Tropisetron attenuates cardiac injury in a rat trauma-hemorrhage model

Activation of alpha-7 nicotinic acetylcholine receptor by tropisetron mitigates 3-nitropropionic acid-induced Huntington's disease in rats: Role of PI3K/Akt and JAK2/NF-κB signaling pathways

Huntington's disease (HD) is an inheritable autosomal-dominant disorder that targets mainly the striatum. 3-Nitropropionic acid (3-NP) induces obvious deleterious behavioral, neurochemical, and histological effects similar to the symptoms of HD. Our study aimed to examine the neuroprotective activity of tropisetron, an alpha-7 neuronal nicotinic acetylcholine receptor (α-7nAChR) agonist, against neurotoxic events associated with 3-NP-induced HD in rats. Forty-eight rats were randomly allocated into four groups. Group I received normal saline, while Groups II, III and IV received 3-NP for 2 weeks. In addition, Group III and IV were treated with tropisetron 1 h after 3-NP administration. Meanwhile, Group IV received methyllycaconitine (MLA), an α-7nAChR antagonist, 30 min before tropisetron administration. Treatment with tropisetron improved motor deficits as confirmed by the behavioral tests and restored normal histopathological features of the striatum. Moreover, tropisetron showed an anti-oxidant activity via increasing the activities of SDH and HO-1 as well as Nrf2 expression along with reducing MDA level. Tropisetron also markedly upregulated the protein expression of p-PI3K and p-Akt which in turn hampered JAK2/NF-κB inflammatory cascade. In addition, tropisetron showed an anti-apoptotic activity through boosting the expression of Bcl-2 and reducing Bax expression and caspase-3 level. Interestingly, all the aforementioned effects of tropisetron were blocked by pre-administration of MLA, which confirms that such neuroprotective effects are mediated via activating of α-7nAChR. In conclusion, tropisetron showed a neuroprotective activity against 3-NP-induced HD via activating PI3K/Akt signaling and suppressing JAK2/NF-κB inflammatory axis. Thus, repositioning of tropisetron could represent a promising therapeutic strategy in management of HD.

Neuroimmune nexus in the pathophysiology and therapy of inflammatory disorders: role of α7 nicotinic acetylcholine receptors

The α7-nicotinic acetylcholine receptor (α7nAChR) is a key protein in the cholinergic anti-inflammatory pathway (CAP) that links the nervous and immune systems. Initially, the pathway was discovered based on the observation that vagal nerve stimulation (VNS) reduced the systemic inflammatory response in septic animals. Subsequent studies form a foundation for the leading hypothesis about the central role of the spleen in CAP activation. VNS evokes noradrenergic stimulation of ACh release from T cells in the spleen, which in turn activates α7nAChRs on the surface of macrophages. α7nAChR-mediated signaling in macrophages reduces inflammatory cytokine secretion and modifies apoptosis, proliferation, and macrophage polarization, eventually reducing the systemic inflammatory response. A protective role of the CAP has been demonstrated in preclinical studies for multiple diseases including sepsis, metabolic disease, cardiovascular diseases, arthritis, Crohn's disease, ulcerative colitis, endometriosis, and potentially COVID-19, sparking interest in using bioelectronic and pharmacological approaches to target α7nAChRs for treating inflammatory conditions in patients. Despite a keen interest, many aspects of the cholinergic pathway are still unknown. α7nAChRs are expressed on many other subsets of immune cells that can affect the development of inflammation differently. There are also other sources of ACh that modify immune cell functions. How the interplay of ACh and α7nAChR on different cells and in various tissues contributes to the anti-inflammatory responses requires additional study. This review provides an update on basic and translational studies of the CAP in inflammatory diseases, the relevant pharmacology of α7nAChR-activated drugs and raises some questions that require further investigation.

Tropisetron Preconditioning Decreases Myocardial Biomarkers in Patients Undergoing Heart Valve Replacement Surgery

Background

Cardioplegic arrest during the heart valve replacement surgery frequently leads to myocardial damage. Tropisetron (TRP) has been demonstrated to reduce myocardial ischemia-reperfusion injury and inflammation in animals. We examined the efficacy of TRP in lowering myocardial biomarkers in patients undergoing heart valve replacement surgery.

Methods

A total of seventy-five patients, scheduled for elective heart valve replacement surgery, were randomly chosen to receive either 10 ml of normal saline or 10 mg/10 ml of TRP immediately after anesthesia induction. Blood samples for the measurement of cardiac troponin I (cTnI), creatine kinase (CK-MB), lactate dehydrogenase (LDH), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-10 (IL-10) were taken before anesthesia, as well as 4, 12, and 24 h after aortic cross-clamp release to evaluate myocardial injury using two-way ANOVA for repeated measurements. The study was registered at www.chictr.org.cn (number, ChiCTR-1800018681).

