The groups had similar baseline characteristics, including age, sex, body mass index, New York Heart Association functional class, causes of heart failure, diabetes, hypertension, coronary artery disease and background use of beta-blockers or mineralocorticoid-receptor antagonists. Both groups also received routine heart-failure management, including health education, medication adherence support, individualized dietary advice, exercise recommendations, smoking cessation, alcohol restriction, weight control and monthly home-care sessions. These measures were part of clinical care rather than interventions assigned specifically for the retrospective analysis. Treatment was selected in routine practice, so the study compared outcomes associated with different regimens rather than randomly allocating patients to a drug combination.

Both treatment pathways were associated with improved cardiac measures. In the sacubitril-valsartan group, mean left-ventricular ejection fraction rose from 37.42% to 48.47%, left-ventricular end-diastolic diameter fell from 56.54 to 50.11 millimetres, left-ventricular end-systolic diameter decreased from 43.83 to 37.98 millimetres, and cardiac output increased from 3.19 to 4.09 litres per minute. The corresponding changes in the combination group were larger: ejection fraction increased from 37.06% to 53.08%, end-diastolic diameter decreased from 56.28 to 46.68 millimetres, end-systolic diameter fell from 43.63 to 35.62 millimetres, and cardiac output rose from 3.32 to 4.96 litres per minute. All between-group post-treatment differences were reported as statistically significant.

The biological markers pointed in the same direction. Three months after treatment, N-terminal pro-B-type natriuretic peptide, or NT-proBNP, declined from 1,791.43 to 882.26 picograms per millilitre in the sacubitril-valsartan group and from 1,775.19 to 380.14 picograms per millilitre in the combination group. Cardiotrophin-1 fell from 321.17 to 221.35 pg/mL with sacubitril-valsartan and from 323.73 to 152.97 pg/mL with combination therapy. Beta-endorphin decreased from 143.19 to 108.21 pg/mL and from 140.99 to 72.67 pg/mL, respectively. The combination group therefore had lower post-treatment values for all three markers, with reported intergroup P values below 0.01.

Combination therapy was also associated with a larger reduction in circulating inflammatory cytokines. Interleukin-1 beta fell from 65.14 to 42.89 nanograms per litre in the sacubitril-valsartan group and from 63.72 to 34.22 ng/L in the combination group. Interleukin-6 declined from 35.25 to 22.37 ng/L with sacubitril-valsartan and from 34.76 to 12.77 ng/L with combination treatment. Tumor necrosis factor alpha decreased from 29.52 to 15.72 ng/L and from 29.87 to 10.72 ng/L, respectively. The post-treatment differences were significant, but the measurements cannot establish a direct molecular mechanism: lower cytokines might reflect an anti-inflammatory effect, improved haemodynamics, or both, and circulating concentrations do not directly reveal the pathways operating in heart tissue.

Researchers classified patients as having an obvious effect, an effective response or no response by combining changes in ejection fraction, ventricular diameters, cardiac output, NT-proBNP, cardiotrophin-1, beta-endorphin and inflammatory markers. On that composite definition, 63 of 75 patients in the sacubitril-valsartan group responded, giving a response rate of 84.00%. Seventy of 75 patients in the combination group responded, producing a rate of 93.33%. The difference was significant by a chi-square test. The Minnesota Living with Heart Failure Questionnaire also showed a larger improvement in the combination group: the mean score declined from 50.66 to 25.37 with sacubitril-valsartan and from 49.42 to 20.14 with combination therapy. Because lower scores indicate less heart-failure-related distress, the result suggests better reported quality of life in the combination arm.

Safety outcomes were numerically more favourable among patients who received combination therapy. Complications occurred in 11 of 75 patients in the sacubitril-valsartan group, or 14.67%, and in four of 75 in the combination group, or 5.33%. The total difference was significant, although individual event categories were not. The combination group had one sudden cardiac death, one heart-failure readmission, one acute myocardial infarction, no stroke and one severe arrhythmia; the sacubitril-valsartan group had two sudden deaths, three readmissions, two acute myocardial infarctions, two strokes and two severe arrhythmias. Drug-related adverse reactions affected 15 patients receiving sacubitril-valsartan alone, or 20.00%, and seven receiving combination therapy, or 9.33%, a significant overall difference. Recorded reactions included dizziness, orthostatic hypotension, urinary frequency, nausea, diarrhoea, liver dysfunction, muscle pain and hyperkalemia.

The results are consistent with the complementary pharmacology of the two treatments. Sacubitril-valsartan blocks angiotensin II receptors while inhibiting neprilysin, the enzyme that degrades natriuretic peptides; the combination therefore combines suppression of the renin-angiotensin-aldosterone system with enhanced natriuretic, vasodilatory and diuretic effects. Dapagliflozin inhibits glucose reabsorption in proximal renal tubules, producing osmotic diuresis and potentially reducing preload. The study also describes effects on myocardial energy metabolism, oxidative stress, inflammation and remodelling. Together, these pathways could plausibly contribute to the observed changes, although the retrospective design and biomarker-only measurements cannot determine whether the benefits arose from pharmacologic synergy, differences in other care, or unmeasured patient characteristics.

