Adenosine receptors expression in cardiac fibroblasts of patients with left ventricular dysfunction due to valvular disease

Blockage of the adenosine A2B receptor prevents cardiac fibroblasts overgrowth in rats with pulmonary arterial hypertension

Sustained pressure overload and fibrosis of the right ventricle (RV) are the leading causes of mortality in pulmonary arterial hypertension (PAH). Although the role of adenosine in PAH has been attributed to the control of pulmonary vascular tone, cardiac reserve, and inflammatory processes, the involvement of the nucleoside in RV remodelling remains poorly understood. Conflicting results exist on targeting the low-affinity adenosine A2B receptor (A2BAR) for the treatment of PAH mostly because it displays dual roles in acute vs. chronic lung diseases. Herein, we investigated the role of the A2BAR in the viability/proliferation and collagen production by cardiac fibroblasts (CFs) isolated from RVs of rats with monocrotaline (MCT)-induced PAH. CFs from MCT-treated rats display higher cell viability/proliferation capacity and overexpress A2BAR compared to the cells from healthy littermates. The enzymatically stable adenosine analogue, 5'-N-ethylcarboxamidoadenosine (NECA, 1-30 μM), concentration-dependently increased growth, and type I collagen production by CFs originated from control and PAH rats, but its effects were more prominent in cells from rats with PAH. Blockage of the A2BAR with PSB603 (100 nM), but not of the A2AAR with SCH442416 (100 nM), attenuated the proliferative effect of NECA in CFs from PAH rats. The A2AAR agonist, CGS21680 (3 and 10 nM), was virtually devoid of effect. Overall, data suggest that adenosine signalling via A2BAR may contribute to RV overgrowth secondary to PAH. Therefore, blockage of the A2AAR may be a valuable therapeutic alternative to mitigate cardiac remodelling and prevent right heart failure in PAH patients.

Renal Metabolomics Study and Critical Pathway Validation of Shenkang Injection in the Treatment of Chronic Renal Failure

To reveal the mechanism of Shenkang injection (SKI) in the treatment of chronic renal failure, and verify the key pathway. In this work, an untargeted metabolomics approach was performed by LC-MS coupled with multivariate statistical analysis to provide new insights into therapeutic mechanism of SKI. Hematoxylin-eosin (H&E) Staining and Immunohistochemistry were used to evaluate the effects of drug treatment, Western blot was used to verify the critical pathway. Then, a total of 44 potential biomarkers of chronic renal failure (CRF) were identified and reversed regulation, including 2,8-dihydroxypurine, 5-methoxytryptophan, uric acid, acetylcarnitine, taurine, etc. Mainly concerned with arginine and proline metabolism, purine metabolism, histidine metabolism, etc. Pathological examination showed that the renal interstitium of SKI group was significantly improved, with fewer inflammatory cells and thinner vascular walls compared with the model group. Immunohistochemical results showed that the expression of α-smooth muscle actin (α-SMA) was decreased, and the expression of E-cadherin was increased in CRF model group, and the two indicators were reversed regulation in SKI injection, indicating that the degree of fibrosis was relieved. Critical signaling pathway phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) and nuclear factor-kappaB (NF-κB) protein expressions were significantly inhibited. This study was the first to employ metabolomics to elucidate the underlying mechanisms of SKI in chronic renal failure. The results would provide some support for clinical application of traditional Chinese medicines in clinic.

Effects of Shenfu injection on myocardial adenosine receptors in rats with myocardial ischemia-reperfusion postconditioning

OBJECTIVE

Shenfu injection (SFI) has been reported to have a protection against myocardial ischemia-reperfusion (MI/R) injury. However, the changes of adenosine receptors in MI/R postconditioning when pretreated with SFI are unclear.

METHODS

Forty-five rats were randomly divided into sham group (sham), MI/R postconditioning group (MI/R-post), low-dose SFI group (1 mL/kg), middle-dose SFI group (2.5 mL/kg), and high-dose SFI group (5 mL/kg). In SFI groups, SFI was intravenously injected before reperfusion, and rats were treated with ischemic postconditioning after ischemia for 30 min. After 24 h of reperfusion, the levels of Ca²⁺ and cAMP in blood platelets were analyzed. Myocardial infarct volume and myocardial pathology were observed. The levels of adenosine receptor subtypes A₁, A_2b, and A₃ in myocardium were analyzed using immunohistochemistry and Western blot. The oxidative stress-related indicators were also observed.

RESULTS

Compared with the MI/R-post group, SFI ameliorated the MI/R injury by decreasing the myocardial infarct area, oxidative stress, and concentration of Ca²⁺ and cAMP (p < 0.01). Pretreatment with SFI enhanced the expression of adenosine receptors A₁ and A_2b in a dose manner compared with the MI/R-post group. In contrast, the levels of adenosine receptor A₃ were increased after MI/R postconditioning compared with the sham group, and its expression continued to increase with the increase of SFI. Furthermore, the oxidative stress reduced with the concentrations of SFI.

CONCLUSION

These results demonstrated that pretreatment with SFI might regulate the expression of adenosine receptors to improve the MI/R postconditioning.