{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,17]],"date-time":"2025-11-17T21:39:26Z","timestamp":1763415566562,"version":"build-2065373602"},"reference-count":29,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2021,9,28]],"date-time":"2021-09-28T00:00:00Z","timestamp":1632787200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmaceuticals"],"abstract":"<jats:p>There is an unmet medical need for non-invasive, sensitive, and quantitative methods for the assessment of fibrosis. Herein, an improved collagelin analogue labelled with gallium-68 for use with positron emission tomography (PET) is presented. A cyclic peptide, c[CPGRVNleHGLHLGDDEGPC], was synthesized by solid-phase peptide synthesis, conjugated to 2-(4,7-bis(2-(tert-butoxy)-2-oxoethyl)-1,4,7-triazonan-1-yl)acetic acid, and labelled with gallium-68. High performance liquid chromatography (HPLC) was used for the quality and stability assessment of the collagelin analogue. Non-specific organ distribution, blood clearance, and excretion rates were investigated in healthy mice and rats using ex vivo organ distribution analysis and dynamic in vivo PET\/CT. Mice with carbon tetrachloride (CCl4) induced liver fibrosis were used for the investigation of specific binding via in vitro frozen section autoradiography, ex vivo organ distribution, and in vivo PET\/CT. A non-decay corrected radiochemical yield (48 \u00b1 6%) of [68Ga]Ga-NOTA-PEG2-c[CPGRVNleHGLHLGDDEGPC] ([68Ga]Ga-NO2A-[Nle13]-Col) with a radiochemical purity of 98 \u00b1 2% was achieved without radical scavengers. The 68Ga-labelling was regioselective and stable at ambient temperature for at least 3 h. The autoradiography of the cryosections of fibrotic mouse liver tissue demonstrated a distinct heterogeneous radioactivity uptake that correlated with the fibrosis scores estimated after Sirius Red staining. The blood clearance and tissue washout from the [68Ga]Ga-NO2A-[Nle13]-Col was fast in both normal and diseased mice. Dosimetry investigation in rats indicated the possibility for 4\u20135 PET\/CT examinations per year. Radiolytic stability of the collagelin analogue was achieved by the substitution of methionine with norleucine amino acid residue without a deterioration of its binding capability. [68Ga]Ga-NO2A-[Nle13]-Col demonstrated a safe dosimetry profile suitable for repeated scanning.<\/jats:p>","DOI":"10.3390\/ph14100990","type":"journal-article","created":{"date-parts":[[2021,9,28]],"date-time":"2021-09-28T21:38:09Z","timestamp":1632865089000},"page":"990","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Improved Radiolytic Stability of a 68Ga-labelled Collagelin Analogue for the Imaging of Fibrosis"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3732-8857","authenticated-orcid":false,"given":"Irina","family":"Velikyan","sequence":"first","affiliation":[{"name":"Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden"},{"name":"PET-Centre, Centre for Medical Imaging, Uppsala University Hospital, SE-75185 Uppsala, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0817-8140","authenticated-orcid":false,"given":"Ulrika","family":"Rosenstr\u00f6m","sequence":"additional","affiliation":[{"name":"Department of Medicinal Chemistry, Uppsala University, SE-75123 Uppsala, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maria","family":"Rosestedt","sequence":"additional","affiliation":[{"name":"Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2515-8790","authenticated-orcid":false,"given":"Olof","family":"Eriksson","sequence":"additional","affiliation":[{"name":"Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gunnar","family":"Antoni","sequence":"additional","affiliation":[{"name":"Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden"},{"name":"PET-Centre, Centre for Medical Imaging, Uppsala University Hospital, SE-75185 Uppsala, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Muzard, J., Sarda-Mantel, L., Loyau, S., Meulemans, A., Louedec, L., Bantsimba-Malanda, C., Hervatin, F., Marchal-Somme, J., Michel, J.B., and Le Guludec, D. (2009). Non-invasive molecular imaging of fibrosis using a collagen-targeted peptidomimetic of the platelet collagen receptor glycoprotein VI. PLoS ONE, 