Several limitations constrain the findings. The study recruited patients from one hospital, and its 150-person sample may not represent the wider population with heart failure. Treatment was not randomized, and although recorded baseline variables were balanced, the analysis did not include multivariate adjustment for potential confounders. Only outcome assessors were blinded; patients and treating clinicians knew which regimen they received. The follow-up was short, with laboratory outcomes measured at three months and echocardiographic outcomes at six months, so the study did not establish long-term effects on mortality, sustained remodelling, repeated hospitalization or quality of life. There were also few cardiovascular events and no stratified analyses by dose, heart-failure subtype, functional class or age. The results therefore show an association with better outcomes, not definitive proof that adding dapagliflozin causes the improvements or reduces major cardiovascular risk. Larger multicentre studies with longer follow-up and prespecified adjustment would be needed to determine how broadly the findings apply.

Subject of Research: Retrospective comparison of sacubitril-valsartan with and without dapagliflozin in 150 Chinese heart-failure patients

Article Title: Mechanisms and clinical outcomes of sacubitril-valsartan and SGLT2 inhibitors in heart failure patients: a retrospective cohort study

Article References: Zhong, X., Xia, L., Li, L., & Tang, B. (2026). Mechanisms and clinical outcomes of sacubitril-valsartan and SGLT2 inhibitors in heart failure patients: a retrospective cohort study. Frontiers in Cardiovascular Medicine, 13, Article 1931636. https://doi.org/10.3389/fcvm.2026.1931636

Image Credits: AI Generated

DOI: 10.3389/fcvm.2026.1931636

Keywords: heart failure, sacubitril-valsartan, dapagliflozin, SGLT2 inhibitors, cardiac function, inflammation, neuropeptide biomarkers, retrospective cohort, Mechanisms, clinical, outcomes, SGLT2

Pulmonary hypertension is one of the most feared complications of heart failure with reduced ejection fraction, the condition in which a damaged left ventricle can no longer pump blood efficiently. As pressure backs up into the vessels of the lungs, the right ventricle must work against rising resistance, eventually failing in its own right. Prognosis worsens sharply once this happens, yet therapeutic options remain frustratingly limited. SGLT2 inhibitors such as dapagliflozin and empagliflozin have already transformed heart failure care after large trials demonstrated reduced hospitalizations and cardiovascular deaths, and earlier work, including the EMBRACE-HF trial of empagliflozin, hinted at favorable effects on pulmonary artery pressures. What remained unclear was whether these drugs influence the pulmonary circulation through mechanisms beyond their established hemodynamic and metabolic effects.

To probe that question, the researchers prospectively enrolled seventy-four patients with ischemic heart failure following acute myocardial infarction, all of whom had a high echocardiographic probability of pulmonary hypertension. In this single-center, non-randomized study, forty-two patients received either dapagliflozin or empagliflozin at 10 milligrams per day on top of guideline-directed medical therapy, while thirty-two patients received guideline-directed therapy alone. The design means the findings show association rather than causation, but the investigators compensated by layering on an unusually deep molecular workup, including untargeted plasma proteomics on pooled samples, microRNA profiling, and selected biomarkers of cellular senescence and oxidative stress. Candidate discoveries were then validated with enzyme-linked immunosorbent assays and quantitative reverse-transcription polymerase chain reaction.

The clinical signal was consistent and encouraging. Patients on SGLT2 inhibitors showed improved World Health Organization functional class, meaning they could tolerate more physical activity before symptoms limited them. They also displayed fewer signs of right-heart failure, a reduced echocardiographic probability of pulmonary hypertension, and enhanced coupling between the right ventricle and the pulmonary artery, a key echocardiographic measure of how efficiently the right heart’s pump matches the load imposed by the lung circulation. Right ventricle-pulmonary artery coupling is increasingly recognized as a powerful prognostic marker in heart failure, and its improvement here aligns with recent secondary analyses of randomized trials suggesting that dapagliflozin favorably reshapes right ventricular-vascular interaction.

Beneath these clinical observations lay the study’s most intriguing molecular thread. Proteomic and microRNA analyses revealed that SGLT2 inhibitor therapy was associated with lower circulating activin A and reduced levels of miR-1306-5p, a small regulatory RNA previously linked to vascular smooth muscle proliferation through the SIRT7 pathway. Activin A belongs to the transforming growth factor beta superfamily, a group of signaling proteins that orchestrate tissue repair, fibrosis, and inflammation. Elevated activin A has long been documented in chronic heart failure, where it is thought to promote adverse myocardial remodeling. By contrast, bone morphogenetic protein signaling, particularly through the BMPR2 receptor, acts as a protective counterweight, and loss of BMPR2 function is a classic driver of pulmonary arterial hypertension. The balance between these opposing arms of the BMP/activin/TGF-beta axis may therefore help determine whether pulmonary vessels adapt or deteriorate under pressure.

