An in vitro model of glucose and lipid metabolism in a multicompartmental bioreactor.

The energy balance in vivo is maintained through inter-organ cross-talk involving several different tissues. As a first step towards recapitulating the metabolic circuitry, hepatocytes, endothelial cells and adipose tissue were connected in a multicompartmental modular bioreactor to reproduce salient aspects of glucose and lipid metabolism in vitro. We first examined how the two-way cellular interplay between adipose tissue and endothelial cells affects glucose and lipid metabolism. The hepatocyte cell line HepG2 was then added to the system, creating a three-way connected culture, to determine whether circulating metabolite concentrations were normalized, or whether metabolic shifts, which may arise when endothelial cells and adipose tissue are placed in connection, were corrected. The addition of hepatocytes to the system prevented the drop in the concentrations of glucose, L-alanine and lactate, and the rise in that of free fatty acids. There was no significant change in glycerol levels in either of the connected cultures. The results show that connected cultures recapitulate complex physiological systemic processes, such as glucose and lipid metabolism, and that the HepG2 hepatocytes normalize circulating metabolites in this in vitro environment in the presence of other cell types.

Hypoglycemic syndrome in a patient with proinsulin-only secreting pancreatic adenoma (proinsulinoma).

We describe an unusual case of hypoglycemic syndrome in a 69-year old woman with a proinsulin-only secreting pancreatic endocrine adenoma. The clinical history was highly suggestive of an organic hypoglycemia, with normal or relatively low insulin concentrations and elevated proinsulin levels. Magnetic resonance and computed tomography of the abdomen showed a 1 cm pancreatic nodule and multiple accessory spleens. The diagnosis was confirmed by selective angiography, showing location and vascularization of the nodule, despite no response to intra-arterial calcium. After resection, the hypoglycemic syndrome resolved. The surgical specimen was comprised of a neuroendocrine adenomatous tissue with high proinsulin immunoreactivity. Study of this unusual case of proinsulinoma underlines (i) the need to assay proinsulin in patients with hypoglycemia and normal immunoreactive insulin, (ii) the differential diagnosis in the presence of accessory spleens, (iii) the unresponsiveness to intra-arterial calcium stimulation, and (iv) the extensive evaluation needed to reach a final diagnosis.

Laparoscopic treatment of benign insulinomas localized in the body and tail of the pancreas: a single-center experience.

BACKGROUND: The increasingly widespread use of minimally invasive surgery has allowed surgeons to exploit this approach for complex procedures, such as pancreatic resections, though its actual role outside simple operations remains debated. METHODS: This is a study of 12 consecutive patients, 5 men and 7 women, with pancreatic insulinoma who were treated at our institution from 2000 to September 2005. All patients presented with typical symptoms and laboratory findings of hyperinsulinism and were good candidates for laparoscopic surgery. Preoperative diagnostic work-up, operating time, postoperative complication rate, length of hospital stayd and clinical outcome were assessed. RESULTS: Successful laparoscopic resection was performed in 11 out of 12 patients: 4 had tumor enucleation, and 7 had distal pancreatectomy; among these latter 5 had spleen-preserving distal pancreatectomy. In 1 case conversion to open surgery was necessary. Mean operative time was 170 minutes. The median tumor size was 18 mm, and all the insulinomas were benign. Four complications were observed in this group, and the median hospital stay was 8 days. CONCLUSIONS: The laparoscopic approach proved to be feasible and safe, although the average operative time was longer and demanded good surgical skills as well as precise localization of the tumor and definition of its nature. Tumors located in the body or tail of the pancreas that are benign in nature can better benefit of laparoscopic approach.