Explore the calcium leak hypothesis linking statins to muscle injury, insulin resistance, and progression to insulin-dependent diabetes. Mechanistic review
Abstract
The well-established cardioprotective efficacy of HMG-CoA reductase inhibitors (statins) is accompanied by two major clinical liabilities: skeletal muscle adverse effects (SMAs) and an increased incidence of new-onset type 2 diabetes mellitus (T2DM), with a subset of patients progressing to insulin dependence. Emerging evidence increasingly supports a shared molecular pathogenesis centred on disruption of intracellular calcium (Ca²⁺) homeostasis. This review integrates recent findings on statin-induced ryanodine receptor (RyR) calcium leak with the broader literature on metabolic dysfunction. We propose a unified mechanistic pathway whereby lipophilic statins destabilise RyR complexes in skeletal muscle and pancreatic β-cells, triggering Ca²⁺-dependent cascades of cellular stress, inflammation, and apoptosis. Importantly, this framework is extended to describe how sustained cytosolic Ca²⁺ overload and the associated inflammatory milieu transcriptionally and translationally suppress GLUT4 transporters and insulin receptor expression, producing profound insulin resistance. This triple-hit pathology—β-cell loss, impaired insulin secretion, and peripheral insulin resistance—offers a coherent explanation for both the diabetogenic risk of statins and the observed clinical trajectory toward oral therapy failure and exogenous insulin dependence. We emphasise that this pathway is modulated by key variables—including statin lipophilicity, dose, genetic predisposition, and baseline metabolic health—which determine individual susceptibility and clinical heterogeneity. The implications for risk stratification and the need for novel therapeutic strategies are discussed.
1. Introduction: The Triad of Statin-Associated Metabolic Dysfunction
Statins represent a cornerstone of primary and secondary prevention of atherosclerotic cardiovascular disease. Nonetheless, their widespread use is constrained by a triad of dose-limiting and progressive adverse outcomes: (1) skeletal muscle adverse effects (SMAs), affecting approximately 10–25% of patients; (2) a consistently reported 9–12% relative increase in the risk of incident T2DM; and (3) clinical observations of accelerated glycaemic deterioration in patients with pre-existing diabetes, frequently culminating in insulin dependence (Golomb & Evans, 2008; Sattar et al., 2010). Historically, these effects were examined as distinct entities—myopathy attributed to mitochondrial dysfunction and diabetes to impaired insulin secretion. The recent identification of a direct statin-induced calcium leak mechanism offers a transformative and unifying paradigm (Columbia University Irving Medical Center, 2026). This review synthesises these findings into an integrated model describing how calcium dyshomeostasis in skeletal muscle and pancreatic islets initiates inflammation, apoptosis, and—critically—a transcriptional collapse of insulin-responsive machinery, collectively driving progression toward insulin-deficient diabetes. Crucially, we frame this not as a deterministic sequence but as a modifiable pathway, where clinical outcomes are shaped by pharmacological and patient-specific factors at key branch points.
2. Schematic Figure: An Integrated Model of Statin-Induced Calcium Dyshomeostasis and Metabolic Decline
This schematic summarises the proposed unified pathway linking statin therapy to skeletal muscle dysfunction, β-cell failure, and progression toward insulin dependence, while highlighting key branch points and modifying factors that shape clinical outcomes.
2.1 Initiating Event and Key Branch Points
- Primary Insult: Lipophilic statin molecules readily cross cell membranes.
- Branch Point A (Molecular Target Specificity): Statins preferentially bind to and destabilise ryanodine receptor (RyR) complexes, representing a common upstream molecular lesion.
- Branch Point B (Tissue-Specific Cascades): RyR destabilisation induces sustained cytosolic calcium elevation ([Ca²⁺]ᵢ), initiating parallel but tissue-specific pathological cascades in skeletal muscle and pancreatic β-cells.
2.2 Converging Pathologies Leading to Insulin Dependency
-
β-Cell Pathway:
Ca²⁺ overload → ER stress and mitochondrial dysfunction → apoptosis and inflammatory insulitis → progressive β-cell mass loss and impaired insulin secretion. -
Skeletal Muscle Pathway:
Ca²⁺ overload → inflammation and oxidative stress → transcriptional and translational suppression of SLC2A4 (GLUT4) and INSR → profound, cell-autonomous insulin resistance.
2.3 Critical Modifiers Influencing Pathway Severity and Clinical Phenotype
Disease trajectory and severity are modulated by multiple non-deterministic factors, including:
- Genetic Susceptibility: Variants in RYR1/2, SLCO1B1, and genes regulating inflammatory and apoptotic thresholds.
- Statin Pharmacology: Lipophilicity (Simvastatin > Atorvastatin ≫ Pravastatin/Rosuvastatin), potency, and dose.
