Cell kinetics in rat small intestine after exposure to 3 Gy of gamma-rays at different times of the day

Effects of Immunonutrition on Chemoradiotherapy Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

We conducted a systematic review to assess the effects of immunonutrition on chemoradiotherapy patients.

METHODS

We searched the Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, CINAHL, and the Web of Science. We assessed the risk of bias using the Cochrane Risk of Bias tool. Our primary outcomes were the incidence of oral mucositis and diarrhea. The secondary outcomes were the incidence of esophagitis, grade ≥3 oral mucositis, grade ≥3 diarrhea, grade ≥3 esophagitis, and body weight loss.

RESULTS

A total of 1478 patients and 27 studies were included. There were no significant differences in the incidence of oral mucositis (relative risk [RR] = 0.91; 95% confidence interval [CI], 0.79-1.05), diarrhea (RR = 0.89; 95% CI, 0.76-1.05), or esophagitis (RR = 0.55; 95% CI, 0.11-2.86) between the immunonutrition group and standard nutrition/placebo group. Nevertheless, immunonutrition significantly reduced the incidence of grade ≥3 oral mucositis (RR = 0.45; 95% CI, 0.22-0.92), grade ≥3 diarrhea (RR = 0.56; 95% CI, 0.35-0.88), grade ≥3 esophagitis (RR = 0.15; 95% CI, 0.04-0.54), and losing >5% body weight (RR = 0.34; 95% CI, 0.18-0.64).

CONCLUSIONS

In this study, immunonutrition failed to reduce the incidence rates of oral mucositis, diarrhea, or esophagitis but was conducive to significantly improving the severity of oral mucositis and diarrhea esophagitis and reducing the rate of body weight loss.

Alanyl-glutamine and glutamine supplementation improves 5-fluorouracil-induced intestinal epithelium damage in vitro

In this study, we have examined the role of glutamine derivatives in reducing 5-fluorouracil (5-FU)-induced epithelial damage in an undifferentiated crypt intestinal cell line, IEC-6. In this model, we have investigated proliferation indirectly by detecting the enzyme-derived formazan dye from the tetrazolium salt WST-1 in viable cells at 24 and 48 h after 5-FU treatment. Migration was measured at 12 and 24 h after razor scraping of the cell monolayer. Cell death was measured by quantifying the percentage of apoptotic and necrotic figures by flow cytometry at 12 and 24 h following 5-FU challenge. Neither glutamine nor alanyl-glutamine prevented 5-FU-induced apoptosis and necrosis in IEC-6 cells at 12 and 24 h after 5-FU challenge. However, glutamine and alanyl-glutamine enhanced migration and proliferation when compared with 5-FU-treated controls (P < 0.05). These new findings support our earlier study on the benefit of oral glutamine in enhancing epithelial recovery after 5-FU challenge.

Effects of radiation damage on intestinal morphology

The current flow of papers on intestinal structure, radiation science, and intestinal radiation response is reflected in the contents of this review. Multiparameter findings and changes in compartments, cells, or subcellular structure all contribute to the overall profile of the response. The well-recognized changes in proliferation, vessels, and fibrogenesis are accompanied by alterations in other compartments, such as neuroendocrine or immune components of the intestinal wall. The responses at the molecular level, such as in levels of hormones, cytokines, or neurotransmitters, are of fundamental importance. The intestine responds to localized radiation, or to changes in other organs that influence its structure or function: some structural parameters respond differently to different radiation schedules. Apart from radiation conditions, factors affecting the outcome include the pathophysiology of the irradiated subject and accompanying treatment or intervention. More progress in understanding the overall responses is expected in the next few years.

Chronobiology of the mammalian response to ionizing radiation. Potential applications in oncology

Ionizing radiation from all sources under appropriate conditions leads to cell death and tissue damage. It is used in cancer treatment under the assumption of a higher radiosensitivity of the fast dividing tumor cells as compared with adjacent host tissues. The radiosensitivities of proliferating host tissues like bone marrow and gastrointestinal lining epithelium are dose limiting. Since these host tissues and many tumors show circadian and other periodicities in their cell proliferation, the timing of radiation treatment according to host and/or tumor rhythms is expected to improve the toxic/therapeutic ratio of the treatment. The experimental data on the chronobiology of radiation exposure show circadian rhythmicity in radiation response after whole body irradiation in mice and rats with highest toxicity in light-dark 12h:12h synchronized animals during their daily activity span. Bone marrow toxicity as well as gastrointestinal epithelial damage show circadian rhythms in part due to radiation damage to the stem cells involved and especially in the intestine also due to damage to the microvasculature. Chronoradiotherapy of malignant tumors seems promising, alone or in combination with response modifiers, provided the host and potential tumor rhythms can be monitored.

