximum and cumulative vasopressor doses, intensive care unit length of stay, and 30-day mortality. Results: One hundred and sixty-eight patients were included and 99 (59%) were on antihypertensives. Distributive shock was the most common type of shock (75.5%) and more patients taking antihypertensives had hypertension, coronary artery disease, and dyslipidemia at baseline. There was no difference in the number of vasopressor-free hours at 72 hours between patients taking an antihypertensive medication(s) and the control group (2 hours vs 1 hour; P = .11). No difference was found between any of the secondary outcomes. Conclusion: Patients taking antihypertensive agents prior to shock onset did not require increased vasopressor doses or duration.

Preadmission Antihypertensive Drug Use and Sepsis Outcome: Impact of Angiotensin-Converting Enzyme Inhibitors (ACEIs) and Angiotensin Receptor Blockers (ARBs)

BACKGROUND

Several studies have reported improved sepsis outcomes when certain preadmission antihypertensive drugs, namely, calcium channel blockers (CCBs), are used. This study aims to determine whether preadmission antihypertensive drug use, especially angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), is associated with decreased total hospital mortality in sepsis.

METHODS

This study was conducted using the unique database of a sepsis cohort from the National Health Insurance Research Database in Taiwan. Frequency matching for age and sex between preadmission antihypertensive drug users (study cohort) and nonusers (comparison cohort) was conducted. The primary outcome was total hospital mortality. Logistic regression analyses were performed to calculate the odds ratios (ORs) of important variables. Further joint effect analyses were carried out to examine the impacts of different combinations of antihypertensive drugs.

RESULTS

A total of 33,213 sepsis antihypertensive drug use patients were retrieved as the study cohort, and an equal number of matched sepsis patients who did not use antihypertensive drugs were identified as the comparison cohort. The study cohort had a higher incidence rate of being diagnosed with septic shock compared with the comparison cohort (4.36%-2.31%, P < 0.001) and a higher rate of total hospital mortality (38.42%-24.57%, P < 0.001). In the septic shock condition, preadmission antihypertensive drug use was associated with a decreased adjusted OR (OR = 0.66, 95% confidence interval [CI], 0.55-0.80) for total hospital mortality, which was not observed for the nonseptic shock condition. Compared with antihypertensive drug nonusers, both ACEI and ARB users had decreased adjusted ORs for total hospital mortality in sepsis (adjusted OR = 0.93, 95% CI, 0.88-0.98 and adjusted OR = 0.85, 95% CI, 0.81-0.90); however, CCB, beta-blocker, and diuretic users did not. In the septic shock condition, ACEI, ARB, CCB, and beta-blocker users all had decreased ORs for total hospital mortality. Joint effect analysis showed ACEI use, except in combination with diuretics, to be associated with a decreased adjusted OR for total hospital mortality in sepsis. Similar results were observed for ARB users.

CONCLUSIONS

Preadmission ACEI or ARB use is associated with a decreased risk of total hospital mortality, regardless of a nonshock or septic shock condition.

Ramipril pretreatment worsened renal injury and survival despite a reduction in renal inflammation in experimentally induced sepsis in mice

INTRODUCTION

The angiotensin converting enzyme inhibitor ramipril is a standard antihypertensive therapy for many patients. Because angiotensin II may promote inflammation, we were interested in whether basal pretreatment with ramipril may modify renal function and inflammation as well as systemic outcome in experimentally induced sepsis in mice.

MATERIAL AND METHODS

Ramipril (10 mg/kg/day) pretreatment or placebo (NaCl) was given intraperitoneally for 5 days to C57BL6/J mice, followed by either sham operation or cecal ligation and puncture sepsis induction. Real-time polymerase chain reaction and immunological stains were used to evaluate renal gene and protein expression, respectively. Plasma creatinine, neutrophil-gelatinase associated lipocalin, and blood urea nitrogen were used as markers for renal function. A clinical severity score was determined.

RESULTS

Administration of ramipril before cecal ligation and puncture surgery was associated with reduced renal inflammation but did not improved renal function and structure and even worsened the clinical status of septic mice.

CONCLUSIONS

The data suggest that the effects of ramipril pretreatment are complex. Additional studies including monitoring of hemodynamic parameters are necessary to elucidate the exact mechanism(s) of this observation. In addition, the timing of the ramipril administration could be of importance.

