Xinmailong injection on left ventricular remodeling and inflammatory mediators in patients with CHF: a systematic review and meta-analysis

Background: Chronic heart failure (CHF) is a prevalent and highly challenging cardiovascular disease associated with high mortality rates. The occurrence and progression of CHF are closely linked to left ventricular remodeling (LVR) and inflammation. Addressing LVR and reducing inflammation can significantly slow down the progression of CHF and improve patient prognosis. Objective: To evaluate the effects of Xinmailong injection (XMLI) on LVR and inflammatory mediators in CHF patients. Method: The randomized controlled trials investigating the effectiveness of XMLI treatment for CHF were retrieved from eight databases up until 31 December 2023. To evaluate the methodological quality of included studies, the Cochrane bias risk tool was employed. Furthermore, statistical analysis, sensitivity analysis, and publication bias assessment were conducted using Stata 17.0 software. Result: Compared with conventional treatment (CT), the combination therapy of XMLI and CT significantly improved LVR and reduced inflammatory mediators, mainly manifested by an increase in LVEF (MD = 6.40, 95% CI: 5.25 to 7.55, p = 0.000), a decrease in LVEDD (MD = −4.63, 95% CI: −5.69 to −3.57, p = 0.000) and LVESD (MD = −4.00, 95% CI: −5.50 to −2.50, p = 0.000), as well as a decrease in TNF-α (MD = −7.93, 95% CI: −9.86 to −6.00, p = 0.000), IL-6 (MD = −5.25, 95% CI: −6.59 to −3.92, p = 0.000), IL-18 (MD = −36.07, 95% CI: −46.76 to −25.38, p = 0.000), CRP (MD = −4.41, 95% CI: −6.40 to −2.42, p = 0.000), hs-CRP (MD = −4.90, 95% CI: −5.71 to −4.08, p = 0.000), and an increase in IL-10 (MD = 20.19, 95% CI: 10.42 to 29.97, p = 0.000). In addition, the combination therapy showed enhanced clinical efficacy (OR = 4.08, 95% CI: 3.10 to 5.37, p = 0.000), decreased expression levels of BNP (MD = −138.48, 95% CI: −155.48 to −121.48, p = 0.000), and NT-pro BNP (MD = −315.63, 95% CI: −359.25 to −272.00, p = 0.000), and increased the 6-MWD (MD = 71.02, 95% CI: 57.23 to 84.81, p = 0.000). It is noteworthy that the combination therapy did not lead to an increase in the incidence of adverse reactions (OR = 1.01, 95% CI: 0.68 to 1.50, p = 0.97). Conclusion: This systematic review and meta-analysis demonstrated the superiority of combining XMLI and CT therapies over CT alone in improving LVR and reducing inflammatory mediators in patients with CHF. Importantly, this combination therapy does not increase adverse reactions. However, it is crucial to exercise caution while interpreting the survey results due to the limited quality of the included studies. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=492715, Identifier CRD42023492715.


