Islet cell dedifferentiation is a pathologic mechanism of long-standing progression of type 2 diabetes.

Dedifferentiation has been implicated in ß cell dysfunction and loss in rodent diabetes. However, the pathophysiological significance in humans remains unclear. To elucidate this, we analyzed surgically resected pancreatic tissues of 26 Japanese subjects with diabetes and 11 nondiabetic subjects, who had been overweight during adulthood but had no family history of diabetes. The diabetic subjects were subclassified into 3 disease stage categories, early, advanced, and intermediate. Despite no numerical changes in endocrine cells immunoreactive for chromogranin A (ChgA), diabetic islets showed profound ß cell loss, with an increase in α cells without an increase in insulin and glucagon double-positive cells. The proportion of dedifferentiated cells that retain ChgA immunoreactivity without 4 major islet hormones was strikingly increased in diabetic islets and rose substantially during disease progression. The increased dedifferentiated cell ratio was inversely correlated with declining C-peptide index. Moreover, a subset of islet cells converted into exocrine-like cells during disease progression. These results indicate that islet remodeling with dedifferentiation is the underlying cause of ß cell failure during the course of diabetes progression in humans.

Recurrent Guillain-Barré and Fisher Syndromes in Two Patients Who Were Subsequently Diagnosed with Aplastic Anemia.

Guillain-Barré (GBS) and Fisher (FS) syndromes rarely recur and the characteristics of recurrence have not been fully elucidated. We describe the cases of 2 patients with GBS or FS that recurred more than twice and who were subsequently diagnosed with aplastic anemia. Case 1 was a 66-year-old man who was diagnosed with aplastic anemia 10 months before admission with limb ataxia and a sensory disturbance of the distal limbs that developed 3 days after an upper respiratory tract infection. He had a history of double vision with ataxia at the ages of 38 and 56 years. Case 2 was a 66-year-old woman who had been treated for aplastic anemia 1 year previously. She had a history of upper limb weakness after upper respiratory tract infections at the ages of 39 and 60 years. Tendon reflexes were absent in both patients at the time of onset and they were respectively diagnosed with FS and GBS and treated with intravenous immunoglobulin. No neurological deficits persisted. Blood findings showed that both were positive for IgG type ganglioside antibodies and HLA-DR15. The positive HLA-DR15 might have been associated with the recurrent GBS or FS and the development of aplastic anemia.