Angiotensin II Receptor Blockers but Not Angiotensin-Converting Enzyme Inhibitors Are Associated With a Reduced Risk of Acute Kidney Injury After Major Surgery

Objective: We investigated the respective effects of preoperative angiotensin-converting-enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) on the incidence of postoperative acute kidney injury (AKI) and mortality.

Methods: In this nested case-control study, we enrolled 20,276 patients who received major surgery. We collected their baseline demographic data, comorbidities and prescribed medication, the outcomes of postoperative AKI and mortality. AKI was defined by the criteria suggested by KDIGO (Kidney disease: Improving Global Outcome). Logistic regression was used to assess the impact of exposure to ACEIs or ARBs.

Results: Compared with patients without ACEI/ARB, patient who received ARBs had a significantly lower risk for postoperative AKI (adjusted odds ratio (OR) 0.82, p = 0.007). However, ACEI users had a higher risk for postoperative AKI than ARB users (OR 1.30, p = 0.027), whereas the risk for postoperative AKI was not significantly different between the ACEI users and patients without ACEI/ARB (OR 1.07, p = 0.49). Compared with patients without ACEI/ARB, both ACEI and ARB users were associated with a reduced risk of long-term all-cause mortality following surgery (OR 0.47, p = 0.002 and 0.60, p < 0.001 in ACEI and ARB users, respectively), without increasing the risk of hyperkalemia during the index hospitalization (p = 0.20). The risk of long-term all-cause mortality following surgery in ACEIs and ARBs users did not differ significantly (OR 0.74, p = 0.27). Furthermore, the higher the defined daily dose of ARB, the better the protection against AKI provided.

Conclusion: Our study revealed that preoperative use of ARBs was associated with reduced postoperative AKI, which is better in high quantity, whereas preoperative use of ACEIs or ARBs were both associated with reduced mortality and did not increase the risk of hyperkalemia.

Angiotensin II receptor type 1 blockade improves hyporesponsiveness to vasopressors in septic shock

Sepsis activates the renin-angiotensin system and the production of angiotensin II, which has a key role in the regulation of blood pressure through AT1 receptors. However, excessive activation of AT1 receptor is associated with deleterious effects. We investigated the consequences of a differential blockade of AT1 receptor caused by two doses of losartan (0.25 mg/kg or 15 mg/kg, s.c), a selective AT1 receptor antagonist on sepsis outcome. These doses reduced the effect of angiotensin II in normal rats by 30% and >90% 8 h after administration, respectively, but only the higher dose maintained its inhibitory effect (~70%) 24 h after injection. Sepsis was induced by cecal ligation and puncture (CLP). Losartan was injected 2 h after CLP and parameters were evaluated 6 and 24 h after CLP. Septic rats developed hypotension and hyporesponsiveness to vasoconstrictors, an intense inflammatory process and increase in plasma markers of organ dysfunction. The lower dose of losartan improved the vasoconstrictive response to phenylephrine and angiotensin II, reduced lung myeloperoxidase and prevented leukopenia 24 h after CLP, but it did not reduce NOS-2 expression, plasma IL-6 levels or organ injury parameters of septic rats. On the other hand, the higher dose of losartan worsened the response to vasoconstrictors, potentiated the hypotension and increased further levels of creatine, urea and lactate in septic rats. Therefore, an early and partial blockade of AT1 receptor with a low dose of losartan may counteract sepsis-induced refractoriness to vasoconstrictors thus providing an opportunity to improve the outcome of this condition.

Effect of angiotensin converting enzyme inhibitor and angiotensin II receptor blocker on the patients with sepsis

BACKGROUND/AIMS

Inhibitors of the renin-angiotensin system, angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), reportedly have anti-inflammatory effects. This study assessed the association of prior use of ACE inhibitors and ARBs with sepsis-related clinical outcomes.

METHODS

A population-based observational study was conducted using the Health Insurance Review and Assessment Service claims data. Among the adult patients hospitalized with new onset of sepsis in 2012, patients who took ARBs or ACE inhibitors at least 30 days prior to hospitalization were analyzed. Generalized linear models and logistic regression were used to examine the relation between the prior use of medication and clinical outcomes, such as in-hospital mortality, mechanical ventilation, and length of stay.

