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

Islet in a type-2 diabetic patient. Most of the islet has beenconverted into amyloid; Congo red, bar 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2553203&req=5

fig1: Islet in a type-2 diabetic patient. Most of the islet has beenconverted into amyloid; Congo red, bar 20 μm.

Mentions: In the pancreata of all individualswith type-2 diabetes and in 7 out of 10 individuals without diabetes, amyloidwas found in islets of Langerhans. All of the diabetic individuals had a verypronounced islet amyloidosis with some islets with little remaining endocrinecells (Figure 1). In the nondiabetic patients, usually only small amyloid depositswere detected but in three individuals amyloid affected more than 20% and inone as much as 38% of the islets. Comparison of the percentage of affectedislets in the two groups when only individuals with some degree of isletamyloidosis were included, showed thatsignificantly more islets contained deposits in the diabetic individuals (98 ± 3%and 13 ± 14%, P = 0.001). The islet amyloid had typical staining properties withCongo red and was strongly labeled with antiserum against IAPP (not shown).


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

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

Islet in a type-2 diabetic patient. Most of the islet has beenconverted into amyloid; Congo red, bar 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig1: Islet in a type-2 diabetic patient. Most of the islet has beenconverted into amyloid; Congo red, bar 20 μm.
Mentions: In the pancreata of all individualswith type-2 diabetes and in 7 out of 10 individuals without diabetes, amyloidwas found in islets of Langerhans. All of the diabetic individuals had a verypronounced islet amyloidosis with some islets with little remaining endocrinecells (Figure 1). In the nondiabetic patients, usually only small amyloid depositswere detected but in three individuals amyloid affected more than 20% and inone as much as 38% of the islets. Comparison of the percentage of affectedislets in the two groups when only individuals with some degree of isletamyloidosis were included, showed thatsignificantly more islets contained deposits in the diabetic individuals (98 ± 3%and 13 ± 14%, P = 0.001). The islet amyloid had typical staining properties withCongo red and was strongly labeled with antiserum against IAPP (not shown).

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