Nature Metabolism

The gut microbiota produces metabolites that circulate to host tissues and are increasingly linked to metabolic health, yet the mechanisms by which individual microbial products regulate liver glucose metabolism remain poorly defined. Here, we identify the tryptophan-derived microbial metabolite indole-3-propionic acid (IPA) as a direct modulator of hepatic glucose production. In primary hepatocytes, a focused screen of indole metabolites revealed that several indole-containing compounds suppress glucagon-stimulated glucose output, with IPA emerging as a physiologically relevant candidate. IPA selectively reduced glucose production from mitochondrial-dependent gluconeogenic substrates while largely preserving glycerol-supported glucose production, suggesting that it does not simply shut down gluconeogenesis but instead alters how hepatocytes use metabolic fuels. Mechanistic analyses showed that IPA redirects lactate-derived carbon away from glucose production and reshapes mitochondrial metabolism, including redox balance, ATP availability, and urea cycle-linked metabolic activity. These effects occurred without detectable disruption of proximal insulin or glucagon signaling, supporting a model in which IPA acts primarily through intracellular metabolic remodeling. In mice, endogenous IPA levels varied with nutritional state, and short-term IPA administration improved fasting glycemia and glucose handling in Western diet-fed animals. Finally, microbiome-depleted mice colonized with IPA-producing Clostridium sporogenes displayed increased circulating IPA and improved glucose tolerance compared with mice colonized with an IPA-deficient mutant C. Sporogenes strain. Together, these findings identify IPA as a microbial metabolite that directly connects gut tryptophan metabolism to hepatic mitochondrial function and systemic glucose regulation, highlighting a mechanistic gut-liver pathway with potential therapeutic relevance to metabolic disease.

Maternal nutrition shapes offspring brain development and influences lifelong risk for neurological disorders, yet the circuit-level mechanisms linking maternal metabolic state to offspring behavior remain poorly defined. Here we show that maternal high-fat diet (mHFD) disrupts microglia-serotonin interactions during a critical postnatal window to drive persistent, sex-specific alterations in mesolimbic circuitry. In mice, mHFD selectively increased serotonergic fiber density in the nucleus accumbens (NAc) of male, but not female, offspring at postnatal day 14, coincident with reduced microglial phagocytosis of serotonin (5-HT) projections. This early-life hyperinnervation persisted into adulthood, where male offspring exhibited elevated NAc 5-HT release and projection-specific changes in dorsal raphe neuron activity. Functionally, these circuit alterations were associated with accelerated reward-motivated learning, a phenotype recapitulated by chemogenetic activation of NAc-projecting 5-HT neurons. Together, these findings reveal a microglia-centric mechanism by which maternal diet programs serotonergic circuit assembly and behavior in a sex-specific manner, providing a potential link between early-life metabolic inflammation and lifelong neural function.

Brown adipose tissue (BAT) regulates systemic metabolism beyond thermogenesis, yet the circulating mediators through which BAT communicates with other organs remain less defined. Here, we performed comprehensive serum metabolomics and lipidomics in BAT-ablated mice and human cohorts with varying BAT activity to delineate how BAT activity shapes the circulating metabolome. By integrating datasets across serum, tissues, extracellular fluids, and conditioned media, we assembled BAT-linked circulating molecular signatures. The analyses support a role for BAT in the clearance of circulating branched-chain amino acids and triglycerides, and also identify a cold-inducible metabolite, 3-hydroxystearic acid (3-OHSA), produced by BAT and released into circulation. 3-OHSA serves as a circulating readout of cold-activated BAT and acts on the liver to reduce mitochondrial membrane potential and reactive oxygen species (ROS) production, thereby limiting oxidative stress. This work provides a framework for identifying BAT-derived mediators and uncovers a BAT-liver axis that coordinates adaptation to metabolic stress. HIGHLIGHTSO_LIComprehensive analyses of BAT-linked circulating metabolome and lipidome in mice and humans. C_LIO_LIMulti-level metabolomics supports the role of BAT in circulating BCAA and triglyceride clearance. C_LIO_LICold-inducible 3-OHSA is secreted by BAT and signals to the liver. C_LIO_LI3-OHSA decreases hepatic oxidative stress by decreasing mitochondrial membrane potential. C_LI

