Propranolol reduces systemic oxidative stress and endotoxemia in cirrhotic patients with esophageal varices

Anticancer effect of propranolol on diethylnitrosamine-induced hepatocellular carcinoma rat model

BACKGROUND

Hepatocellular carcinoma (HCC) is the most widespread type of primary liver cancer. Diethylnitrosamine (DEN), a hepatotoxic hepatocarcinogenic compound, is used to induce HCC in animal models. The non-selective β-blocker propranolol demonstrated antiproliferative activity in many cancer types.

OBJECTIVE

This investigation aimed to evaluate the anticancer effect of propranolol against DEN-induced HCC in rats.

METHODS

Thirty adult male rats were divided into the following groups: Group I (C, control), Group II (HCC); received DEN, 70 mg/kg body weight (b.wt.) once a week for 10 weeks, to induce HCC, and Group III (HCC/Prop); received DEN for 10 weeks for HCC induction, then received 20 mg/kg b.wt. propranolol, intraperitoneally for four successive weeks.

RESULTS

HCC was developed in rats' livers and confirmed via significant liver architecture changes, significantly elevated activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), α-fetoprotein (AFP), total- and direct-bilirubin (Bil), and a decline in albumin (ALB) level in serum. HCC group demonstrated elevated levels of malondialdehyde (MDA), nitric oxide (NO), HIF-1α, IL-8, NF-κB, PGE2, TGF-β1, VEGF, and CD8, but significant decline of GSH, and IL-10 level, with suppression of the antioxidant enzymes' activities. In addition, the gene expression of the hepatic inducible nitric oxide synthase (iNOS), and LAG-3 were up-regulated. Moreover, the protein expression of p-PKC was up-regulated, while that of PD-1 and PD-L1 were down-regulated in the liver tissues of the HCC group. However, propranolol ameliorated the investigated parameters in the HCC/Prop group.

CONCLUSION

Propranolol exhibited an anticancer effect and thus can be considered as a promising treatment for HCC. Blocking of PD-1/PD-L1 and LAG-3 signals participated in the anti-tumor effect of propranolol on HCC.

Oxidative Mechanisms and Cardiovascular Abnormalities of Cirrhosis and Portal Hypertension

In patients with portal hypertension, there are many complications including cardiovascular abnormalities, hepatorenal syndrome, ascites, variceal bleeding, and hepatic encephalopathy. The underlying mechanisms are not yet completely clarified. It is well known that portal hypertension causes mesenteric congestion which produces reactive oxygen species (ROS). ROS has been associated with intestinal mucosal injury, increased intestinal permeability, enhanced gut bacterial overgrowth, and translocation; all these changes result in increased endotoxin and inflammation. Portal hypertension also results in the development of collateral circulation and reduces liver mass resulting in an overall increase in endotoxin/bacteria bypassing detoxication and immune clearance in the liver. Endotoxemia can in turn aggravate oxidative stress and inflammation, leading to a cycle of gut barrier dysfunction → endotoxemia → organ injury. The phenotype of cardiovascular abnormalities includes hyperdynamic circulation and cirrhotic cardiomyopathy. Oxidative stress is often accompanied by inflammation; thus, blocking oxidative stress can minimize the systemic inflammatory response and alleviate the severity of cardiovascular diseases. The present review aims to elucidate the role of oxidative stress in cirrhosis-associated cardiovascular abnormalities and discusses possible therapeutic effects of antioxidants on cardiovascular complications of cirrhosis including hyperdynamic circulation, cirrhotic cardiomyopathy, and hepatorenal syndrome.

The impact of propranolol on nitric oxide and total antioxidant capacity in patients with resistant hypertension-evidence from the APPROPRIATE trial

Objectives

The objective was to assess the effect of propranolol on oxidative stress and anti-oxidant potential in patients with resistant hypertension as a secondary analysis of the APPROPRIATE trial. This randomized double blinded clinical trial recruited patients with resistant hypertension and allocated forty patients to propranolol and placebo in 1:1 ratio. The pro-oxidant state (nitrate and nitrite) was assessed using modified Griess assay. The total anti-oxidant capacity was measured using ABTS assay.

Results

Analysis was performed for 18 patients from the propranolol group and 15 from the placebo group. A decline in end point ambulatory blood pressure (p = 0.031) and greater mean reduction in office SBP (29.7 ± 13.0 mmHg, p = 0.021) was noted in the propranolol arm. Nitrate and nitrite levels were lower at the end of a 90 day follow up period in both arms, with a greater mean reduction with propranolol. A significant increase in the AOC was noted in both arms with higher incremental value with Propranolol. The findings of this study do not demonstrate a statistically significant effect of propranolol on the oxidative stress/antioxidant balance in patients with resistant hypertension. The observed trends merit further evaluation.