The hormone in question is insulin-like growth factor-1, or IGF-1, a small protein secreted largely by the liver that circulates in the blood and acts as a master anabolic signal for skeletal muscle. When IGF-1 binds to receptors on muscle fibers, it activates the AKT/mTOR pathway, an intracellular circuit that drives protein synthesis, cell growth, and repair. When that signal weakens, muscles tip toward atrophy, ramping up destruction machinery such as the E3 ubiquitin ligases Atrogin-1 and MuRF1, which tag contractile proteins for degradation. The Korean team’s central finding is that two commonly prescribed statins, lovastatin and atorvastatin, appear to disrupt this liver-to-muscle endocrine axis by first aging the liver.

Cellular senescence is a state in which a cell stops dividing but does not die, instead accumulating damage markers and secreting a cocktail of inflammatory and regulatory molecules known as the senescence-associated secretory phenotype, or SASP. In the new work, the researchers treated hepatocytes with lovastatin and atorvastatin and observed the classic fingerprints of senescence: increased activity of senescence-associated beta-galactosidase, an enzyme used as a standard histochemical marker of aged cells, and elevated expression of p21 and p16, two tumor-suppressor proteins that enforce the senescence program by halting the cell cycle. These changes were seen both in cultured liver cells and in liver tissue from animals exposed to the drugs, indicating that the phenomenon is not merely an artifact of the culture dish.

The most striking result came when the team catalogued what the senescent hepatocytes were secreting. Among the many components of the SASP, one factor stood out for moving in the wrong direction: IGF-1 was selectively and significantly reduced. In other words, rather than gaining inflammatory secretions, the statin-aged liver cells lost a key growth factor output. Because circulating IGF-1 is produced predominantly by the liver, a drop in hepatic IGF-1 expression translates directly into lower levels of the hormone in the bloodstream, potentially affecting tissues throughout the body that rely on it for maintenance and repair.

To test whether this hormonal shortfall actually harms muscle, the researchers set up a transwell coculture system, an experimental arrangement in which two cell types share a medium but are separated by a porous membrane, allowing soluble factors to pass while keeping the cells physically apart. When senescent AML12 mouse hepatocytes were cocultured with C2C12 myoblasts, the muscle cells’ ability to differentiate into myotubes was impaired, the resulting myotubes were thinner, and the muscle atrophy markers Atrogin-1 and MuRF1 were upregulated. Because the cells never touched, the effect must have been mediated by secreted factors — consistent with the idea that the senescent liver cells’ diminished IGF-1 output starves muscle of an essential growth signal.

The in vivo experiments reinforced the picture. The team exposed animals to a combination of lovastatin and ezetimibe, a cholesterol-absorption inhibitor that is often co-prescribed with statins to achieve greater low-density lipoprotein reduction. In the livers of these animals, the area staining positive for senescence-associated beta-galactosidase expanded, p21 and p16 expression rose, and circulating IGF-1 fell. Downstream, in the tibialis anterior muscle — a standard lower-leg muscle used in rodent studies of skeletal muscle physiology — the researchers measured a reduced average fiber cross-sectional area and a size distribution shifted toward smaller fibers, exactly what one expects when atrophy outpaces growth.

The molecular readout in the muscle told a coherent mechanistic story. AKT/mTOR pathway activation was diminished, meaning the anabolic circuit that IGF-1 normally engages had gone quiet, and the atrophy-associated proteins Atrogin-1 and MuRF1 were elevated, indicating that the ubiquitin-proteasome degradation machinery had been switched on. Together, these changes describe a muscle caught between reduced protein synthesis and increased protein breakdown — the biochemical definition of atrophy. The authors propose that this cascade constitutes a liver-to-muscle endocrine axis: statin-induced hepatic senescence suppresses IGF-1, and the resulting attenuation of IGF-1 signaling in muscle secondarily impairs myogenesis and promotes wasting.