4.","DOI":"10.1371\/journal.pone.0005585"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Velikyan, I., Rosenstrom, U., Bulenga, T.N., Eriksson, O., and Antoni, G. (2016). Feasibility of Multiple Examinations Using (68)Ga-Labelled Collagelin Analogues: Organ Distribution in Rat for Extrapolation to Human Organ and Whole-Body Radiation Dosimetry. Pharmaceuticals, 9.","DOI":"10.3390\/ph9020031"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"728","DOI":"10.1016\/j.nucmedbio.2014.06.001","article-title":"Synthesis and preclinical evaluation of Ga-labeled collagelin analogs for imaging and quantification of fibrosis","volume":"41","author":"Velikyan","year":"2014","journal-title":"Nucl. Med. Biol."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"D\u00e9sog\u00e8re, P., Tapias, L.F., Hariri, L.P., Rotile, N.J., Rietz, T.A., Probst, C.K., Blasi, F., Day, H., Mino-Kenudson, M., and Weinreb, P. (2017). Type I collagen-targeted PET probe for pulmonary fibrosis detection and staging in preclinical models. Sci. Transl. Med., 9.","DOI":"10.1126\/scitranslmed.aaf4696"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/j.nucmedbio.2020.07.009","article-title":"GMP production of [(68)Ga]Ga-BOT5035 for imaging of liver fibrosis in microdosing phase 0 study","volume":"88","author":"Velikyan","year":"2020","journal-title":"Nucl. Med. Biol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1016\/j.nucmedbio.2020.11.006","article-title":"Radiolabelling and positron emission tomography imaging of a high-affinity peptide binder to collagen type 1","volume":"93","author":"Rosestedt","year":"2021","journal-title":"Nucl. Med. Biol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1950","DOI":"10.2967\/jnumed.110.079962","article-title":"68Ga-DOTANOC PET\/CT Allows Somatostatin Receptor Imaging in Idiopathic Pulmonary Fibrosis: Preliminary Results","volume":"51","author":"Ambrosini","year":"2010","journal-title":"J. Nucl. Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1016\/j.clpt.2006.05.008","article-title":"Use of microdosing to predict pharmacokinetics at the therapeutic dose: Experience with 5 drugs","volume":"80","author":"Lappin","year":"2006","journal-title":"Clin. Pharmacol. Ther."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1111\/j.1365-2125.2006.02575.x","article-title":"The phase 0 microdosing concept","volume":"61","author":"Garner","year":"2006","journal-title":"Br. J. Clin. Pharmacol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1007\/s00228-003-0643-x","article-title":"Positron emission tomography microdosing: A new concept with application in tracer and early clinical drug development","volume":"59","author":"Bergstrom","year":"2003","journal-title":"Eur. J. Clin. Pharmacol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"577","DOI":"10.1038\/sj.bjc.6603925","article-title":"The impact of FDA and EMEA guidelines on drug development in relation to Phase 0 trials","volume":"97","author":"Marchetti","year":"2007","journal-title":"Br. J. Cancer"},{"key":"ref_12","first-page":"45N","article-title":"The exploratory IND","volume":"49","author":"Mills","year":"2008","journal-title":"J. Nucl. Med."},{"key":"ref_13","unstructured":"Nonclinical Safety Studies for the Conduct of Human Clinical Trials and Marketing Authorization for Pharmaceuticals (2021, September 27). ICH Harmonised Tripartite Guideline M3 (R2). Available online: https:\/\/www.ema.europa.eu\/en\/documents\/scientific-guideline\/ich-guideline-m3r2-non-clinical-safety-studies-conduct-human-clinical-trials-marketing-authorisation_en.pdf."},{"key":"ref_14","unstructured":"Position Paper on the Non-Clinical Safety Studies to Support Clinical Trials with a Single Microdose (2021, September 27). The European Medicines Agency (EMEA), 2004, CPMP\/SWP\/2599\/02\/Rev 1. Available online: http:\/\/www.iaa-ams.co.jp\/img_bsnss\/MD1.pdf."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1760","DOI":"10.1016\/S0140-6736(11)60405-4","article-title":"Pirfenidone in patients with idiopathic pulmonary fibrosis (CAPACITY): Two randomised trials","volume":"377","author":"Noble","year":"2011","journal-title":"Lancet"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2083","DOI":"10.1056\/NEJMoa1402582","article-title":"A phase 3 trial of pirfenidone in patients with idiopathic pulmonary fibrosis","volume":"370","author":"King","year":"2014","journal-title":"N. Engl. J. Med."