RESULTS

Of a total of 27,628 patients who were hospitalized for sepsis, the ACE inhibitor, ARB, and non-user groups included 1,214 (4.4%), 3,951 (14.4%), and 22,463 (82.1%) patients, respectively. As the patients in the ACE inhibitor and ARB groups had several comorbid conditions, higher rates of intensive care unit admission, hemodialysis, and mechanical ventilation were observed. However, after covariate adjustment, the use of ACE inhibitor (odds ratio [OR], 0.752; 95% confidence interval [CI], 0.661 to 0.855) or ARB (OR, 0.575; 95% CI, 0.532 to 0.621) was significantly associated with a lower rate of in-hospital mortality.

CONCLUSION

Pre-hospitalization use of ACE inhibitors or ARBs for sepsis was an independent factor for a lower rate of in-hospital mortality.

Pharmacological hypothesis: TPC2 antagonist tetrandrine as a potential therapeutic agent for COVID-19

More than ten million patients worldwide have been diagnosed with coronavirus disease 19 (COVID-19) to date (WHO situation report, 1st July 2020). There is no vaccine to prevent infection with the causative organism, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), nor a cure. In the struggle to devise potentially useful therapeutics in record time, the repurposing of existing compounds is a key route of action. In this hypothesis paper, we argue that the bisbenzylisoquinoline and calcium channel blocker tetrandrine, originally extracted from the plant Stephania tetrandra and utilized in traditional Chinese medicine, may have potential in the treatment of COVID-19 and should be further investigated. We collate and review evidence for tetrandrine's putative mechanism of action in viral infection, specifically its recently discovered antagonism of the two-pore channel 2 (TPC2). While tetrandrine's particular history of use provides a very limited pharmacological dataset, there is a suggestion from the available evidence that it could be effective at doses used in clinical practice. We suggest that further research to investigate this possibility should be conducted.

Inhibition of Angiotensin Converting Enzyme Impairs Anti-staphylococcal Immune Function in a Preclinical Model of Implant Infection

Background: Evidence suggests the renin-angiotensin system (RAS) plays key immunomodulatory roles. In particular, angiotensin-converting enzyme (ACE) has been shown to play a role in antimicrobial host defense. ACE inhibitors (ACEi) and angiotensin receptor blockers (ARB) are some of the most commonly prescribed medications, especially in patients undergoing invasive surgery. Thus, the current study assessed the immunomodulatory effect of RAS-modulation in a preclinical model of implant infection.

Methods:In vitro antimicrobial effects of ACEi and ARBs were first assessed. C57BL/6J mice subsequently received either an ACEi (lisinopril; 16 mg/kg/day), an ARB (losartan; 30 mg/kg/day), or no treatment. Conditioned mice blood was then utilized to quantify respiratory burst function as well as Staphylococcus aureus Xen36 burden ex vivo in each treatment group. S. aureus infectious burden for each treatment group was then assessed in vivo using a validated mouse model of implant infection. Real-time quantitation of infectious burden via bioluminescent imaging over the course of 28 days post-procedure was assessed. Host response via monocyte and neutrophil infiltration within paraspinal and spleen tissue was quantified by immunohistochemistry for F4/80 and myeloperoxidase, respectively.

Results: Blood from mice treated with an ACEi demonstrated a decreased ability to eradicate bacteria when mixed with Xen36 as significantly higher levels of colony forming units (CFU) and biofilm formation was appreciated ex vivo (p < 0.05). Mice treated with an ACEi showed a higher infection burden in vivo at all times (p < 0.05) and significantly higher CFUs of bacteria on both implant and paraspinal tissue at the time of sacrifice (p < 0.05 for each comparison). There was also significantly decreased infiltration and respiratory burst function of immune effector cells in the ACEi group (p < 0.05).

Conclusion: ACEi, but not ARB, treatment resulted in increased S. aureus burden and impaired immune response in a preclinical model of implant infection. These results suggest that perioperative ACEi use may represent a previously unappreciated risk factor for surgical site infection. Given the relative interchangeability of ACEi and ARB from a cardiovascular standpoint, this risk factor may be modifiable.

Renin-angiotensin-aldosterone system inhibition decreased contrast-associated acute kidney injury in chronic kidney disease patients

BACKGROUND/PURPOSE

Chronic kidney disease (CKD) is a risk factor for contrast associated acute kidney injury (CA-AKI). The risk of renin-angiotensin-aldosterone system inhibitor (RASi) use in patients with CKD before the administration of contrast is not clear.

METHODS

In this nested case-control study, 8668 patients received contrast computed tomography (CT) from 2013 to 2018 during index administration in a multicenter hospital cohort. The identification of AKI is based on the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria within 48 h after contrast medium used.