Resilience requires neural systems that mobilise active coping during stress while limiting its persistence to preserve homeostasis under sustained challenge1-4. Here we identify a self-limiting orexin-habenula circuit in which lateral hypothalamic orexin neurons engage aromatic L-amino acid decarboxylase-expressing D-neurons (encoded by Ddc) in the lateral habenula via orexin receptor type 2 (OX2R)5-7. Activation of this pathway increased nucleus accumbens dopamine and promoted active coping and positive valence. Optotagging revealed rapid stress-evoked recruitment followed by post-stress suppression. In lateral habenula neurons, orexin peptides exerted dissociable effects: orexin-A engaged an OX2R-dependent inhibitory programme superimposed on a parallel inward current, whereas orexin-B did not reproduce this inhibitory profile and instead exerted a distinct membrane effect. Chronic stress disrupted this buffering system through coordinated inflammatory activation, promoter methylation and erosion of D-neuron identity and orexin responsiveness. Restoring orexin-A reversed behavioural and molecular deficits through OX2R-dependent suppression of nuclear factor kappa B signalling, preservation of Tet2 expression, and demethylation-linked maintenance of the Ddc programme. Together, these findings define a self-limiting orexin-habenula resilience circuit that enables adaptive coping while constraining stress-induced vulnerability.

Adiponectin signaling is essential for hepatic glucose homeostasis, yet the molecular basis of adiponectin receptor responsiveness remains incompletely understood. Here, we identify the Nogo-B receptor (NgBR; NUS1) as a regulator of hepatic adiponectin sensitivity. Across human, cynomolgus monkey, and mouse datasets, hepatic NgBR expression is consistently reduced in obesity-associated diabetes, indicating a conserved metabolic signature. Hepatocyte-specific NgBR deletion abolishes the metabolic effects of the adiponectin agonist AdipoRon, resulting in impaired AMPK activation, persistent gluconeogenesis, and ceramide accumulation. Mechanistically, NgBR loss suppresses KAT7 expression and reduces histone acetylation at AdipoR1 and AdipoR2 promoters, thereby limiting receptor expression. Adeno-associated virus (AAV)-mediated restoration of hepatic NgBR reinstates KAT7-dependent chromatin activation, adiponectin receptor expression, and glucose homeostasis. These findings support a hepatocellular mechanism in which NgBR maintains adiponectin receptor competence and suggest a potential therapeutic strategy for restoring adiponectin responsiveness in metabolic disease. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/726643v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@117fa66org.highwire.dtl.DTLVardef@1385297org.highwire.dtl.DTLVardef@b64369org.highwire.dtl.DTLVardef@3dd55_HPS_FORMAT_FIGEXP M_FIG C_FIG

Mitochondrial protein homeostasis intersects with metabolic control, but the in vivo roles of specific mitochondrial co-chaperones remain unclear. The chaperone mtHSP70 plays a key role in import and folding of nuclear-encoded proteins targeted to mitochondrial matrix. Its protein folding cycle is regulated by the GrpE-like nucleotide exchange factor GRPEL1. Vertebrates also have a GRPEL2 paralog, postulated as the stress-sensitive counterpart, but its physiological relevance is not known. We show here that GRPEL2 is not essential for viability in mice, and its absence does not induce proteotoxic stress responses in stark contrast to GRPEL1. However, we find that GRPEL2 has a role in regulating body weight homeostasis. GRPEL2 knockout mice are protected from age- and diet-induced weight gain and maintain a better metabolic health and insulin sensitivity. Transcriptional profiling revealed minimal changes in liver and skeletal muscle, whereas white adipose tissue from Grpel2-deficient mice lacked the obesity-associated remodeling seen in controls. We propose that GRPEL2 fine-tunes metabolic setpoints without broadly perturbing mitochondrial protein import, thereby maintaining adipose tissue health during nutritional excess. These findings show that subtle alterations in mitochondrial chaperone systems reshape systemic metabolism and could suggest strategies to mitigate obesity and insulin resistance through targeted modulation of mitochondrial proteostasis.

