There is a close relationship between diabetes mellitus and heart failure, and diabetes is an independent risk factor for heart failure. Diabetes and heart failure are linked by not only the complication of ischemic heart disease, but also by metabolic disorders such as glucose toxicity and lipotoxicity based on insulin resistance. Cardiac dysfunction in the absence of coronary artery disease, hypertension, and valvular disease is called diabetic cardiomyopathy. Diabetes-induced hyperglycemia and hyperinsulinemia lead to capillary damage, myocardial fibrosis, and myocardial hypertrophy with mitochondrial dysfunction. Lipotoxicity with extensive fat deposits or lipid droplets is observed on cardiomyocytes. Furthermore, increased oxidative stress and inflammation cause cardiac fibrosis and hypertrophy. Treatment with a sodium glucose cotransporter 2 (SGLT2) inhibitor is currently one of the most effective treatments for heart failure associated with diabetes. However, an effective treatment for lipotoxicity of the myocardium has not yet been established, and the establishment of an effective treatment is needed in the future. This review provides an overview of heart failure in diabetic patients for the clinical practice of clinicians.

Background: Effects of sodium‐glucose cotransporter 2 inhibitors on reducing hospitalization for heart failure have been reported in randomized controlled trials, but their effects on patients with heart failure with preserved ejection fraction ( HF p EF ) are unknown. This study aimed to evaluate the drug efficacy of luseogliflozin, a sodium‐glucose cotransporter 2 inhibitor, in patients with type 2 diabetes mellitus and HF p EF . Methods and Results: We performed a multicenter, open‐label, randomized, controlled trial for comparing luseogliflozin 2.5 mg once daily with voglibose 0.2 mg 3 times daily in patients with type 2 diabetes mellitus suffering from HF p EF (left ventricular ejection fraction >45% and BNP [B‐type natriuretic peptide] concentrations ≥35 pg/mL) in a 1:1 randomization fashion. The primary outcome was the difference from baseline in BNP levels after 12 weeks of treatment between the 2 drugs. A total of 173 patients with diabetes mellitus and HF p EF were included. Of these, 83 patients were assigned to receive luseogliflozin and 82 to receive voglibose. There was no significant difference in the reduction in BNP concentrations after 12 weeks from baseline between the 2 groups. The ratio of the mean BNP value at week 12 to the baseline value was 0.79 in the luseogliflozin group and 0.87 in the voglibose group (percent change, −9.0% versus −1.9%; ratio of change with luseogliflozin versus voglibose, 0.93; 95% CI, 0.78–1.10; P =0.26). Conclusion: In patients with type 2 diabetes mellitus and HF p EF , there is no significant difference in the degree of reduction in BNP concentrations after 12 weeks between luseogliflozin and voglibose. Registration: URL : https://www.umin.ac.jp/ctr/index.htm ; Unique identifier: UMIN 000018395.

Background: To investigate the individual profile of each SGLT2 (sodium‐glucose cotransoporter‐2) inhibitor in patients with different backgrounds. Methods and Results: This study included 21 placebo‐controlled randomized controlled trials with a total of 96 196 participants, investigating empagliflozin, ertugliflozin, dapagliflozin, canagliflozin, and sotagliflozin. The primary efficacy end point was the composite of cardiovascular death and hospitalizations for heart failure. The secondary efficacy end points were all‐cause death, cardiovascular death, hospitalizations for heart failure, kidney disease progression, and acute kidney injury. We conducted subgroup analyses based on the underlying comorbidities, including diabetes and chronic kidney disease. Safety end points were also assessed among SGLT2 inhibitors in the overall cohort. In the overall cohort, there were no significant differences in the primary efficacy outcome among the SGLT2 inhibitors, while empagliflozin (hazard ratio [HR], 0.70 [95% CI, 0.53–0.92]) and dapagliflozin (HR, 0.73 [95% CI, 0.56–0.96]) were associated with lower risk of acute kidney injury than sotagliflozin. The presence or absence of diabetes did not alter the results. In patients with chronic kidney disease, there were no differences in the efficacy outcomes among SGLT2 inhibitors, while in patients without chronic kidney disease, empagliflozin was associated with lower risk of the primary outcome compared with ertugliflozin (HR, 0.77 [95% CI, 0.60–0.98]). For safety outcomes, no significant differences were observed in amputation, urinary tract infection, genital infection, hypoglycemia, and diabetic ketoacidosis. Conclusions: The differences in reducing cardiovascular and kidney outcomes as well as safety profiles across SGLT2 inhibitors were not consistently significant, although empagliflozin might be preferred in patients without chronic kidney disease. Further investigations are needed to better understand the mechanism and clinical effectiveness of each SGLT2 inhibitor in certain populations.

There are three critical pathways for the pathogenesis and progression of pulmonary arterial hypertension (PAH): the prostacyclin (prostaglandin I₂) (PGI₂), nitric oxide (NO), and endothelin pathways. The current approved drugs targeting these three pathways, including prostacyclin (PGI₂), phosphodiesterase type-5 (PDE5) inhibitors, and endothelin receptor antagonists (ERAs), have been shown to be effective, however, PAH remains a severe clinical condition and the long-term survival of patients with PAH is still suboptimal. The full therapeutic abilities of available drugs are reduced by medication, patient non-compliance, and side effects. Nanoparticles are expected to address these problems by providing a novel drug delivery approach for the treatment of PAH. Drug-loaded nanoparticles for local delivery can optimize the efficacy and minimize the adverse effects of drugs. Prostacyclin (PGI₂) analogue, PDE5 inhibitors, ERA, pitavastatin, imatinib, rapamycin, fasudil, and oligonucleotides-loaded nanoparticles have been reported to be effective in animal PAH models and in vitro studies. However, the efficacy and safety of nanoparticle mediated-drug delivery systems for PAH treatment in humans are unknown and further clinical studies are required to clarify these points.

Nanoparticles have been used as a novel drug delivery system. Drug-incorporated nanoparticles for local delivery might optimize the efficacy and minimize the side effects of drugs. The efficacy and safety of intratracheal administration of prostacyclin analog (beraprost) -incorporated nanoparticles and imatinib (a PDGF-receptor tyrosine kinase inhibitor) -incorporated nanoparticles in Sugen-hypoxia-normoxia or monocrotaline rat models of pulmonary arterial hypertension (PAH) and in human PAH-pulmonary arterial smooth muscle cells have been reported. The use of inhaled drug-incorporated nanoparticles might be a novel approach for the treatment of PAH.

Pulmonary hypertension associated with lung diseases and/or hypoxia is classified as group 3 in the clinical classification of pulmonary hypertension. The efficacy of existing selective pulmonary vasodilators for group 3 pulmonary hypertension is still unknown, and it is currently associated with a poor prognosis. The mechanisms by which pulmonary hypertension occurs include hypoxic pulmonary vasoconstriction, pulmonary vascular remodeling, a decrease in pulmonary vascular beds, endothelial dysfunction, endothelial-to-mesenchymal transition, mitochondrial dysfunction, oxidative stress, hypoxia-inducible factors (HIFs), inflammation, microRNA, and genetic predisposition. Among these, hypoxic pulmonary vasoconstriction and subsequent pulmonary vascular remodeling are characteristic factors involving the pulmonary vasculature and are the focus of this review. Several factors have been reported to mediate vascular remodeling induced by hypoxic pulmonary vasoconstriction, such as HIF-1α and mechanosensors, including TRP channels. New therapies that target novel molecules, such as mechanoreceptors, to inhibit vascular remodeling are awaited.