RESULTS

Finally, 986 patients (age, 63.36 ± 12.22; men, 72.92%) with CKD (estimated glomerular filtration rate (eGFR) = 35.0 ± 19.8 mL/min/1.73 m²) were eligible for analysis. After the index date, RASi users (n = 315) were less likely to develop CA-AKI (13.65% vs 30.4%, p < 0.001), and had a lower hospital mortality (8.25% vs 19.23%, p < 0.001) compared with non-users. The pre-contrast use of RASi decrease the risk of AKI (OR, 0.342, p < 0.001) and hospital mortality (OR, 0.602, p = 0.045). Even a few defined daily doses (DDDs) of RASi treatment, more than 0.02 prior to contrast CT could attenuate CA-AKI. The hospital mortality was higher in RASi non-users if their eGFR value was more than 17.9 mL/min/1.73 m².

CONCLUSION

RASi use in patients with CKD prior to contrast CT has the potential to mitigate the incidence of AKI and hospital mortality. Even a low dose of RASi will noticeably decrease the risk of AKI and will not increase the risk of hyperkalemia.

Role of angiotensin-converting enzyme in myeloid cell immune responses

Angiotensin-converting enzyme (ACE), a dicarboxypeptidase, plays a major role in the regulation of blood pressure by cleaving angiotensin I into angiotensin II (Ang II), a potent vasoconstrictor. Because of its wide substrate specificity and tissue distribution, ACE affects many diverse biological processes. In inflammatory diseases, including granuloma, atherosclerosis, chronic kidney disease and bacterial infection, ACE expression gets upregulated in immune cells, especially in myeloid cells. With increasing evidences connecting ACE functions to the pathogenesis of these acquired diseases, it is suggested that ACE plays a vital role in immune functions. Recent studies with mouse models of bacterial infection and tumor suggest that ACE plays an important role in the immune responses of myeloid cells. Inhibition of ACE suppresses neutrophil immune response to bacterial infection. In contrast, ACE overexpression in myeloid cells strongly induced bacterial and tumor resistance in mice. A detailed biochemical understanding of how ACE activates myeloid cells and which ACE peptide(s) (substrate or product) mediate these effects could lead to the development of novel therapies for boosting immunity against a variety of stimuli, including bacterial infection and tumor.

Comparisons of Staphylococcus aureus infection and other outcomes between users of angiotensin-converting-enzyme inhibitors and angiotensin II receptor blockers: lessons for COVID-19 from a nationwide cohort study

Background: Mice receiving angiotensin converting enzyme inhibitor (ACEI) drugs show increased susceptibility to infection by Staphylococcus aureus ( S. aureus). We sought to investigate whether humans using ACEI were at increased risk of S. aureus infection, comparing them to users of Angiotensin II Receptor Blockers (ARB) with multiple control outcomes to assess the potential for residual confounding.

Methods: Using the UK Clinical Practice Research Datalink linked to Hospital Episode Statistics between 1997 and 2017, we identified adults starting ACEI or ARB (as an active comparator drug). We regarded prescription of ACEI or ARB as time-dependent exposure and used a Cox regression model to compare incidence of first hospitalisation with infection due to S. aureus in periods with ACEI to periods with ARB prescriptions. We repeated the analysis using control outcomes that we did not expect to be associated with use of ACEI versus ARB (Gram-negative sepsis, hip fracture and herpes zoster) and one that we did (dry cough).

Results: We identified 445,341 new users of ACEI (mean age 64.0±14.0, male 51.7%) and 41,824 new users of ARB (mean age 64.1±14.0, male 45.5%). The fully adjusted hazard ratio for S. aureus infection (ACEI vs. ARB) was 1.18 (95% CI 1.10–1.27), consistent across sensitivity analyses. However, we also found associations with all control outcomes; rates of Gram-negative sepsis, hip fracture and dry cough were also increased during periods of time treated with ACEI compared to ARB while herpes zoster was more common during time treated with ARB.

Conclusions: Our results suggest that although ARB users appear an ideal control for analyses of ACEI effects, there is residual confounding even after multivariable adjustment. This has implications for observational analyses comparing users of these drug classes, in particular the effect of these drugs in relation to COVID-19 infection.