Recognizing that a non-randomized clinical observation can only go so far, the team turned to experimental models to test whether the drug could actually drive the molecular changes they had observed. In animal models of ischemia-reperfusion injury, empagliflozin reduced activin A, increased BMPR2 expression, and improved post-ischemic ventricular function. Parallel experiments in human pulmonary artery endothelial cells and cardiomyocytes exposed to hypoxia, the low-oxygen conditions that mimic the hostile environment of failing pulmonary circulation, showed similar molecular shifts. The convergence of clinical and laboratory findings on the same signaling pathway is what gives the study its persuasive force, suggesting that activin A suppression is not an incidental biomarker but a plausible mechanistic link between the drug and the improved pulmonary phenotype.

The researchers also gained a hint about how the drug might exert these effects. When they added chloroquine, an inhibitor of autophagy, the cellular recycling process that degrades damaged components, the beneficial molecular changes were partially attenuated. This points to autophagy as a possible intermediary in the signaling cascade, consistent with earlier work by the same group showing that empagliflozin modulates excessive autophagy through the AMPK/GSK3-beta pathway in diabetic cardiomyopathy. Autophagy has emerged as a central theme in both cardiac and pulmonary vascular disease, and age-related decline in this quality-control system is one of the hallmarks of aging biology, which is precisely why the study appears in GeroScience, a journal focused on the molecular mechanisms of aging.

The findings also resonate with a broader therapeutic landscape that is shifting toward the TGF-beta superfamily. Sotatercept, a fusion protein that traps activin and related ligands, recently demonstrated impressive results in a phase 3 trial of pulmonary arterial hypertension, effectively validating activin signaling as a drug target. The new study raises the tantalizing possibility that SGLT2 inhibitors achieve a gentler version of the same effect through endogenous means, dialing down activin A production rather than sequestering the ligand after release. If confirmed, patients already taking these drugs for heart failure or diabetes might be accruing pulmonary vascular benefits that no one had fully appreciated, simply as a byproduct of a prescription they were already filling.

Important caveats remain. The clinical arm was non-randomized and single-center, with a modest sample size, so confounding by indication, disease severity, or co-treatment cannot be excluded, and the pooled proteomic design limits individual-level inference. The authors themselves frame the work as showing that modulation of the BMP/activin/TGF-beta pathway is biologically plausible and consistently associated with SGLT2 inhibitor therapy across complementary models, rather than proving it as the definitive mechanism. Still, the triangulation from patient plasma to animal hearts to hypoxic human cells is exactly the kind of convergent evidence that typically precedes randomized testing. If future trials confirm that SGLT2 inhibitors meaningfully lower pulmonary pressures and improve right-heart outcomes through activin A suppression, a drug class born as a glucose-lowering agent will have added yet another chapter to one of the most remarkable therapeutic repurposing stories in cardiovascular medicine, and patients with the doubly burdened heart-and-lung phenotype of advanced heart failure may gain a new lease on survival.

Subject of Research: SGLT2 inhibitor effects on activin A and BMP/activin signaling in ischemic cardiomyopathy with pulmonary hypertension

Article Title: Sodium-glucose cotransporter 2 inhibitors are associated with reduced circulating activin A and modulation of BMP/activin signaling in ischemic cardiomyopathy with high echocardiographic probability of pulmonary hypertension

Article References: Madonna, R., Del Boccio, P., Borghini, A., Alberti, M., Biondi, F., Cufaro, M. C., Morganti, R., Pieragostino, D., Andreassi, M. G., Rocca, C., Ferdinandy, P., Mattii, L., Angelone, T., & De Caterina, R. (2026). Sodium-glucose cotransporter 2 inhibitors are associated with reduced circulating activin A and modulation of BMP/activin signaling in ischemic cardiomyopathy with high echocardiographic probability of pulmonary hypertension. GeroScience. https://doi.org/10.1007/s11357-026-02497-0

Image Credits: AI Generated

DOI: 10.1007/s11357-026-02497-0

Keywords: SGLT2 inhibitors, pulmonary hypertension, activin A, BMPR2, heart failure, ischemic cardiomyopathy, empagliflozin, dapagliflozin, autophagy, miR-1306-5p, right ventricle, TGF-beta signaling

The triple combination is becoming increasingly common in the management of type 2 diabetes, and for good reason. Each drug attacks high blood sugar through a different biological route: metformin suppresses glucose production in the liver and improves insulin sensitivity, gliclazide prods the pancreas to release more insulin, and dapagliflozin forces the kidneys to flush excess glucose out through the urine. Combining them in a single pill improves patient compliance and delivers better glycaemic control than any one agent alone. But that therapeutic synergy creates an analytical headache, because a quality-control laboratory must be able to verify the exact amount of each ingredient in every batch before the tablets reach patients.