- Exposure Duration: Cumulative statin exposure influences progression from reversible cellular stress to irreversible dysfunction.
- Host Metabolic Context: Baseline insulin resistance, residual β-cell reserve, and systemic inflammatory tone.
2.4 Final Convergent Outcome
The combined effects of declining insulin production and impaired insulin action culminate in oral antihyperglycaemic therapy failure and, in a susceptible subset of patients, progression to exogenous insulin dependence.
3. Core Mechanism: Statin-Induced Ryanodine Receptor Dysfunction and Calcium Leak
A central mechanistic advance arises from evidence that certain lipophilic statins (e.g., simvastatin, atorvastatin) directly bind to and destabilise ryanodine receptor 1 (RyR1) in skeletal muscle (Columbia University Irving Medical Center, 2026). RyRs are large calcium release channels located on the sarcoplasmic reticulum (SR), essential for excitation–contraction coupling. Under physiological conditions, these channels open transiently in response to membrane depolarisation, releasing tightly regulated Ca²⁺ pulses. Statin binding destabilises the closed-state conformation of the RyR, converting it into a pathological “leak” channel. This results in chronic, low-level Ca²⁺ efflux from the SR into the cytosol during diastole, elevating resting intracellular Ca²⁺ concentrations ([Ca²⁺]ᵢ) (Ward et al., 2020). This step represents the first critical branch point in the pathological cascade, with the lipophilicity and dose of the statin acting as primary modifiers of its severity.
4. From Calcium Leak to Myopathy: Inflammation and Cell Death
Persistent elevation of resting [Ca²⁺]ᵢ initiates multiple pathological signalling pathways:
- Mitochondrial overload and oxidative stress: Excess cytosolic Ca²⁺ is buffered by mitochondria, leading to Ca²⁺ overload, disruption of the electron transport chain, reduced ATP generation, and increased reactive oxygen species (ROS) production (Dirks & Jones, 2006).
- Protease activation: Ca²⁺-dependent proteases such as calpain are activated, resulting in cleavage of structural proteins including titin and nebulin, thereby compromising sarcomeric integrity (Huang & Zhu, 2016).
- Inflammasome activation: Mitochondrial ROS and Ca²⁺ signalling activate the NLRP3 inflammasome, promoting maturation and release of pro-inflammatory cytokines such as IL-1β and IL-18 (Gurung et al., 2015).
- Apoptosis induction: Sustained mitochondrial Ca²⁺ overload lowers the threshold for mitochondrial permeability transition pore (mPTP) opening, leading to cytochrome c release and caspase activation, culminating in apoptosis (Giorgi et al., 2012).
Together, this self-reinforcing cycle—calcium leak → oxidative stress and proteolysis → inflammation → apoptosis—accounts for the full spectrum of SMAs, from benign myalgia to rare rhabdomyolysis.
5. Extension to the Pancreatic β-Cell: A Pathway to Dysfunction and Loss
The hypothesis gains further relevance when extended to pancreatic β-cells, which depend critically on finely regulated Ca²⁺ dynamics for glucose-stimulated insulin secretion (GSIS). The β-cell endoplasmic reticulum (ER), analogous to muscle SR, expresses RyRs and IP₃ receptors (IP₃Rs). This represents Branch Point B, where the same initiating molecular insult (RyR destabilisation) manifests in a distinct, tissue-specific pathology.
- Dual-insult model: Lipophilic statins are hypothesised to similarly destabilise RyR/IP₃R function in β-cells, causing ER Ca²⁺ depletion and sustained cytosolic Ca²⁺ elevation (Yaluri et al., 2016).
- Impaired insulin secretion: Chronically elevated basal [Ca²⁺]ᵢ blunts the oscillatory Ca²⁺ signals required for effective GSIS, leading to secretory failure.
- β-Cell apoptosis: ER stress from Ca²⁺ depletion and mitochondrial dysfunction from Ca²⁺ overload activate intrinsic apoptotic pathways, rendering β-cells particularly vulnerable (Lupi et al., 2002).
- Inflammatory amplification: Apoptotic β-cells release damage-associated molecular patterns (DAMPs), promoting local insulitis and chronic inflammatory stress that accelerates islet loss (Donath et al., 2019).
This establishes a vicious cycle of Ca²⁺ leak, dysfunction, inflammation, and progressive β-cell depletion, the severity of which is modified by intrinsic β-cell resilience and the individual’s inflammatory tone.
6. Hypothesised Pathway: Calcium Overload, Transcriptional Dysregulation, and Downregulation of GLUT4 and Insulin Receptors
Beyond acute cell death, sustained cytosolic Ca²⁺ overload and the attendant inflammation are proposed to disrupt the machinery responsible for maintaining cellular insulin sensitivity, representing a slower but highly consequential pathway to metabolic dysfunction.