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2071","DOI":"10.1056\/NEJMoa1402584","article-title":"Efficacy and safety of nintedanib in idiopathic pulmonary fibrosis","volume":"370","author":"Richeldi","year":"2014","journal-title":"N. Engl. J. Med."},{"key":"ref_18","first-page":"483","article-title":"Clinical Molecular Imaging of the Chemokine Receptor CXCR4 in Idiopathic Pulmonary Fibrosis using 68Ga-Pentixafor PET\/CT","volume":"57","author":"Derlin","year":"2016","journal-title":"J. Nucl. Med."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Stabin, M.G., Wendt, R.E., and Flux, G.D. (2021). RADAR Guide: Standard Methods for Calculating Radiation Doses for Radiopharmaceuticals Part 2. Data Analysis and Dosimetry. J. Nucl. Med., 62.","DOI":"10.2967\/jnumed.121.262034"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"ICRP (1991). 1990 Recommendations of the International Commission on Radiological Protection, Pergamon Press. ICRP Publication 60. Ann. ICRP 21 (1\u20133).","DOI":"10.1016\/0146-6453(91)90066-P"},{"key":"ref_21","unstructured":"ICRP (2007). 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann. ICRP, 37, 1\u2013332."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2019","DOI":"10.1016\/j.bbamem.2016.06.002","article-title":"Does a methionine-to-norleucine substitution in PGLa influence peptide-membrane interactions?","volume":"1858","author":"Radchenko","year":"2016","journal-title":"Biochim. Biophys. Acta"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"839","DOI":"10.1016\/j.nucmedbio.2008.09.006","article-title":"Optimised labeling, preclinical and initial clinical aspects of CCK-2 receptor-targeting with 3 radiolabeled peptides","volume":"35","author":"Breeman","year":"2008","journal-title":"Nucl. Med. Biol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"104","DOI":"10.5603\/NMR.2016.0021","article-title":"Oxidation of methionine\u2014Is it limiting the diagnostic properties of 99mTc-labeled Exendin-4, a Glucagon-Like Peptide-1 receptor agonist?","volume":"19","author":"Janota","year":"2016","journal-title":"Nucl. Med. Rev. Cent. East. Eur."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"366","DOI":"10.1007\/s11307-011-0506-2","article-title":"Preclinical evaluation of radiolabeled DOTA-derivatized cyclic minigastrin analogs for targeting cholecystokinin receptor expressing malignancies","volume":"14","author":"Rangger","year":"2012","journal-title":"Mol. Imaging Biol."},{"key":"ref_26","first-page":"1029","article-title":"Radiolabeled peptides for targeting cholecystokinin-B\/gastrin receptor-expressing tumors","volume":"40","author":"Behr","year":"1999","journal-title":"J. Nucl. Med."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1209","DOI":"10.1007\/s00259-006-0348-3","article-title":"99mTc-labelled HYNIC-minigastrin with reduced kidney uptake for targeting of CCK-2 receptor-positive tumours","volume":"34","author":"Dietrich","year":"2007","journal-title":"Eur. J. Nucl. Med. Mol. Imaging"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"477","DOI":"10.2967\/jnumed.108.056036","article-title":"MIRD pamphlet No. 21: A generalized schema for radiopharmaceutical dosimetry-standardization of nomenclature","volume":"50","author":"Bolch","year":"2009","journal-title":"J. Nucl. Med."},{"key":"ref_29","unstructured":"Loevinger, R., Budinger, T., and Watson, E. (1988). MIRD Primer for Absorbed Dose Calculations, Society of Nuclear Medicine."}],"container-title":["Pharmaceuticals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8247\/14\/10\/990\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:06:40Z","timestamp":1760166400000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8247\/14\/10\/990"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,9,28]]},"references-count":29,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2021,10]]}},"alternative-id":["ph14100990"],"URL":"https:\/\/doi.org\/10.3390\/ph14100990","relation":{},"ISSN":["1424-8247"],"issn-type":[{"type":"electronic","value":"1424-8247"}],"subject":[],"published":{"date-parts":[[2021,9,28]]}}}