Involvement of Abnormal Gut Microbiota Composition and Function in Doxorubicin-Induced Cardiotoxicity

Xinshuaining preparation ameliorates doxorubicin-induced cardiac injury in heart failure rats by regulating gut microbiota

Heart failure (HF) has a serious impact on patients' lives and health. Gut microbiota plays an important role in the development of HF. Xinshuaining (XSN) preparation has a therapeutic effect on the HF. However, the mechanism of action of XSN in HF is still unclear. Our study aimed to explore the possible function and mechanism of XSN on HF induced by doxorubicin (DOX) in rats. DOX-induced HF rat models were prepared, grouped and treated. The ultrasound indexes of rat heart were measured before sampling, and the indexes of cardiac pathology, fibrosis degree, gut microbiota and metabolites were detected by ELISA, HE staining, Masson staining, immunohistochemistry, 16SrDNA sequencing, liquid chromatography-mass spectrometry (LC/MS) after sampling. XSN can significantly improve the cardiac function of HF rats, including increasing LVEF, LVFS, decreasing LVESD, LVESV, LVEDV levels, and at the same time, XSN can also reduce the heart weight index, reduce the cardiac histopathological damage and fibrosis. In addition, XSN can regulate the abundance and function of gut microbiota, inhibit the level of TMAO, and regulate plasma metabolites in HF rats. In conclusions, XSN improves cardiac function and delays the process of cardiac fibrosis in HF rats, and its mechanism may be related to the regulation of gut microbiota and metabolites.

Akkermansia muciniphila ameliorates doxorubicin-induced cardiotoxicity by regulating PPARα-dependent mitochondrial biogenesis

Doxorubicin (DOX) is a key chemotherapeutic agent but is also a leading cause of DOX-induced cardiotoxicity (DIC), limiting its clinical use. Akkermansia muciniphila (A. muciniphila), known for its benefits as a probiotic in treating metabolic syndrome, has uncertain effects in the context of DIC. Here, 16S rRNA sequencing of fecal samples from anthracycline-treated patients and DIC mice revealed marked depletion of A. muciniphila. Cardiac transcriptomics, supported by in vitro experiments, showed that A. muciniphila colonization improved mitochondrial function and alleviated DIC by activating the PPARα/PGC1α signaling pathway in both normal and antibiotic-treated C57BL/6 mice. Further analysis uncovered a restructured microbiome-metabolome network following A. muciniphila administration, which contributed to DIC protection. Notably, A. muciniphila supplementation increased serum levels of the tryptophan metabolite indole-3-propionic acid (IPA), which binds to the cardiac aryl hydrocarbon receptor (AhR), leading to the activation of the PPARα/PGC1α signaling pathway. In conclusion, our study sheds light on the potential of A. muciniphila as a probiotic in mitigating DIC.

The Gut-Heart Axis and Its Role in Doxorubicin-Induced Cardiotoxicity: A Narrative Review

Doxorubicin is a widely used chemotherapy for the treatment of several types of cancer. However, its application is restricted due to adverse effects, particularly cardiotoxicity, which can progress to heart failure-a chronic and debilitating condition. Several mechanisms have been identified in the pathophysiology of doxorubicin-induced cardiotoxicity, including oxidative stress, mitochondrial dysfunction, inflammation, and disruption of collagen homeostasis. More recently, dysbiosis of the gut microbiota has been implicated in the development and perpetuation of cardiac injury. Studies have reported alterations in the composition and abundance of the microbiota during doxorubicin treatment. Therefore, as of recent, there is a new field of research in order to develop strategies involving the gut microbiota to prevent or attenuate cardiotoxicity since there is no effective therapy at the moment. This narrative review aims to provide an update on the role of gut microbiota and intestinal permeability in the pathophysiology of cardiovascular diseases, and more specifically doxorubicin-induced cardiotoxicity. Additionally, it seeks to establish a foundation for future research targeting gut microbiota to alleviate cardiotoxicity.