6.1 Calcium-Mediated Disruption of Anabolic Signalling
Chronic elevation of [Ca²⁺]ᵢ aberrantly activates Ca²⁺-dependent kinases, including PKC isoforms and CaMKII, which inhibit insulin signalling through serine phosphorylation and degradation of IRS-1, impairing PI3K/Akt activation (Bouzakri & Zierath, 2007). Reduced Akt signalling suppresses mTORC1, a master regulator of protein synthesis necessary for GLUT4 expression (Kjobsted et al., 2018).
6.2 Inflammatory Suppression of Metabolic Gene Expression
Calcium-driven inflammasome activation releases TNF-α and IL-1β, which activate stress kinases such as JNK and IKKβ. These pathways inhibit insulin signalling and activate NF-κB, which antagonises transcriptional regulators required for SLC2A4 (GLUT4) and INSR gene expression, including PPARγ (Shoelson et al., 2007).
6.3 Disruption of mRNA Stability and Translation
Inflammation and ER stress destabilise GLUT4 and INSR mRNA via RNA-binding proteins targeting their 3′-UTRs, while activation of the integrated stress response phosphorylates eIF2α, broadly suppressing translation of insulin-signalling proteins (Pakos-Zebrucka et al., 2016).
6.4 Unified Model of Transcriptional–Translational Collapse
Collectively, these processes result in a sustained, compound loss of GLUT4 and insulin receptor proteins at the cell surface, producing severe, cell-autonomous insulin resistance that is refractory to physiological insulin signalling.
7. Progression to Insulin Dependence: Converging β-Cell Failure and Peripheral Resistance
Progression to insulin dependence arises from the convergence of two inexorable pathologies: (1) declining β-cell mass due to Ca²⁺-mediated apoptosis and (2) entrenched peripheral insulin resistance driven by loss of GLUT4 and insulin receptors. Oral hypoglycaemic therapies become ineffective as β-cell reserve collapses and downstream insulin signalling is transcriptionally compromised (Del Guerra et al., 2005). Once β-cell mass falls below a critical threshold and muscle resistance is solidified, endogenous insulin secretion becomes grossly insufficient, necessitating exogenous insulin replacement (Butler et al., 2003; Swinnen et al., 2009). The duration of statin exposure acts as a key temporal modifier of this convergence.
8. Acknowledging Modifiers and Clinical Heterogeneity: Beyond a Linear Cascade
While the schematic pathway provides a coherent mechanistic narrative, it does not imply inevitability. Clinical outcomes are contingent upon several modifying factors:
- Genetic Predisposition: Variants in RYR1/2 and SLCO1B1, as well as genes governing inflammatory and apoptotic thresholds, influence susceptibility (Ward et al., 2020).
- Statin Pharmacology: Lipophilicity, dose, and potency determine tissue penetration and magnitude of the initiating insult.
- Baseline Metabolic Health: Pre-existing insulin resistance, limited β-cell reserve, and pro-inflammatory states lower the threshold for pathway activation.
9. Conclusion and Future Research Directions
The calcium leak hypothesis provides a coherent and testable framework linking statin-associated myopathy, β-cell dysfunction, and insulin resistance through a shared upstream event. By positioning RyR-mediated Ca²⁺ dyshomeostasis as the initiator, it explains the observed progression from hyperglycaemia to oral therapy failure and insulin dependence in susceptible individuals. Incorporation of pharmacological, genetic, and host modifiers accounts for clinical heterogeneity and guards against oversimplification. Future research should directly validate Ca²⁺ leak in human muscle and β-cells, characterise transcriptional repression of metabolic genes, identify predictive biomarkers, and evaluate adjunctive therapies capable of stabilising Ca²⁺ handling without compromising lipid-lowering efficacy. If confirmed, this paradigm may enable safer and more personalised statin therapy while preserving its substantial cardiovascular benefits.
References
Bouzakri, K. & Zierath, J.R. (2007) MAP4K4 gene silencing in human skeletal muscle prevents tumor necrosis factor-α-induced insulin resistance. Journal of Biological Chemistry, 282(11), 7783-7789.
Butler, A.E., Janson, J., Bonner-Weir, S., Ritzel, R., Rizza, R.A. & Butler, P.C. (2003) Beta-cell deficit and increased beta-cell apoptosis in humans with type 2 diabetes. Diabetes, 52(1), 102-110.
Cholesterol Treatment Trialists' (CTT) Collaboration. (2012) The effects of lowering LDL cholesterol with statin therapy in people at low risk of vascular disease: meta-analysis of individual data from 27 randomised trials. The Lancet, 380(9841), 581–590.
Columbia University Irving Medical Center. (2026) Scientists finally uncover why statins cause muscle pain. ScienceDaily. [Online] Available at: www.sciencedaily.com/releases/2026/01/260114110816.htm [Accessed 15 January 2026].
