title: Diabetes increases stiffness of live cardiomyocytes measured by atomic force microscopy nanoindentation.
abstract: Stiffness of live cardiomyocytes isolated from control and diabetic mice was measured using the atomic force microscopy nanoindentation method. Type 1 diabetes was induced in mice by streptozotocin administration. Histological images of myocardium from mice that were diabetic for 3 mo showed disorderly lineup of myocardial cells, irregularly sized cell nuclei, and fragmented and disordered myocardial fibers with interstitial collagen accumulation. Phalloidin-stained cardiomyocytes isolated from diabetic mice showed altered (i.e., more irregular and diffuse) actin filament organization compared with cardiomyocytes from control mice. Sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA2a) pump expression was reduced in homogenates obtained from the left ventricle of diabetic animals compared with age-matched controls. The apparent elastic modulus (AEM) for live control or diabetic isolated cardiomyocytes was measured using the atomic force microscopy nanoindentation method in Tyrode buffer solution containing 1.8 mM Ca(2+) and 5.4 mM KCl (physiological condition), 100 nM Ca(2+) and 5.4 mM KCl (low extracellular Ca(2+) condition), or 1.8 mM Ca(2+) and 140 mM KCl (contraction condition). In the physiological condition, the mean AEM was 112% higher for live diabetic than control isolated cardiomyocytes (91 ± 14 vs. 43 ± 7 kPa). The AEM was also significantly higher in diabetic than control cardiomyocytes in the low extracellular Ca(2+) and contraction conditions. These findings suggest that the material properties of live cardiomyocytes were affected by diabetes, resulting in stiffer cells, which very likely contribute to high diastolic LV stiffness, which has been observed in vivo in some diabetes mellitus patients.
authors.affiliation: Laboratorio de Señalización Celular y Nanobiología, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay; jbenech@iibce.edu.uy juanclaudio.benech@gmail.com.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Benech
authors.affiliation: Instituto de Física, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay; and.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Benech
authors.affiliation: Laboratorio de Señalización Celular y Nanobiología, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay;
authors.forename: Ana I
authors.initials: AI
authors.lastname: Zambrana
authors.affiliation: Laboratorio de Señalización Celular y Nanobiología, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay;
authors.forename: Inés
authors.initials: I
authors.lastname: Rauschert
authors.affiliation: Laboratorio de Señalización Celular y Nanobiología, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay;
authors.forename: Verónica
authors.initials: V
authors.lastname: Bervejillo
authors.affiliation: Laboratorio de Señalización Celular y Nanobiología, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay;
authors.forename: Natalia
authors.initials: N
authors.lastname: Oddone
authors.affiliation: Laboratorio de Señalización Celular y Nanobiología, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay; Departamento de Biología Molecular y Celular, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Damián
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003920:Diabetes Mellitus / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D051379:Mice; D018625:Microscopy, Atomic Force / Q000379:methods*; D032383:Myocytes, Cardiac / Q000473:pathology*; D036103:Nanotechnology / Q000379:methods*; D059289:Vascular Stiffness / Q000502:physiology*
keywords: atomic force microscopy; diabetes; live cardiomyocyte stiffness