Results

Treatment with TRP decreased the increment of cTnI (Fgroup = 4.911, p = 0.030; Ftime = 55.356, p = 0.001; Fgroup × time = 5.340, p = 0.002) at 12 and 24 h; of CK-MB (Fgroup = 6.552, p = 0.013; Ftime = 49.276, p = 0.001; Fgroup × time = 7.627, p = 0.003) at 4, 12, and 24 h; of TNF-α (Fgroup = 4.153, p = 0.046; Ftime = 28.244, p = 0.002; Fgroup × time = 4.692, p = 0.006) at 4 and 12 h; and of LDH (Fgroup = 4.275, p = 0.043; Ftime = 63.225, p = 0.001; Fgroup × time = 2.501, p = 0.083) at 24 h after the release of the aortic cross-clamp. It increased IL-10 (Fgroup = 5.958, p = 0.018; Ftime = 31.226, p = 0.002; Fgroup × time = 1.464, p = 0.236) at 12 h after the release of the aortic cross-clamp. Multiple linear regression analysis showed that cardiopulmonary bypass (CPB) time was a risk factor, and that TRP treatment was a protective factor for postoperative cTNI change (β = 4.449, 95% CI [0.97–7.92], p = 0.013 for CPB time; and β = −381, 95% CI [−613.4 to −148.5], p = 0.002 for TRP treatment).

Conclusions

Tropisetron had cardioprotective and anti-inflammatory effects in patients undergoing heart valve replacement surgery with cardioplegic arrest. The addition of TRP and reduction of CPB time should be considered for myocardial protection in heart valve replacement surgery.

Clinical Trial Registration

[www.chictr.org.cn/index.aspx], identifier [ChiCTR1800018681].

State-of-the-Art Review: Sex Hormone Therapy in Trauma-Hemorrhage

ABSTRACT

Trauma-hemorrhage is the leading cause of prehospital and early in-hospital deaths, while also significantly contributing to the later development of multisystem organ dysfunction/failure and sepsis. Common and advanced resuscitative methods would potentially demonstrate benefits in the prehospital setting; however, they face a variety of barriers to application and implementation. Thus, a dialogue around a novel adjunct has arisen, sex hormone therapy. Proposed candidates include estradiol and its derivatives, metoclopramide hydrochloride/prolactin, dehydroepiandrosterone, and flutamide; with each having demonstrated a range of salutary effects in several animal model studies. Several retrospective analyses have observed a gender-based dimorphism in mortality following trauma-hemorrhage, thus suggesting that estrogens contribute to this pattern. Trauma-hemorrhage animal models have shown estrogens offer protective effects to the cardiovascular, pulmonary, hepatic, gastrointestinal, and immune systems. Additionally, a series of survival studies utilizing 17α-ethinylestradiol-3-sulfate, a potent, water-soluble synthetic estrogen, have demonstrated a significant survival benefit and beneficial effects on cardiovascular function. This review presents the findings of retrospective clinical studies, preclinical animal studies, and discusses how and why 17α-ethinylestradiol-3-sulfate should be considered for investigation within a prospective clinical trial.

Trauma, a Matter of the Heart-Molecular Mechanism of Post-Traumatic Cardiac Dysfunction

Trauma remains a leading global cause of mortality, particularly in the young population. In the United States, approximately 30,000 patients with blunt cardiac trauma were recorded annually. Cardiac damage is a predictor for poor outcome after multiple trauma, with a poor prognosis and prolonged in-hospitalization. Systemic elevation of cardiac troponins was correlated with survival, injury severity score, and catecholamine consumption of patients after multiple trauma. The clinical features of the so-called "commotio cordis" are dysrhythmias, including ventricular fibrillation and sudden cardiac arrest as well as wall motion disorders. In trauma patients with inappropriate hypotension and inadequate response to fluid resuscitation, cardiac injury should be considered. Therefore, a combination of echocardiography (ECG) measurements, echocardiography, and systemic appearance of cardiomyocyte damage markers such as troponin appears to be an appropriate diagnostic approach to detect cardiac dysfunction after trauma. However, the mechanisms of post-traumatic cardiac dysfunction are still actively being investigated. This review aims to discuss cardiac damage following trauma, focusing on mechanisms of post-traumatic cardiac dysfunction associated with inflammation and complement activation. Herein, a causal relationship of cardiac dysfunction to traumatic brain injury, blunt chest trauma, multiple trauma, burn injury, psychosocial stress, fracture, and hemorrhagic shock are illustrated and therapeutic options are discussed.