Introduction
Chronic heart failure (CHF) is a major public health problem, affecting 26 million people worldwide and leading to a high incidence rate and mortality.This condition brings a huge burden to both patients and society due to its complex clinical syndrome caused by multiple etiologies (Conrad et al., 2018;Mensah et al., 2023).CHF can be classified into two distinct subtypes, namely, heart failure with reduced ejection fraction (HFrEF, LVEF less than 40%) and heart failure with mid-range ejection fraction (HFmrEF, LVEF ranging from 40% to 49%).While the pathological and physiological mechanisms of CHF are not fully understood, left ventricular remodeling (LVR) and increased inflammation are known characteristics of the condition (Dick and Epelman, 2016;Aimo et al., 2019).There is a close relationship between LVR, inflammatory response, and the occurrence and progression of CHF (Hartupee and Mann, 2013;Dick and Epelman, 2016;Tong et al., 2018).Elevated levels of pro-inflammatory factors have been found to be positively correlated with the severity and adverse outcomes of CHF (Smart and Steele, 2011).Therefore, an important strategy to alleviate symptoms and improve prognosis in CHF patients is to enhance LVR and reduce inflammation.
LVR, which refers to the structural and functional changes in the left ventricle of the heart, is a consequence of various etiologies that contribute to the development of CHF (Aimo et al., 2019).These changes in ventricular structure and function can significantly impair cardiac performance, leading to worsened symptoms and outcomes for patients.Numerous studies have demonstrated the potential of interventions aimed at improving LVR to delay or even reverse the progression of CHF (Biering-Sørensen et al., 2020;Lee et al., 2021).In addition to LVR, inflammation has been recognized as a key pathophysiological factor in CHF (Hartupee and Mann, 2013).Elevated levels of pro-inflammatory factors, including tumor necrosis factor α (TNF-a), interleukin-6 (IL-6), IL-18, C-reactive protein (CRP), and hypersensitive C-reactive protein (hs-CRP), have been closely associated with the severity and adverse consequences of the disease in CHF patients (Arvunescu et al., 2023).Promising results have been reported in targeting or regulating the activity of these inflammatory mediators (Murphy et al., 2020).Consequently, targeting both LVR and inflammatory mediators has emerged as a significant therapeutic strategy for alleviating symptoms and improving prognosis in patients with CHF.
Xinmailong injection (XMLI) is a composite peptide injection extracted from Periplaneta americana L, containing adenosine, inosine, protocatechuic acid, and pyroglutamyl dipeptide as its main active ingredients (Qi et al., 2017).Modern pharmacological studies have elucidated the cardioprotective properties of XMLI, notably in inhibiting oxidative stress (Jiang et al., 2021) and inflammatory response (Jin et al., 2022), regulating cell autophagy (Li et al., 2016), and modulating cytokine expression (Liu et al., 2017).Jiang et al. (Jiang et al., 2021) observed that XMLI modulates HO-1 mediated lysosomal function and autophagy in H9C2 cells, reduces oxidative stress and mitigates DOX-induced cardiac toxicity.Jin et al. (Jin et al., 2022) revealed that XMLI can reduce ROS production, minimize inflammatory response, and decrease cell apoptosis by improving PKC and PLA2 proteinmediated myocardial ischemia.Li et al. (Li et al., 2016) demonstrated that XMLI targets autophagy by activating the PI3K/Akt pathway and inhibiting Erk1/2 and P38 MAPK pathways, effectively alleviating epirubicin-induced cardiomyopathy.Additionally, Liu et al. (Liu et al., 2017) highlighted that XMLI inhibits connective tissue growth factor (CTGF), enhancement of heart function, and reduction of alcoholic myocardial fibrosis in rat models.As a result, XMLI is widely utilized as an adjuvant medication for CHF in China.However, there is a limited comprehensive evaluation of XMLI's impact on LVR and inflammatory mediators in patients with CHF.Given the crucial role of LVR and inflammation in the development and progression of CHF, this study aims to bridge this knowledge gap through a meta-analysis of clinical randomized controlled trials (RCTs).
Library, Wanfang Data, China Knowledge Infrastructure Database (CNKI), China Biomedical Database (CBM), and China Science and Technology Journal Database (VIP).The search employed a combination of MeSH terminology and textual terminology.The search terms include "Xinmailong injection", "Xinmailong ", "heart failure", and "chronic heart failure".The search was conducted from their establishment to 31 December 2023.In addition, the reviewers manually searched the reference lists of published literature to ensure comprehensive coverage.Detailed search strategies can be found in the Supplementary Material.

Inclusion and exclusion criteria
According to the PICOS principle, the following conditions must be met for inclusion in the study: 1) RCTs without any language restrictions on publication.2) Participants diagnosed with CHF, aged 18 and above.3) The intervention group received a combination of XMLI and conventional treatment (CT), while the control group received CT based on heart failure (HF) guidelines.4) The primary outcome measures primarily focus on LVR (LVEF, LVEDD, LVESD) and inflammatory mediators (TNF-α, IL-6, IL-10, IL-18, CRP, hs-CRP).
The exclusion criteria are as follows: 1) Non-RCTs.2) Unstable heart failure.3) Repeated publication, retaining only complete data for research.4) Research without primary outcome measures.5) The full study cannot be obtained through databases or other means.