The mTOR pathway is a central regulator of cellular metabolism and growth whose downregulation extends life span across taxa. In C. elegans, mTOR acts cell non-autonomously to influence organismal longevity, yet underlying mechanisms remain elusive. Here, we show that deletion of the TORC1 regulator, raga-1/RRAGA, enhances production of the bile acid-like hormone, dafachronic acid (DA), and extends life span dependent on DA-hormone biosynthetic genes and DA-cognate nuclear hormone receptor DAF-12, a homolog of mammalian farnesoid X receptor (FXR). Through functional genomic screens, we identify the evolutionarily conserved short chain dehydrogenase DHS-26/DHRS1 as a previously uncharacterized downstream regulatory target and effector of the mTOR-steroid axis essential for organismal longevity. Worm DHS-26 is expressed prominently in the canal associated neurons, cells which are essential to growth and development, suggesting a neuroendocrine mechanism. Murine DHRS1 also exhibits regulation by mTOR signaling and nuclear receptor FXR suggesting that the mTOR-DHS-26/DHRS1 axis is evolutionarily conserved. These findings suggest that mTOR signaling systemically impacts metazoan longevity through the regulation of bile acid-like hormone availability and nuclear receptor signal transduction.

Copper and iron are redox-active micronutrients with tightly coupled homeostasis, yet how copper modulates iron-dependent stress responses remains unclear. Using Saccharomyces cerevisiae under nutrient-limited conditions, we uncoupled proliferative growth from long-term survival to dissect metal-dependent adaptation. Copper selectively preserved survival without affecting growth, whereas iron showed similar effects. Iron chelation impaired growth and suppressed electron transport chain gene expression; copper partially rescued these defects but required iron for its pro-survival activity. Despite this interdependence, copper and iron engaged distinct signaling programs. Iron-dependent survival required a Target of Rapamycin complex 1 (TORC1)-permissive state and was attenuated by rapamycin, whereas copper remained active under TORC1 inhibition. In contrast, copper promoted survival through AMP-activated protein kinase (AMPK) and antioxidant pathways, while iron exhibited context-dependent AMPK reliance. Together, these findings identify copper and iron as state-dependent regulators of cellular survival.

The liver plays a central role in systemic metabolism, yet large-scale genetic studies of quantitative liver imaging phenotypes remain limited. Here, we applied deep learning-based segmentation and radiomics extraction to derive 200 well-defined liver MRI features across multiple categories and imaging contrasts in 43,176 UK Biobank participants. Association analyses revealed steatosis-independent radiomic signals predicting incident chronic liver disease beyond conventional risk factors. We conducted genome-wide association studies in 37,725 individuals and identified multiple heritable liver MRI features; joint genetic structure and pleiotropy analyses demonstrated that these radiomic traits capture complex genetic architecture beyond the extent of hepatic steatosis. These MRI features showed widespread genetic overlap with plasma proteins, metabolites, and cardiometabolic traits through shared genetic loci and genetic correlations independent of adiposity. We identified putative causal links between liver MRI traits and cardiometabolic and liver-related outcomes, as well as evidence for pathway-specific imaging biomarkers to track activity of hepatically-influenced therapeutics.

Glycosuria, whether genetically induced or triggered by SGLT2 inhibitors, activates compensatory glucose-producing pathways that limit glucose lowering in type 2 diabetes. To define these pathways, we studied renal Glut2 knockout mice, which progressively lose Slc5a2 (encoding SGLT2) expression yet maintain normoglycemia despite marked urinary glucose loss. Metabolic profiling and isotope tracing revealed coordinated adaptations in mannose and glutamine metabolism during glycosuria. Skeletal muscle reduced glucose utilization and instead oxidized mannose, while whole-body glycolysis declined, establishing a systemic glucose-sparing state. Disruption of glutamine transport or mannose utilization caused hypoglycemia in mice treated with an SGLT2 inhibitor, demonstrating dependence on these substrates to maintain glucose homeostasis during glycosuria. Multiomic profiling revealed increased expression and chromatin accessibility of mannose and glutamine transport pathways. These findings identify a kidney-driven metabolic program that preserves systemic glucose homeostasis during glycosuria and may inform strategies to optimize the glucose-lowering efficacy of SGLT2 inhibitors.

