Proteostasis Failure in Age-Related Internal Diseases: Mechanisms, Clinical Relevance, and Advances

Abstract

Proteostasis, the tightly regulated balance of protein synthesis, folding, trafficking, and degradation, is crucial for cellular homeostasis. In age-related internal diseases, proteostasis failure emerges as a central pathogenic mechanism, contributing to organ dysfunction and progression of chronic illnesses. This review delineates the epidemiology, mechanistic underpinnings, clinical implications, and therapeutic prospects for proteostasis impairment in aging-related disorders, integrating up-to-date evidence and expert recommendations for clinicians.

Introduction

Age-related internal diseases encompassing neurodegeneration, cardiovascular, metabolic, and renal disorders share common molecular pathologies, among which proteostasis failure is increasingly recognized as pivotal. Proteostasis collapse leads to accumulation of misfolded and aggregated proteins, driving cellular dysfunction. Understanding the mechanisms and clinical impact of proteostasis disruption is critical for developing targeted interventions in the context of aging populations.

Epidemiology / Disease Burden

Global demographic shifts towards older age groups have amplified the prevalence of chronic internal diseases. Alzheimer's disease, Parkinson's disease, type 2 diabetes mellitus, heart failure, and chronic kidney disease are all characterized by proteostasis failure. Epidemiological studies indicate that up to 70% of individuals over 65 manifest at least one chronic disease with a proteostasis component. The economic and societal burden is substantial, with neurodegenerative diseases alone projected to triple in incidence by 2050. This underscores the urgency of deciphering proteostasis pathways in age-related pathologies.

Pathophysiology

Proteostasis is orchestrated by an intricate network including molecular chaperones (e.g., HSP70, HSP90), the ubiquitin-proteasome system, and autophagy-lysosome pathways. With aging, there is a decline in the capacity of chaperones, reduced proteasomal activity, and impaired autophagic flux. These deficits result in accumulation of damaged or misfolded proteins, forming toxic aggregates hallmarks in disorders such as Alzheimer's (Aβ plaques, tau tangles), Parkinson's (α-synuclein Lewy bodies), and cardiac amyloidosis. Mitochondrial dysfunction and increased oxidative stress further exacerbate proteostatic imbalance, creating a vicious cycle of cellular injury.

Risk Factors

Genetic predispositions, such as mutations in APP, PSEN1/2 (Alzheimer's), SNCA (Parkinson's), or transthyretin (cardiac amyloidosis), elevate the risk of proteostasis failure. Environmental stressors including chronic inflammation, metabolic syndrome, toxins, and infections contribute to proteostatic burden. Aging per se impairs proteostasis through epigenetic changes, reduced expression of molecular chaperones, and cumulative oxidative damage. Comorbid conditions (e.g., diabetes, hypertension) further destabilize proteostatic mechanisms, aggravating disease progression.

Clinical Features

Clinical manifestations depend on the affected organ system. In neurodegenerative disorders, cognitive decline, movement abnormalities, and neuropsychiatric symptoms predominate. Cardiac involvement presents as restrictive cardiomyopathy, arrhythmias, and heart failure symptoms. In diabetes and metabolic syndrome, proteostasis failure manifests as insulin resistance and β-cell dysfunction. Renal diseases show proteinuria and progressive decline in glomerular filtration. Importantly, proteostasis failure may underlie increased frailty, sarcopenia, and multimorbidity in the elderly, complicating clinical management.

Diagnosis

Diagnosis of proteostasis-related diseases relies on a combination of clinical criteria, biomarker assays, and imaging. Cerebrospinal fluid analysis and PET imaging aid in detecting amyloid and tau pathology in Alzheimer's disease. Cardiac amyloidosis is diagnosed using echocardiography, cardiac MRI, and tissue biopsy with Congo red staining. Serum and urinary protein electrophoresis, genetic testing, and biomarkers such as NT-proBNP, troponins, or neurofilament light chain assist in diagnosis and prognostication. Emerging omics approaches, including proteomics and transcriptomics, are refining early detection and risk stratification.

Treatment & Management

Current management focuses on symptom alleviation, slowing disease progression, and mitigating complications. Cholinesterase inhibitors and NMDA antagonists are mainstays in Alzheimer's, while dopamine replacement therapy is standard for Parkinson's. Management of cardiac amyloidosis involves diuretics, antiarrhythmics, and transthyretin stabilizers. In metabolic diseases, glycemic control and cardiometabolic risk reduction are crucial. Multidisciplinary care, addressing nutrition, physical activity, and psychosocial aspects, is vital for improving outcomes in the elderly with proteostasis-related disorders.

Recent Advances / Emerging Therapies

Therapeutic strategies targeting proteostasis pathways are advancing rapidly. Pharmacological chaperones (e.g., tafamidis for transthyretin amyloidosis), proteasome activators, autophagy enhancers (e.g., rapalogs, spermidine), and small molecules modulating heat shock response are under investigation. Immunotherapies targeting pathological protein aggregates (e.g., aducanumab for amyloid-β) have shown promise but require further validation regarding efficacy and safety. Gene-editing technologies and RNA-based therapeutics represent frontier approaches for correcting underlying molecular defects. Combination therapies addressing multiple nodes of the proteostasis network hold potential for synergistic benefits.

Guideline Recommendations

Recent clinical guidelines emphasize early recognition and multidisciplinary management of age-related diseases with proteostasis failure. The American Academy of Neurology and European Society of Cardiology recommend biomarker-supported diagnostics and individualized care plans. For amyloidosis, consensus statements endorse genetic counseling and tailored pharmacotherapy. Guidelines highlight the importance of addressing modifiable risk factors such as hypertension, diabetes, and obesity to mitigate proteostatic burden. Regular monitoring, patient education, and advance care planning are integral to optimizing long-term outcomes.

Conclusion

Proteostasis failure is a unifying pathomechanism linking diverse age-related internal diseases. Advances in mechanistic understanding have illuminated novel therapeutic targets and refined clinical approaches. Early diagnosis, integrated management, and ongoing research into proteostasis modulation are essential to address the growing burden of chronic diseases in aging populations. Continued collaboration between basic scientists and clinicians will accelerate translation of emerging therapies into improved patient care and healthier aging trajectories.