Oridonin Alleviates Doxorubicin-Induced Cardiotoxicity by Inhibiting p38 MAPK/MMP3 Signaling Pathway

Although doxorubicin (DOX) is an efficient chemotherapeutic drug for human tumors, severe cardiotoxicity restricts its clinical use. Oridonin (Ori), a bioactive component isolated from Isodon rubescens (Hemsl.) H. Hara, possesses potent anti-inflammatory and anticancer potentials. Therefore, our study aimed to evaluate the protective effects of Ori against DOX-induced cardiotoxicity. DIC models were established in vivo and in vitro. The action targets and pharmaceutical mechanism of Ori against DIC were comprehensively examined by network pharmacology, RNA-sequencing, and experimental validation. Ori relieved Dox-induced cell apoptosis in vitro and in vivo. A total of 7084 DEGs, 196 Ori, and 8172 DIC targets were screened by transcriptomics and network pharmacology, respectively. The three sets contained 11 intersection genes, including Ccl2, Myc, Mmp3, Egfr, p38 MAPK (MAPK14), Esr1, Tnf, Jun, Cdk1, Alb, and Ccnd1. The experimental results showed that Ori significantly decreased MMP-3 activity and the expression of p38 MAPK, thereby attenuating myocardial apoptosis and inflammatory infiltration. This study suggests that Ori is a potential therapeutic agent for DOX-induced cardiotoxicity that exerts its effects by inhibiting the p38 MAPK/MMP-3 signaling pathway.

Indole-3-Lactic Acid Inhibits Doxorubicin-Induced Ferroptosis Through Activating Aryl Hydrocarbon Receptor/Nrf2 Signalling Pathway

The clinical application of doxorubicin (DOX) is limited due to its cardiotoxicity, which is primarily attributed to its interaction with iron in mitochondria, leading to lipid peroxidation and myocardial ferroptosis. This study aimed to investigate the role of the gut microbiota-derived metabolite, indole-3-lactic acid (ILA), in mitigating DOX-induced cardiotoxicity (DIC). Cardiac function, pathological changes, and myocardial ferroptosis were assessed in vivo. The cardioprotective effects and mechanisms of ILA were explored using multi-omics approaches, including single-nucleus RNA sequencing (snRNA-seq) and bulk RNA-seq, and were further validated in Nrf2 knockout mice. The findings revealed that DOX treatment disrupted gut microbiota, significantly reducing the levels of the tryptophan metabolite ILA. In DIC models, ILA supplementation markedly improved cardiac function, reduced collagen deposition, and mitigated cardiac atrophy. The bulk and snRNA-seq analyses indicated that myocardial ferroptosis played a crucial role in the cardioprotective effects of ILA. Experimental data demonstrated that ILA decreased DOX-induced ferroptosis in both DIC mice and DOX-treated H9C2 cells, evidenced by restoration of GPX4 and SLC7A11 levels and reduction of ACSL4. Mechanistically, ILA functions as a ligand for the aryl hydrocarbon receptor (AhR), leading to the upregulation of Nrf2 expression. The protective effects of ILA against ferroptosis were abolished by silencing AhR. Moreover, the beneficial effects of ILA on DIC were eliminated in Nrf2-deficient mice. In conclusion, ILA exerts therapeutic effects against DIC by inhibiting ferroptosis through activation of the AhR/Nrf2 signalling pathway. Identifying the cardioprotective role of the microbial metabolite ILA could offer viable therapeutic strategies for DIC.

Crosstalk between gut microbiota and cancer chemotherapy: current status and trends

BACKGROUND

Chemotherapy is crucial in the management of tumors, but challenges such as chemoresistance and adverse reactions frequently lead to therapeutic delays or even premature cessation. A growing body of research underscores a profound connection between the gut microbiota (GM) and cancer chemotherapy (CC). This paper aims to pinpoint highly influential publications and monitor the current landscape and evolving trends within the realm of GM/CC research.

METHODS

On October 1st, 2024, a comprehensive search for GM/CC publications spanning the past 20 years from 2004 to 2023 was conducted utilizing the Web of Science Core Collection (WoSCC). The scope encompassed both articles and reviews, and the data was subsequently extracted. To gain insights into the evolution and dynamics of this research field, we employed bibliometric analysis tools such as the Bibliometrix R package, VOSviewer, and Microsoft Excel to visualize and analyze various dimensions, including prominent journals, leading authors, esteemed institutions, contributing countries/regions, highly cited papers, and frequently occurring keywords.

RESULTS

A total of 888 papers were obtained. The number of publications about GM/CC studies has increased gradually. China and the United States published the largest number of papers. The INSERM was in the leading position in publishers. The most productive authors were Zitvogel L from France. Cancers had the largest number of papers. Citation analysis explained the historical evolution and breakthroughs in GM/CC research. Highly cited papers and common keywords illustrated the status and trends of GM/CC research. Four clusters were identified, and the hot topics included the role of the GM in the efficacy and toxicity of CC, the targeting of the GM to improve the outcome of CC, the mechanism by which the GM affects CC, and the correlation of the GM with carcinogenesis and cancer therapy. Metabolism, GM-derived metabolites, tumor microenvironment, immunity, intestinal barrier, tumor microbiota and Fusobacterium nucleatum may become the new hotspots and trends of GM/CC research.

