Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (825 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Historically, a heterogeneous group of acute and chronic diseases, including rheumatoid arthritis, systemic lupus erythematosus, progressive systemic sclerosis, dermatomyositis, etc. This classification was based on the notion that collagen was equivalent to connective tissue, but with the present recognition of the different types of collagen and the aggregates derived from them as distinct entities, the term collagen diseases now pertains exclusively to those inherited conditions in which the primary defect is at the gene level and affects collagen biosynthesis, post-translational modification, or extracellular processing directly. (From Cecil Textbook of Medicine, 19th ed, p1494)
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Collagen Disease; Disease, Collagen; Diseases, Collagen.
Where it fits in the MeSH classification
- Broader topics
- Connective Tissue Diseases
- Narrower topics
- Ehlers-Danlos Syndrome; Epidermolysis Bullosa Dystrophica; Keloid; Necrobiotic Disorders; Nephritis, Hereditary; Osteogenesis Imperfecta
Research landscape
PubMed indexes 26,738 records tagged with the MeSH heading “Collagen Diseases” (counts retrieved 2026-11-04). 4,502 of them (16.8%) were published from 2020 onward, and the busiest period so far is through 1999 with 12,955 records.
Reviews account for 3,652 records (13.7%) and meta-analyses for 92. Randomized controlled trials number 202 (0.8%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 12,955 |
| 2000-2009 | 3,898 |
| 2010-2019 | 5,383 |
| 2020 onward | 4,502 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 3,652 | 13.7% |
| Meta-analyses | 92 | 0.3% |
| Randomized controlled trials | 202 | 0.8% |
Method: PubMed query "Collagen Diseases"[MeSH Terms] with publication-type and date filters, retrieved 2026-11-04.
Reading the evidence in bones, joints, muscles and skin
Joint, bone, muscle and skin conditions are often judged by pain scores, function questionnaires, imaging or photographs, and symptoms can fluctuate, so placebo response and natural improvement matter. Imaging changes are common in people without symptoms. Nothing on this page is advice about treatment. Check how outcomes were measured, whether the comparison group received a placebo or usual care, and how long the benefit lasted.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Cytokines, chemokines and growth factors involved in keloids pathogenesis | 2025 | Review article Design not recorded in structured metadata | 11 | cc by PMID 39799030 · DOI · PMC11963030 |
| The administration of exogenous HSP47 as a collagen-specific therapeutic approach | 2025 | Research article Design not recorded in structured metadata | 10 | cc by PMID 39913197 · DOI · PMC11949040 |
| Increased expression of the PIEZO2 mechanoreceptor in fibroblasts and endothelial cells within the lymphatic and vascular vessels of keloids | 2025 | Research article Design not recorded in structured metadata | 9 | cc by PMID 40742741 · DOI · PMC12337814 |
| From RAAS blockade to regenerative medicine: evolving treatment strategies in Alport syndrome | 2026 | Review article Design not recorded in structured metadata | 6 | cc by PMID 41243004 · DOI · PMC12852298 |
Cytokines, chemokines and growth factors involved in keloids pathogenesis [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Keloid is a common fibrotic disease, which is difficult to treat.
- Closing excerpt
- This paper presents a detailed and comprehensive literature review on this subject.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (122 words)
Keloid is a common fibrotic disease, which is difficult to treat. It often causes itching and pain, which greatly disturbs patients in their work and daily life and causing difficulties in social interaction. Its pathogenesis is not clear, but may be related to several aspects: genetic susceptibility, environmental, immunological and endocrine factors, trauma and tension. The central point of its pathogenesis is the excessive proliferation of fibroblasts, with excessive synthesis and secretion of extracellular matrix such as collagen. However, the cause of fibroblast excessive proliferation and differentiation is not clear. Immune abnormalities may play an important role, with cytokines, chemokines, growth factors, and other important immune molecules acting on fibroblasts. This paper presents a detailed and comprehensive literature review on this subject.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39799030 · DOI · PMC11963030
The administration of exogenous HSP47 as a collagen-specific therapeutic approach [2]
Abstract reading summary — source excerpts
- Opening excerpt
- The proof of principle of the therapeutic potential of heat shock protein 47 (HSP47) for diseases characterized by defects in collagen I synthesis is here demonstrated in osteogenesis imperfecta (OI), a prototype of collagen disorders.