Data extraction
Two reviewers (XH and XC) independently evaluated the included studies and extracted data.If any discrepancies or disagreements arose during the evaluation process, a third reviewer (MY) was available for discussion and resolution.The data extraction was conducted by the two researchers (XH and XC) using a pre-established table that included several important parameters.These parameters encompassed the article title, first author, publication year, sample size, intervention drugs, dosage and course of treatment, outcome measures, and adverse reactions.

Quality assessment
Two reviewers (YL and JY) independently evaluated the methodological quality of the included studies using the Cochrane Collaboration risk of bias tool (Sterne et al., 2019).The evaluation encompassed various aspects, including randomization methods, allocation concealment, blinding, completeness of outcome data, selective reporting, and other sources of bias.The results of the evaluations were then cross-checked to ensure accuracy and consistency.The risk of bias for each study was classified as low, unclear, or high.Any disagreements that arose during the methodological quality assessment process were resolved through discussions involving third reviewer (XM).

Data analysis
All meta-analyses were conducted using RevMan5.4 and Stata 17.0 software.For dichotomous data, a 95% confidence interval (CI) risk ratio (RR) was calculated, while continuous data utilized a mean difference (MD) with a 95% CI.Heterogeneity among the included studies was evaluated using I 2 .I 2 ≤ 50% was considered as low heterogeneity, and a fixed-effects model was applied.Conversely, a random-effects model was applied.Furthermore, subgroup analysis was performed based on differences in LVEF to investigate possible factors influencing the results.Sensitivity analysis was performed on the primary outcome measures to evaluate the impact of individual studies on the combined effect size.The Egge's tests were employed to test for potential publication bias.
Frontiers in Pharmacology frontiersin.org10 Forest plot for IL-10 expression levels.

FIGURE 8
Forest plot for IL-18 expression levels.

Sensitivity analysis
To assess the reliability and robustness of the consolidation results, a sensitivity analysis was conducted.This analysis involved sequentially excluding individual studies and examining their impact on various variables, including LVEF (Figure 14A), LVEDD (Figure 14B), LVESD (Figure 14C), TNF-α (Figure 14D), IL-6 (Figure 14E), IL-10 (Figure 14F), IL-18 (Figure 14G), CRP (Figure 14H), and hs-CRP (Figure 14I).Interestingly, the exclusion of any of these studies had no significant effect on the combined results.This finding suggests that the merged results are both robust and reliable, as clearly shown in Figure 14.

Summary of findings
This meta-analysis is the first to investigate the effects of XMLI on LVR and inflammatory mediators in patients with CHF.A total  Forest plot for 6-MWD.Frontiers in Pharmacology frontiersin.org14 Han et al. 10.3389/fphar.2024.1370448 of 32 RCTs were included in this analysis, revealing several important findings.Firstly, the combination of XMLI and CT significantly improved LVR in HF patients.This improvement was supported by an increase in LVEF, as well as a decrease in LVEDD and LVESD.As well as levels of BNP, and NT-pro BNP were decreased.Furthermore, the combination therapy also resulted in a significant reduction in inflammatory mediators.Specifically, there was a decrease in the expression levels of pro-inflammatory cytokines TNF-a, IL-6, IL-18, CRP, and hs-CRP.Conversely, there was an increase in the expression levels of the anti-inflammatory cytokine IL-10.In addition to improving LVR and reducing inflammatory mediators, the combination therapy showed higher clinical efficacy and improvement of the 6-MWD.Importantly, the combination therapy demonstrated good safety, with only minor adverse events reported.These events were manageable in terms of symptoms and had no impact on treatment outcomes.Based on these compelling results, our meta-analysis suggests that XMLI effectively improves LVR in HF patients, reduces inflammatory mediators, and enhances overall clinical efficacy.
To ensure the robustness and reliability of our findings, sensitivity analysis was conducted.Individual studies were sequentially deleted, and sensitivity analysis was performed on key indicators of LVR and inflammatory mediators, further confirming the validity of our results.Additionally, Egger's test was conducted to evaluate publication bias, with the results showing no significant publication bias.This further strengthens the validity and reliability of our findings.