CONCLUSION

This study analyzed global publications and bibliometric characteristics of the links between GM and CC, identified highly cited papers in GM/CC, provided insight into the status, hotspots, and trends of global GM/CC research, and showed that the GM can be used to predict the efficacy and toxicity of CC and modifying the GM can improve the outcomes of chemotherapeutics, which may inform clinical researchers of future directions.

Alterations in the gut microbiome and metabolism with doxorubicin-induced heart failure severity

Objective

This study aimed to explore the changes in gut microbiota and its metabolites in different pathophysiological stages of doxorubicin (DOX)-induced heart failure (DIHF) and the relationship between gut microbiota and metabolites in various degrees of DIHF.

Materials and methods

C57BL/6 J mice were injected intraperitoneally with 5 mg/kg of DOX once a week for 5 consecutive weeks. At different times after injection, the cardiac function and histopathological analysis was conducted, the serum levels of creatine kinase (CK), CK-MB, lactic dehydrogenase, and cardiac troponin T were determined. 16S rRNA gene sequencing of feces and the nontargeted metabolomics analysis of serum were performed. Multi-omics analyses were used to explore the correlation between gut microbiota and serum metabolites.

Results

The results showed that DOX caused cardiac contractile dysfunction and left ventricular (LV) dilation. The levels of myocardial enzymes significantly increase in 3 and 5 weeks after DOX injection. DOX-treated mice showed significant differences in the composition and abundance of gut microorganisms, and the levels of serum metabolites at different times of treatment. Multi-omics analyses showed that intestinal bacteria were significantly correlated with the differential metabolites. Some bacteria and metabolites can be used as biomarkers of DIHF (AUC > 0.8). KEGG analyses showed the involvement of different metabolic pathways in various degrees of DIHF.

Conclusion

Marked differences were found in the composition and abundance of gut microorganisms, the levels of serum metabolites and metabolic pathways in different degrees of DIHF. The intestinal bacteria were significantly correlated with differential metabolites in different degrees of DIHF. The gut microbiota may serve as new targets for the treatment of DIHF.

Circ-0006332 stimulates cardiomyocyte pyroptosis via the miR-143/TLR2 axis to promote doxorubicin-induced cardiac damage

Doxorubicin (DOX)-mediated cardiotoxicity can impair the clinical efficacy of chemotherapy, leading to heart failure (HF). Given the importance of circRNAs and miRNAs in HF, this paper intended to delineate the mechanism of the circular RNA 0006332 (circ -0,006,332)/microRNA (miR)-143/Toll-like receptor 2 (TLR2) axis in doxorubicin (DOX)-induced HF. The binding of miR-143 to circ -0,006,332 and TLR2 was assessed with the dual-luciferase assay, and the binding between miR-143 and circ -0,006,332 was determined with FISH, RIP, and RNA pull-down assays. miR-143 and/or circ -0,006,332 were overexpressed in rats and cardiomyocytes, followed by DOX treatment. In cardiomyocytes, miR-143 and TLR2 expression, cell viability, LDH release, ATP contents, and levels of IL-1β, IL-18, TNF-α, and pyroptosis-related molecules were examined. In rats, cardiac function, serum levels of cardiac enzymes, apoptosis, myocardial fibrosis, and levels of IL-1β, IL-18, TNF-α, TLR2, and pyroptosis-related molecules were detected. miR-143 diminished TLR2 expression by binding to TLR2, and circ -0,006,332 bound to miR-143 to downregulate miR-143 expression. miR-143 expression was reduced and TLR2 expression was augmented in DOX-induced cardiomyocytes. miR-143 inhibited DOX-induced cytotoxicity by suppressing pyroptosis in H9C2 cardiomyocytes. In DOX-induced rats, miR-143 reduced cardiac dysfunction, myocardial apoptosis, myocardial fibrosis, TLR2 levels, and pyroptosis. Furthermore, overexpression of circ -0,006,332 blocked these effects of miR-143 on DOX-induced cardiomyocytes and rats. Circ -0,006,332 stimulates cardiomyocyte pyroptosis by downregulating miR-143 and upregulating TLR2, thus promoting DOX-induced cardiac injury.

Shenxiang Suhe pill improves cardiac function through modulating gut microbiota and serum metabolites in rats after acute myocardial infarction

CONTEXT

Shenxiang Suhe pill (SXSH), a traditional Chinese medicine, is clinically effective against coronary heart disease, but the mechanism of cardiac-protective function is unclear.

OBJECTIVE

We investigated the cardiac-protective mechanism of SXSH via modulating gut microbiota and metabolite profiles.