Tropisetron attenuates tumor growth and progression in an experimental model of mouse lung cancer

The antineoplastic effects of 5-hydroxytryptamine (5-HT) receptor antagonists have been shown in previous studies. However, the exact underlying mechanisms mediating these antineoplastic effects are unclear. In the present study, we assessed the antineoplastic effects of tropisetron, a 5-HT receptor antagonist, in an experimental model of lung cancer in BALB/c mouse. Lewis lung carcinoma cell line was used to induce lung cancer. Mice were divided into four groups (n = 6) as follows: tumor-bearing mice + tropisetron (5 mg/kg intraperitoneally [IP]), tumor-bearing mice + tropisetron (10 mg/kg IP), tumor-bearing mice + saline, healthy mice + tropisetron (10 mg/kg). Tumor burden, interferon-γ (IFN-γ), interleukin (IL)-4, pathological response, Ki-67, and E-cadherin were assessed using enzyme-linked immunosorbent assay, and real-time polymerase chain reaction. Comet assay was used to assess DNA toxicity. Tropisetrone-treated animals (either 5 or 10 mg/kg) showed significantly lower tumor sizes at the day 24th after tumor induction. Tropisetron received animals also showed significantly higher levels of IFN-γ, E-cadherin, pathologic response, and necrotic cells compared to the saline-treated counterparts. In addition, the levels of IL-4, and Ki-67 were significantly lower in tropisetrone treated mice in comparison with control. Furthermore, tropisteron coadministration signifcantly reduced H₂ O₂ -induced DNA toxicity while treatment with tropisteron alone showed no adverse effect on DNA. Tropisetrone can be used as a potential antineoplastic drug in lung cancer. This agent can promote its antineoplastic effects in part through modulating inflammatory and proliferating markers.

The Role and Use of Estrogens Following Trauma

Several lines of evidence indicate that female sex is a protective factor in trauma and hemorrhage. In both clinical and experimental studies, proestrus females have been shown to have better chances of survival and reduced rates of posttraumatic sepsis. Estrogen receptors are expressed in a variety of tissues and exert genomic, as well as nongenomic effects. By improving cardiac, pulmonary, hepatic, and immune function, estrogens have been shown to prolong survival in animal models of hemorrhagic shock. Despite encouraging results from experimental studies, retrospective clinical studies have not clearly pointed to advantages of estrogens following trauma-hemorrhage, which may be due to insufficient study design. Therefore, this review aims to give an overview on the current evidence and emphasizes on the importance of further clinical investigation on estrogens following trauma.

Plasma metabolite profiles following trauma-hemorrhage: effect of posttreatment with resveratrol

Resveratrol (RSV) has been shown to inhibit the inflammatory reaction and ameliorate the organ damage resulting from trauma-hemorrhage (TH). However, the effects of RSV on the metabolomic profiles under these conditions remain unclear. The aim of this study was to determine the metabolomic profiles of plasma in TH rats and to evaluate the therapeutic effects of RSV using high-performance liquid chromatography-mass spectrometry. Thirty male Sprague-Dawley rats were divided into sham operation (n = 10), sham-operation plus RSV treatment (n = 10), TH (n = 10), and TH plus RSV treatment (n = 10) groups. Plasma samples were obtained at 24 h after surgery. Electrospray ionization-tandem mass spectrometry was used to characterize the plasma metabolomes. The systemic analyses of plasma metabolomes and their targets were determined using a number of computational approaches, including principal component analysis, partial least squares discriminant analysis, and heat map analysis. Using these methods, the effects of RSV on the metabolomic profiles in animals that underwent trauma-hemorrhagic injury were determined. These approaches allowed a clear discrimination of the pathophysiological characteristics among the groups. The results demonstrate RSV treatment significantly reduced the metabolic derangements caused by TH. Compared with the sham-operated rats, the plasma levels of carnitine in the TH rats were relatively lower, but the levels of acetylcarnitine and butyrylcarnitine were higher, suggesting that RSV ameliorated the deranged carnitine metabolism in TH rats. There was a statistically significant increase in carnitine. In addition, RSV treatment reduced ketoacidosis and protein degradation, as evidenced by the attenuation of the elevated plasma branched-chain amino acid levels in the TH rats. Our study showed that the alterations of the metabolomic profiles in the rats subjected to trauma-hemorrhagic shock were attenuated by RSV treatment. In view of the metabolomic evidence, we conclude that RSV exerts beneficial effects in trauma-hemorrhagic shock injury and that these effects are partially mediated by improving energy metabolism and reducing protein degradation.

