Positive association between proinsulin and fatty liver index in people with type 2 diabetes.

The post-hoc study, derived from our previous prospective observational study, investigated the association between fasting serum proinsulin levels and hepatic steatosis in people with type 2 diabetes. The severity of hepatic steatosis was assessed using the fatty liver index. A total of 268 participants were divided into three groups: low (n = 110), moderate (n = 75), and high fatty liver index (n = 83). In both the crude and age/sex-adjusted analysis, logarithm-transformed proinsulin was significantly higher in the high fatty liver index group than in the low or moderate groups (all p < 0.01). The moderate fatty liver index group showed higher logarithm-transformed proinsulin than the low group (both p < 0.01). Positive associations between proinsulin and fatty liver index shown in this study would support an involvement of hepato-pancreatic crosstalk in the pathophysiology of type 2 diabetes.

Silent pituitary adenoma and metabolic disorders: obesity, abnormal glucose tolerance, hypertension and dyslipidemia.

A silent pituitary adenoma (SPA) is characterized by the expression of pituitary hormones, detected by immunohistochemical staining, in the absence of clinical signs or symptoms of hormonal excess. Compared with functional pituitary adenomas, little is known regarding the involvement of SPAs in metabolic disorders. This study aimed to examine the correlations between SPAs and metabolic disorders, including obesity, abnormal glucose tolerance, hypertension and dyslipidemia. Seventy-four patients with nonfunctional pituitary adenomas who underwent a pituitary adenomectomy in Hokkaido University Hospital from 2008 to 2016 were retrospectively examined. Pituitary adenomas were immunohistochemically classified into pituitary hormone positive or negative groups. Twenty whole hormone-negative pituitary adenomas were excluded because we couldn't identify pituitary transcription factors which is necessary for the diagnosis of a null cell adenoma. The preoperative rates of obesity, abnormal glucose tolerance, hypertension and dyslipidemia were compared between each group. Twenty-seven GH positive adenomas (50.0%), 32 gonadotroph positive adenomas (59.3%), 28 TSH positive adenomas (51.9%) and 21 ACTH positive adenomas (38.9%) were identified. Evaluation of the preoperative clinical data showed 25 cases of obesity (46.2%), 16 cases of abnormal glucose tolerance (29.6%), 29 cases of hypertension (53.7%) and 35 cases of dyslipidemia (64.8%). The rate of hypertension was significantly lower in the GH positive group (37.0%) than the GH negative group (70.4%) (p = 0.0140). In the GH negative group, postoperative systolic and diastolic blood pressure levels were significantly lower than preoperative values. GH positive SPAs may affect the homeostasis of blood pressure.

Nivolumab-induced hypophysitis causing secondary adrenal insufficiency after transient ACTH elevation.

A 62-year-old man was referred to our department for elevation of plasma ACTH and cortisol levels during nivolumab administration for renal cell carcinoma. Although his ACTH and cortisol levels had been maintained within their reference ranges, they were elevated to 232.7 pg/mL and 21.9 µg/dL, respectively, after eight courses of nivolumab without any subjective symptoms or Cushing's sign. He was hospitalized for endocrinological investigation. ACTH and cortisol returned to their normal ranges (29.18 pg/mL and 11.4 µg/dL, respectively) in the early morning on day 1, but fell down sharply to 3.7 pg/mL and 1.6 µg/dL, respectively, in the early morning on day 2 without subjective symptoms or vital sign changes. Brain magnetic resonance imaging showed no abnormality in his pituitary gland. ACTH response to CRH was apparently normal, but cortisol did not respond to increased ACTH. A rapid ACTH stimulation test showed slightly reduced response of cortisol to exogenous ACTH (1-24). These findings and his clinical course suggested secondary adrenal insufficiency arising from nivolumab-induced hypophysitis. In previous reports, most cases of immune checkpoint inhibitor (ICI)-induced hypophysitis were diagnosed based on adrenal insufficiency symptoms or hyponatremia with low ACTH and cortisol. The ACTH elevation observed in the present case may reflect destruction of the pituitary gland, suggesting that this finding may be important for early detection of ICI-induced hypophysitis. Our case underlines the necessity of close monitoring for subsequent onset of adrenal insufficiency when ACTH elevation is observed during ICI administration.