MATERIALS AND METHODS

Sprague-Dawley (SD) male rats were randomly divided into 6 groups (n = 8): Sham, Model, SXSH (Low, 0.063 g/kg; Medium, 0.126 g/kg; High, 0.252 g/kg), and Ato (atorvastatin, 20 mg/kg). Besides the Sham group, rats were modelled with acute myocardial infarction (AMI) by ligating the anterior descending branch of the left coronary artery (LAD). After 3, 7, 14 days' administration, ultrasound, H&E staining, serum enzymic assay, 16S rRNA sequencing were conducted to investigate the SXSH efficacy. Afterwards, five groups of rats: Sham, Model, Model-ABX (AMI with antibiotics-feeding), SXSH (0.126 g/kg), SXSH-ABX were administrated for 14 days to evaluate the gut microbiota-dependent SXSH efficacy, and serum untargeted metabolomics test was performed.

RESULTS

0.126 g/kg of SXSH intervention for 14 days increased ejection fraction (EF, 78.22%), fractional shortening (FS, 109.07%), and aortic valve flow velocities (AV, 21.62%), reduced lesion area, and decreased serum LDH (8.49%) and CK-MB (10.79%). Meanwhile, SXSH upregulated the abundance of Muribaculaceae (199.71%), Allobaculum (1744.09%), and downregulated Lactobacillus (65.51%). The cardiac-protective effect of SXSH was disrupted by antibiotics administration. SXSH altered serum metabolites levels, such as downregulation of 2-n-tetrahydrothiophenecarboxylic acid (THTC, 1.73%), and lysophosphatidylcholine (lysoPC, 4.61%).

DISCUSSION AND CONCLUSION

The cardiac-protective effect and suggested mechanism of SXSH could provide a theoretical basis for expanding its application in clinic.

Dose-Dependent Cognitive Decline, Anxiety, and Locomotor Impairments Induced by Doxorubicin: Evidence from an Animal Model

Cognitive impairment and anxiety are common side effects of chemotherapy, particularly with the use of doxorubicin (DOX), known as "chemobrain". This study aimed to examine the dose-dependent effects of DOX on cognitive decline, anxiety, and locomotor activity in healthy female Wistar rats. The rats were divided into groups receiving low (2 mg/kg), intermediate (4 mg/kg), and high (5 mg/kg) doses of DOX for four weeks, alongside a control group. Behavioral tests, including open field, elevated plus maze, and Y-maze tests, assessed anxiety, locomotion, and cognitive performance, while brain tissue analysis evaluated neuroinflammation using markers such as GFAP and Iba-1. The results showed that all doses of DOX induced anxiety-like behavior, reduced locomotion, and caused neuroinflammation in the hippocampus, with more severe effects at higher doses. Notably, high-dose DOX also caused short-term memory deficits. These findings highlight the dose-dependent nature of DOX's impact on behavior and cognition, suggesting that DOX plays a key role in the development of cognitive symptoms during chemotherapy. Further research is needed to understand the mechanisms behind these effects and to explore potential interventions.

Stabilization of hypoxia-inducible factor 1α and regulation of specific gut microbes by EGCG contribute to the alleviation of ileal barrier disorder and obesity

Tea polyphenols have a regulatory effect on metabolic-related diseases, however, the underlying mechanism remains elusive. Our study aims to explore the dietary intervention effect of Epigallocatechin gallate (EGCG), the major polyphenol in green tea, on obesity and intestinal barrier disorders in mice fed a high-fat diet. By supplementing with 50 mg kg-1 EGCG, we observed a significant amelioration in body weight gain, fat accumulation, and liver dysfunction. Furthermore, EGCG modulated the HFD-induced metabolomic alterations. In particular, EGCG intervention restored the ileal barrier by enhancing the expression of tight junction proteins and antimicrobial peptides. At the mechanistic level, EGCG treatment stabilized hypoxia-inducible factor 1α (HIF1α) both in vitro and in vivo. Meanwhile, EGCG significantly increased the abundance of Dubosiella and Akkermansia, along with the elevated SCFA contents. These findings suggest that the ability of EGCG to stabilize HIF1α and regulate specific gut microbes is pivotal in mitigating ileal barrier dysfunction and obesity. Moreover, serum metabolomics revealed potential biomarkers following EGCG intervention. This study supports the intake of EGCG or green tea in obesity management and offers a novel perspective for investigating the metabolic regulatory mechanism of other dietary polyphenols.