The findings carry several important caveats and implications. First, the study was conducted in cell culture and in animal models, so the results will need to be confirmed in human studies before they can reshape clinical practice; the authors themselves frame the work as supporting a potential axis rather than proving it in patients. Second, the observation that ezetimibe was part of the in vivo regimen raises questions about how much of the hepatic effect is attributable to statin-specific inhibition of HMGCR, the enzyme that both statins target and that sits at the head of the mevalonate pathway, versus broader metabolic stress. HMGCR catalyzes a rate-limiting step in the production of mevalonate, from which cells synthesize not only cholesterol but also isoprenoid intermediates needed for protein prenylation — processes implicated in cell survival and stress responses. Blocking this pathway in hepatocytes may therefore trigger senescence through mechanisms that go well beyond cholesterol lowering itself.

For the millions of people who take statins, the study should not prompt anyone to stop their medication; the cardiovascular benefits of statins are firmly established, and statin-associated muscle symptoms, while real, affect a minority of users and are often manageable by adjusting dose or switching agents. But the research does suggest a new therapeutic frontier. If hepatic senescence is a driver of muscle complications, then drugs that clear senescent cells — so-called senolytics — or agents that dampen the senescence program might one day protect muscle in susceptible patients. Alternatively, restoring IGF-1 signaling, whether by supplementing the hormone, boosting its hepatic production, or activating AKT/mTOR downstream, could counteract the atrophy signal at its source. The authors explicitly propose targeting hepatic senescence or restoring IGF-1/AKT/mTOR activity as candidate strategies to mitigate statin-associated myopathy.

More broadly, the work adds to a growing appreciation that aging-like states induced in one organ can propagate systemically through endocrine signals. The liver, as the body’s metabolic factory and a major source of circulating growth factors, is uniquely positioned to broadcast its internal state to muscle, bone, and brain. A drug that quietly ages hepatocytes may therefore have consequences far beyond lipid numbers on a lab report. As the population on long-term statin therapy continues to grow — and as those patients themselves age — understanding how hepatic senescence reshapes the hormonal environment of muscle could prove essential not only for making statins safer but for preserving strength and independence in later life. The Korean team’s liver-muscle axis offers a testable framework for that effort, and it transforms a side effect long dismissed as a pharmacological mystery into a biological pathway that can, in principle, be measured, modeled, and targeted.

Subject of Research: Statin-induced hepatic senescence and reduced IGF-1 signaling driving skeletal muscle atrophy

Article Title: Hepatic senescence triggered by statins decreases systemic IGF-1 signaling to drive skeletal muscle atrophy

Article References: Kim, W.-K., Yeon, M., Yoo, Y., Shin, H.-B., Yang, Y. R., & Seo, Y.-K. (2026). Hepatic senescence triggered by statins decreases systemic IGF-1 signaling to drive skeletal muscle atrophy. Cell Death Discovery. https://doi.org/10.1038/s41420-026-03399-y

Image Credits: AI Generated

DOI: 10.1038/s41420-026-03399-y

Keywords: statins, hepatic senescence, IGF-1, skeletal muscle atrophy, AKT/mTOR signaling, SASP, Atrogin-1, MuRF1, HMGCR, liver-muscle axis, myopathy, cell senescence

The research team, working at the University of Florida, engineered mice in which FAPs could be selectively eliminated at will. They crossed animals carrying a tamoxifen-activated Cre recombinase driven by the Pdgfra promoter, which is active in FAPs, with mice carrying a diphtheria toxin A gene inserted into the Rosa26 locus. When adult mice, aged twelve to thirteen weeks, received five consecutive daily injections of tamoxifen, the toxin switched on inside FAPs and killed them. Three weeks later, the researchers found that FAP abundance in the muscle had plummeted by roughly 90 percent. The consequences were dramatic and systemic: total body mass and lean mass fell in both males and females, hindlimb muscles including the tibialis anterior, extensor digitorum longus and soleus shrank significantly, and even the spleen, liver and inguinal fat pads lost substantial weight, shrinking by up to 30 percent.