Comparison with previous studies
Although Lu et al.'s (Lu et al., 2018) previous meta-analysis evaluated the clinical efficacy of XMLI in treating CHF, our study specifically focuses on its effects on LVR and inflammatory mediators.It should be noted that there are several shortcomings in previous studies: Firstly, HF is classified into different subtypes based on ejection fraction according to the HF management guidelines.However, previous studies did not consider these subtypes or conduct subgroup analysis based on ejection fraction during meta-analysis, which may introduce heterogeneity and bias.Secondly, sensitivity analysis was not performed, and only funnel plots were used to evaluate publication bias in previous studies, which affects the robustness and reliability of the research findings.Finally, previous studies mainly focused on clinical indicators such as symptom improvement, exercise tolerance, and quality of life in CHF patients treated with XMLI.The impact of XMLI on LVR and inflammatory mediators has not been extensively explored.Understanding these specific effects is crucial for a comprehensive assessment of XMLI's therapeutic potential in CHF patients.Forest plot for adverse reactions.
Frontiers in Pharmacology frontiersin.org

Strengths and limitations
This meta-analysis of RCTs is the first to specifically investigate the effects of XMLI on LVR and inflammatory mediators in patients with CHF.To enhance the reliability of our findings, we will conduct subgroup analyses based on different types of HF, eliminating potential confounding factors associated with disease types.Additionally, our study addresses a crucial aspect of CHF by evaluating the impact of XMLI on LVR, a key pathological and physiological mechanism contributing to high hospitalization and mortality rates in CHF patients.Furthermore, we comprehensively evaluate the role of inflammatory response in LVR, highlighting its significance in the progression of HF, an aspect that previous studies have yet to fully address.
Several limitations should be considered when interpreting the results of this study.Firstly, the included studies in this metaanalysis exhibit relatively low overall quality, with limited reporting of allocation concealment and blinding, which poses a serious risk of bias.Secondly, significant heterogeneity is observed among the RCTs, although subgroup and sensitivity analyses are conducted without identifying the sources of heterogeneity.This variation may be associated with the lack of standardized dosage and intervention duration.Thirdly, the small size of the included studies highlights the need for larger scale research to ensure result reliability.Therefore, caution should be exercised when interpreting the findings.Fourthly, it is important to note that all studies included in this analysis were conducted in China and exclusively involved Chinese participants.This limited geographical scope may introduce sources of heterogeneity.To ensure the applicability of these findings to different races, future studies should incorporate with more diverse samples from various geographical regions.Lastly, the limited number of studies examining TNF-α, IL-10, IL-8, and CRP results in low supporting evidence.Future research should prioritize larger scale and more rigorous studies to verify the stability of our findings.

Implication
To strengthen the evidence regarding the efficacy of XMLI treatment for CHF, future clinical research should address the following areas.Firstly, studies should be conducted on different types of HF to comprehensively assess the efficacy of XMLI in treating HF.By doing so, bias can be minimized, and more accurate conclusions can be generated.Secondly, rigorous adherence to clinical research standards, including strict

Conclusion
The results of the systematic review and meta-analysis suggest that the combination of XML and CT can effectively improve LVR and reduce inflammatory mediators in CHF patients, with a good safety profile.However, it is crucial to approach these findings with caution due to the low level of Frontiers in Pharmacology frontiersin.orgevidence and high heterogeneity observed in the included studies, particularly in regard to the evaluation of inflammatory mediators.To strengthen these conclusions, future research should prioritize high-quality RCTs that can provide more substantive evidence.
FIGURE 10Forest plot for clinical efficacy.

FIGURE 12 Forest
FIGURE 12Forest plot for BNP and NT-pro BNP expression levels.(A) BNP.(B) NT-pro BNP.

TABLE 1
Study characteristics.