- Closing excerpt
- A beneficial effect on bone mineralization was demonstrated in vivo in the zebrafish p3h1-/- OI model.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (199 words)
The proof of principle of the therapeutic potential of heat shock protein 47 (HSP47) for diseases characterized by defects in collagen I synthesis is here demonstrated in osteogenesis imperfecta (OI), a prototype of collagen disorders. Most of the OI mutations delay collagen I chain folding, increasing their exposure to posttranslational modifications that affect collagen secretion and impact extracellular matrix fibril assembly. As a model, we used primary fibroblasts from OI individuals with a defect in the collagen prolyl 3-hydroxylation complex, since they are characterized by the synthesis of homogeneously overmodified collagen molecules. We demonstrated that exogenous recombinant HSP47 (rHSP47) is taken up by the cells and localizes at the ER exit sites and ER-Golgi intermediate compartment. rHSP47 treatment increased collagen secretion, reduced collagen posttranslational modifications and intracellular collagen retention, and ameliorated general ER proteostasis, leading to improved cellular homeostasis and vitality. These positive changes were also mirrored by an increased collagen content in the OI matrix. A mutation-dependent effect was found in fibroblasts from 3 probands with collagen I mutations, for which rHSP47 was effective only in cells with the most N-terminal defect. A beneficial effect on bone mineralization was demonstrated in vivo in the zebrafish p3h1-/- OI model.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39913197 · DOI · PMC11949040
Increased expression of the PIEZO2 mechanoreceptor in fibroblasts and endothelial cells within the lymphatic and vascular vessels of keloids [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Keloids are scars that grow abnormally due to excessive extracellular matrix production by fibroblasts and increased angiogenesis.
- Closing excerpt
- The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (260 words)
Keloids are scars that grow abnormally due to excessive extracellular matrix production by fibroblasts and increased angiogenesis. Chronic tension is implicated in their growth, but the exact pathology remains unclear. This study investigated the increased expression of molecules responsible for sensing pressure in keloids compared with lymphedema, which is also a non-tumorous fibroproliferative disease caused by another etiology. Higher expression levels of COL1A2, PIEZO2, and POSTN were observed in the keloid group compared with the lymphedema group. PIEZO2 expression levels showed a strong correlation with both COL1A2 (r = 0.9252, 95% CI 0.8474-0.9641, p < 0.001) and POSTN (r = 0.9118, 95% CI 0.8213-0.9575, p < 0.001). Additionally, PIEZO2 expression levels were significantly higher in recurrent keloids than in non-recurrent keloids (3,032.5 ± 1,090.2 versus 1,241.9 ± 860.7, p = 0.032). Analysis of gene expression at the single-cell level found upregulation of PIEZO2 in vascular and lymphatic endothelial cells, and a subgroup of fibroblasts. Additionally, COL1A1, COL1A2, COL3A1, and POSTN expression was also increased in the fibroblast subgroup. Furthermore, in fibroblasts with high PIEZO2 expression, extracellular matrix collagen production signaling was augmented. Histological analysis confirmed the presence of PIEZO2-positive cells in the perivascular stroma active area of keloid tissue, together with inflammatory cells. Therefore, since PIEZO2-positive cells are highly expressed specifically in keloids and are deeply involved in their recurrence and activity, we propose that the pathogenesis of keloids is constructed by PIEZO2-positive cells. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 40742741 · DOI · PMC12337814
From RAAS blockade to regenerative medicine: evolving treatment strategies in Alport syndrome [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Alport syndrome (AS) is a hereditary glomerulopathy caused by mutations in the COL4A3, COL4A4, or COL4A5 genes, leading to progressive kidney decline and extrarenal manifestations.