Crucially, the atrophy was not selective. Because the three muscles examined span a range of metabolic and contractile properties, the wasting appeared to be entirely independent of fiber type. Yet when the team tested muscle function directly, a surprising picture emerged. Absolute maximum isometric force was significantly reduced in both fast-twitch and slow-twitch muscles of the FAP-depleted mice, exactly as expected from smaller muscles. But when force was normalized to the muscle’s reduced cross-sectional area, the so-called specific force was completely unchanged. The contractile machinery inside each fiber was working perfectly fine. Even eccentric contractions, which subject muscles to damaging lengthening forces, revealed no increase in fragility. In other words, the muscle was losing quantity, not quality.

One long-standing hypothesis held that FAPs keep muscle healthy by supporting the neuromuscular junction, the synapse where nerves command fibers to contract. FAPs do cluster physically around these junctions, and previous work had suggested their deletion triggers synaptic degeneration and denervation-like atrophy. To test this rigorously, the researchers performed whole-mount immunofluorescence on the junctions of the EDL and soleus muscles, labeling presynaptic nerve terminals with antibodies against neurofilament and synaptic vesicle proteins, and postsynaptic acetylcholine receptors with fluorescently tagged alpha-bungarotoxin. The result was unambiguous: complete overlap between pre- and postsynaptic structures, intact endplate gutters, no fragmentation, and normal terminal Schwann cell morphology. Functional testing told the same story. When the team compared force produced by direct muscle stimulation against force evoked through the nerve, the ratios were equivalent in control and FAP-depleted mice, indicating flawless synaptic transmission. Molecular markers of denervation, such as shifts in acetylcholine receptor subunit genes, were also absent.

With the neuromuscular hypothesis ruled out for this acute setting, the team turned to the timeline of the wasting itself. Longitudinal body composition measurements revealed that most of the lean mass loss occurred during the active tamoxifen dosing window, not during the weeks of washout that followed. Apoptotic FAPs, identified by cleaved caspase 3 staining, were detectable as early as one day after the first injection. By day three, FAP numbers had collapsed. And by day five, the muscle was flooded with innate immune cells: myeloperoxidase-positive neutrophils and CD68-positive macrophages arrived in a massive, synchronized wave. The temporal sequence was telling. Cell death came first, immune infiltration followed, and only then did the muscle begin to visibly shrink.

Transcriptional profiling filled in the molecular plot. The researchers tracked two families of genes over time: atrogenes, which include the E3 ubiquitin ligases Trim63 and Fbxo32 and the autophagy markers Ulk1 and Sqstm1, and inflammatory chemokines and cytokines. An early spike in atrogene expression at day one occurred in both control and experimental mice and was attributed to the stress of tamoxifen treatment itself. But at day five, only the FAP-depleted muscles mounted a second, powerful surge of proteolytic gene expression. Preceding that surge, chemokine expression exploded. Ccl2, Ccl12, Cxcl1 and Cxcl2 rose fifty- to one-hundred-fold above control levels, peaking at day three, precisely before the atrogene wave. Interleukin-6, a cytokine with well-established links to muscle catabolism, climbed roughly fifteen-fold and stayed elevated. Notably, circulating IL-6 rose only modestly, showing that this was a fiercely local inflammatory response rather than a systemic one, and the entire transcriptional storm resolved by day twenty-eight, marking the atrophy as acute rather than chronic.

The most counterintuitive finding came when the researchers removed the immune cells themselves. Using clodronate liposomes to deplete macrophages and an anti-Ly6G antibody to eliminate neutrophils, they tested whether the infiltrating cells were culprits or protectors. The answer was neither simple nor expected: depleting either population, or both simultaneously, made the muscle wasting significantly worse. Even control mice with fully intact FAPs lost muscle when their myeloid cells were cleared. Macrophage depletion blunted the expression of Ccl2 and Ccl12, identifying macrophages as a likely source of those chemokines, yet this reduction failed to rescue muscle mass or fiber size. Neutrophil depletion, meanwhile, pushed Cxcl1 and Cxcl2 even higher, correlating with heightened atrogene expression and more severe atrophy. The infiltrating immune cells, it seems, perform essential housekeeping, clearing debris from the dying progenitors and resolving tissue stress, and their absence leaves the muscle more vulnerable, not less.

