Effects of 1, 25-Dihydroxyvitamin D3 on Experimental Autoimmune Myocarditis in Mice

The improvement of homocysteine-induced myocardial inflammation by vitamin D depends on activation of NFE2L2 mediated MTHFR

OBJECTIVES

Myocardial inflammation underlies a broad spectrum of conditions that cause damage to the myocardium and lead to structural and functional defects. Homocysteine (Hcy) is closely related to the occurrence and development of cardiovascular diseases. We investigated the mechanism underlying the effects of vitamin D as a prophylactic treatment for Hcy-induced cardiac inflammation.

METHODS

The levels of 25(OH)D3 and Hcy were assessed using ELISA kits. Expression levels of the vitamin D receptor (VDR), NFE2 like bZIP transcription factor 2 (NFE2L2), methylenetetrahydrofolate reductase (MTHFR) and inflammatory factors were examined by Western blotting, immunohistochemistry and real time polymerase chain reaction. NFE2L2/MTHFR-knockdown HL-1 cells and NFE2L2+/- mouse were used to test the effects of vitamin D.

RESULTS

We found the levels of Hcy in the serum and myocardial tissue of mice in the Hcy + CCE group were lower than in the Hcy groups, which was opposed to the trend exhibited by the serum 25(OH)D3 level of mice. The mRNA and protein expression levels of the inflammatory factors in cardiac tissues and cardiomyocytes were strongly decreased by the Hcy treatment, compared to the Hcy + CCE/Hcy + 1,25(OH)2D3 groups. Moreover, the results revealed that the level of nuclear NFE2L2 in Hcy + CCE/Hcy + 1,25(OH)2D3 group was increased compared to Hcy group with a reciprocal decrease in the level of cytosolic NFE2L2 in vivo and in vitro. Similarly, the MTHFR mRNA and protein expression in the Hcy + CCE group was higher than the Hcy group. We determined that NFE2L2 promoted the expression of MTHFR. However, based on Hcy treatment, the combination of 1,25(OH)2D3 and MTHFR-/- reversed the decline in IL-6 and TNFα expression caused by 1,25(OH)2D3 alone. Chromatin immunoprecipitation and luciferase reporter assays showed the up-regulation effect of VDR on NFE2L2 and NFE2L2 on MTHFR.

CONCLUSIONS

Our findings indicate that vitamin D/VDR could improve Hcy-induced myocardial inflammation through activation of NFE2L2 mediated MTHFR.

The Heart of the Matter: Immune Checkpoint Inhibitors and Immune-Related Adverse Events on the Cardiovascular System

Cancer remains a prominent global cause of mortality, second only to cardiovascular disease. The past decades have witnessed substantial advancements in anti-cancer therapies, resulting in improved outcomes. Among these advancements, immunotherapy has emerged as a promising breakthrough, leveraging the immune system to target and eliminate cancer cells. Despite the remarkable potential of immunotherapy, concerns have arisen regarding associations with adverse cardiovascular events. This review examines the complex interplay between immunotherapy and cardiovascular toxicity and provides an overview of immunotherapy mechanisms, clinical perspectives, and potential biomarkers for adverse events, while delving into the intricate immune responses and evasion mechanisms displayed by cancer cells. The focus extends to the role of immune checkpoint inhibitors in cancer therapy, including CTLA-4, PD-1, and PD-L1 targeting antibodies. This review underscores the multifaceted challenges of managing immunotherapy-related cardiovascular toxicity. Risk factors for immune-related adverse events and major adverse cardiac events are explored, encompassing pharmacological, treatment-related, autoimmune, cardiovascular, tumor-related, social, genetic, and immune-related factors. The review also advocates for enhanced medical education and risk assessment tools to identify high-risk patients for preventive measures. Baseline cardiovascular evaluations, potential prophylactic strategies, and monitoring of emerging toxicity symptoms are discussed, along with the potential of adjunct anti-inflammatory therapies.

