Limits...
Transthyretin and amyloid in the islets of Langerhans in type-2 diabetes.

Westermark GT, Westermark P - Exp Diabetes Res (2008)

Bottom Line: Islets from type-2 diabetic patients had proportionally more transthyretin-reactive islet cells, including beta cells.In seeding experiments in vitro, we found that TTR fibrils did not seed IAPP while IAPP fibrils seeded TTR.It is suggested that islet expression of transthyretin may be altered in type-2 diabetes.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden. per.westermark@genpat.uu.se

ABSTRACT
Transthyretin (TTR) is a major amyloid fibril protein in certain systemic forms of amyloidosis. It is a plasma protein, mainly synthesized by the liver but expression occurs also at certain minor locations, including the endocrine cells in the islets of Langerhans. With the use of immunohistochemistry and in situ hybridization, we have studied the distribution of transthyretin-containing cells in islets of Langerhans in type-2 diabetic and nondiabetic individuals. TTR expression was particularly seen in alpha (glucagon) cells. Islets from type-2 diabetic patients had proportionally more transthyretin-reactive islet cells, including beta cells. A weak transthyretin immunoreaction in IAPP-derived amyloid occurred in some specimens. In seeding experiments in vitro, we found that TTR fibrils did not seed IAPP while IAPP fibrils seeded TTR. It is suggested that islet expression of transthyretin may be altered in type-2 diabetes.

Show MeSH

Related in: MedlinePlus

In (a), (b), and (c), an islet double labeled for glucagon (red)and TTR (green). Yellow color indicates colocalization. A largenumber of islet cells show TTR but not glucagon content. The isletin (d) is double labeled for insulin (green) and TTR (red). Many betacells exhibit both TTR and insulin immunoreactivity (yellow). Theamyloid (A) is weakly labeled for TTR. Bar (a)–(c) 25 μm, (d) 200 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2553203&req=5

fig3: In (a), (b), and (c), an islet double labeled for glucagon (red)and TTR (green). Yellow color indicates colocalization. A largenumber of islet cells show TTR but not glucagon content. The isletin (d) is double labeled for insulin (green) and TTR (red). Many betacells exhibit both TTR and insulin immunoreactivity (yellow). Theamyloid (A) is weakly labeled for TTR. Bar (a)–(c) 25 μm, (d) 200 μm.

Mentions: Double labelingfor glucagon and TTR showed that all glucagon cells also exhibited TTRimmunoreactivity (Figures 3(a) and 3(b)). In addition, a large number of isletcells, negative for glucagon, showed an evident TTR-reactivity (Figure 3(c)). Colocalization of insulin and TTR was seen in many, but not all, beta cells (Figure 3(d)).


Transthyretin and amyloid in the islets of Langerhans in type-2 diabetes.

Westermark GT, Westermark P - Exp Diabetes Res (2008)

In (a), (b), and (c), an islet double labeled for glucagon (red)and TTR (green). Yellow color indicates colocalization. A largenumber of islet cells show TTR but not glucagon content. The isletin (d) is double labeled for insulin (green) and TTR (red). Many betacells exhibit both TTR and insulin immunoreactivity (yellow). Theamyloid (A) is weakly labeled for TTR. Bar (a)–(c) 25 μm, (d) 200 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2553203&req=5

fig3: In (a), (b), and (c), an islet double labeled for glucagon (red)and TTR (green). Yellow color indicates colocalization. A largenumber of islet cells show TTR but not glucagon content. The isletin (d) is double labeled for insulin (green) and TTR (red). Many betacells exhibit both TTR and insulin immunoreactivity (yellow). Theamyloid (A) is weakly labeled for TTR. Bar (a)–(c) 25 μm, (d) 200 μm.
Mentions: Double labelingfor glucagon and TTR showed that all glucagon cells also exhibited TTRimmunoreactivity (Figures 3(a) and 3(b)). In addition, a large number of isletcells, negative for glucagon, showed an evident TTR-reactivity (Figure 3(c)). Colocalization of insulin and TTR was seen in many, but not all, beta cells (Figure 3(d)).

Bottom Line: Islets from type-2 diabetic patients had proportionally more transthyretin-reactive islet cells, including beta cells.In seeding experiments in vitro, we found that TTR fibrils did not seed IAPP while IAPP fibrils seeded TTR.It is suggested that islet expression of transthyretin may be altered in type-2 diabetes.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden. per.westermark@genpat.uu.se

ABSTRACT
Transthyretin (TTR) is a major amyloid fibril protein in certain systemic forms of amyloidosis. It is a plasma protein, mainly synthesized by the liver but expression occurs also at certain minor locations, including the endocrine cells in the islets of Langerhans. With the use of immunohistochemistry and in situ hybridization, we have studied the distribution of transthyretin-containing cells in islets of Langerhans in type-2 diabetic and nondiabetic individuals. TTR expression was particularly seen in alpha (glucagon) cells. Islets from type-2 diabetic patients had proportionally more transthyretin-reactive islet cells, including beta cells. A weak transthyretin immunoreaction in IAPP-derived amyloid occurred in some specimens. In seeding experiments in vitro, we found that TTR fibrils did not seed IAPP while IAPP fibrils seeded TTR. It is suggested that islet expression of transthyretin may be altered in type-2 diabetes.

Show MeSH
Related in: MedlinePlus