If the cells were not the problem, perhaps their signaling was. The team turned to pharmacology, treating mice with either SB225002, a selective antagonist of the CXCR2 receptor through which CXCL1 and CXCL2 act, or VBP15, also known as vamorolone, a dissociative anti-inflammatory steroid that inhibits the NF-kappa-B pathway, a central transcriptional regulator of wasting programs. Both interventions produced striking protection. Treated FAP-depleted mice retained their lean mass and fat mass, their muscles kept significantly more wet weight and fiber cross-sectional area, and their atrogene expression was substantially suppressed. Critically, immunofluorescence confirmed that neither drug changed the number of immune cells entering the tissue. The protection came from quieting inflammatory signaling, not from blocking infiltration. The two drugs also worked through distinguishable mechanisms: vamorolone broadly suppressed chemokine expression, while CXCR2 blockade triggered a compensatory rise in CXCL1 and CXCL2, a classic feedback loop when ligands can no longer engage their receptor.

The study’s authors are careful about what these results do and do not prove. Because eliminating FAPs necessarily involves killing them, the design cannot fully separate the loss of FAP-derived trophic support from the consequences of cell death itself. The transient drop in muscle Igf1 expression and the modest rise in myostatin hint that trophic factors may contribute, yet previous work showing that deleting Igf1 specifically from FAPs does not shrink muscle argues against trophic loss as the primary driver. The authors suggest that the early atrophy reflects the inflammatory fallout of progenitor death rather than evidence that FAPs actively protect muscle mass under normal conditions, though they acknowledge that other FAP-derived factors likely matter for long-term homeostasis, particularly given that transplanting FAPs back into muscle partially rescues the atrophy.

The implications reach well beyond this mouse model. Inflammation has long been recognized as a driver of muscle wasting in cancer cachexia, sarcopenia and chronic disease, and therapies that blunt inflammatory signaling are actively pursued. This study adds a crucial nuance: the same immune cells can be simultaneously protective and destructive, depending on whether one removes the cells or modulates their signals. Physical depletion of myeloid populations worsened wasting, while receptor-level and transcriptional modulation of their inflammatory output preserved muscle. For clinicians and drug developers, the lesson is that the target is not the inflammatory cells themselves but the molecular conversations they conduct, particularly the CXCL1/2-CXCR2 axis and the NF-kappa-B pathway it feeds. As the population ages and muscle wasting syndromes impose enormous clinical burdens, understanding how the death of a single supporting cell type can ignite a self-sustaining cycle of inflammation and proteolysis may prove to be one of the most consequential insights in muscle biology.

Subject of Research: Mechanisms of inflammation-mediated skeletal muscle atrophy following fibro-adipogenic progenitor ablation in mice

Article Title: Fibro‐Adipogenic Progenitor Ablation Triggers Muscle Atrophy Through Cell Death‐Induced Inflammation

Article References: Luo, Y. E., Lee, Y. I., Abe‐Teh, Z., Young, R. Y., Wei‐LaPierre, L., & Barton, E. R. (2026). Fibro‐Adipogenic Progenitor Ablation Triggers Muscle Atrophy Through Cell Death‐Induced Inflammation. Journal of Cachexia, Sarcopenia and Muscle, 17(5), Article e70393. https://doi.org/10.1002/jcsm.70393

Image Credits: AI Generated

DOI: 10.1002/jcsm.70393

Keywords: fibro-adipogenic progenitors, skeletal muscle atrophy, inflammation, CXCR2, NF-kappa-B, neuromuscular junction, macrophages, neutrophils, cachexia, sarcopenia, chemokines, vamorolone

Cachexia is one of oncology’s most feared complications. More than half of patients with advanced non-small cell lung cancer, which accounts for over 85 percent of lung cancer cases, develop the syndrome, which is characterized by anorexia, progressive weight loss and the relentless erosion of skeletal muscle and fat. Unlike simple malnutrition, cachexia cannot be reversed with nutritional support alone. It is driven by systemic inflammation and profound metabolic dysregulation, and it directly contributes to as much as 20 percent of all cancer-related deaths. Patients with cachexia tolerate anti-tumour therapies poorly, suffer diminished quality of life and die sooner. Despite decades of research, no effective pharmacological therapy exists, leaving clinicians to rely on multimodal strategies aimed at reducing inflammation, preserving lean body mass and improving appetite.