The difficulty lies in chemistry. Metformin is a small, strongly polar, highly hydrophilic molecule with a log P value of roughly minus 2.64, which means it barely interacts with the oily, hydrophobic surface of a reverse-phase column and tends to zip through unretained. Dapagliflozin and gliclazide, by contrast, are far more lipophilic, with log P values around 2 or higher, so they cling to the stationary phase much longer. On top of that, the dose disparity is enormous: commercial tablets contain 500 to 1000 milligrams of metformin, 40 to 80 milligrams of gliclazide, and a mere 5 to 10 milligrams of dapagliflozin, so any single method must accurately quantify compounds whose concentrations in solution differ by orders of magnitude.

Led by Rajendra Patel, with Nishith Teraiya and Anjali Prajapati, all of the K.B. Institute of Pharmaceutical Education and Research in Gandhinagar, the team systematically tuned every variable that governs chromatographic behavior. They tested water-methanol and water-acetonitrile mixtures in various ratios, but unbuffered systems produced broad, asymmetrical peaks with poor resolution. The breakthrough came from adding a volatile 20 millimolar ammonium acetate buffer adjusted to pH 3.0 with ortho-phosphoric acid. At that acidity, metformin remains fully protonated and water-loving, so it elutes first, while the more lipophilic dapagliflozin and gliclazide linger progressively longer on the hydrophobic C18 stationary phase, producing clean, well-resolved peaks.

The final recipe is elegantly simple. Separation occurs on a Kromasil C18 column, 250 millimeters long with a 4.6 millimeter internal diameter and 5 micrometer particles, using a mobile phase of the acetate buffer and acetonitrile mixed 35:65 by volume, pumped at a constant 0.8 milliliters per minute in isocratic mode. A UV detector set at 224 nanometers, a wavelength where the absorption spectra of all three drugs overlap acceptably, monitors the eluate. Under these conditions metformin appears at 2.47 minutes, dapagliflozin at 3.90 minutes, and gliclazide at 6.46 minutes. Because the solvent composition never changes during the run, the method avoids the complexity, variability, and extra solvent consumption of gradient elution, keeping both analysis time and operating costs low.

Validation followed the International Council for Harmonisation’s Q2 (R2) guidelines, the global benchmark for analytical procedures. Calibration curves were linear across 125 to 375 micrograms per milliliter for metformin, 2.5 to 7.5 for dapagliflozin, and 15 to 45 for gliclazide, with correlation coefficients all above 0.997. Recovery experiments, in which known amounts of standard drug were spiked into tablet samples at 80, 100, and 120 percent of target, yielded recoveries between 98 and 102 percent for every analyte, demonstrating negligible interference from tablet excipients. Precision testing, repeated within a single day and across three separate days, produced relative standard deviations consistently below 2 percent, the accepted threshold for repeatability in pharmaceutical analysis.

The robustness trials are particularly reassuring for routine laboratories. The researchers deliberately nudged the method’s settings, slightly altering mobile phase composition, flow rate, detection wavelength, buffer pH, and column temperature, and found that the separation held up every time, with peaks remaining symmetrical, well resolved, and statistically unchanged. Sample solutions stored for 48 hours at room temperature and at refrigerator temperature showed no degradation and no loss of assay value, meaning laboratories can prepare samples in advance without compromising results. Limits of detection and quantification, calculated from the regression statistics of the calibration lines, confirmed the method is sensitive enough for the low-dose dapagliflozin component.

The most dramatic evidence for the method’s stability-indicating power came from forced degradation studies, which regulators require to prove that an analytical method can spot decomposition before it spots nothing at all. The team exposed the drugs to 0.1 normal hydrochloric acid for one hour, 0.1 normal sodium hydroxide for two hours, 3 percent hydrogen peroxide for one hour, 40 degrees Celsius heat for one hour, and direct sunlight for two hours. Each stressor told a chemical story: gliclazide degraded most under acid, consistent with hydrolysis of its sulfonylurea linkage; dapagliflozin proved most vulnerable to light, its aromatic glucoside structure susceptible to photo-oxidation; and metformin, shielded by its highly polar biguanide scaffold, stayed comparatively stable even under heat. Crucially, in every case the degradation products eluted as separate peaks that never overlapped the three drug peaks.