Mitochondria and lipid droplets (LDs) are functionally coupled to coordinate fatty acid utilization and storage. However, a comprehensive understanding of mitochondria-LD alliances remains elusive. We have identified a previously unrecognized role for optical atrophy 1 (OPA1), a mitochondrial fusion factor, in the regulation of fatty acid release from LDs. We demonstrated that OPA1s exon 4 adapts an amphipathic helix to target OPA1 to LDs. OPA1 localized to LDs promote fatty acid release by facilitating the recruitment of lipases to LDs. In addition, OPA1s residence on LDs competes with its mitochondrial entry, influencing mitochondria fusion and connectivity. Furthermore, the S158N polymorphism within OPA1s exon 4 exhibiting attenuated fatty acid release from LDs is associated with changes in metabolic traits in pediatric cancer survivors. Altogether, our findings reveal that OPA1 actively mediates fatty acid release from LDs and provide a mechanistic link between OPA1 and human metabolism.

GLP-1 receptor agonists (GLP-1 RAs) effectively reduce weight in obesity, although significant weight regain typically follows discontinuation. Here, in a randomized clinical trial (ChiCTR2200066014), we found that GLP-1 RA (semaglutide) and a high-fibre diet achieved similar 12-week weight reduction, but semaglutide recipients exhibited significantly higher weight rebound at the 14th week after intervention cessation. Shotgun metagenomic sequencing revealed that semaglutide aggravated the proinflammatory signature in the gut microbiome, which contrasted with high-fibre diet intervention. The microbiota transplanted from semaglutide-treated subjects to germ-free mice induced gut barrier dysfunction, systemic inflammation and an increase in the bacterial antigen load in the liver and adipose tissue, which activated the NF-{kappa}B pathway to drive lipid accumulation. Using a diet-induced obesity mouse model, we found that semaglutide exacerbated gut microbiome dysbiosis by weakening host immune surveillance of the gut microbiota through downregulating IFN-{gamma} to reduce antimicrobial peptides expression and delaying gut transit time to shift microbial metabolism from saccharolysis towards proteolysis. Crucially, combining semaglutide with dietary fibre in mice mitigated microbiome dysbiosis and attenuated weight regain post-cessation. These findings suggest that GLP-1 RA-exacerbated gut microbiome dysbiosis in obesity as a key mediator of post-treatment weight rebound and propose adjunctive fibre supplementation as a strategy to sustain weight loss.

Neutrophils are the most abundant leukocytes in humans and play a central role in immune regulation. Although traditionally viewed as terminally differentiated cells with limited plasticity, growing evidence indicates that neutrophils exhibit substantial functional heterogeneity in response to stress. To date, however, most studies have focused on transcriptional and signaling changes, while metabolic heterogeneity, especially beyond central carbon metabolism, remains poorly characterized. Here, we systematically investigate metabolic reprogramming in neutrophils under three stress conditions: granulocyte colony-stimulating factor (G-CSF) treatment, hematopoietic stem cell transplantation (HSCT), and pancreatic ductal adenocarcinoma (PDAC). Using condition-specific genome-scale metabolic (GSM) models, we identify distinct metabolic vulnerabilities across neutrophil states. Vitamin metabolism emerged as a key differentiating feature between G-CSF- and HSCT-treated neutrophils, whereas PDAC-associated neutrophils displayed globally enhanced metabolic activity coupled with restricted metabolite exchange fluxes. Furthermore, solute carrier (SLC) family transporters were identified as major metabolic regulators underlying stress-induced neutrophil reprogramming. Together, our findings demonstrate that neutrophil heterogeneity extends beyond transcriptional programs to encompass profound metabolic specialization, highlighting metabolism as a critical dimension of neutrophil plasticity in health and disease.

Early life nutrition profoundly influences long-term metabolic health, and breast milk not only provides nutrients but also conveys maternal signals shaping infant metabolic development. While postpartum exercise by lactating women benefits maternal health, its impact on milk-borne signaling remains largely undefined. Small extracellular vesicles (sEVs) in breast milk are key mediators of maternal to infant communication because of their selectively packaged bioactive cargo and resistance to infant digestive enzymes and acids, enabling delivery of their cargo to peripheral tissues. Here, we show that a single session of moderate-intensity postpartum aerobic exercise robustly increases human breast milk sEV concentration, which persists for multiple post-exercise milk collections. Exercise enriches breast milk with sEVs containing regulatory metabolic cargo (proteins, miRNAs, and metabolites), which translates into enhanced mitochondrial capacity in neonatal stage cells. These findings implicate sEVs as an exercise-responsive signaling compartment in breast milk capable of connecting postpartum maternal physical activity to beneficial infant metabolic programming.