Effect of Antihypertensive Medications on Sepsis-Related Outcomes: A Population-Based Cohort Study

OBJECTIVES

Although the effect of antihypertensive agents on sepsis has been studied, evidence for survival benefit was limited in the literature. We investigated differences in sepsis-related outcomes depending on the antihypertensive drugs given prior to sepsis in patients with hypertension.

DESIGN

Population-based cohort study.

SETTING

Sample cohort Database of the National Health Insurance Service from 2003 to 2013 in South Korea.

PATIENTS

Patients over 30 years old who were diagnosed with sepsis after receiving hypertension treatment.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Primary outcomes, 30-day and 90-day mortality rates, were analyzed for differences among three representative antihypertensive medications: angiotensin- converting enzyme inhibitors or angiotensin II receptor blockers, calcium channel blockers, and thiazides. In total, 4,549 patients diagnosed with hypertension prior to hospitalization for sepsis were identified. The 30-day mortality was significantly higher among patients who did not receive any medications within 1 month before sepsis (36.8%) than among patients who did (32.0%; p < 0.001). The risk for 90-days mortality was significantly lower in prior angiotensin-converting enzyme inhibitors or angiotensin II receptor blocker users (reference) than in other drug users (odds ratio, 1.27; 95% CI, 1.07-1.52). There was no difference in the risk for 30-day and 90-day mortality depending on whether calcium channel blockers or thiazides were used. Use of calcium channel blockers was associated with a decreased risk for inotropic agent administration, compared with those of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (odds ratio, 1.23; 95% CI, 1.05-1.44) and thiazides (odds ratio, 1.33; 95% CI, 1.12-1.58).

CONCLUSIONS

In patients with sepsis, lower mortality rate was associated with prior use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers not with use of calcium channel blockers or thiazides. The requirement of inotropic agents was significantly lower in prior use of calcium channel blockers, although the survival benefits were not prominent.

Comparative Efficacy of Angiotensin Converting Enzyme Inhibitors and Angiotensin Receptor Blockers after Coronary Artery Bypass Grafting

Although angiotensin receptor blockers (ARBs) are considered as an alternative for those with angiotensin converting enzyme inhibitors (ACEi) intolerance, the comparative effectiveness of ARBs and ACEi remains controversial in patients who underwent coronary artery bypass grafting (CABG). We aimed to compare the clinical effects of the two types of renin-angiotensin-aldosterone system (RAAS) inhibitors in patients who underwent CABG. From January 2001 to January 2015, among the 5456 patients, data from 1198 (20.1%) patients who used a RAAS inhibitor at discharge were analyzed. These 1198 patients were classified into ACEi (N = 900) and ARB (N = 298) groups. The primary outcome was major adverse cardiovascular and cerebrovascular events (MACCE) during a median follow-up period of 48 months. Propensity-matched analysis revealed that the incidence of MACCE over a 48 month follow-up period did not differ between the groups (HR, 0.65; 95% CI, 0.36–1.21; p = 0.17), but it was significantly lower in the ARB group during the 12 month follow-up period (HR, 0.46; 95% CI, 0.22–0.96; p = 0.04). In conclusion, ARBs may have comparable protective effects to ACEi and be a reasonable alternative for intolerant patients after CABG. The beneficial effects of ARBs depending on follow-up period require further investigation.

Effect of Renin-Angiotensin-Aldosterone System Inhibitors on Short-Term Mortality After Sepsis: A Population-Based Cohort Study

Antagonists of the renin-angiotensin-aldosterone system (RAAS), including ACEIs (angiotensin-converting enzyme inhibitors) and ARBs (angiotensin II receptor blockers), may prevent organ failure. We, therefore, investigated whether specific RAAS inhibitors are associated with reduced mortality in patients with sepsis.We conducted a population-based retrospective cohort study using multivariable propensity score-based regression to control for differences among patients using different RAAS inhibitors. A multivariable-adjusted Cox proportional-hazards regression model was used to determine the association between RAAS inhibitors and sepsis outcomes. To directly compare ACEI users, ARB users, and nonusers, a 3-way propensity score matching approach was performed. Results were pooled with previous evidence via a random-effects meta-analysis. A total of 52 727 patients were hospitalized with sepsis, of whom 7642 were prescribed an ACEI and 4237 were prescribed an ARB. Using propensity score-matched analyses, prior ACEI use was associated with decreased 30-day mortality (hazard ratio, 0.84 [95% CI, 0.75-0.94]) and 90-day mortality (hazard ratio, 0.83 [95% CI, 0.75-0.92]) compared with nonuse. Prior ARB use was associated with an improved 90-day survival (hazard ratio, 0.88 [95% CI, 0.83-0.94]). These results persisted in sensitivity analyses focusing on patients without cancer and patients with hypertension. By contrast, no beneficial effect was found for antecedent β-blockers exposure (hazard ratio, 0.99 [95% CI, 0.94-1.05]). The pooled estimates obtained from the meta-analysis was 0.71 (95% CI, 0.58-0.87) for prior use of ACEI/ARB.The short-term mortality after sepsis was substantially lower among those who were already established on RAAS inhibitor treatment when sepsis occurred.