Applied to a real commercial tablet containing 10 milligrams of dapagliflozin, 60 milligrams of gliclazide, and 500 milligrams of metformin, the method returned assay values of 101.52, 98.19, and 99.64 percent respectively, comfortably within pharmacopoeial expectations and confirming that the technique works outside the pristine world of pure standards. That real-world performance matters because regulators and manufacturers increasingly rely on such methods for batch release, shelf-life determination, and post-market surveillance. A method that is simultaneously accurate, robust, and stability-indicating gives quality-control chemists a single, streamlined workflow where they previously might have needed multiple runs or separate methods for each drug pair.

The broader significance extends past one formulation. As fixed-dose combinations multiply across modern pharmacotherapy, the analytical community faces growing pressure to verify ever more complex mixtures with fewer resources. This study demonstrates that careful exploitation of fundamental properties, lipophilicity, ionization state, and spectral overlap, can tame even a three-drug combination spanning a hundredfold dose range in a simple isocratic run. For the millions of patients taking triple antidiabetic therapy, the work represents an invisible but vital layer of assurance: every tablet’s contents can now be confirmed, and its chemical deterioration detected, in under seven minutes of chromatography.

Subject of Research: Development and validation of a stability-indicating RP-HPLC method for simultaneous quantification of dapagliflozin, gliclazide, and metformin in antidiabetic combination tablets

Article Title: Development of a robust stability-indicating RP-HPLC method for simultaneous estimation of triple antidiabetic combination containing dapagliflozin, gliclazide and metformin

Article References: Patel, R., Teraiya, N., & Prajapati, A. (2026). Development of a robust stability-indicating RP-HPLC method for simultaneous estimation of triple antidiabetic combination containing dapagliflozin, gliclazide and metformin. Discover Chemistry, 3(1), Article 518. https://doi.org/10.1007/s44371-026-00978-x

Image Credits: AI Generated

DOI: 10.1007/s44371-026-00978-x

Keywords: RP-HPLC, dapagliflozin, gliclazide, metformin, type 2 diabetes, stability-indicating method, forced degradation, pharmaceutical analysis, ICH Q2 (R2), chromatography, quality control, fixed-dose combination

TMAO is a small, low-molecular-weight metabolite with an outsized reputation. It begins its life in the gut, where bacteria convert dietary precursors such as choline, phosphatidylcholine, betaine, and L-carnitine, abundant in red meat, eggs, dairy, and saltwater fish, into trimethylamine, or TMA. The liver then oxidizes TMA into TMAO via the enzyme flavin monooxygenase 3. From there, TMAO circulates in the blood and is excreted almost entirely by the kidneys, without undergoing any meaningful biotransformation along the way. Elevated plasma TMAO has been associated in numerous studies with cardiovascular disease, atherosclerosis, chronic kidney disease, and type 2 diabetes itself, and in diabetic patients specifically, higher TMAO has been tied to more cardiovascular events, faster loss of kidney function, and greater all-cause mortality.

The new analysis was prompted by a puzzling observation from a secondary analysis of the EMMY trial, in which patients treated with empagliflozin after a myocardial infarction showed a more pronounced rise in serum TMAO than those on placebo. That result raised an obvious question: does the same thing happen in people with type 2 diabetes, and does it extend to other drugs in the class, such as dapagliflozin? To find out, investigators combined individual patient data and stored samples from two prospective, randomised, placebo-controlled, double-blind crossover trials conducted at the University of Erlangen-Nuremberg, registered as NCT02471963 and NCT02383238. In each trial, patients were randomised after a run-in phase to receive either 25 mg empagliflozin or 10 mg dapagliflozin, or matching placebo, once daily for six weeks, followed by a one-week washout and a switch to the alternate treatment for another six weeks.

Fasting blood samples and 24-hour urine collections were obtained at baseline and at the end of both treatment periods, then stored at minus 80 degrees Celsius until analysis. TMAO concentrations were quantified with a validated liquid chromatography tandem mass spectrometry assay, using a deuterated internal standard and protein precipitation with methanol. After excluding a small number of samples that could not be quantified, the final analytical population comprised 123 patients, 69 from the empagliflozin trial and 54 from the dapagliflozin trial. The cohort had a mean age of 61.2 years, was 59 percent male, had a mean HbA1c of 6.7 percent, and a mean estimated glomerular filtration rate of 93.8 mL/min/1.73 m², with more than 70 percent of participants above 90. Compliance, assessed by tablet counts, averaged 99 percent in both trials.

The results were consistent in direction across the pooled population. Median plasma TMAO was 3.71 μmol/L at baseline and 3.60 μmol/L after placebo, but rose to 4.19 μmol/L after active treatment, a crossover difference of 0.36 μmol/L with a p-value of 0.006. The median intraindividual percentage change was 11.5 percent, significantly different from zero. When the drugs were analysed separately, the effect was clearer for dapagliflozin, where median TMAO climbed from 3.30 to 4.44 μmol/L, a 23.4 percent median increase, than for empagliflozin, which produced a numerically similar but statistically non-significant rise of 8.4 percent. The authors suggest the pattern points toward a possible class effect of SGLT-2 inhibitors, echoing the EMMY findings and extending them to a second drug and a different patient population.