Hepatic gene expression patterns following trauma-hemorrhage: effect of posttreatment with estrogen

The aim of this study was to examine the role of estrogen on hepatic gene expression profiles at an early time point following trauma-hemorrhage in rats. Groups of injured and sham controls receiving estrogen or vehicle were killed 2 h after injury and resuscitation, and liver tissue was harvested. Complementary RNA was synthesized from each RNA sample and hybridized to microarrays. A large number of genes were differentially expressed at the 2-h time point in injured animals with or without estrogen treatment. The upregulation or downregulation of a cohort of 14 of these genes was validated by reverse transcription-polymerase chain reaction. This large-scale microarray analysis shows that at the 2-h time point, there is marked alteration in hepatic gene expression following trauma-hemorrhage. However, estrogen treatment attenuated these changes in injured animals. Pathway analysis demonstrated predominant changes in the expression of genes involved in metabolism, immunity, and apoptosis. Upregulation of low-density lipoprotein receptor, protein phosphatase 1, regulatory subunit 3C, ring-finger protein 11, pyroglutamyl-peptidase I, bactericidal/permeability-increasing protein, integrin, αD, BCL2-like 11, leukemia inhibitory factor receptor, ATPase, Cu transporting, α polypeptide, and Mk1 protein was found in estrogen-treated trauma-hemorrhaged animals. Thus, estrogen produces hepatoprotection following trauma-hemorrhage likely via antiapoptosis and improving/restoring metabolism and immunity pathways.

Sirtinol attenuates trauma hemorrhage-induced hepatic injury through Akt-dependent pathway in rats

BACKGROUND

Recent evidences show that sirtinol possesses anti-inflammatory properties and protective effects after shocklike states, but the mechanism of these effects remains unknown. Akt (also known as protein kinase B) exerts anti-inflammatory effects in injury. The aim of this study was to investigate whether Akt plays any role in the sirtinol-mediated attenuation of hepatic injury after trauma hemorrhage.

METHODS

Male Sprague-Dawley rats underwent trauma hemorrhage (mean blood pressure maintained at approximately 35-40 mm Hg for 90 minutes), followed by fluid resuscitation. During resuscitation, a single dose of sirtinol (1 mg/kg i.v.) with and without a PI3K inhibitor wortmannin (1 mg/kg i.v.), wortmannin, or vehicle was administered. Plasma alanine aminotransferase with aspartate aminotransferase (AST) concentrations and various hepatic parameters were measured (n = 8 rats per group) at 24 h after resuscitation. One-way analysis of variance and Tukey testing were used for statistical analysis.

RESULTS

Trauma hemorrhage increased hepatic myeloperoxidase activity, intercellular adhesion molecule-1 (ICAM-1) and interleukin-6 levels, and plasma alanine aminotransferase and aspartate aminotransferase concentrations. These parameters were significantly improved in the sirtinol-treated rats subjected to trauma hemorrhage. Sirtinol treatment also increased hepatic phospho-Akt expression compared with vehicle-treated trauma-hemorrhaged rats. The coadministration of wortmannin with sirtinol abolished the sirtinol-induced beneficial effects on the above parameters and hepatic injury.

CONCLUSION

These results suggest the protective effect of sirtinol administration on the alleviation of hepatic injury after trauma hemorrhage, which is, at least in part, through Akt-dependent pathway.

Protective effect of tropisetron on rodent hepatic injury after trauma-hemorrhagic shock through P38 MAPK-dependent hemeoxygenase-1 expression

Tropisetron can decrease inflammatory cell responses and alleviate organ damage caused by trauma-hemorrhage, but the mechanism of these effects remains unknown. The p38 mitogen-activated protein kinase/hemeoxygenase-1 (p38 MAPK/HO-1) pathway exerts anti-inflammatory effects on different tissues. The aim of this study was to investigate whether p38 MAPK/HO-1 plays any role in the tropisetron-mediated attenuation of hepatic injury after trauma-hemorrhage. Male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure maintained at approximately 35–40 mmHg for 90 min), followed by fluid resuscitation. During resuscitation, several treatment regimens were administered: four doses of tropisetron alone (0.1, 0.3, 1, 3 mg/kg body weight), or a single dose of tropisetron (1 mg/kg body weight) with and without a p38 MAPK inhibitor (SB-203580, 2 mg/kg body weight) or HO antagonist (chromium-mesoporphyrin, 2.5 mg/kg body weight). Various parameters were measured, and the animals were sacrificed at 24 h post-resuscitation. The results showed that trauma-hemorrhage increased the following parameters: plasma concentrations of aspartate (AST) and alanine aminotransferases (ALT), hepatic myeloperoxidase (MPO) activity, and levels of cytokine-induced neutrophil chemoattractant-1 and -3 (CINC-1 and CINC-3), intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and macrophage inflammatory protein-1α (MIP-1α). These parameters were significantly improved in the tropisetron-treated rats subjected to trauma-hemorrhage. Tropisetron treatment also increased hepatic p38 MAPK and HO-1 expression compared with vehicle-treated trauma-hemorrhaged rats. Co-administration of SB-203580 or chromium-mesoporphyrin with tropisetron abolished the tropisetron-induced beneficial effects on the above parameters and hepatic injury. These results suggest that the protective effect of tropisetron administration on alleviation of hepatic injury after trauma-hemorrhage is likely mediated through p38 MAPK-dependent HO-1 expression.