Antimicrobial and Immune-Modulatory Effects of Vitamin D Provide Promising Antibiotics-Independent Approaches to Tackle Bacterial Infections - Lessons Learnt from a Literature Survey

Antimicrobial multidrug-resistance (MDR) constitutes an emerging threat to global health and makes the effective prevention and treatment of many, particularly severe infections challenging, if not impossible. Many antibiotic classes have lost antimicrobial efficacy against a plethora of infectious agents including bacterial species due to microbial acquisition of distinct resistance genes. Hence, the development of novel anti-infectious intervention strategies including antibiotic-independent approaches is urgently needed. Vitamins such as vitamin D and vitamin D derivates might be such promising molecular candidates to combat infections caused by bacteria including MDR strains. Using the Pubmed database, we therefore performed an in-depth literature survey, searching for publications on the antimicrobial effect of vitamin D directed against bacteria including MDR strains. In vitro and clinical studies between 2009 and 2019 revealed that vitamin D does, in fact, possess antimicrobial properties against both Gram-positive and Gram-negative bacterial species, whereas conflicting results could be obtained from in vivo studies. Taken together, the potential anti-infectious effects for the antibiotic-independent application of vitamin D and/or an adjunct therapy in combination with antibiotic compounds directed against infectious diseases such as tuberculosis, H. pylori infections, or skin diseases, for instance, should be considered and further investigated in more detail.

Classic and Nonclassic Renin-Angiotensin Systems in the Critically Ill

Classic and nonclassic renin-angiotensin systems (RAS) are 2 sides of an ubiquitous endocrine/paracrine cascade regulating blood pressure and homeostasis. Angiotensin II and angiotensin-converting enzyme (ACE) levels are associated with severity of disease in the critically ill, and are central to the physiology and the pathogenesis of circulatory shock. Angiotensin (1-7) and ACE2 act as an endogenous counterregulatory arm to the angiotensin II/ACE axis. The tissue-based RAS has paracrine effects dissociated from those of the circulating RAS. Exogenous angiotensin II or ACE2 may improve the outcome of septic shock and acute respiratory distress syndrome, respectively.

Angiotensin II Brings More Questions Than Answers

The approval of synthetic human angiotensin II (Giapreza, LaJolla Pharmaceuticals) by the FDA in December 2017 provides clinicians with a new tool in the treatment of distributive shock. Angiotensin II (ATII) was approved based on the results of the ATHOS-3 trial. In this trial, patients who received angiotensin II were more likely to achieve a mean arterial pressure of 75 mmHg or an increase in mean arterial pressure of 10 mmHg above that seen in patients who received a placebo. However, the results of ATHOS-3 also highlighted important concerns about thrombotic and infectious complications associated with ATII. Given that the cost of medication acquisition is approximately $1,500 per vial, practitioners must also decide how to implement ATII into practice in the most cost-effective manner. This commentary examines the current controversies surrounding both the safety and efficacy of ATII.

Calcium Ion Channels: Roles in Infection and Sepsis Mechanisms of Calcium Channel Blocker Benefits in Immunocompromised Patients at Risk for Infection

Immunosuppression may occur for a number of reasons related to an individual's frailty, debility, disease or from therapeutic iatrogenic intervention or misadventure. A large percentage of morbidity and mortality in immunodeficient populations is related to an inadequate response to infectious agents with slow response to antibiotics, enhancements of antibiotic resistance in populations, and markedly increased prevalence of acute inflammatory response, septic and infection related death. Given known relationships between intracellular calcium ion concentrations and cytotoxicity and cellular death, we looked at currently available data linking blockade of calcium ion channels and potential decrease in expression of sepsis among immunosuppressed patients. Notable are relationships between calcium, calcium channel, vitamin D mechanisms associated with sepsis and demonstration of antibiotic-resistant pathogens that may utilize channels sensitive to calcium channel blocker. We note that sepsis shock syndrome represents loss of regulation of inflammatory response to infection and that vitamin D, parathyroid hormone, fibroblast growth factor, and klotho interact with sepsis defense mechanisms in which movement of calcium and phosphorus are part of the process. Given these observations we consider that further investigation of the effect of relatively inexpensive calcium channel blockade agents of infections in immunosuppressed populations might be worthwhile.

