Alterations in trimethylamine-N-oxide in response to Empagliflozin therapy: a secondary analysis of the EMMY trial

Microbiome-Derived Trimethylamine N-Oxide (TMAO) as a Multifaceted Biomarker in Cardiovascular Disease: Challenges and Opportunities

Biomarkers play a crucial role in various stages of disease management, including screening, diagnosis, prediction, prognosis, treatment, and safety monitoring. Although they are powerful tools in disease diagnosis, management, and drug development, identifying and validating reliable biomarkers remains a significant challenge. Among potential microbiome-derived biomarkers, trimethylamine N-oxide (TMAO) has gained notable attention for its link to atherosclerosis and cardiovascular risk. However, despite the growing body of research on TMAO, its practical application in clinical settings for disease management and patient outcome enhancement is still not a reality. This paper presents recent data on the utility of TMAO as a cardiovascular biomarker, categorized by its various roles: diagnostic, prognostic, susceptibility/risk, monitoring, pharmacodynamic/response, predictive, and safety. It also briefly discusses research on TMAO's potential role in cardiovascular disease development. While TMAO shows promise, particularly in prognostic applications, its reliability as a biomarker has been inconsistent across studies. These variances may result from several confounding factors that affect TMAO plasma levels, including diet, kidney function, and demographic variables. The review aims to elucidate the specific contexts in which TMAO can be valuable, potentially leading to more personalized and effective management of cardiovascular disease.

Sodium-Glucose Cotransporter-2 Inhibitors in Patients With Acute Coronary Syndrome: A Modern Cinderella?

PURPOSE

Atherosclerotic cardiovascular disease remains a prominent global cause of mortality, with coronary artery disease representing its most prevalent manifestation. Recently, a novel class of antidiabetic medication, namely sodium-glucose cotransporter-2 (SGLT2) inhibitors, has been reported to have remarkable cardiorenal advantages for individuals with type 2 diabetes mellitus (DM), and they may reduce cardiorenal risk even in individuals without pre-existing DM. Currently, there is no evidence regarding the safety and efficacy of these drugs in acute coronary syndrome (ACS), regardless of diabetes status. This review aims to comprehensively present the available preclinical and clinical evidence regarding the potential role of SGLT2 inhibitors in the context of ACS, as adjuncts to standard-of-care treatment for this patient population, while also discussing potential short- and long-term cardiovascular benefits.

METHODS

A literature search was performed through MEDLINE (via PubMed), Cochrane Central Register of Controlled Trials, and Scopus until February 26, 2024. Eligible were preclinical and clinical studies, comprising randomized controlled trials (RCTs), real-world studies, and meta-analyses.

FINDINGS

Evidence from preclinical models indicates that the use of SGLT2 inhibitors is associated with a blunted ischemia-reperfusion injury and decreased myocardial infarct size, particularly after prior treatment. Although RCTs and real-world data hint at a potential benefit in acute ischemic settings, showing improvements in left ventricular systolic and diastolic function, decongestion, and various cardiometabolic parameters such as glycemia,body weight, and blood pressure, the recently published DAPA-MI (Dapagliflozin in Myocardial Infarction without Diabetes or Heart Failure) trial did not establish a clear advantage regarding surrogate cardiovascular end points of interest. SGLT2 inhibitors appear to provide a benefit in reducing contrast-induced acute kidney injury events in patients with ACS undergoing percutaneous coronary intervention. However, data on other safety concerns, such as treatment discontinuation because of hypotension, hypovolemia, or ketoacidosis, are currently limited.

IMPLICATIONS

Despite the well-established cardiovascular benefits observed in the general population with type 2 DM and, more recently, in other patient groups irrespective of diabetes status, existing evidence does not support the use of SGLT2 inhibitors in the context of ACS. Definitive answers to this intriguing research question, which could potentially expand the therapeutic indications of this novel drug class, require large-scale, well-designed RCTs.

Intra-hospital variation of gut microbiota product, trimethylamine N-oxide (TMAO), predicts future major adverse cardiovascular events after myocardial infarction

OBJECTIVE

Trimethylamine N-oxide (TMAO) has been associated with atherosclerosis and poor outcome. We evaluated the prognostic impact of intra-hospital TMAO variation on patient outcome.

METHODS AND RESULTS

Blood samples from 149 patients with acute myocardial infarction (AMI) were taken on admission and discharge. Plasma TMAO was determined by HPLC-MS. The endpoint was a composite three-point MACE (major adverse cardiovascular events), including all-cause mortality, re-infarction, or heart failure (HF) development. Median TMAO concentration on admission was significantly higher than on discharge (respectively, 7.81 [3.47-19.98] vs 3.45 [2.3-4.78] μM, p < 0.001). After estimating the 3.45 μM TMAO cut-off with the analysis of the continuous hazard ratio, we divided our cohort into two groups. The first group included 75 (50.3%) patients whose TMAO levels remained below or decreased under cut-off (low-low/high-low; LL/HL), while the second group included 74 (49.7%) patients whose TMAO levels remained high or increased above the cut-off during hospitalisation (high-high/low-high; HH/LH). During the median 30-month follow-up, 21.5% of patients experienced the composite endpoint. At Kaplan-Meier analysis, a trend of increasing MACE risk was observed in patients in the HH/LH group (p = 0.05). At multivariable Cox analysis, patients from the HH/LH group had more than two times higher risk of MACE during the follow-up than the LL/HL group (HR = 2.15 [95% CI, 1.03-4.5], p = 0.04). Other independent predictors of MACE were older age and worse left ventricular systolic function.