Effects of Vitamin D3 Supplementation and Aerobic Training on Autophagy Signaling Proteins in a Rat Model Type 2 Diabetes Induced by High-Fat Diet and Streptozotocin

The aim of this study was to investigate the combined effects of vitamin D3 supplementation and aerobic training on regulating the autophagy process in rats with type 2 diabetic induced by a high-fat diet and streptozotocin. A total of 40 Wistar rats were divided into five groups: normal control (NC), diabetic control (DC), diabetic + aerobic training (DAT), diabetic + vitamin D3 (DVD), and diabetic + aerobic training + vitamin D3 (DVDAT). The rats underwent eight weeks of aerobic training with an intensity of 60% maximum running speed for one hour, along with weekly subcutaneous injections of 10,000 units of vitamin D3. The protein levels of different autophagy markers were assessed in the left ventricular heart tissue. The results showed that the protein levels of AMPK, pAMPK, mTOR, and pmTOR were significantly lower in the DC group compared to the NC group. Conversely, the levels of ULK, Beclin-1, LC3II, Fyco, and Cathepsin D proteins were significantly higher in the DC group. However, the interventions of aerobic training and vitamin D3 supplementation, either individually or in combination, led to increased levels of AMPK, pAMPK, mTOR, and pmTOR, and decreased levels of ULK, Beclin-1, LC3II, Fyco, and Cathepsin D (p < 0.05). Additionally, the aerobic capacity in the DAT and DVDAT groups was significantly higher compared to the NC, DC, and DVD groups (p < 0.05). These findings suggest that type 2 diabetes is associated with excessive autophagy in the left ventricle. However, after eight weeks of vitamin D3 supplementation and aerobic training, a significant reduction in excessive autophagy was observed in rats with type 2 diabetes.

Vitamin D supplementation modulates autophagy in the pristane-induced lupus model

Introduction/objectives

Clinical evidence of skeletal muscle involvement is not uncommon in systemic lupus erythematosus (SLE). Because of the poor understanding of signaling pathways involved in SLE muscle wasting, the  aim of this study was to evaluate the effects of vitamin D supplementation on skeletal muscle in mice with pristane-induced lupus.

Methods

Balb/c mice with lupus-like disease induced by pristane injection were randomized into three groups: pristane-induced lupus (PIL; n = 10), pristane-induced lupus + vitamin D supplementation (PIL + VD; n = 10) and healthy controls (CO; n = 8). Physical function was evaluated on days 0, 60, 120 and 180. The tibialis anterior and gastrocnemius muscles were collected to evaluate myofiber cross-sectional area (CSA) and protein expression.

Results

The PIL + VD group showed lower muscle strength compared to the CO and PIL groups at different time points. PIL mice showed similar myofiber CSA compared to CO and PIL + VD groups. LC3-II expression was higher in PIL compared to CO and PIL + VD groups. MyoD expression was higher in PIL mice compared to PIL + VD, while myostatin expression was higher in PIL + VD than PIL group. Myogenin expression levels were decreased in the PIL + VD group compared with the CO group. The Akt, p62 and MuRF expressions and mobility assessment showed no significance.

Conclusions

Changes in skeletal muscle in PIL model happen before CSA reduction, possibly due to autophagy degradation, and treatment with Vitamin D has a impact on physical function by decreasing muscle strength and time of fatigue.. Vitamin D supplementation has a potential role modulating physical parameters and signaling pathways in muscle during pristane-induced lupus model.

Protective role of nutraceuticals against myocarditis

Myocarditis is an inflammatory disease of the myocardium that mostly affects young adults. The disease is commonly caused by viral infection, medications, autoimmune disorders, and inflammatory conditions. Nearly 50% of the cases of myocarditis are due to post-viral immune response in a setting of an identifiable or non-identifiable infection. The clinical manifestation is nonspecific ranging from asymptomatic courses to sudden death in infants and young patients. This review describes the properties of phytochemicals as plant-derived active ingredients which can be used in the prevention and treatment of myocarditis and its associated risk factors. Meanwhile, it has illustrated epidemiological analyses, mechanism of action, and the metabolism of phytochemicals in animal and human clinical trials. We also mentioned the precise mechanism of action by which phytochemicals elicit their anti-viral, anti-inflammatory, antioxidant, and immunomodulatory effects and how they regulate signal transduction pathways. Nevertheless, comprehensive clinical trials are required to study the properties of phytochemicals in vivo, in vitro, and in silico for a proper management of myocarditis. Our findings indicate that phytochemicals function as potent adjunctive therapeutic drugs in myocarditis and its related complications.