Chronomodulated chemotherapy and irradiation: an idea whose time has come?

The chronomodulated delivery of systemic chemotherapy given with irradiation (chemoradiation) is driven by an understanding of: the chronobiology of normal tissue response to cytotoxic insult, chronopharmacology, and by technologic advances in vascular access and in the availability of portable programmable pumps. Since circadian variation exists in the proliferative activity of acute-reacting normal tissues like the gut and bone marrow, a potential therapeutic gain can be realized by the chronomodulated administration of S-phase chemotherapeutic agents at biological times when these normal tissues are in a different cell phase and thus relatively spared (chronotolerance). The reasons for this are complex and possibly include newly described time-keeping genes that may influence the cell cycle. Another important aspect of chronotolerance is based on chronopharmacologic behavior of S-phase chemotherapeutic radiation sensitizing agents, especially 5-fluorouracil (5-FU). In this review laboratory and clinical evidence is presented for using chronomodulated 5-FU or the topoisomerase-I inhibitor, camptothecin, when best tolerated biologically. Although the main body of this work has been accomplished with pure chemotherapy schedules, there is emerging clinical evidence this approach to treatment also applies to the application of chemoradiation. This knowledge has been exploited only recently in the clinic. These data should be viewed as a call for additional studies to investigate the precise timing of systemic chemotherapeutic radio sensitizers to ameliorate toxicity and maximize treatment effect, especially with newer and potentially more toxic chemoradiation programs.

Colonic cell proliferation in normal mucosa of patients with colon cancer

Cell kinetics parameters have been analysed in colonic mucosa at different distances from a tumour in patients with colon carcinoma. Total cell number (TCN), 3H thymidine labelling index (TLI), mitotic index (MI), Goblet cell index (GCI) and the distribution of labelled cells along the crypt column (cell position frequency plot) were determined in well-aligned crypts. Total cell number, GCI and the labelled cell position frequency plots were similar in different samples from the same individual. A negative linear correlation between TCN and TLI was observed. The analysis of the cell position plots showed two patterns 1) with a high concentration in the bottom fifth of the crypt and 2) with frequent labelled cells at high positions. Whereas a negative correlation between overall TLI and the percent contribution to the TLI of the lowermost fifth was seen, the correlation was positive for the next 3 fifths and labelling was absent in the last part of the crypt.

Differential survival of murine small and large intestinal crypts following ionizing radiation

Radiation survival curves have been obtained for crypts in the small and large intestine of male BDF1 mice using the microcolony assay. Four regions of the small intestine and three regions of the large intestine were studied. One of the major objectives was to determine the optimal conditions for the microcolony assay in the large bowel. Various times post-irradiation were studied using different approaches and threshold criteria for surviving crypts. Small, but statistically significant, differences were observed along the length of the small intestine, but no differences were observed between different regions of the large intestine. There was a marked difference (p < 0.001) in the response in the large compared with the small intestine (D0 = 291 +/- 14 compared with 151 +/- 4 cGy respectively with corresponding extrapolation numbers of 18 +/- 4 and 377 +/- 65). The use of tritiated thymidine or vincristine helped in the identification of true survivors in the large bowel, but these approaches are not necessary in the small bowel. The longer the time after irradiation that the samples were fixed the easier it was to identify survivors in the colon. However, the longer the time the more animals died. The optimum compromise in these studies was to use partial-body irradiation (abdomen only) and to sample on the fifth day after irradiation. With these criteria the mid-colon survival curve had a D0 = 274 +/- 28 cGy and an extrapolation number of 22 +/- 10. The results can be considered in relation to published data on the levels of p53 and bcl-2 expression and apoptosis in murine small and large bowel.