Targeting the gut microbiota to alleviate chemotherapy-induced toxicity in cancer

Despite ongoing breakthroughs in novel anticancer therapies, chemotherapy remains a mainstream therapeutic modality in different types of cancer. Unfortunately, chemotherapy-related toxicity (CRT) often leads to dose limitation, and even results in treatment termination. Over the past few years, accumulating evidence has indicated that the gut microbiota is extensively engaged in various toxicities initiated by chemotherapeutic drugs, either directly or indirectly. The gut microbiota can now be targeted to reduce the toxicity of chemotherapy. In the current review, we summarized the clinical relationship between the gut microbiota and CRT, as well as the critical role of the gut microbiota in the occurrence and development of CRT. We then summarized the key mechanisms by which the gut microbiota modulates CRT. Furthermore, currently available strategies to mitigate CRT by targeting the gut microbiota were summarized and discussed. This review offers a novel perspective for the mitigation of diverse chemotherapy-associated toxic reactions in cancer patients and the future development of innovative drugs or functional supplements to alleviate CRT via targeting the gut microbiota.

Let food be your medicine - dietary fiber

Dietary fiber (DF) cannot be digested and absorbed by the digestive tract, nor can it provide the energy needed to be burned for metabolic activities. Therefore, from the 1950s to the 1980s, DF received little attention in nutrition studies. With in-depth research and developments in global nutrition, people have gradually paid attention to the fact that DF occupies an essential position in the structure of nutrition, and it can ensure the healthy development of human beings. As early as 390 B.C., the ancient Greek physician Hippocrates proposed, "Let your food be your medicine, and your medicine be your food". This concept has been more systematically validated in modern scientific research, with numerous epidemiological studies showing that the dietary intake of DF-rich foods such as whole grains, root vegetables, legumes, and fruits has the potential to regulate the balance of the gut microbiota and thereby prevent diseases. However, the crosstalk between different types of DF and the gut microbiota is quite complex, and the effects on the organism vary. In this paper, we discuss research on DF and the gut microbiota and related diseases, aiming to understand the relationship between all three better and provide a reference basis for the risk reduction of related diseases.

Fecal Microbiota Transplantation in Mice Exerts a Protective Effect Against Doxorubicin-Induced Cardiac Toxicity by Regulating Nrf2-Mediated Cardiac Mitochondrial Fission and Fusion

Aims: The relationship between the gut microbiota and cardiovascular system has been increasingly clarified. Fecal microbiota transplantation (FMT), used to improve gut microbiota, has been applied clinically for disease treatment and has great potential in combating doxorubicin (DOX)-induced cardiotoxicity. However, the application of FMT in the cardiovascular field and its molecular mechanisms are poorly understood. Results: During DOX-induced stress, FMT alters the gut microbiota and serum metabolites, leading to a reduction in cardiac injury. Correlation analysis indicated a close association between serum metabolite indole-3-propionic acid (IPA) and cardiac function. FMT and IPA achieve this by facilitating the translocation of Nfe2l2 (Nrf2) from the cytoplasm to the nucleus, thereby activating the expression of antioxidant molecules, reducing reactive oxygen species production, and inhibiting excessive mitochondrial fission. Consequently, mitochondrial function is preserved, leading to the mitigation of cardiac injury under DOX-induced stress. Innovation: FMT has the ability to modify the composition of the gut microbiota, providing not only protection to the intestinal mucosa but also influencing the generation of serum metabolites and regulating the Nrf2 gene to modulate the balance of cardiac mitochondrial fission and fusion. This study comprehensively demonstrates the efficacy of FMT in countering DOX-induced myocardial damage and elucidates the pathways linking the microbiota and the heart. Conclusion: FMT alters the gut microbiota and serum metabolites of recipient mice, promoting nuclear translocation of Nrf2 and subsequent activation of downstream antioxidant molecule expression, while inhibiting excessive mitochondrial fission to preserve cardiac integrity. Correlation analysis highlights IPA as a key contributor among differentially regulated metabolites.

Role of gut microbiota in doxorubicin-induced cardiotoxicity: from pathogenesis to related interventions

Doxorubicin (DOX) is a broad-spectrum and highly efficient anticancer agent, but its clinical implication is limited by lethal cardiotoxicity. Growing evidences have shown that alterations in intestinal microbial composition and function, namely dysbiosis, are closely linked to the progression of DOX-induced cardiotoxicity (DIC) through regulating the gut-microbiota-heart (GMH) axis. The role of gut microbiota and its metabolites in DIC, however, is largely unelucidated. Our review will focus on the potential mechanism between gut microbiota dysbiosis and DIC, so as to provide novel insights into the pathophysiology of DIC. Furthermore, we summarize the underlying interventions of microbial-targeted therapeutics in DIC, encompassing dietary interventions, fecal microbiota transplantation (FMT), probiotics, antibiotics, and natural phytochemicals. Given the emergence of microbial investigation in DIC, finally we aim to point out a novel direction for future research and clinical intervention of DIC, which may be helpful for the DIC patients.

