"Th\u00E8ses et \u00E9crits acad\u00E9miques" . "calcitonin" . "amylose r\u00E9nale" . . "carcinome m\u00E9dullaire de la thyro\u00EFde" . . . "calcitonine" . . . "Text" . . . . "Rein -- Maladies" . . . "Une nouvelle forme d'amylose r\u00E9nale, l'amylose de la calcitonine" . . "Une nouvelle forme d'amylose r\u00E9nale, l'amylose de la calcitonine" . "Amyloidosis is characterized by extracellular deposition of insoluble fibrils from misfolded proteins. Renal involvement is common in systemic forms. Approximately thirty precursors have been identified, among which ten involved in renal amyloidosis. Some cases of renal amyloidosis still remain unclassified. We describe a 48-year-old Caucasian female who presented for persistent proteinuria. She had been diagnosed with type 2 multiple endocrine neoplasia, and was discovered with medullary thyroid carcinoma thirteen years ago. Despite initial surgical treatment, several metastasis occurred. She was noted to have very high blood concentrations of calcitonin since diagnosis. A kidney biopsy revealed mesangial deposits which stained positive for Congo red with green birefringence under polarized light. By immunofluorescence, staining for SAA, immunoglobulin light chains, heavy chains, apolipoprotein A1, \u03B22-microglobulin, fibrinogen A\u03B1-chain, transthyretin and lysozyme was negative. Over the five following years, she progressively developed nephrotic syndrome with chronic kidney disease. A second kidney biopsy showed predominant glomerular amyloid deposits. She finally died from her cancer with undiagnosed amyloidosis. The kidney biopsy blocks were subsequently reviewed for amyloid typing. Immunohistochemistry staining for calcitonin was strongly positive on glomerular amyloid deposits. Immunoelectron microscopic analysis assessed that the renal amyloid fibrils were specifically labelled by gold-conjugated anti-calcitonin antibody. Amyloid subtyping was finally confirmed by laser microdissection/mass spectrometry-based proteomics on the first kidney biopsy. Up to our knowledge, we describe the first calcitonin systemic amyloidosis, with exclusive renal involvement. Calcitonin amyloidosis is very common within tumor tissue of medullary thyroid carcinoma, but has never been described as a systemic disease. The structural characteristics of calcitonin, the high blood concentrations, the long time exposure and the preferential interaction of calcitonin with negatively charged phospholipids may explain widespread deposition of calcitonin amyloidosis." . . . . "renal amyloidosis" . "medullary thyroid carcinoma" . . "2016" . . "Calcitonine" . . "Amylose" . "L'amylose est caract\u00E9ris\u00E9e par le d\u00E9p\u00F4t extracellulaire de fibrilles insolubles, compos\u00E9es de prot\u00E9ines anormalement repli\u00E9es. L'atteinte r\u00E9nale est fr\u00E9quente dans les formes syst\u00E9miques. Une trentaine de pr\u00E9curseurs ont \u00E9t\u00E9 identifi\u00E9s \u00E0 ce jour, dont douze environ impliqu\u00E9s dans les amyloses r\u00E9nales. Certains cas d'amyloses r\u00E9nales demeurent toutefois inclassifi\u00E9s. Une patiente de 48 ans est adress\u00E9e pour prot\u00E9inurie persistante. Elle a pour principal ant\u00E9c\u00E9dent une n\u00E9oplasie endocrinienne multiple de type 2a familiale. Un carcinome m\u00E9dullaire de la thyro\u00EFde a \u00E9t\u00E9 d\u00E9couvert treize ans auparavant, compliqu\u00E9 de m\u00E9tastases multiples. Les concentrations plasmatiques de calcitonine sont tr\u00E8s \u00E9lev\u00E9es depuis le diagnostic. La ponction-biopsie r\u00E9nale montre un \u00E9paississement m\u00E9sangial diffus par des d\u00E9p\u00F4ts, rouge Congo positifs, bir\u00E9fringents jaune-vert en lumi\u00E8re polaris\u00E9e. L'\u00E9tude en immunofluorescence des d\u00E9p\u00F4ts amylo\u00EFdes \u00E0 l'aide des conjugu\u00E9s anti-SAA, cha\u00EEnes l\u00E9g\u00E8res et lourdes d'immunoglobuline, \u03B22-microglobuline, cha\u00EEne A\u03B1 du fibrinog\u00E8ne, apolipoprot\u00E9ine A1, transthyr\u00E9tine et lyzozyme revient n\u00E9gative. Pendant les cinq ann\u00E9es suivantes, la patiente d\u00E9veloppe un syndrome n\u00E9phrotique, avec insuffisance r\u00E9nale. Une deuxi\u00E8me biopsie r\u00E9nale montre des d\u00E9p\u00F4ts amylo\u00EFdes glom\u00E9rulaires. La patiente d\u00E9c\u00E8de finalement de son cancer. Les blocs des biopsies r\u00E9nales sont relus pour typage de l'amylose. L'immunohistochimie met en \u00E9vidence un marquage indiscutable des d\u00E9p\u00F4ts amylo\u00EFdes avec l'anticorps anti-calcitonine. En microscopie \u00E9lectronique, les d\u00E9p\u00F4ts fibrillaires sont marqu\u00E9s par le conjugu\u00E9 anti-calcitonine coupl\u00E9 \u00E0 l'or collo\u00EFdal. L'analyse prot\u00E9omique apr\u00E8s microdissection laser et spectrom\u00E9trie de masse des d\u00E9p\u00F4ts amylo\u00EFdes corrobore le diagnostic d'amylose r\u00E9nale \u00E0 la calcitonine. \u00C0 notre connaissance, nous d\u00E9crivons ici la premi\u00E8re amylose syst\u00E9mique \u00E0 la calcitonine, sous la forme d'une atteinte r\u00E9nale. L'amylose \u00E0 la calcitonine est fr\u00E9quente dans le tissu tumoral des carcinomes m\u00E9dullaires de la thyro\u00EFde, mais n'est d\u00E9crite que comme une amylose localis\u00E9e. Les caract\u00E9ristiques structurales de la calcitonine, sa concentration plasmatique \u00E9lev\u00E9e, la longue dur\u00E9e d'exposition et des interactions pr\u00E9f\u00E9rentielles avec les phospholipides charg\u00E9s n\u00E9gativement de la membrane basale glom\u00E9rulaire pourrait expliquer ce tableau." .