Vitamin D in autophagy signaling for health and diseases: Insights on potential mechanisms and future perspectives

Vitamin D regulates the pleiotropic effect to maintain cellular homeostasis and epidemiological evidence establishes an association between vitamin D deficiency and various human diseases. Here, the role of autophagy, the cellular self-degradation process, in vitamin D-dependent function is documented in different cellular settings and discussed the molecular aspects for treating chronic inflammatory, infectious diseases, and cancer. Vitamin D activates autophagy through a genomic and non-genomic signaling pathway to influence a wide variety of physiological functions of different body organs along with bone health and calcium metabolism. Moreover, it induces autophagy as a protective mechanism to inhibit oxidative stress and apoptosis to regulate cell proliferation, differentiation, and immune modulation. Furthermore, vitamin D and its receptor regulate autophagy signaling to control inflammation and host immunity by activating antimicrobial defense mechanisms. Vitamin D has been revealed as a potent anticancer agent and induces autophagy to increase the response to radiation and chemotherapeutic drugs for potential cancer therapy. Increasing vitamin D levels in the human body through timely exposure to sunlight or vitamin D supplements could activate autophagy as part of the homeostasis mechanism to prevent multiple human diseases and aging-associated dysfunctions.

An Emergent Form of Cardiotoxicity: Acute Myocarditis Induced by Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that activate the immune system, aiming at enhancing antitumor immunity. ICIs have shown great promise in the treatment of several advanced malignancies. However, therapy with these immunomodulatory antibodies may lead to a wide spectrum of immune-related adverse events in any organ and any tissue. Cardiologic immune-related events include pericarditis, pericardial effusion, various types of arrhythmias including the occurrence of complete atrioventricular block, myocardial infarction, heart failure, and myocarditis. Although relatively rare, myocarditis is associated with a very high reported mortality in comparison to other adverse events. Myocarditis often presents significant diagnostic complexity and may be under-recognized. When confronted with an unexpected change in the clinical picture, the physician must differentiate between immune-related adverse events, cancer worsening, or other causes unrelated to the cancer or its therapy. However, this is not always easy. Therefore, with the increasing use of checkpoint inhibitors in cancer, all providers who care for patients with cancer should be made aware of this rare, but potentially fatal, cardiologic immune-related adverse event, and able to recognize when prompt consultation with a cardiologist specialist is indicated. In this review, we evaluate currently available scientific evidence and discuss clinical manifestations and new potential approaches to the diagnosis and therapy of acute myocarditis induced by ICIs. Temporary or permanent discontinuation of the ICIs and high-dose steroids have been administered to treat myocarditis, but symptoms may worsen in some patients despite therapy.

Autophagy participates in the protection role of 1,25-dihydroxyvitamin D3 in acute myocardial infarction via PI3K/AKT/mTOR pathway

Vitamin D deficiency is associated with acute myocardial infarction (AMI); thus we aimed to explore improvement effects of 1,25-dihydroxyvitamin D3 (VD3) on the AMI and its potential mechanism. AMI models were constructed using male C57/BL6J mice and randomly treated with normal saline or VD3, using sham rats as control. Heart functions, myocardial damage, apoptosis, and inflammation were evaluated. Cardiomyocytes isolated from 3-day-old suckling mice were used for in vitro verification. After VD3 treatment, AMI-induced cardiac dysfunction was reversed with better cardiac function parameters. VD3 treatment reduced inflammatory cell infiltration and myocardial infarction area accompanied by the reduction of inflammatory factors and myocardial infarction markers compared with the AMI group. VD3 treatment obviously alleviated AMI-induced myocardial apoptosis, along with Bcl-2 upregulation and downregulation of caspase-3, caspase-9, and Bax. Both in vivo and in vitro experiments revealed that VD3 enhanced the expression of LC3II and Beclin-1 and decreased soluble p62. Furthermore, VD3 enhanced the AMI-caused inhibition of PI3K, p-AKT, and p-mTOR expression, which was conversely reversed by the addition of 3-methyladenine in vitro. The study highlights the improvement effects of VD3 on cardiac functions. We proposed a potential mechanism that VD3 protects against myocardial damage, inflammation, and apoptosis by promoting autophagy through PI3K/AKT/mTOR pathway.

