Effect of nutrient starvation on proliferation and cytokine secretion of peripheral blood lymphocytes.

Proliferating cancer cells are exposed to nutrient deprivation. Numerous previous studies have demonstrated how nutrient deprivation affects cancer cells; however, immune cells exposed to the identical conditions have not been completely examined. Furthermore, T-helper 2 lymphocyte predominance in certain neoplastic diseases has been reported; however, the mechanism remains unclear. The present study aimed to confirm whether nutrient deprivation affected proliferation and cytokine secretion of peripheral blood lymphocytes (PBLs). The proliferation of PBLs from healthy donors, cultured in a medium containing various glucose levels, was assessed by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. The expression levels of interleukin (IL)-4 and interferon (IFN)-γ among CD4(+) T cells, cultured with or without glucose and activated with phorbol 12-myristate 13-acetate and ionomycin, were examined using an intracellular cytokine staining method. The proliferation of PBLs cultured in a medium containing <100 mg/dl glucose of the standard blood sugar (BS) level was significantly reduced compared with the proliferation observed in a medium containing a standard BS level or higher. PBLs cultured in a glucose-free medium contained a significantly higher percentage of IL-4-positive and a lower percentage of IFN-γ-positive CD4(+) T cells compared with those cultured in a high-glucose medium. Nutrient deprivation suppressed the proliferation of PBLs, fostered the secretion of IL-4 and reduced secretion of IFN-γ. It is therefore possible that glucose-deficient microenvironments in local cancer tissues cause a partial immunodeficiency, which is advantageous to cancer growth.

PET/CT colonography for the preoperative evaluation of the colon proximal to the obstructive colorectal cancer.

PURPOSE: This study was designed to evaluate the usefulness of 18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) colonography in preoperative diagnosis of the tumors proximal to obstructive colorectal cancers, which were defined as cancers that cannot be traversed colonoscopically. METHODS: A whole-body PET/CT protocol for tumor staging and a protocol for CT colonography were integrated into one examination. No cathartic bowel preparation was used before this examination. Thirteen prospective patients with obstructive cancer were examined. We compared the detection rates for obstructive colorectal cancers and tumors proximal to the obstruction using air-inflated PET/CT colonography to intraoperative examinations, histopathologic outcome, and follow-up colonoscopy. RESULTS: PET/CT colonography correctly identified all 13 primary obstructive colorectal cancers and all 2 synchronous colon cancers proximal to the obstruction. The two synchronous colon cancers detected at PET/CT colonography were confirmed and removed at single-stage surgical procedures. PET/CT colonography was able to localize all colorectal cancers precisely. There were no false-negative or false-positive proximal colorectal cancers by PET/CT colonography. Other preoperative examinations missed the synchronous colon cancers. CONCLUSIONS: In patients with obstructive colorectal cancers, preoperative PET/CT colonography provided valuable anatomic and functional information of the entire colon to properly address surgery of colorectal cancer.