CONCLUSION

In patients with AMI, permanently high or increasing TMAO levels during hospitalisation are associated with a higher risk of MACE during long-term follow-up.

New-onset syncope in diabetic patients treated with sodium-glucose cotransporter-2 inhibitors versus dipeptidyl peptidase-4 inhibitors: a Chinese population-based cohort study

BACKGROUND AND AIMS

Syncope is a symptom that poses an important diagnostic and therapeutic challenge, and generates significant cost for the healthcare system. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have demonstrated beneficial cardiovascular effects, but their possible effects on incident syncope have not been fully investigated. This study compared the effects of SGLT2i and dipeptidyl peptidase-4 inhibitors (DPP4i) on new-onset syncope.

METHODS AND RESULTS

This was a retrospective, territory-wide cohort study enrolling type 2 diabetes mellitus (T2DM) patients treated with SGLT2i or DPP4i between 1 January 2015 and 31 December 2020, in Hong Kong, China. The outcomes were hospitalization of new-onset syncope, cardiovascular mortality, and all-cause mortality. Multivariable Cox regression and different approaches using the propensity score were applied to evaluate the association between SGLT2i and DPP4i with incident syncope and mortality. After matching, a total of 37 502 patients with T2DM were included (18 751 SGLT2i users vs. 18 751 DPP4i users). During a median follow-up of 5.56 years, 907 patients were hospitalized for new-onset syncope (2.41%), and 2346 patients died from any cause (6.26%), among which 471 deaths (1.26%) were associated with cardiovascular causes. Compared with DPP4i users, SGLT2i therapy was associated with a 51% lower risk of new-onset syncope [HR 0.49; 95% confidence interval (CI) 0.41-0.57; P < 0.001], 65% lower risk of cardiovascular mortality (HR 0.35; 95% CI 0.26-0.46; P < 0.001), and a 70% lower risk of all-cause mortality (HR 0.30; 95% CI 0.26-0.34; P < 0.001) in the fully adjusted model. Similar associations with syncope were observed for dapagliflozin (HR 0.70; 95% CI 0.58-0.85; P < 0.001), canagliflozin (HR 0.48; 95% CI 0.36-0.63; P < 0.001), and ertugliflozin (HR 0.45; 95% CI 0.30-0.68; P < 0.001), but were attenuated for empagliflozin (HR 0.79; 95% CI 0.59-1.05; P = 0.100) after adjusting for potential confounders. The subgroup analyses suggested that, compared with DPP4i, SGLT2i was associated with a significantly decreased risk of incident syncope among T2DM patients, regardless of gender, age, glucose control status, Charlson comorbidity index, and the association remained constant amongst those with common cardiovascular drugs and most antidiabetic drugs at baseline.

CONCLUSION

Compared with DPP4i, SGLT2i was associated with a significantly lower risk of new-onset syncope in patients with T2DM, regardless of gender, age, degree of glycaemic control, and comorbidity burden.

Timing of SGLT2i initiation after acute myocardial infarction

BACKGROUND

Pharmacological post-MI treatment is routinely initiated at intensive/cardiac care units. However, solid evidence for an early start of these therapies is only available for dual platelet therapy and statins, whereas data on beta blockers and RAAS inhibitors are heterogenous and mainly limited to STEMI and heart failure patients. Recently, the EMMY trial provided the first evidence on the beneficial effects of SGLT2 inhibitors (SGLT2i) when initiated early after PCI. In patients with type 2 diabetes mellitus, SGLT2i are considered "sick days drugs" and it, therefore, remains unclear if very early SGLT2i initiation following MI is as safe and effective as delayed initiation.

METHODS AND RESULTS

The EMMY trial evaluated the effect of empagliflozin on NT-proBNP and functional and structural measurements. Within the Empagliflozin group, 22 (9.5%) received early treatment (< 24 h after PCI), 98 (42.2%) within a 24 to < 48 h window (intermediate), and 111 (48.1%) between 48 and 72 h (late). NT-proBNP levels declined by 63.5% (95%CI: - 69.1; - 48.1) in the early group compared to 61.0% (- 76.0; - 41.4) in the intermediate and 61.9% (- 70.8; - 45.7) in the late group (n.s.) within the Empagliflozin group with no significant treatment groups-initiation time interaction (pint = 0.96). Secondary endpoints of left ventricular function (LV-EF, e/e`) as well as structure (LVESD and LVEDD) were also comparable between the groups. No significant difference in severe adverse event rate between the initiation time groups was detected.

CONCLUSION

Very early administration of SGLT2i after acute myocardial infarction does not show disadvantageous signals with respect to safety and appears to be as effective in reducing NT-proBNP as well as improving structural and functional LV markers as initiation after 2-3 days.