Elevated aldolase 1A, retrogene 1 expression induces cardiac apoptosis in rat experimental autoimmune myocarditis model

Acute myocarditis is an unpredictable heart disease that is caused by inflammation-associated cell death. Although viral infection and drug exposure are known to induce acute myocarditis, the molecular basis for its development remains undefined. Using proteomics and molecular analyses in myosin-induced rat experimental autoimmune myocarditis (EAM), we identified that elevated expression of aldolase 1A, retrogene 1 (Aldoart1) is critical to induce mitochondrial dysfunction and acute myocarditis development. Here, we demonstrate that cardiac cell death is associated with increased expressions of proapoptotic genes in addition to high levels of glucose, lactate, and triglyceride in metabolite profiling. The functional protein association network analysis also suggests that Aldoart1 upregulation correlates with high levels of dihydroxyacetone kinase and triglyceride. In H9c2 cardiac cells, lipopolysaccharides (LPS) or high glucose exposure significantly increases the cytochrome c release and the conversion of pro-caspase 3 into the cleaved form of caspase 3. We also found that LPS- or glucose-induced toxicities are almost completely reversed by siRNA-mediated knockdown of Aldoartl, which consequently increases cell viability. Together, our study strongly suggests that Aldoart1 may be involved in inducing mitochondrial apoptotic processes and can be a novel therapeutic target to prevent the onset of acute myocarditis or cardiac apoptosis.

Myocarditis: somethings old and something new

"Since the pathological conditions take place at the cellular level, viral myocarditis and postinfectious autoimmunity can be suggested but not diagnosed clinically. All clinical methods including imaging techniques are misleading if infectious agents are involved. Accurate diagnosis demands simultaneous histologic, immunohistochemical, and molecular biological workup of the tissue. If the primary infectious or immune-mediated causes of the disease are carefully defined by clinical and biopsy-based tools, specific antiviral treatment options in addition to basic symptomatic therapy are available under certain conditions. These may allow a tailored cause-specific treatment that improves symptoms and prognosis of patients with acute and chronic disease." Uwe Kühl; Heinz-Peter SchultheissViral myocarditis.Swiss Medical Weekly. 144():w14010, JAN 2014 DOI:10.4414/smw.2014.14010.

Autoimmune myocarditis is not associated with left ventricular systolic dysfunction

BACKGROUND

Experimental autoimmune myocarditis (EAM) is a common animal model for the investigation of the pathophysiology of myocarditis. Because of diverging findings from previous studies, we performed serial echocardiographic examinations throughout the course of the disease and investigated the dimensions of the murine heart and left ventricular (LV) systolic function.

MATERIALS AND METHODS

Experimental autoimmune myocarditis was induced in male Balb/c mice by subcutaneous injection of a fragment of the α-myosin heavy chain (MyHC-α 614-629: Ac-SLKLMATLFSTYASAD). Transthoracic echocardiography was performed on days 0, 7 and 21 in healthy animals and mice with EAM.

RESULTS

Experimental autoimmune myocarditis was associated with a reduction in LV systolic function and an increase in LV internal diameter in diastole (LVIDd) and systole (LVIDs) 7 days postimmunization. After 21 days, EAM led to a significant increase in LV-thickness (1.3-fold increase in LV anterior wall diameter in diastole [LVAWDd]), but there was no difference in LV systolic function between immunized animals and healthy controls. LV-thickness correlated well with the severity of myocarditis in the histopathological examination (LVAWDd: rs = 0.603, P = 0.003, LV anterior wall diameter in systole (LVAWDs): rs = 0.718, P < 0.0001).

CONCLUSION

Our results indicate that EAM leads to an initial dilatation of the LV that is followed by ventricular "hypertrophy." On day 21, there was no significant difference in LV systolic function between immunized animals and controls. Furthermore, the ageing of the animals had a major impact on the echocardiographic parameters; therefore, the use of healthy age-matched controls seems warranted when echocardiography is performed in rodents.