insulin resistance

Overview

Insulin resistance is a biological process in which target tissues such as skeletal muscle, liver, adipose tissue, and, in some contexts, the brain respond less effectively to insulin. As a result, normal insulin signaling is impaired, glucose uptake and metabolic regulation are reduced, and compensatory hyperinsulinemia may develop. It is a central feature of type 2 diabetes and is also implicated in gestational diabetes mellitus, metabolic dysfunction-associated steatotic liver disease, obesity, polycystic ovary syndrome, cardiovascular risk, and several other metabolic and inflammatory disorders.

At the molecular level, insulin resistance is commonly associated with altered insulin receptor signaling and downstream pathways such as IRS-1/PI3K/AKT, PPARγ-driven signaling, and related metabolic regulators including PTP1B, mTORC1, and FOXO1. It is also linked to adiposity, ectopic fat accumulation, oxidative stress, inflammation, mitochondrial dysfunction, and changes in hepatokine and adipokine production. Recent studies have continued to frame insulin resistance as both a mechanistic driver and a therapeutic target across metabolic disease, pregnancy complications, pulmonary impairment, cognitive decline, and tissue repair.

Recent Publications Summary

Recent publications on insulin resistance have focused on its role as both a mechanistic marker and a clinical mediator across metabolic, cardiovascular, hepatic, pulmonary, and neuropsychiatric conditions. In a randomized controlled trial in non-diabetic patients with metabolic dysfunction-associated steatotic liver disease (MASLD), high-dose N-acetylcysteine (2400 mg/day) plus lifestyle intervention was compared with lifestyle intervention alone for 12 weeks, with insulin resistance assessed using leptin, fasting insulin, and HOMA-IR; no significant between-group differences were observed in these markers or in liver steatosis and fibrosis outcomes 42587287Aug. In another trial of men with obesity, fisetin supplementation was tested alongside interval resistance and aerobic training to evaluate effects on Maresin-1, inflammatory markers, and insulin resistance, reflecting ongoing interest in combining exercise and nutraceutical strategies to modulate metabolic dysfunction 42218768May.

Several observational studies examined insulin resistance indices as predictors, correlates, or mediators of disease risk. In a very large UK Biobank analysis, intrinsic capacity was associated with ischemic heart disease incidence and progression, and the investigators specifically assessed mediation by insulin resistance-related indices 42401064Jul. In US adults, triglyceride-glucose-based indices and HOMA-IR were evaluated for their ability to distinguish clinical from preclinical obesity phenotypes, highlighting their use as surrogate markers of insulin resistance in population studies 42175452May. In preserved ratio impaired spirometry, insulin resistance surrogates were studied for associations with this abnormal pulmonary phenotype, again underscoring insulin resistance as a systemic cardiometabolic marker 42061475Apr. In type 2 diabetes, estimated glucose disposal rate (eGDR) was used as an insulin resistance metric to examine links with vascular events, death, and possible modification of treatment effects in the ADVANCE study 41804187Mar.

Interventional and translational studies also explored whether reducing insulin resistance could alter disease pathways. In mice exposed to intermittent hypoxia, photobiomodulation was reported to alleviate hypoxia-induced insulin resistance by preserving adipose tissue insulin signaling and reducing hepatic oxidative stress 42216497May. In type 2 diabetes mellitus, Simiao Yong'an decoction was investigated using serum pharmacochemistry, network pharmacology, and in vivo validation for its ability to ameliorate insulin resistance via the PI3K/AKT pathway 41974236Apr. A post hoc analysis from the CALERIE-2 trial examined how sustained weight loss versus weight regain affected the insulin-IGF-1 nutrient-sensing pathway, with attention to insulin resistance and type 2 diabetes risk 41838032Mar. Another post hoc analysis evaluated liraglutide and recurrent stroke according to baseline insulin resistance, asking whether insulin resistance modifies treatment benefit 42145088May.

Other publications treated insulin resistance as part of broader disease models or mechanistic frameworks. In bipolar disorder and major depressive disorder, insulin resistance was considered among immune-metabolic factors potentially mediating suicide risk and white matter changes 42212480May. A mathematical modeling study of obesity-diabetes progression reconstructed individualized trajectories of glucose, insulin, insulin sensitivity, and beta-cell function and interpreted hyperinsulinemia primarily as compensation for insulin resistance, while also modeling a subgroup with ABCC8 loss-of-function-related primary hyperinsulinemia 41800787Mar. Across these studies, insulin resistance was consistently used as a central biological process linking metabolism, inflammation, organ dysfunction, and disease progression.

What Changes, What Holds

1. No clear biological effect was shown for adding these interventions
REINFORCES High-dose N-acetylcysteine plus lifestyle change did not materially alter insulin-resistance markers or liver outcomes beyond lifestyle alone, so the established view of insulin resistance as a relevant MASLD target stands, but this trial does not strengthen a specific claim that NAC improves it 42587287Aug. The fisetin-plus-training study is directionally consistent with ongoing attempts to modulate metabolic dysfunction, yet it does not yet establish a new effect on insulin resistance in humans 42218768May.

2. insulin-resistance indices are becoming broader risk markers rather than disease-specific readouts
NEW DIRECTION Intrinsic capacity, pulmonary impairment, and obesity phenotyping work extend insulin resistance beyond its classic role in diabetes and metabolic syndrome, showing it is being used as a systemic surrogate across cardiovascular and respiratory epidemiology 42401064Jul42175452May42061475Apr. This does not contradict the Overview, but it broadens the practical meaning of insulin resistance from a mechanistic feature of metabolic disease to a cross-disease predictor and mediator. eGDR likewise functions here as a risk-stratification tool in vascular outcomes rather than a purely diagnostic metric 41804187Mar.

3. Lowering insulin resistance remains a plausible mechanism, but the evidence is still model-dependent
REINFORCES photobiomodulation, Simiao Yong'an decoction, and weight-loss trajectory analyses all fit the established account that improving insulin signaling or sensitivity can affect metabolic and vascular risk 42216497May41974236Apr41838032Mar. What changes is not the baseline biology but the range of candidate interventions and analytic frameworks now being used to probe it. The liraglutide post hoc analysis adds a modifier question, asking whether baseline insulin resistance helps define treatment benefit rather than overturning the role of insulin resistance itself 42145088May.

4. Insulin resistance is being treated as a shared mechanism in neuropsychiatric disease models, but that role is still exploratory
NEW DIRECTION Immune-metabolic modeling in bipolar disorder and major depressive disorder places insulin resistance inside hypotheses about suicide risk and white matter change, a context not covered by the Overview’s established metabolic and inflammatory disorders 42212480May. The trajectory model of obesity-diabetes progression also sharpens the compensatory hyperinsulinemia framework already in the Overview, while separating it from a subgroup with primary hyperinsulinemia 41800787Mar. Together these studies broaden the conceptual reach of insulin resistance without displacing the established account.

Overview update candidates: insulin resistance indices as broader cross-disease predictors; exploratory links to neuropsychiatric outcomes and white matter change.