The research team, led by Yingjia Zhou, Shaoli Zhao and Huantian Cui, chose Huangqi Guizhi Wuwu Decoction, commonly abbreviated HGWD, because of its well-documented immunomodulatory, anti-inflammatory and microcirculatory properties. The formula is already used clinically in China to manage metabolic dysfunction and immune dysregulation, particularly chemotherapy-related side effects such as peripheral neuropathy. Yet its potential role in tumour-induced cachexia had never been examined. To test it, the researchers implanted Lewis lung carcinoma cells into eight-week-old male C57BL/6 mice, a widely used model of lung cancer cachexia, and randomly assigned fifty animals to five groups: tumour-free controls, untreated cachectic mice, mice treated with the chemotherapy drug cisplatin, and cachectic mice given either a low or high dose of HGWD by daily gastric gavage for fourteen consecutive days.

The results were unambiguous. By days seven and fourteen of treatment, untreated cachectic mice showed a marked decline in grip strength and wire-hang endurance, while mice receiving the high dose of HGWD maintained significantly greater muscle strength. Cisplatin, notably, failed to improve muscle function and in some measures made matters worse. HGWD also increased tumour-free body weight, gastrocnemius and quadriceps muscle mass, and epididymal fat mass, all of which were severely depleted in the untreated cachectic animals. Histological examination confirmed the protective effect: the cross-sectional area of skeletal muscle fibres, which shrank dramatically in cachectic mice, was substantially preserved in the HGWD-treated groups.

At the molecular level, the remedy appeared to reinvigorate the muscle’s own building machinery. Cachectic mice showed sharp reductions in MYHC, MYOD1 and MYOG, proteins essential for myogenesis, along with elevated ATROGIN-1, a key marker of muscle atrophy. HGWD partially restored the myogenic proteins and suppressed ATROGIN-1. The treatment also corrected metabolic and oxidative stress abnormalities in the muscle: glycogen levels, which had collapsed, recovered; lactic acid accumulation diminished; the antioxidant enzymes superoxide dismutase and glutathione peroxidase rebounded; and malondialdehyde, a marker of lipid peroxidation, fell. Intriguingly, HGWD also reduced tumour volume and weight, whereas cisplatin did not rescue, and sometimes worsened, the wasting parameters despite its antitumour action. HGWD-treated mice additionally ate and drank more, a factor the authors acknowledge could contribute to the improvements.

To uncover the mechanism, the team turned to transcriptome sequencing of the gastrocnemius muscle. Comparing untreated cachectic mice with healthy controls revealed widespread disruption of pathways including amino acid biosynthesis, cysteine and methionine metabolism, arginine and proline metabolism, glycolysis, the HIF-1 signalling pathway and cytokine receptor interactions. When the high-dose HGWD group was compared with the untreated cachectic group, the picture shifted dramatically: the most enriched pathways were again dominated by amino acid metabolism, alongside the PPAR signalling pathway, cholesterol metabolism, galactose metabolism and calcium signalling. Crucially, HGWD markedly upregulated genes encoding motor proteins, including Myhas, Mylpf and Myl1, which are critical for maintaining muscle mass, driving myogenesis and regulating contractility.

Untargeted metabolomics of the same muscle tissue told a complementary story. Principal component and discriminant analyses showed that HGWD substantially reshaped the aberrant metabolite profile of cachectic muscle, and pathway enrichment again pointed squarely at amino acid biosynthesis. Among the metabolites restored by the treatment were S-adenosylmethionine, known as SAM, L-arginine, L-tryptophan, L-ornithine, L-leucine and spermidine. Each of these molecules has established links to muscle health: arginine and leucine supplementation has been shown to partially mitigate cachexia in prior studies, accelerated tryptophan catabolism contributes to sarcopenia, ornithine supports mitochondrial and redox function in wasting states, and spermidine plays a well-documented role in protecting against muscle ageing and preserving muscle homeostasis.

