Angiotensin-converting enzyme inhibitors slow recovery from anemia following cardiac surgery

The Hematopoietic Function of Medicinal Wine Maoji Jiu Revealed in Blood Deficiency Model Rats

Maoji Jiu (MJ), a medicinal wine, has been used commonly by the Chinese to enrich and nourish the blood. In this study, the aim is to examine the hematopoietic function of MJ and investigate its hematopoietic regulation mechanism. Thirty-six female Sprague-Dawley rats (200 ± 20 g) were randomly divided into six groups with six rats in each group. The blood deficiency model was induced by injecting hypodermically with N-acetylphenylhydrazine (APH) and injecting intraperitoneally with cyclophosphamide (CTX), and treatment drugs were given by oral gavage twice a day for continuous 10 days from the start of the experiments. The administration of MJ improved the levels of white blood cells (WBCs), red blood cells (RBCs), hemoglobin (HGB), and hematocrit (HCT) in the blood deficiency model rats. Hematopoietic effect involves regulating the antioxidant activity in the liver and the levels of Bcl-2, Bax, erythropoietin (EPO), transforming growth factor-beta-1 (TGF-β1), and macrophage colony-stimulating factor (M-CSF) mRNA in spleen tissues to enhance extramedullary hematopoiesis. This study suggests that MJ has a beneficial effect on blood deficiency model rats.

Renin-angiotensin system inhibitors linked to anemia: a systematic review and meta-analysis

BACKGROUND

The objective of this meta-analysis was to evaluate the risk of anemia in patients who received renin-angiotensin system (RAS) inhibitors.

METHODS

A literature search was performed using MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from inception through November, 2014. Studies that reported relative risks, odd ratios or hazard ratios comparing the anemia risk in patients who received angiotensin-converting-enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) vs. those who did not were included. We performed the prespecified sensitivity analysis including only only studies with confounder adjusted analysis. Pooled risk ratios (RRs) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method.

RESULTS

Seven studies (2 cohort and 5 cross-sectional studies) with 29,061 patients were included in the analysis to assess the risk of anemia and the RAS inhibitors use. The pooled RR of anemia in patients receiving ACEIs was 1.56 (95% CI, 1.40-1.73, I(2) = 17%). When meta-analysis was limited only to studies with confounder adjusted analysis, the pooled RR of anemia in patients using ACEIs was 1.57 (95% CI, 1.43-1.73, I(2) = 0%) The pooled RR of anemia in patients receiving ARBs was 1.60 (95% CI, 1.27-2.00, I(2) = 39%). The meta-analysis of studies with confounder adjusted analysis demonstrated the pooled RR of anemia in patients using ARBs of 1.59 (95% CI, 1.38-1.83, I(2) = 0%).

CONCLUSIONS

Our meta-analysis demonstrates an association between anemia and the use of RAS inhibitors. Hematological parameters should be monitored in patients treated with RAS inhibitors.

Erythropoiesis and Blood Pressure Are Regulated via AT1 Receptor by Distinctive Pathways

The renin–angiotensin system (RAS) plays a central role in blood pressure regulation. Although clinical and experimental studies have suggested that inhibition of RAS is associated with progression of anemia, little evidence is available to support this claim. Here we report that knockout mice that lack angiotensin II, including angiotensinogen and renin knockout mice, exhibit anemia. The anemia of angiotensinogen knockout mice was rescued by angiotensin II infusion, and rescue was completely blocked by simultaneous administration of AT1 receptor blocker. To genetically determine the responsible receptor subtype, we examined AT1a, AT1b, and AT2 knockout mice, but did not observe anemia in any of them. To investigate whether pharmacological AT1 receptor inhibition recapitulates the anemic phenotype, we administered AT1 receptor antagonist in hypotensive AT1a receptor knockout mice to inhibit the remaining AT1b receptor. In these animals, hematocrit levels barely decreased, but blood pressure further decreased to the level observed in angiotensinogen knockout mice. We then generated AT1a and AT1b double-knockout mice to completely ablate the AT1 receptors; the mice finally exhibited the anemic phenotype. These results provide clear evidence that although erythropoiesis and blood pressure are negatively controlled through the AT1 receptor inhibition in vivo, the pathways involved are complex and distinct, because erythropoiesis is more resistant to AT1 receptor inhibition than blood pressure control.

