Postprandial hyperlipidemia showing postprandial increase in serum triglyceride (TG) is atherogenic and associated with the development of coronary artery disease (CAD). To diagnose postprandial hyperlipidemia, the oral fat loading test (OFLT) should be performed, however, this test is very time-consuming and is difficult to perform. Ele-vated serum TG levels reflect an increase in TG-rich lipoproteins (TRL) such chylomi-crons (CM), very low-density lipoproteins (VLDL) and their remnants (CM remnant [CMR] and VLDL remnant [VLDLR]). Understanding of elevation in CMR and/or VLDLR can lead us to understand the existence of postprandial hyperlipidemia. The measurements of apo B48 which is a constituent of CM and CMR, non-fasting TG which includes TG content in all lipoproteins including CM and CMR, non-high-density lipoprotein-cholesterol (non-HDL-C) which includes TRL and low-density lipoprotein, and remnant cholesterol, are useful to suspect the existence of postprandial hyperlipidemia. Postprandial hyperlipidemia is observed in patients with familial type III hyperlipoproteinemia, familial combined hyperlipidemia, chronic kidney disease, metabolic syndrome and type 2 diabetes. Postprandial hyperlipidemia is closely related to postprandial hyperglycemia, and insulin resistance may be an in-ducing and enhancing factor for both postprandial hyperlipidemia and postprandial hyperglycemia. Remnant lipoproteins and metabolic disorders associated with post-prandial hyperlipidemia have various atherogenic properties such as induction of in-flammation and endothelial dysfunction. A healthy diet, calorie restriction, weight loss and exercise, positively impact postprandial hyperlipidemia. Anti-hyperlipidemic drugs such pemafibrate, bezafibrate, ezetimibe and eicosapentaenoic acid have shown to improve postprandial hyperlipidemia. Anti-diabetic drugs including metformin, alpha-glucosidase inhibitors, pioglitazone, dipeptidyl-peptidase-4 inhibitors and glu-cagon like peptide 1 analogues, have shown to ameliorate postprandial hyperlipidemia. Although sodium glucose cotransporter-2 inhibitors have not been proven to reduce postprandial hyperlipidemia, they reduced fasting apo B48 and remnant lipoprotein cholesterol. In conclusion, it is important to appropriately understand the existence of postprandial hyperlipidemia and to connect it to optimal treatments.

Beyond plasma glucose-lowering in patients with type 2 diabetes, sodium- glucose cotransporter 2 inhibitors (SGLT2i) significantly reduced the hospitalization for heart failure (HF) and retarded the progression of chronic kidney disease (CKD). Endothelial dysfunction is not only involved in the development and progression of cardiovascular disease (CVD), and is also associated with the progression of CKD. In patients with type 2 diabetes, hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia induce the development of endothelial dysfunction. SGLT2i have shown an improvement in endothelial dysfunction, as assessed by flow-mediated vasodila-tion, in individuals at high risk for CVD. Along with an improvement of endothelial dysfunction, SGLT2i showed improvements in oxidative stress, inflammation, mitochondrial dysfunction, glucotoxicity such as advanced glycation end products signaling and nitric oxide bioavailability. The improvements in endothelial dysfunc-tion and such endothelium-derived factors may play an important role in preventing the development of coronary artery disease, coronary microvascular dysfunction and diabetic cardiomyopathy which cause HF and in retarding CKD. The suppression of the development of HF and the progression of CKD achieved by SGLT2i might have been largely induced by the improvement of vascular endothelial function by SGLT2i.

Renal uric acid (UA) reabsorption is mainly mediated by urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9). Dotinurad selectively inhibits URAT1 and do not inhibit other UA transporters such as GLUT9, ATP-binding cassette transporter G2 (ABCG2) and organic anion transporter1/3 (OAT1/3). We discovered that dotinurad improved metabolic parameters and renal function in hyperuricemic patients. We consider a significance of high selectivity in inhibiting URAT1 by dotinurad for metabolic syndrome, chronic kidney disease (CKD), and cardiovascular disease (CVD). Dotinurad inhibits selectively URAT1 and increases UA in the proximal tubules, and UA may compete with glucose for GLUT9, reducing glucose reabsorption. The inhibition of UA entry via URAT1 to liver and adipose tissues by dotinurad increased energy expenditure and decrease lipid synthesis and inflammation in rats. The inhibition of URAT1 in kidney, liver and adipose tissues improve metabolic parameters. CKD patients accumulate uremic toxins such as indoxyl sulfate (IS) in the body. ABCG2 regulates renal and intestinal excretion of IS which strongly affects CKD. OAT1/3 inhibitors suppress IS uptake into kidney, increasing plasma IS, which produces oxidative stress, inducing vascular endothelial dysfunction in CKD patients. The high-selective inhibition of URAT1 by dotinurad may be beneficial for metabolic syndrome, CKD and CVD.

Metabolic-dysfunction associated steatotic liver disease (MASLD) is a chronic liver disease that affects more than a quarter of the global population, and is increasing worldwide, due to the pandemic of obesity. Insulin resistance is closely associated with the development and progression of MASLD. Hepatic entry of increased fatty acids (FA) released from adipose tissue, increase in FA synthesis and reduced FA oxidation in the liver, and hepatic overproduction of triglyceride (TG)-rich lipoproteins may induce the development of MASLD. Since insulin resistance also induces atherosclerosis, the leading cause for death in MASLD patients is cardiovascular disease (CVD). Considering that the development of CVD determines the prognosis of MASLD patients, the ideal therapeutic interventions for MASLD should reduce body weight, improve coronary risk factors, in addition to an improvement in liver functiom. Lifestyle modification such as diet and exercise and surgical interventions such as bariatric surgery and intragastric balloons have shown to improve MASLD by reducing body weight. Sodium glucose cotransporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) have been shown to improve coronary risk factors and to suppress the occurrence of CVD. Both SGLT2i and GLP-1 have been reported to improve liver enzymes, hepatic steatosis and fibrosis. We recently reported that the selective peroxisome proliferator-activated receptor-alpha (PPARα) modulator, pemafibrate, improved liver function. PPARα agonists have multiple anti-atherogenic properties. Here, we consider the pathophysiology of MASLD and the mechanisms of action of such drugs, and consider whether such drugs and the combination therapy of such drugs could be the ideal treatments for MASLD.