{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T06:47:52Z","timestamp":1782456472559,"version":"3.54.5"},"reference-count":21,"publisher":"Croatian Society for Medical Biochemistry and Laboratory Medicine","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biochem. med. (Online)"],"published-print":{"date-parts":[[2026,6,15]]},"abstract":"<jats:p>\n                    <jats:bold>Introduction:<\/jats:bold>\n                    Gla-rich protein (GRP) is a vitamin K-dependent protein involved in the regulation of ectopic calcification and inflammatory processes. However, data on circulating GRP concentrations in healthy adults remain limited.\n                    <jats:bold>Materials and methods:<\/jats:bold>\n                    This cross-sectional observational study evaluated serum total GRP (tGRP) concentrations in 254 healthy adult blood donors (48% male), aged 18-65 years, using a sandwich enzyme-linked immunosorbent assay (ELISA) (GenoGla Diagnostics, Faro, Portugal). Participants were stratified by age tertiles, and associations between serum tGRP concentrations and demographic and laboratory parameters were assessed using non-parametric statistical tests, Spearman correlation, and stepwise linear regression.\n                    <jats:bold>Results:<\/jats:bold>\n                    The median serum tGRP concentration in the overall population was 1809.5 pg\/mL (interquartile range: 1197.4-2476.0 pg\/mL). Serum tGRP concentrations differed significantly across age tertiles (P = 0.038), with higher concentrations observed in younger adults. Serum tGRP concentrations showed a weak but statistically significant inverse correlation with age (r = - 0.30, P = 0.001), while no significant differences were observed between sexes (P = 0.420). In multivariable analysis, age and serum calcium concentration remained independently associated with serum tGRP concentrations, jointly explaining approximately 7% of their variability.\n                    <jats:bold>Conclusion:<\/jats:bold>\n                    This study establishes robust reference data for circulating tGRP concentrations in healthy adults, providing a foundation for the interpretation of GRP measurements in future clinical and epidemiological research.\n                  <\/jats:p>","DOI":"10.11613\/bm.2026.020709","type":"journal-article","created":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T07:46:31Z","timestamp":1781163991000},"page":"344-353","source":"Crossref","is-referenced-by-count":0,"title":["Factors associated with Gla-rich protein serum concentrations in healthy adults"],"prefix":"10.11613","volume":"36","author":[{"given":"Dina Costa","family":"Simes","sequence":"first","affiliation":[{"name":"Centre of Marine Sciences (CCMAR\/CIMAR LA), Universidade do Algarve, Faro, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mar\u00edlia","family":"Fa\u00edsca","sequence":"additional","affiliation":[{"name":"SYNLAB Algarve, Faro; Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leon","family":"Schurgers","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ana Paula","family":"Silva","sequence":"additional","affiliation":[{"name":"Department of Nephology, Unidade Local de Sa\u00fade do Algarve (ULSA), Faro, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Selene","family":"Nunes","sequence":"additional","affiliation":[{"name":"Department of Imunology, Unidade Local de Sa\u00fade do Algarve (ULSA), Faro, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Catarina","family":"Marreiros","sequence":"additional","affiliation":[{"name":"Centre of Marine Sciences (CCMAR\/CIMAR LA), Universidade do Algarve, Faro, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carla","family":"Viegas","sequence":"additional","affiliation":[{"name":"Centre of Marine Sciences (CCMAR\/CIMAR LA), Universidade do Algarve, Faro, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"4885","published-online":{"date-parts":[[2026,6,15]]},"reference":[{"key":"key20260611074631_r1","doi-asserted-by":"crossref","first-page":"36655","DOI":"10.1074\/jbc.M802761200","article-title":"Gla-rich Protein (GRP), A