Lacidipine attenuates TNF-α-induced cardiomyocyte apoptosis

Insights into SGLT2 inhibitor treatment of diabetic cardiomyopathy: focus on the mechanisms

Among the complications of diabetes, cardiovascular events and cardiac insufficiency are considered two of the most important causes of death. Experimental and clinical evidence supports the effectiveness of SGLT2i for improving cardiac dysfunction. SGLT2i treatment benefits metabolism, microcirculation, mitochondrial function, fibrosis, oxidative stress, endoplasmic reticulum stress, programmed cell death, autophagy, and the intestinal flora, which are involved in diabetic cardiomyopathy. This review summarizes the current knowledge of the mechanisms of SGLT2i for the treatment of diabetic cardiomyopathy.

Transmembrane tumor necrosis factor alpha attenuates pressure-overload cardiac hypertrophy via tumor necrosis factor receptor 2

Tumor necrosis factor-alpha (TNF-α) plays an important pathogenic role in cardiac hypertrophy and heart failure (HF); however, anti-TNF is paradoxically negative in clinical trials and even worsens HF, indicating a possible protective role of TNF-α in HF. TNF-α exists in transmembrane (tmTNF-α) and soluble (sTNF-α) forms. Herein, we found that TNF receptor 1 (TNFR1) knockout (KO) or knockdown (KD) by short hairpin RNA or small interfering RNA (siRNA) significantly alleviated cardiac hypertrophy, heart dysfunction, fibrosis, and inflammation with increased tmTNF-α expression, whereas TNFR2 KO or KD exacerbated the pathological phenomena with increased sTNF-α secretion in transverse aortic constriction (TAC)- and isoproterenol (ISO)-induced cardiac hypertrophy in vivo and in vitro, respectively, indicating the beneficial effects of TNFR2 associated with tmTNF-α. Suppressing TNF-α converting enzyme by TNF-α Protease Inhibitor-1 (TAPI-1) to increase endogenous tmTNF-α expression significantly alleviated TAC-induced cardiac hypertrophy. Importantly, direct addition of exogenous tmTNF-α into cardiomyocytes in vitro significantly reduced ISO-induced cardiac hypertrophy and transcription of the pro-inflammatory cytokines and induced proliferation. The beneficial effects of tmTNF-α were completely blocked by TNFR2 KD in H9C2 cells and TNFR2 KO in primary myocardial cells. Furthermore, we demonstrated that tmTNF-α displayed antihypertrophic and anti-inflammatory effects by activating the AKT pathway and inhibiting the nuclear factor (NF)-κB pathway via TNFR2. Our data suggest that tmTNF-α exerts cardioprotective effects via TNFR2. Specific targeting of tmTNF-α processing, rather than anti-TNF therapy, may be more useful for the treatment of hypertrophy and HF.

In contrast to detrimental effects of soluble tumor necrosis factor-alpha (TNF-α) via TNFR1, this study shows that transmembrane TNF-α protects the heart by suppressing pressure overload-induced cardiac hypertrophy and inflammation via TNFR2. Targeting tmTNF-α processing may be more useful than TNF-antagonist for treatment of hypertrophy and heart failure.

Vaspin Prevents Tumor Necrosis Factor-α-Induced Apoptosis in Cardiomyocytes by Promoting Autophagy

Visceral adipose tissue-derived serine protease inhibitor (Vaspin) is an adipocytokine that has been shown to exert anti-inflammatory effects and inhibits apoptosis under diabetic conditions. This study was designed to investigate the impact of vaspin on autophagy in tumor necrosis factor (TNF)-α-induced injury in cardiomyocytes and its cardioprotective effects in the pathogenesis of diabetic cardiomyopathy (DCM). H9C2 cells were treated with TNF-α with or without vaspin in vitro. Tumor necrosis factor-α treatment inhibited autophagy and promoted apoptosis in H9C2 cells after stimulating for 24 hours. Pretreatment with vaspin significantly mitigated apoptosis induced by TNF-α partly because of augment effects of vaspin on autophagy as demonstrated by a higher ratio of LC3-II/LC3-I, higher expression of Beclin-1, and increased autophagosomes formation. Furthermore, the AKT agonist IGF-1 significantly reversed the effect of vaspin on autophagy. In vivo DCM model was also developed by treating rats with streptozotocin followed by intraperitoneal injection with vaspin. In DCM rats, upregulation of vaspin reversed cardiac dysfunction, as identified by increased left ventricular ejection fractions and fractional shortening levels, a higher Em/Am ratio, and lower levels of TNF-α, lactate dehydrogenase, creatine kinase, and creatine kinase-myocardial isoenzyme. In conclusion, vaspin attenuated the TNF-α-induced apoptosis by promoting autophagy probably through inhibiting the PI3K/AKT/mTOR pathway and further ameliorated the cardiac dysfunction in DCM rats.

Cardioprotective effect of caffeic acid phenethyl ester on cardiac contusion following blunt chest trauma in rats

We investigated the effects of caffeic acid phenethyl ester (CAPE) on cardiac damage after blunt chest injury. Forty male adult Wistar albino rats were divided into four groups; control, cardiac contusion, cardiac contusion + CAPE, and CAPE. CAPE, 10 mmol/kg, was administered intraperitoneally for 7 days following cardiac contusion. Heart tissue and blood were obtained at the end of the experimental period. Cardiac histopathology was determined using hematoxylin & eosin (H & E) staining. Expression of tumor necrosis factor-alpha (TNF-α) in cardiomyocytes was determined using immunohistochemistry. Cardiac apoptosis was determined using the TUNEL method. Serum creatine kinase (CK), creatine kinase-muscle/brain (CK-MB) and lactate dehydrogenase (LDH) levels were determined using spectrophotometric methods. The serum cardiac troponin I (C-TI) level was measured using the ELISA method. Myofibril loss was detected in the cardiomyocytes of the cardiac contusion group. Increased apoptosis and TNF-α expression were observed in the cardiac contusion group compared to the control group. Increased CK, CK-MB, LDH and C-TI levels were found in the cardiac contusion group. We found that CAPE administration improved myocardial function. Compared to the cardiac contusion group, CK, CK-MB, LDH and C-TI levels decreased significantly in the cardiac contusion + CAPE group. Administration of CAPE significantly inhibited apoptosis and cardiac TNF-α expression. Our findings demonstrate the therapeutic effects of CAPE for cardiac contusion damage after blunt chest trauma.