Just as intriguing was what happened in the kidneys. Because TMAO is cleared almost exclusively by renal excretion, the researchers calculated its renal clearance from paired plasma and 24-hour urine measurements. Across all 123 patients, median renal clearance of TMAO fell from 95.8 mL/min on placebo to 83.9 mL/min on active drug, a statistically significant decline. In the dapagliflozin group the drop was significant on its own, falling from 109.2 to 97.8 mL/min, while the empagliflozin subgroup showed a non-significant downward trend. Yet the total amount of TMAO excreted in 24-hour urine barely changed, rising only non-significantly. That combination, lower clearance with unchanged total excretion, is a biochemical clue that the kidneys may not be the whole story.

The most obvious candidate explanation is the well-known initial dip in estimated glomerular filtration rate that occurs when SGLT-2 inhibitor therapy begins, a reversible haemodynamic effect of tubuloglomerular feedback. The study did observe a small but significant eGFR decline overall, and TMAO levels correlated negatively with eGFR at all time points, as expected from prior literature. But the eGFR dip was marginal, particularly in the dapagliflozin group, which showed the larger TMAO changes, and crucially, there was no correlation between individual patients’ eGFR changes and their TMAO changes. A reduced filtration rate alone, the authors conclude, cannot adequately explain the rise in plasma TMAO.

That leaves transporters and production. TMAO is eliminated primarily by glomerular filtration with a substantial contribution from transporter-mediated secretion in the proximal tubule, where the organic cation transporter 2 shuttles TMAO from blood into tubular cells and the multidrug and toxin extrusion protein 1 exports it into the urine. Animal work has shown that SGLT-2 inhibition broadly downregulates renal transport proteins, and drug interactions with OCT2 or MATE1 could theoretically reduce TMAO secretion. But if transporter-mediated excretion were truly impaired, the total urinary excretion of TMAO should have fallen, and it did not. The authors therefore favour a different hypothesis: SGLT-2 inhibitors may increase the production of TMAO, most plausibly through changes in the gut microbiome, even though some prior studies had suggested these drugs shift the microbiome in ways that should lower TMAO-producing bacteria. A subgroup analysis of the 20 participants who took antibiotics during the trials found no significant difference in TMAO changes, and the crossover design, in which each patient served as their own control, makes dietary shifts an unlikely confounder, although diets were not formally documented.

The clinical implications remain deliberately open. TMAO is widely characterised as a risk marker, and possibly a risk factor, for cardiovascular and kidney disease, so a drug-induced rise of roughly 10 to 20 percent would seem, on its face, unwelcome. Yet SGLT-2 inhibitors have delivered unmistakable benefits on cardiovascular outcomes and mortality in enormous outcome trials, in diabetic and non-diabetic patients alike, benefits that clearly operate through mechanisms beyond glucose control. Whether the TMAO increase is a harmless bystander, a counterbalancing signal, or something that modulates the drugs’ net benefit is unknown, and the authors call for studies examining outcomes in relation to baseline and on-treatment TMAO levels, as well as cohorts with much higher starting concentrations.

The study’s limitations temper any strong conclusions. Six weeks per treatment period is short, so long-term trajectories of TMAO, whether the rise plateaus, persists, or reverses, cannot be determined. No second baseline was established after the washout, so carryover effects may have blunted the measured effect in some patients. All participants had preserved kidney function, with eGFR above 60, leaving the question unanswered for the many diabetic patients with renal impairment, who typically have the highest TMAO levels. Compliance was assessed by counting returned tablets, and diet went unrecorded. Still, the pooled crossover data are internally consistent, and the message is clear enough to unsettle a comfortable assumption: a drug class celebrated for protecting the heart and kidneys may simultaneously raise circulating levels of one of the most talked-about microbiome-derived risk markers in cardiovascular medicine, and the reason why remains an open and compelling scientific question.