FGF12 restrains mitochondria-dependent ferroptosis in doxorubicin-induced cardiomyocytes through the activation of FGFR1/AMPK/NRF2 signaling

Fibroblast growth factor-12 (FGF12) has been reported to play important role in regulating heart diseases. We aimed to explore the role of FGF12 in doxorubicin (DOX)-induced myocardial injury. DOX-induced mice and DOX-induced HL-1 cells were used as the myocardial injury in vivo and in vitro. Then, FGF12, Anp, Bnp, and Myh7 expression was detected. The pathological injury in myocardium tissue was observed by H&E staining. The levels of markers related to myocardial damage and oxidative stress were assessed. Then, immunohistochemistry and immunofluorescence staining were used to detect FGF12 and 4-HNE expression. Ferroptosis were detected by Prussian blue staining and western blot. The FGFR1/AMPK/NRF2 signaling was measured by western blot. FGF12 expression was downregulated in DOX-induced mice myocardium tissues. FGF12 overexpression alleviated DOX-induced myocardial tissue pathological injury and reduced Anp, Bnp, and Myh7 expression. Additionally, the levels of CK-MB, LDH and cTnT in serum were decreased after FGF12 upregulation in DOX-induced mice. Moreover, FGF12 overexpression reduced the levels of ROS, MDA, and 4-HNE but increased SOD and GSH-Px activities. Meanwhile, FGF12 led to less deposition of iron ion, decreased ACSL4, PTGS2 and increased GPX4, FTH1 expression. Additionally, FGF12 activated the expressions of FGFR1, p-AMPK, and NRF2. Moreover, FGFR1 silencing reversed the protective effects of FGF12 overexpression on cell viability, oxidative stress, ferroptosis, and FGFR1/AMPK/NRF2 pathway. To sum up, FGF12 inhibited mitochondria-dependent ferroptosis in cardiomyocytes induced by DOX through activation of FGFR1/AMPK/NRF2 signaling. These findings clarify a new mechanism of DOX-induced cardiac injury and provide a promising target to limit the disease development.

Toll-like Receptor 4 Inflammatory Perspective on Doxorubicin-Induced Cardiotoxicity

Doxorubicin (Dox) is one of the most frequently used chemotherapeutic drugs in a variety of cancers, but Dox-induced cardiotoxicity diminishes its therapeutic efficacy. The underlying mechanisms of Dox-induced cardiotoxicity are still not fully understood. More significantly, there are no established therapeutic guidelines for Dox-induced cardiotoxicity. To date, Dox-induced cardiac inflammation is widely considered as one of the underlying mechanisms involved in Dox-induced cardiotoxicity. The Toll-like receptor 4 (TLR4) signaling pathway plays a key role in Dox-induced cardiac inflammation, and growing evidence reports that TLR4-induced cardiac inflammation is strongly linked to Dox-induced cardiotoxicity. In this review, we outline and address all the available evidence demonstrating the involvement of the TLR4 signaling pathway in different models of Dox-induced cardiotoxicity. This review also discusses the effect of the TLR4 signaling pathway on Dox-induced cardiotoxicity. Understanding the role of the TLR4 signaling pathway in Dox-induced cardiac inflammation might be beneficial for developing a potential therapeutic strategy for Dox-induced cardiotoxicity.

Exploring the Involvement of Gut Microbiota in Cancer Therapy-Induced Cardiotoxicity

Trillions of microbes in the human intestinal tract, including bacteria, viruses, fungi, and protozoa, are collectively referred to as the gut microbiome. Recent technological developments have led to a significant increase in our understanding of the human microbiome. It has been discovered that the microbiome affects both health and the progression of diseases, including cancer and heart disease. Several studies have indicated that the gut microbiota may serve as a potential target in cancer therapy modulation, by enhancing the effectiveness of chemotherapy and/or immunotherapy. Moreover, altered microbiome composition has been linked to the long-term effects of cancer therapy; for example, the deleterious effects of chemotherapy on microbial diversity can, in turn, lead to acute dysbiosis and serious gastrointestinal toxicity. Specifically, the relationship between the microbiome and cardiac diseases in cancer patients following therapy is poorly understood. In this article, we provide a summary of the role of the microbiome in cancer treatment, while also speculating on a potential connection between treatment-related microbial changes and cardiotoxicity. Through a brief review of the literature, we further explore which bacterial families or genera were differentially affected in cancer treatment and cardiac disease. A deeper understanding of the link between the gut microbiome and cardiotoxicity caused by cancer treatment may help lower the risk of this critical and potentially fatal side effect.