Del Guerra, S., Lupi, R., Marselli, L., Masini, M., Bugliani, M., Sbrana, S., Torri, S., Pollera, M., Boggi, U., Mosca, F., Del Prato, S. & Marchetti, P. (2005) Functional and molecular defects of pancreatic islets in human type 2 diabetes. Diabetes, 54(3), 727-735.
Dirks, A.J. & Jones, K.M. (2006) Statin-induced apoptosis and skeletal myopathy. American Journal of Physiology-Cell Physiology, 291(6), C1208-C1212.
Donath, M.Y., Dinarello, C.A. & Mandrup-Poulsen, T. (2019) Targeting innate immune mediators in type 1 and type 2 diabetes. Nature Reviews Immunology, 19(12), 734-746.
Giorgi, C., Baldassari, F., Bononi, A., Bonora, M., De Marchi, E., Marchi, S., Missiroli, S., Patergnani, S., Rimessi, A., Suski, J.M., Wieckowski, M.R. & Pinton, P. (2012) Mitochondrial Ca²⁺ and apoptosis. Cell Calcium, 52(1), 36-43.
Golomb, B.A. & Evans, M.A. (2008) Statin adverse effects: a review of the literature and evidence for a mitochondrial mechanism. American Journal of Cardiovascular Drugs, 8(6), 373-418.
Gurung, P., Lukens, J.R. & Kanneganti, T.D. (2015) Mitochondria: diversity in the regulation of the NLRP3 inflammasome. Trends in Molecular Medicine, 21(3), 193-201.
Huang, Y. & Zhu, M. (2016) The mechanism of statin-associated myopathy: a role for the ubiquitin-proteasome pathway. Therapeutic Advances in Chronic Disease, 7(5), 289-296.
Kawai, T., Autieri, M.V. & Scalia, R. (2015) Adipose tissue inflammation and metabolic dysfunction in obesity. American Journal of Physiology-Cell Physiology, 320(3), C375-C391.
Kjobsted, R., Hingst, J.R., Fentz, J., Foretz, M., Sanz, M.N., Pehmoller, C., Shum, M., Marette, A., Mounier, R., Treebak, J.T., Viollet, B., Lantier, L. & Wojtaszewski, J.F.P. (2018) AMPK in skeletal muscle function and metabolism. The FASEB Journal, 32(4), 1741-1777.
Lupi, R., Dotta, F., Marselli, L., Del Guerra, S., Masini, M., Santangelo, C., Patané, G., Boggi, U., Piro, S., Anello, M., Bergamini, E., Mosca, F., Di Mario, U., Del Prato, S. & Marchetti, P. (2002) Prolonged exposure to free fatty acids has cytostatic and pro-apoptotic effects on human pancreatic islets: evidence that beta-cell death is caspase mediated, partially dependent on ceramide pathway, and Bcl-2 regulated. Diabetes, 51(5), 1437-1442.
Pakos-Zebrucka, K., Koryga, I., Mnich, K., Ljujic, M., Samali, A. & Gorman, A.M. (2016) The integrated stress response. EMBO Reports, 17(10), 1374-1395.
Sattar, N., Preiss, D., Murray, H.M., Welsh, P., Buckley, B.M., de Craen, A.J., Seshasai, S.R., McMurray, J.J., Freeman, D.J., Jukema, J.W., Macfarlane, P.W., Packard, C.J., Stott, D.J., Westendorp, R.G., Shepherd, J., Davis, B.R., Pressel, S.L., Marchioli, R., Marfisi, R.M., Maggioni, A.P., Tavazzi, L., Tognoni, G., Kjekshus, J., Pedersen, T.R., Cook, T.J., Gotto, A.M., Clearfield, M.B., Downs, J.R., Nakamura, H., Ohashi, Y., Mizuno, K., Ray, K.K. & Ford, I. (2010) Statins and risk of incident diabetes: a collaborative meta-analysis of randomised statin trials. The Lancet, 375(9716), 735-742.
Shoelson, S.E., Lee, J. & Goldfine, A.B. (2007) Inflammation and insulin resistance. Journal of Clinical Investigation, 116(7), 1793-1801.
Swinnen, S.G., Hoekstra, J.B. & DeVries, J.H. (2009) Insulin therapy for type 2 diabetes. Diabetes Care, 32(Suppl 2), S253-S259.
Ward, N.C., Watts, G.F. & Eckel, R.H. (2020) Statin Toxicity: Mechanistic Insights and Clinical Implications. Circulation Research, 124(2), 328-350.
Yaluri, N., Modi, S., López Rodríguez, M., Stančáková, A., Kuusisto, J., Kokkola, T. & Laakso, M. (2016) Simvastatin impairs insulin secretion by multiple mechanisms in MIN6 cells. PLOS ONE, 11(2), e0149872.
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