Subject of Research: Effects of SGLT-2 inhibitors on plasma TMAO concentrations and renal clearance in patients with type 2 diabetes

Article Title: Effects of SGLT‐2 Inhibitors on Plasma Concentrations and Renal Clearance of the Risk Marker Trimethylamine‐N‐Oxide in Patients With Type‐2 Diabetes

Article References: Zimmer, K. B., Gessner, A., Kannenkeril, D., Bosch, A., Ströbel, A., Schmieder, R. E., & Maas, R. (2026). Effects of SGLT ‐2 Inhibitors on Plasma Concentrations and Renal Clearance of the Risk Marker Trimethylamine‐N‐Oxide in Patients With Type‐2 Diabetes. Endocrinology, Diabetes & Metabolism, 9(6), Article e70318. https://doi.org/10.1002/edm2.70318

Image Credits: AI Generated

DOI: 10.1002/edm2.70318

Keywords: SGLT-2 inhibitors, TMAO, type 2 diabetes, empagliflozin, dapagliflozin, gut microbiome, renal clearance, cardiovascular risk, kidney function, eGFR, clinical trial, biomarkers

Researchers at Ankara Etlik City Hospital compared 224 patients with type 2 diabetes who had been taking either empagliflozin or dapagliflozin for at least six months against 106 age- and sex-matched patients with type 2 diabetes who had never used the drug class. The study, published in BMC Endocrine Disorders, tracked two principal outcomes: thyroid-stimulating hormone, or TSH, the pituitary messenger that regulates thyroid function, and the systemic immune-inflammation index, known as SII, a simple blood-derived marker calculated from platelet, neutrophil, and lymphocyte counts that is increasingly used as a low-cost gauge of systemic inflammation. Crucially, the investigators excluded anyone with known thyroid disease, thyroid autoantibody positivity, active inflammatory or autoimmune conditions, advanced organ failure, or ongoing immunomodulatory therapy, ensuring that the comparison was as clean as retrospective data allow.

The headline numbers tell a story of remarkable similarity across the groups. Median TSH was 1.6 micro-international units per milliliter in the empagliflozin group, 1.8 in the dapagliflozin group, and 1.9 in the control group, a difference that failed to reach statistical significance with a p-value of 0.338. The SII told the same tale: medians of 481, 531, and 468.5 respectively, with a p-value of 0.509. In plain terms, people on SGLT-2 inhibitors had thyroid function markers and inflammatory indices that were statistically indistinguishable from their peers on other diabetes regimens.

What lends this result weight is the study’s statistical diligence, which goes beyond the simple group comparison. The team ran correlation analyses, multivariate linear regression, multicollinearity diagnostics using variance inflation factors, and even a post-hoc power calculation, an unusually transparent step for a retrospective design. The power analysis showed the study had 80 percent ability to detect a Cohen’s f effect size of 0.17 or larger, yet the observed effect sizes for TSH and SII were dramatically smaller, at f of 0.02 and approximately 0.00 respectively. In other words, the study was adequately powered to find a meaningful signal, and the signal simply was not there, suggesting that if any true effect of SGLT-2 inhibitors on these markers exists, it is likely too small to matter clinically.

The regression analysis did, however, surface an unexpected protagonist. When the researchers modeled log-transformed TSH as the outcome, female sex emerged as an independent predictor, with a standardized coefficient of 0.161 and a p-value of 0.015, a finding consistent with the well-documented observation that thyroid parameters differ by sex. More intriguingly, estimated glomerular filtration rate, or eGFR, the standard measure of kidney function, independently predicted TSH levels with a coefficient of minus 0.0043 and a p-value of 0.037, meaning that as kidney function declined, TSH tended to rise regardless of which diabetes medications a patient was taking. SGLT-2 inhibitor use itself, along with SII, neutrophil-to-lymphocyte ratio, age, metformin use, and diabetes duration, all fell away as non-significant in the final model.

This renal-thyroid connection is more than a statistical footnote. The hypothalamic-pituitary-thyroid axis and the kidneys are intertwined in ways that clinicians sometimes underestimate. Declining renal clearance alters the metabolism and excretion of thyroid hormones, chronic kidney disease can produce a state resembling non-thyroidal illness, and conversely, hypothyroidism can impair renal hemodynamics. The finding that eGFR independently tracks with TSH in a population deliberately screened free of thyroid disease suggests that kidney function deserves closer attention when interpreting thyroid tests in patients with type 2 diabetes, a group in which diabetic nephropathy is common. The authors argue that this axis warrants further study independent of any drug exposure.

The mechanistic backdrop explains why the question was worth asking in the first place. SGLT-2 transporters are expressed not only in the kidney’s proximal tubule but also in extrarenal tissues, and some animal and small human studies had hinted at crosstalk between glucose-lowering agents and thyroid physiology. Meanwhile, the systemic immune-inflammation index and its cousin, the neutrophil-to-lymphocyte ratio, have become fashionable proxies for the chronic low-grade inflammation that underlies both insulin resistance and diabetic complications. Because SGLT-2 inhibitors appear to dampen inflammatory pathways in some experimental models, researchers suspected the drugs might measurably shift these indices in patients. The Turkish dataset, one of the largest head-to-head comparisons to date, found no evidence of such a shift; notably, SII and NLR were themselves strongly correlated in the sample, with a correlation coefficient of 0.467 and a p-value below 0.001, confirming that the inflammatory markers were behaving as expected even if the drugs did not move them.