Mixed Nuts as Healthy Snacks: Effect on Tryptophan Metabolism and Cardiovascular Risk Factors

We recently demonstrated that the consumption of mixed tree nuts (MTNs) during caloric restriction decreased cardiovascular risk factors and increased satiety. Tryptophan (Trp) metabolism has been indicated as a factor in cardiovascular disease. Here, we investigated the effect of MTNs on Trp metabolism and the link to cardiovascular risk markers. Plasma and stool were collected from 95 overweight individuals who consumed either MTNs (or pretzels) daily as part of a hypocaloric weight loss diet for 12 weeks followed by an isocaloric weight maintenance program for an additional 12 weeks. Plasma and fecal samples were evaluated for Trp metabolites by LC-MS and for gut microbiota by 16S rRNA sequencing. Trp-kynurenine metabolism was reduced only in the MTNs group during weight loss (baseline vs. week 12). Changes in Trp-serotonin (week 24) and Trp-indole (week 12) metabolism from baseline were increased in the MTNs group compared to the pretzel group. Intergroup analysis between MTN and pretzel groups does not identify significant microbial changes as indicated by alpha diversity and beta diversity. Changes in the relative abundance of genus Paludicola during intervention are statistically different between the MTNs and pretzel group with p < 0.001 (q = 0.07). Our findings suggest that consumption of MTNs affects Trp host and microbial metabolism in overweight and obese subjects.

Changes in the gut microbiota structure and function in rats with doxorubicin-induced heart failure

Objectives

The rat model of heart failure (HF) induced by doxorubicin (DOX), a broad spectrum and highly effective chemotherapeutic anthracycline with high-affinity to myocardial tissue that causes severe dose-dependent irreversible cardiotoxicity has been widely recognized and applied in HF pathogenesis and drug therapy studies. The gut microbiota (GM) has attracted significant attention due to its potential role in HF, and research in this area may provide beneficial therapeutic strategies for HF. Considering the differences in the route, mode, and total cumulative dose of DOX administration used to establish HF models, the optimal scheme for studying the correlation between GM and HF pathogenesis remains to be determined. Therefore, focusing on establishing the optimal scheme, we evaluated the correlation between GM composition/function and DOX-induced cardiotoxicity (DIC).

Methods

Three schemes were investigated: DOX (at total cumulative doses of 12, 15 or 18 mg/kg using a fixed or alternating dose via a tail vein or intraperitoneal injection) was administered to Sprague Dawley (SD) for six consecutive weeks. The M-mode echocardiograms performed cardiac function evaluation. Pathological changes in the intestine were observed by H&E staining and in the heart by Masson staining. The serum levels of N-terminal pre-B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) were measured by ELISA. The GM was analysed by 16S rRNA gene sequencing.

Key findings

Strikingly, based on the severity of cardiac dysfunction, there were marked differences in the abundance and grouping of GM under different schemes. The HF model established by tail vein injection of DOX (18 mg/kg, alternating doses) was more stable; moreover, the degree of myocardial injury and microbial composition were more consistent with the clinical manifestations of HF.

Conclusions

The model of HF established by tail vein injection of doxorubicin, administered at 4mg/kg body weight (2mL/kg) at weeks 1, 3 and 5, and at 2mg/kg body weight (1mL/kg) at weeks 2, 4 and 6, with a cumulative total dose of 18mg/kg, is a better protocol to study the correlation between HF and GM.

Characterization and diagnostic value of the gut microbial composition in patients with minimal change disease

Background: Minimal change disease (MCD) is one of the most common causes of primary nephrotic syndrome with high morbidity. This study aimed to explore the typical alterations of gut microbiota in MCD and establish a non-invasive classifier using key gut microbiome. We also aimed to evaluate the therapeutic efficiency of gut microbiota intervention in MCD through animal experiments. Methods: A total of 222 stool samples were collected from MCD patients and healthy controls at the First Affiliated Hospital of Zhengzhou University and Shandong Provincial Hospital for 16S rRNA sequencing. Optimum operational taxonomic units (OTUs) were obtained for constructing a diagnostic model. MCD rat models were established using doxorubicin hydrochloride for exploring the therapeutic efficiency of gut microbial intervention through fecal microbiota transplantation (FMT). Results: The α-diversity of gut microbiota decreased in MCD patients when compared with healthy controls. The relative abundance of bacterial species also changed significantly. We constructed a diagnostic model based on eight optimal OTUs and it achieved efficiency of 97.81% in discovery cohort. The high efficiency of diagnostic model was also validated in the patients with different disease states and cross-regional cohorts. The treatment partially recovered the gut microbial dysbiosis in patients with MCD. In animal experiments, likewise, the gut microbiota changed sharply in MCD rats. However, gut microbial interventions did not reduce urinary protein or pathological kidney damage. Conclusion: Gut Microbiota shifts sharply in both patients and rats with MCD. Typical microbial changes can be used as biomarkers for MCD diagnosis. The gut microbiota compositions in patients with MCD tended to normalize after treatment. However, the intervention of gut microbiota seems to have no therapeutic effect on MCD.