The deepest insight came from integrating the two datasets. The researchers found that HGWD upregulated the genes Amd1, Amd2 and Smox while downregulating Gnmt. AMD1 and AMD2 are rate-limiting enzymes that convert SAM into decarboxylated SAM, supplying the propylamine groups needed to synthesize polyamines such as spermidine. SMOX then converts decarboxylated SAM into spermidine, and its expression positively correlates with muscle mass and function. GNMT, by contrast, channels SAM toward S-adenosylhomocysteine, and its dysregulation lowers the SAM/SAH ratio, a change closely linked to muscle ageing and cachexia progression. Western blot analysis confirmed the pattern at the protein level: AMD1 and SMOX rose, GNMT fell. The authors propose that HGWD alleviates cachexia by suppressing GNMT, raising the SAM/SAH ratio and enhancing the conversion of SAM into spermidine, thereby restoring amino acid metabolic homeostasis in skeletal muscle.

The study is not without caveats, which the authors address candidly. Because HGWD also reduced tumour burden and increased food intake, the muscle-protective effect could be secondary to reduced tumour-derived catabolic signalling or improved nutrition rather than a direct metabolic action within muscle tissue; a pair-feeding experiment would be needed to disentangle these possibilities. The findings are also correlational, lacking direct causal proof, and the specific bioactive compounds within the multi-herb formula responsible for the effect remain unidentified. The team plans follow-up work using in vitro myotube atrophy models treated with HGWD-containing serum, combined with siRNA knockdown of AMD1 or SMOX and enzyme inhibitors, alongside multi-omics integration and target-validation techniques such as surface plasmon resonance and drug affinity responsive target stability assays.

Even so, the implications are considerable. With no approved pharmacological therapy for cancer cachexia and more than half of advanced lung cancer patients affected, a well-tolerated, orally available formula that simultaneously preserves muscle, corrects metabolic derangement and modestly inhibits tumour growth represents an unusually attractive therapeutic profile. The identification of the SAM-to-spermidine axis as a plausible mechanism also gives researchers a concrete molecular handle for drug development, whether inspired by the herbal formula itself or by synthetic compounds that mimic its enzymatic effects. For now, the work stands as a rigorous, multi-omics demonstration that a medicine brewed from herbs first described centuries ago can act on modern molecular targets, and it opens a promising path toward clinical evaluation of HGWD in patients whose cancers are stealing their muscle, strength and time.

Subject of Research: Mechanisms of a traditional Chinese medicine formula in treating lung cancer–induced cachexia through amino acid metabolism regulation

Article Title: Huangqi Guizhi Wuwu Decoction Ameliorates Cachexia in Lung Cancer Mice Through Regulating Amino Acid Metabolism: Insights From Transcriptomics, Metabolomics and Experimental Validation

Article References: Zhou, Y., Zhao, S., Shen, H., Wu, J., Li, M., Liu, S., Yang, J., Jin, X., Li, F., & Cui, H. (2026). Huangqi Guizhi Wuwu Decoction Ameliorates Cachexia in Lung Cancer Mice Through Regulating Amino Acid Metabolism: Insights From Transcriptomics, Metabolomics and Experimental Validation. Journal of Cellular and Molecular Medicine, 30(19), Article e71387. https://doi.org/10.1111/jcmm.71387

Image Credits: AI Generated

DOI: 10.1111/jcmm.71387

Keywords: cancer cachexia, lung cancer, Huangqi Guizhi Wuwu Decoction, traditional Chinese medicine, amino acid metabolism, spermidine, S-adenosylmethionine, skeletal muscle atrophy, transcriptomics, metabolomics, Lewis lung carcinoma, myogenesis