- Closing excerpt
- Emphasis is placed on the molecular mechanisms underlying podocyte injury and fibrosis, recent preclinical findings, and ongoing clinical trials that may shift future therapeutic paradigms.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (244 words)
Alport syndrome (AS) is a hereditary glomerulopathy caused by mutations in the COL4A3, COL4A4, or COL4A5 genes, leading to progressive kidney decline and extrarenal manifestations. Advances in genetic testing have enabled the reclassification of AS into X-linked, autosomal recessive, and autosomal dominant forms, facilitating more accurate diagnosis and risk stratification. While renin-angiotensin-aldosterone system (RAAS) blockade remains the foundation of treatment to delay kidney failure, it does not directly target the underlying molecular pathology. Adjunctive commercially available metabolic modulators, including SGLT2i, mineralocorticoid receptor antagonists, ezetimibe and GLP-1 receptor agonists, may offer additional kidney protection. Ameliorating therapies being tested in Phase II trials include endothelin receptor antagonists (e.g., atrasentan), dual endothelin receptor antagonist and angiotensin II receptor inhibition (e.g., sparsentan) FXR agonists (e.g., vonafexor), inducers of cholesterol efflux (e.g., VAR200 and R3R01), and NOX1/4 inhibitors (e.g., setanaxib), several of which are currently being evaluated in clinical trials. Novel strategies such as exon skipping, gene editing, and nonsense mutation readthrough (e.g., ELX-02) are advancing toward precision medicine approaches as disease modifying agents targeting the genetic cause of AS. Moreover, therapies targeting mitochondrial function, such as mitophagy enhancers, have demonstrated preclinical promise. Stem cell-based approaches are also being explored for their regenerative and anti-fibrotic effects. This review summarizes the current landscape of AS classification and treatment, highlighting both standard interventions and experimental therapies. Emphasis is placed on the molecular mechanisms underlying podocyte injury and fibrosis, recent preclinical findings, and ongoing clinical trials that may shift future therapeutic paradigms.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41243004 · DOI · PMC12852298
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article The Most Current Algorithms for the Treatment and Prevention of Hypertrophic Scars and Keloids: A 2020 Update of the Algorithms Published 10 Years Ago [5]
- Research article Scars [6]
- Research article Treatment of keloids and hypertrophic scars: a meta-analysis and review of the literature [7]
- Research article Inflammation in Wound Healing and Pathological Scarring [8]
- Research article Keloid treatments: an evidence-based systematic review of recent advances [9]
- Research article Hypertrophic Scars and Keloids: Advances in Treatment and Review of Established Therapies [10]
References
- Liu M. Cytokines, chemokines and growth factors involved in keloids pathogenesis. . 2025. PMID 39799030 · DOI · PMC11963030
- Besio R, Garibaldi N, Sala A, Tonelli F, Aresi C, Maffioli E, et al.. The administration of exogenous HSP47 as a collagen-specific therapeutic approach. . 2025. PMID 39913197 · DOI · PMC11949040
- Akita S, Ikehara S, Kiuchi M, Kokubo K, Azuma K, Ohki S, et al.. Increased expression of the PIEZO2 mechanoreceptor in fibroblasts and endothelial cells within the lymphatic and vascular vessels of keloids. . 2025. PMID 40742741 · DOI · PMC12337814
- Lo Re C, Kim JJ, Fornoni A. From RAAS blockade to regenerative medicine: evolving treatment strategies in Alport syndrome. . 2026. PMID 41243004 · DOI · PMC12852298
- Ogawa R. The Most Current Algorithms for the Treatment and Prevention of Hypertrophic Scars and Keloids: A 2020 Update of the Algorithms Published 10 Years Ago. Plast Reconstr Surg. 2022. PMID 34813576 · DOI · PMC8687618
- Jeschke MG, Wood FM, Middelkoop E, Bayat A, Teot L, Ogawa R, et al.. Scars. Nat Rev Dis Primers. 2023. PMID 37973792 · DOI
- Leventhal D, Furr M, Reiter D. Treatment of keloids and hypertrophic scars: a meta-analysis and review of the literature. Arch Facial Plast Surg. 2006. PMID 17116782 · DOI
- Hong YK, Chang YH, Lin YC, Chen B, Guevara BEK, Hsu CK. Inflammation in Wound Healing and Pathological Scarring. Adv Wound Care (New Rochelle). 2023. PMID 36541356 · DOI
- Walsh LA, Wu E, Pontes D, Kwan KR, Poondru S, Miller CH, et al.. Keloid treatments: an evidence-based systematic review of recent advances. Syst Rev. 2023. PMID 36918908 · DOI · PMC10012475
- Frech FS, Hernandez L, Urbonas R, Zaken GA, Dreyfuss I, Nouri K. Hypertrophic Scars and Keloids: Advances in Treatment and Review of Established Therapies. Am J Clin Dermatol. 2023. PMID 36662366 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-11-04; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-11-04.
See how EvidenceLib is built. Spotted an error? Email support@evidencehelix.com.
Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.