Fatty acid biosynthesis is a central metabolic process required for membrane formation, organelle maintenance, and cellular proliferation, yet its broader relationship with stress responses and cellular aging remains incompletely understood. Here, we combined human and yeast interactome analyses with transcriptomic profiling and chronological lifespan assays to investigate the systems-level organization of fatty acid metabolic pathways and their relationship to cellular longevity. Integrated interactome mapping of mammalian fatty acid metabolic regulators, including ACACA, FASN, SCD, ACSL, ELOVL, and SLC27 family proteins, together with conserved yeast orthologs including ACC1, FAS1/FAS2, ELO1-3, OLE1, FAA1-4, ACS1/ACS2, and FAT1 revealed strong enrichment of anabolic growth regulation, membrane organization, vesicle trafficking, proteostasis, and endoplasmic reticulum (ER)-associated stress pathways. In yeast, fatty acid metabolic networks segregated into distinct anabolic and membrane-associated functional modules. Pharmacological inhibition of fatty acid synthesis using cerulenin suppressed cellular proliferation while extending chronological lifespan and induced broad downregulation of translation-associated anabolic pathways together with activation of stress-associated and membrane lipid remodeling programs. ER-associated interactome analyses of DPAGT1 and ALG7 further identified strong enrichment of membrane trafficking and unfolded protein response (UPR)-associated pathways, while pharmacological ER stress induction using tunicamycin also promoted enhanced chronological longevity. Collectively, our findings support a conserved model in which perturbation of fatty acid metabolic pathways remodels anabolic growth and ER-associated stress responses to promote cellular longevity.

Citrate is a central metabolite linking tricarboxylic acid (TCA) cycle activity to energy and lipid metabolism and supports the synthesis of inflammatory mediators, including itaconate, in macrophages. While citrate is primarily generated endogenously, extracellular citrate levels are elevated under pathological conditions such as citrate transporter disorder. Cells import extracellular citrate through SLC13 transporters, including the sodium-dependent citrate transporter NaCT (encoded by SLC13A5). However, whether macrophages take up extracellular citrate and how this affects metabolism and function remains unclear. Here, we combined mass spectrometry and tracing approaches to investigate the metabolic fate of citrate in human macrophage cell lines, primary, and iPSC-derived macrophages. We demonstrate that cells take up extracellular citrate, which was enhanced under metabolic stress conditions. Exogenous citrate was not substantially utilized as a carbon source but selectively altered glutamine metabolism and responses to bacterial infection with Salmonella enterica Typhimurium and Legionella pneumophila Corby. Our work identifies extracellular citrate as a context-dependent regulator in macrophages that decouples uptake from metabolic utilization. HighlightsO_LIMacrophages import extracellular citrate via SLC13 transporters C_LIO_LIExtracellular citrate accumulates under hypoxia and inflammatory activation C_LIO_LIExtracellular citrate does not fuel central carbon metabolism in human macrophages C_LIO_LICitrate modulates glutamine immunometabolism and modulates immune responses C_LI eTOC blurbVo{beta}-Willenbockel et al. demonstrate that human macrophages accumulate extracellular citrate without using it as a major carbon source. Instead, citrate modulates glutamine utilization, inflammatory responses, and host-pathogen interactions revealing a context-dependent regulatory role for extracellular metabolites in immune cell function.