New Vitamin K-dependent Protein Identified from Sturgeon Cartilage and Highly Conserved.","volume":"283","author":"Viegas","year":"2008","journal-title":"J Biol 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Turnover.","volume":"69","author":"Stock","year":"2017","journal-title":"Arthritis Rheumatol"},{"key":"key20260611074631_r5","doi-asserted-by":"crossref","first-page":"1051","DOI":"10.1007\/s00018-015-2033-9","article-title":"Gla-rich protein is involved in the cross-talk between calcification and inflammation in osteoarthritis.","volume":"73","author":"Cavaco","year":"2016","journal-title":"Cell Mol Life Sci"},{"key":"key20260611074631_r6","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0177829","article-title":"Gla-rich protein function as an anti-inflammatory agent in monocytes\/ macrophages: Implications for calcification-related chronic inflammatory diseases.","volume":"12","author":"Viegas","year":"2017","journal-title":"PLoS One"},{"key":"key20260611074631_r7","doi-asserted-by":"crossref","first-page":"680","DOI":"10.1016\/j.bbrc.2020.07.114","article-title":"Unique cartilage matrix-associated protein inhibits the migratory and invasive potential of triple-negative breast cancer.","volume":"530","author":"Lee","year":"2020","journal-title":"Biochem Biophys Res Commun"},{"issue":"5","key":"key20260611074631_r8","doi-asserted-by":"crossref","first-page":"1959","DOI":"10.21873\/anticanres.16355","article-title":"Anti-cancer Effect of Unique Cartilage Matrix-associated Protein in Breast Cancer Cells Depends on \u03b3-Carboxylation.","volume":"43","author":"Park","year":"2023","journal-title":"Anticancer Res"},{"key":"key20260611074631_r9","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1161\/ATVBAHA.114.304823","article-title":"Gla-rich protein acts as a calcification inhibitor in the human cardiovascular system.","volume":"35","author":"Viegas","year":"2015","journal-title":"Arterioscler Thromb Vasc Biol"},{"key":"key20260611074631_r10","doi-asserted-by":"crossref","first-page":"81","DOI":"10.46497\/ArchRheumatol.2024.10066","article-title":"Comparison of the protective effect of the upper zone of the growth plate and unique cartilage matrix-associated protein with hyaluronic acid and corticosteroids on an experimental rat osteoarthritis model.","volume":"39","author":"G\u00f6kdemir","year":"2024","journal-title":"Arch Rheumatol"},{"key":"key20260611074631_r11","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1186\/s13075-018-1583-2","article-title":"Upper zone of growth plate and cartilage matrix associated protein protects cartilage during inflammatory arthritis.","volume":"20","author":"Seuffert","year":"2018","journal-title":"Arthritis Res Ther"},{"key":"key20260611074631_r12","doi-asserted-by":"crossref","first-page":"365","DOI":"10.3390\/jcm9030635","article-title":"Gla-Rich Protein (GRP) as an Early and Novel Marker of Vascular Calcification and Kidney Dysfunction in Diabetic Patients with CKD: A Pilot Cross-Sectional Study.","volume":"9","author":"Silva","year":"2020","journal-title":"J Clin Med"},{"key":"key20260611074631_r13","doi-asserted-by":"crossref","first-page":"496","DOI":"10.3390\/diagnostics12020496","article-title":"Gla-Rich Protein, Magnesium and Phosphate Associate with Mitral and Aortic Valves Calcification in Diabetic Patients with Moderate CKD.","volume":"12","author":"Silva","year":"2022","journal-title":"Diagnostics (Basel)"},{"key":"key20260611074631_r14","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3390\/jcm13237429","article-title":"Gla-Rich Protein Is Associated with Vascular Calcification, Inflammation, and Mineral Markers in Peritoneal Dialysis Patients.","volume":"13","author":"Marreiros","year":"2024","journal-title":"J Clin Med"},{"key":"key20260611074631_r15","first-page":"21","article-title":"Is Circulating Gla-Rich Protein Linked With Coronary Calcium And Cardiovascular Pathology In Patients With Atrial Fibrillation Or Heart Failure?\u202fA Pilot Study.","volume":"53","author":"Vankova","year":"2021","journal-title":"Scripta Sci 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