For the millions of people taking empagliflozin or dapagliflozin, the practical message is one of reassurance. The study population, 330 adults in total, had used the drugs for at least six months, a duration long enough for any steady-state effect on thyroid physiology or immune-cell dynamics to manifest. The absence of significant differences in TSH or SII means there is currently no basis for routine thyroid monitoring specifically triggered by SGLT-2 inhibitor initiation in patients without preexisting thyroid conditions, and no signal that the drugs are provoking systemic inflammation. At the same time, the authors are careful to frame the result within the limits of its design: it was a single-center, retrospective, observational study, and it relied on TSH rather than the full panel of free thyroxine and triiodothyronine measurements that would capture the complete thyroid picture. Subclinical shifts in peripheral hormone conversion, for example, could theoretically escape a TSH-only lens.

Those caveats point directly at the research agenda the authors propose. Prospective, multicenter studies incorporating free thyroxine and triiodothyronine measurements, longer follow-up, and perhaps more granular inflammatory biomarkers such as interleukin-6 or C-reactive protein would settle the question with greater authority. Until then, this study stands as a well-powered negative result, a category of evidence that science needs more of. It trims the list of things clinicians must worry about with one of the most widely prescribed drug classes in modern medicine, while quietly spotlighting renal function as a variable that genuinely shapes thyroid readings. In a field saturated with hyped drug effects, a rigorous demonstration that nothing is happening can be its own kind of headline news.

The choice of the systemic immune-inflammation index as an outcome reflects a broader shift in diabetes research toward hematological composite markers. Because the index is derived from routine complete blood counts rather than specialized assays, it can be computed cheaply and repeatedly in ordinary clinical settings, which explains its growing popularity as a surrogate for the inflammatory burden associated with insulin resistance, atherosclerosis, and microvascular complications. Its strong correlation with the neutrophil-to-lymphocyte ratio in this cohort, with a correlation coefficient of 0.467, indicates that both markers captured overlapping aspects of the same underlying inflammatory physiology, lending internal coherence to the null finding.

The thyroid measurements were performed using electrochemiluminescence immunoassay, a widely adopted platform for thyrotropin detection that offers high analytical sensitivity at the low concentrations relevant to suppression and subclinical disease. This matters for interpretation, because a null result obtained with a precise assay is more convincing than one obtained with older, noisier methods. The reliance on a single TSH measurement per patient, however, means that within-person biological variation, which can be substantial for thyrotropin, was not accounted for, a limitation inherent to the retrospective design.

The composition of the cohort also deserves note. Patients taking empagliflozin outnumbered those on dapagliflozin by 139 to 85, and both active groups were pooled for some analyses rather than analyzed as separate exposures, since the two agents share the same mechanism of glucose excretion through urinary inhibition of the sodium-glucose cotransporter. Metformin use was deliberately included as a covariate because the drug is nearly ubiquitous in type 2 diabetes and has itself been anecdotally linked to thyroid parameters, yet it showed no independent association with thyrotropin in the final regression model.

The sex difference in thyrotropin, with female sex independently predicting higher values, aligns with decades of epidemiological data showing that thyroid dysfunction and mildly elevated thyrotropin are more prevalent in women, particularly with advancing age. Its emergence in a cohort screened free of thyroid disease suggests that even within the normal reference range, physiological sex-based variation persists and should be considered when clinicians interpret borderline results.

Finally, the ethics approval from the Ankara Etlik City Hospital committee and the waiver of individual consent, justified by anonymized extraction from the hospital information system, illustrate the standard governance pathway for retrospective chart-based endocrine research in Türkiye. The open-access publication under a Creative Commons license ensures that this carefully powered negative result is freely available to the clinicians and researchers best positioned to build on it.

Subject of Research: Effects of long-term SGLT-2 inhibitor use on thyroid-stimulating hormone and systemic immune-inflammation index in patients with type 2 diabetes

Article Title: Effects of SGLT-2 inhibitors on thyroid-stimulating hormone and systemic immune-inflammation index in type 2 diabetes: a retrospective study

Article References: Bayram, S. M., Demirci, H., Üçgül, E., Canlar, Ş., Cinel, M., Menekşe, B., Kuşabbi, İ. A., & Çakal, E. (2026). Effects of SGLT-2 inhibitors on thyroid-stimulating hormone and systemic immune-inflammation index in type 2 diabetes: a retrospective study. BMC Endocrine Disorders. https://doi.org/10.1186/s12902-026-02483-9

Image Credits: AI Generated

DOI: 10.1186/s12902-026-02483-9

Keywords: SGLT-2 inhibitors, empagliflozin, dapagliflozin, type 2 diabetes, TSH, systemic immune-inflammation index, neutrophil-to-lymphocyte ratio, thyroid function, estimated glomerular filtration rate, retrospective study, endocrinology, inflammation