Myocardial ischemia/reperfusion (I/R) injury is a major determinant of infarct size and clinical outcome, yet effective therapies remain limited. Although metabolic remodeling is central to I/R pathology, the contribution of nucleotide biosynthesis remains unclear. Here, we identify CAD, the multifunctional rate-limiting enzyme of de novo pyrimidine biosynthesis, as a previously unrecognized regulator of myocardial reperfusion injury. CAD activation exacerbated cardiomyocyte death during simulated I/R, whereas CAD knockdown or pharmacological inhibition was protective in vitro. Mechanistically, CAD enhanced dihydroorotate dehydrogenase (DHODH)-dependent electron transfer, increased the CoQH2/CoQ ratio, and promoted complex I reverse electron transport (RET), thereby amplifying mitochondrial ROS. In parallel, CAD suppressed de novo purine synthesis, causing purine insufficiency, DIS3L-dependent RNA decay, and cytosolic ROS. Importantly, cardiomyocyte-specific CAD deletion protected against cardiac I/R injury in vivo. Together, these findings establish CAD as a metabolic hub linking nucleotide flux to dual-compartment ROS signaling and identify nucleotide metabolism as a therapeutic vulnerability in myocardial I/R injury. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=187 HEIGHT=200 SRC="FIGDIR/small/725578v1_ufig1.gif" ALT="Figure 1"> View larger version (87K): org.highwire.dtl.DTLVardef@14c4fedorg.highwire.dtl.DTLVardef@1138ed2org.highwire.dtl.DTLVardef@1057d8borg.highwire.dtl.DTLVardef@17546bd_HPS_FORMAT_FIGEXP M_FIG C_FIG

The electron shuttle and coenzyme nicotinamide adenine nucleotide (NAD) is essential for cellular metabolism and homeostasis. NAD levels significantly fluctuate in cells, whilst several age-related diseases are associated with depletion of this metabolite. However, how NAD changes are monitored by nutrient/energy sensing signalling pathways remains poorly understood. We found that at physiological concentrations NAD controls the activity of the AMP-activated protein kinase (AMPK) in vitro and in human cells. Mechanistically, NAD binds gamma subunit of AMPK, and mutagenesis of the putative binding site renders the holoenzyme insensitive to NAD inhibition. Hyperactivation of AMPK in response to NAD depletion suppresses metabolic pathways including mammalian Target of Rapamycin Complex I (mTORC1) and autophagy. These results demonstrate that in addition to monitoring cellular energy levels AMPK functions as a NAD sensor, providing novel insight into how cells and tissues detect and respond to metabolic fluctuations with implications for stress resistance and ageing.

White adipose tissue and pancreatic islets play central roles in the regulation of metabolic homeostasis. Although ectopic lipid accumulation is established as a driver of impaired insulin secretion, the acute contribution of adipocyte lipolysis to islet function remains poorly documented. Here, we investigated a mouse model with inducible adipocyte-specific deletion of both adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL), which leads to defective adipocyte lipolysis. Despite preserved ex vivo islet function, these mice displayed a marked reduction in insulin secretion in response to stimulation of adipocyte {beta}3-adrenoceptors, as well as following glucose and arginine challenges. Mechanistically, we identified non-esterified fatty acids as critical mediators of lipolysis-driven insulin secretion, engaging pancreatic signaling of the free fatty acid receptors FFAR4 (a.k.a. GPR120) and FFAR1 (a.k.a. GPR40). The regulation of insulin secretion by adipocyte lipolysis was preserved in high-fat diet-induced obesity. These findings identify an underappreciated adipose-islet crosstalk that couples adipocyte lipolysis to insulin secretion and links lipid and glucose metabolism.

Adipokines are key metabolic hormones that modulate cardiometabolic risk through multiple distinct biological pathways. To delineate these pathways, we systematically mapped adipokineassociated variants to putative effector genes (V2G) across{square}1,669 human traits in three ancestries from the Million Veteran Program. Grouping the variants by their associations with insulinresistance-related traits yielded six discrete variant clusters, including a "Lipodystrophy" cluster characterised by lower bodymass index but higher waisttohip ratio, fasting glucose, and insulin levels. V2G mapping implicated TGFB2 and VEGFA as candidate effector genes in the Lipodystrophy cluster. VEGFA also appeared in a distinct "Thyroid-adiposity" cluster that was strongly associated with increased insulin resistance and decreased thyroid function. The Thyroid-adiposity cluster comprised variants that are thyroid eQTLs, unlike those in the Lipodystrophy cluster. These findings indicate that VEGFA may influence insulin resistance via two separate mechanisms: abnormal adiposity and altered thyroid function. Although both clusters increased coronary artery disease risk, only the Lipodystrophy cluster increased type{square}2 diabetes risk. Our results highlight mechanistically distinct routes by which adipokines modulate insulin resistance and cardiometabolic disease.