The haematopoietic effect of Panax japonicus on blood deficiency model mice

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Panax japonicus C. A. Mey. var. major (Burk.) C. Y. Wu et K. M. Feng (PJ) is a commonly used traditional Chinese medicine to promote hematopoietic effects, promote blood circulation and supporting healthy energy. Aim of the study is to investigate the haematopoietic effects of PJ and determine the mechanism of its haematopoietic activity.

MATERIALS AND METHODS

The crude extract from PJ (PJE) was separated into two fractions: polysaccharides (PJPS) and low-molecular-weight compounds (PJSM). PJPS, and PJSM were incubated with mice spleen cells, and their haematopoietic activities were evaluated by determining the haematopoietic growth factor levels (HGFs) in vitro. The in vivo experiments used anaemia model mice that were given hypodermic injections of N-acetyl phenylhydrazine (APH) and intraperitoneal injections of cyclophosphamide (CTX).

RESULTS

Both PJPS and PJSM were significantly involved in the haematopoietic effect of PJE. The administration of PJPS and PJSM could accelerate the recovery of the white blood cell (WBC), red blood cell (RBC), and haemoglobin (HGB) levels in the blood deficiency model mice. Haematopoietic activity may result from stimulating the secretion of interleukin-3 (IL-3), interleukin-6 (IL-6), erythropoietin (EPO), GM colony-stimulating factor (CSF), and M-CSF and by the resistance of spleen cells to apoptosis.

CONCLUSIONS

The study results support the potential use of PJPS and PJSM for the treatment of anaemia.

Association of angiotensin-converting enzyme inhibitor therapy initiation with a reduction in hemoglobin levels in patients without renal failure

OBJECTIVE

To investigate whether treatment initiated with an angiotensin-converting enzyme inhibitor (ACE-I) or an angiotensin II receptor blocker (ARB) for patients with ischemic heart disease, hypertension, or diabetes causes a reduction in hemoglobin (Hb) levels.

PATIENTS AND METHODS

This was a retrospective cohort analysis using the computerized database of a large health maintenance organization. Included were all adults with a first purchase of an ACE-I, an ARB, or a calcium channel blocker (CCB) between January 1, 2004, and December 31, 2009, defined as the index date. Measures of Hb levels before and 1 year after the index date were reviewed, and the change was calculated. All the analyses were stratified by pharmaceutical class. The main exposure variables were the proportion of days covered (PDC) by these drugs and the mean enalapril dosage (for enalapril users only).

RESULTS

Levels of Hb before and after treatment were available for 14,754 patients taking ACE-Is, 751 taking ARBs, and 3087 taking CCBs. A high PDC was significantly associated with greater yearly reductions in Hb levels compared with a low PDC for CCB use, but was more pronounced for ACE-I and ARB use. A high PDC was also associated with a higher odds of developing anemia in ACE-I users (odds ratio [OR], 1.59; P<.001) and ARB users (OR, 2.21; P=.05). In nonanemic enalapril users, every 10-mg increment in daily dose was associated with an OR of 1.45 for the development of anemia (P<.001). The association remained after excluding nonadherent patients.

CONCLUSION

Levels of Hb are reduced during the first year of use of ACE-Is and to a lesser extent with use of ARBs. This association is dose dependent and is not explained by patient adherence.

Treatment of hypertension in patients undergoing coronary artery by-pass grafting

Hypertension occurs in up to 80% of patients scheduled to coronary artery by-pass grafting (CABG). In hemodynamically stable patients all anti-hypertensive drugs should be continued till a day of surgery. For vast majority of patients there is no need to use blood pressure lowering agents during CABG, however it is necessary to maintain blood pressure level and avoid extreme blood pressure variations. Upon CABG hypotensive therapy should be modified to the needs of the individual patient and should be monitored individually. Treatment of hypertension ought to be started with caution with lowest possible dosage. Aggressive therapy is strongly discouraged to avoid hemodynamic collapse. Beta-blockers should be administered to all CABG patients unless contraindicated.