Short-Chain Fatty Acids in Gut-Heart Axis: Their Role in the Pathology of Heart Failure

Heart failure (HF) is a syndrome with global clinical and socioeconomic burden worldwide owing to its poor prognosis. Accumulating evidence has implicated the possible contribution of gut microbiota-derived metabolites, short-chain fatty acids (SCFAs), on the pathology of a variety of diseases. The changes of SCFA concentration were reported to be observed in various cardiovascular diseases including HF in experimental animals and humans. HF causes hypoperfusion and/or congestion in the gut, which may lead to lowered production of SCFAs, possibly through the pathological changes of the gut microenvironment including microbiota composition. Recent studies suggest that SCFAs may play a significant role in the pathology of HF, possibly through an agonistic effect on G-protein-coupled receptors, histone deacetylases (HDACs) inhibition, restoration of mitochondrial function, amelioration of cardiac inflammatory response, its utilization as an energy source, and remote effect attributable to a protective effect on the other organs. Collectively, in the pathology of HF, SCFAs might play a significant role as a key mediator in the gut-heart axis. However, these possible mechanisms have not been entirely clarified and need further investigation.

Roles of Gut Microbiome in Bone Homeostasis and Its Relationship with Bone-Related Diseases

The extended microbial genome-the gut microbiome (GM)-plays a significant role in host health and disease. It is able to influence a number of physiological functions. During dysbiosis, GM is associated with the development of various chronic diseases with impaired bone quality. In general, GM is important for bone homeostasis and can affect it via several mechanisms. This review describes the roles of GM in bone homeostasis through influencing the immune and endocrine functions, short-chain fatty acids production, calcium absorption and the gut-brain axis. The relationship between GM composition and several bone-related diseases, specifically osteoporosis, osteoarthritis, rheumatoid arthritis, diabetes mellitus, obesity and bone cancer, is also highlighted and summarized. GM manipulation may become a future adjuvant therapy in the prevention of many chronic diseases. Therefore, the beneficial effects of probiotic therapy to improve the health status of individuals with aforementioned diseases are provided, but further studies are needed to clearly confirm its effectiveness. Recent evidence suggests that GM is responsible for direct and indirect effects on drug efficacy. Accordingly, various GM alterations and interactions related to the treatment of bone-related diseases are mentioned as well.

Neurotoxic Effect of Doxorubicin Treatment on Cardiac Sympathetic Neurons

Doxorubicin (DOXO) remains amongst the most commonly used anti-cancer agents for the treatment of solid tumors, lymphomas, and leukemias. However, its clinical use is hampered by cardiotoxicity, characterized by heart failure and arrhythmias, which may require chemotherapy interruption, with devastating consequences on patient survival and quality of life. Although the adverse cardiac effects of DOXO are consolidated, the underlying mechanisms are still incompletely understood. It was previously shown that DOXO leads to proteotoxic cardiomyocyte (CM) death and myocardial fibrosis, both mechanisms leading to mechanical and electrical dysfunction. While several works focused on CMs as the culprits of DOXO-induced arrhythmias and heart failure, recent studies suggest that DOXO may also affect cardiac sympathetic neurons (cSNs), which would thus represent additional cells targeted in DOXO-cardiotoxicity. Confocal immunofluorescence and morphometric analyses revealed alterations in SN innervation density and topology in hearts from DOXO-treated mice, which was consistent with the reduced cardiotropic effect of adrenergic neurons in vivo. Ex vivo analyses suggested that DOXO-induced denervation may be linked to reduced neurotrophic input, which we have shown to rely on nerve growth factor, released from innervated CMs. Notably, similar alterations were observed in explanted hearts from DOXO-treated patients. Our data demonstrate that chemotherapy cardiotoxicity includes alterations in cardiac innervation, unveiling a previously unrecognized effect of DOXO on cardiac autonomic regulation, which is involved in both cardiac physiology and pathology, including heart failure and arrhythmias.