Angiotensin-converting enzyme in innate and adaptive immunity

Angiotensin-converting enzyme (ACE) - a zinc-dependent dicarboxypeptidase with two catalytic domains - plays a major part in blood pressure regulation by converting angiotensin I to angiotensin II. However, ACE cleaves many peptides besides angiotensin I and thereby affects diverse physiological functions, including renal development and male reproduction. In addition, ACE has a role in both innate and adaptive responses by modulating macrophage and neutrophil function - effects that are magnified when these cells overexpress ACE. Macrophages that overexpress ACE are more effective against tumours and infections. Neutrophils that overexpress ACE have an increased production of superoxide, which increases their ability to kill bacteria. These effects are due to increased ACE activity but are independent of angiotensin II. ACE also affects the display of major histocompatibility complex (MHC) class I and MHC class II peptides, potentially by enzymatically trimming these peptides. Understanding how ACE expression and activity affect myeloid cells may hold great promise for therapeutic manipulation, including the treatment of both infection and malignancy.

Angiotensin-converting enzyme in innate and adaptive immunity

Angiotensin-converting enzyme (ACE) - a zinc-dependent dicarboxypeptidase with two catalytic domains - plays a major part in blood pressure regulation by converting angiotensin I to angiotensin II. However, ACE cleaves many peptides besides angiotensin I and thereby affects diverse physiological functions, including renal development and male reproduction. In addition, ACE has a role in both innate and adaptive responses by modulating macrophage and neutrophil function - effects that are magnified when these cells overexpress ACE. Macrophages that overexpress ACE are more effective against tumours and infections. Neutrophils that overexpress ACE have an increased production of superoxide, which increases their ability to kill bacteria. These effects are due to increased ACE activity but are independent of angiotensin II. ACE also affects the display of major histocompatibility complex (MHC) class I and MHC class II peptides, potentially by enzymatically trimming these peptides. Understanding how ACE expression and activity affect myeloid cells may hold great promise for therapeutic manipulation, including the treatment of both infection and malignancy.

Comparative effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on the risk of pneumonia and severe exacerbations in patients with COPD

Objectives

This study aimed to compare the effects of angiotensin-converting-enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) on the risk of pneumonia and severe exacerbations in patients with COPD.

Patients and methods

All patients with COPD who used ACEis and ARBs for >90 days between 2000 and 2005 were recruited. Pairwise matching (1:1) of the ACEi and ARB groups resulted in two similar subgroups, with 6,226 patients in each. The primary outcomes were pneumonia and COPD exacerbations, and the secondary outcome was death.

Results

During the follow-up period, the incidence of pneumonia was 7.20 per 100 person-years in the ACEi group and 5.89 per 100 person-years in the ARB group. The ACEi group had a higher risk of pneumonia (adjusted hazard ratio [aHR], 1.22; 95% CI, 1.15–1.29) than the ARB group. The incidence of severe exacerbations was 0.65 per person-year for the patients receiving ACEis and 0.52 per person-year for those receiving ARBs. The patients receiving ACEis had a higher risk of severe exacerbations (aHR, 1.19; 95% CI, 1.16–1.21) than those receiving ARBs. Similar trends were noted in terms of severe exacerbations requiring hospitalization (aHR, 1.24; 95% CI, 1.21–1.28) or emergency department visits (aHR, 1.16; 95% CI, 1.13–1.18), pneumonia requiring mechanical ventilation (aHR, 1.35; 95% CI, 1.24–1.47), and mortality (aHR, 1.33; 95% CI, 1.26–1.42).

Conclusion

ARBs were associated with lower rates of pneumonia, severe pneumonia, and mortality than ACEis in patients with COPD.

Calcium channel blockade and survival in recipients of successful renal transplant: an analysis of the FAVORIT trial results

INTRODUCTION

Single-center and observational studies have suggested that calcium channel blocking agents may decrease the expression of sepsis in individual populations. In the renal transplant population, a role for calcium channel blockers in allograft protection and in prevention of sepsis has been postulated. We hypothesized that any important survival benefit or risk related to chronic use of calcium channel blocking agents should be discernable through an analysis of a large database of stable recipients of renal allografts who had enrolled in a large international trial.

METHODS

A retrospective analysis of 4,110 renal transplant recipients who enrolled in the international Folic Acid for Vascular Outcome Reduction in Transplantation trial between 2002 and 2007 and were followed until 2010 was undertaken comparing cohorts (FAVORIT) of patients either taking (n=1,436) or not taking (n=2,674) calcium channel blocking medications. The endpoint was all-cause mortality (cardiovascular, noncardiovascular mortality, or unknown). Results were adjusted for country, age, race, sex, smoker, systolic blood pressure, diabetes mellitus, low-density lipoprotein, and chronic kidney disease status.

RESULTS

There were no statistically significant differences in incidence rates of cardiovascular, noncardiovascular, and all-cause mortality between patients taking or not taking calcium channel blocking medications.

CONCLUSION

Although physiologic reasoning and small series results suggest a benefit for calcium channel blocking agents for allograft protection and sepsis prevention in immunosuppressed patients, we find no clear survival benefit in a large international renal transplant trial.

Angiotensin-converting enzyme enhances the oxidative response and bactericidal activity of neutrophils

Angiotensin-converting enzyme (ACE) inhibitors are widely used to reduce blood pressure. Here, we examined if an ACE is important for the antibacterial effectiveness of neutrophils. ACE knockout mice or mice treated with an ACE inhibitor were more susceptible to bacterial infection by methicillin-resistant Staphylococcus aureus (MRSA). In contrast, mice overexpressing ACE in neutrophils (Neu^ACE mice) have increased resistance to MRSA and better in vitro killing of MRSA, Pseudomonas aeruginosa, and Klebsiella pneumoniae ACE overexpression increased neutrophil production of reactive oxygen species (ROS) following MRSA challenge, an effect independent of the angiotensin II AT1 receptor. Specifically, as compared with wild-type (WT) mice, there was a marked increase of superoxide generation (>twofold, P < .0005) in Neu^ACE neutrophils following infection, whereas ACE knockout neutrophils decreased superoxide production. Analysis of membrane p47-phox and p67-phox indicates that ACE increases reduced NAD phosphate oxidase activity but does not increase expression of these subunits. Increased ROS generation mediates the enhanced bacterial resistance of Neu^ACE mice because the enhanced resistance is lost with DPI (an inhibitor of ROS production by flavoenzymes) inhibition. Neu^ACE granulocytes also have increased neutrophil extracellular trap formation and interleukin-1β release in response to MRSA. In a mouse model of chemotherapy-induced neutrophil depletion, transfusion of ACE-overexpressing neutrophils was superior to WT neutrophils in treating MRSA infection. These data indicate a previously unknown function of ACE in neutrophil antibacterial defenses and suggest caution in the treatment of certain individuals with ACE inhibitors. ACE overexpression in neutrophils may be useful in boosting the immune response to antibiotic-resistant bacterial infection.

Does calcium channel blockade have a role in prevention of expression of sepsis in renal transplant recipients?

Many antihypertensive agents have been demonstrated to assist in preservation of kidney function, among them those that modulate calcium channels. Calcium channel blockers may also be of value in protecting hemodialysis patients from complications of sepsis. In diabetic recipients of kidney transplant allografts treated with cyclosporine, calcium channel blockade has been retrospectively linked to improved graft preservation and to fewer episodes of sepsis. This brief review outlines clinical and experimental publications on potential protection from sepsis by addition of calcium channel blockers to standard antibiotic therapy in individuals who may or may not have normal kidney function, or in the presence or absence of immunosuppression. Such mechanisms include blockade of antibiotic cytosolic extrusion in the cases of Pneumococci, Mycobacterium tuberculosis, Plasmodium falciparum malaria, or Schistosoma mansoni; blockade of the calcineurin/calmodulin pathway (in immunosuppressed patients allowing for lower dosage of cyclosporine); stabilization of calcium movement at the level of sarcoplasmic reticulum by which shock (vasopressor instability) is prevented; or of cytosolic calcium influx and cell death (in the case of allograft acute tubular necrosis). Given the high cost of development of new antibiotics, a role for generic calcium channel blockade in sepsis prevention should be pursued by additional studies to investigate potential links between blockade of calcium channels and expression of sepsis in at-risk populations.