Microbiota-Derived Lactate Accelerates Intestinal Stem-Cell-Mediated Epithelial Development.

Symbionts play an indispensable role in gut homeostasis, but underlying mechanisms remain elusive. To clarify the role of lactic-acid-producing bacteria (LAB) on intestinal stem-cell (ISC)-mediated epithelial development, we fed mice with LAB-type symbionts such as Bifidobacterium and Lactobacillus spp. Here we show that administration of LAB-type symbionts significantly increased expansion of ISCs, Paneth cells, and goblet cells. Lactate stimulated ISC proliferation through Wnt/ß-catenin signals of Paneth cells and intestinal stromal cells. Moreover, Lactobacillus plantarum strains lacking lactate dehydrogenase activity, which are deficient in lactate production, elicited less ISC proliferation. Pre-treatment with LAB-type symbionts or lactate protected mice in response to gut injury provoked by combined treatments with radiation and a chemotherapy drug. Impaired ISC-mediated epithelial development was found in mice deficient of the lactate G-protein-coupled receptor, Gpr81. Our results demonstrate that LAB-type symbiont-derived lactate plays a pivotal role in promoting ISC-mediated epithelial development in a Gpr81-dependent manner.

Effects of mucus thickness and goblet cell hyperplasia on microdosimetric quantities characterizing the bronchial epithelium upon radon exposure.

PURPOSE: The most exposed tissue upon radon exposure is the bronchial epithelium where goblet cells serve as responsive and adaptable front-line defenders. They can rapidly produce a vast amount of mucus, and can change in number, in response to airway insults. The objective of the present study is to quantify the effects of mucus discharge and goblet cell hyperplasia on the microscopic dose consequences of macroscopic radon exposures. METHODS: For this purpose, computational models of the bronchial epithelium and alpha-particle transport have been prepared and applied to quantify the hits received and doses absorbed by cell nuclei in case of different mucus thicknesses and goblet cell number. RESULTS AND CONCLUSIONS: Both mucus discharge and induction of goblet cell hyperplasia reduce radiation burden at the cellular level, and as such they both can be considered as radioadaptive responses to radon exposure. As compared to basal cell hyperplasia, goblet cell hyperplasia is more effective in reducing the microscopic dose consequences of a given macroscopic exposure. Such changes in exposure geometry highlight the need for improvements in the application of biokinetic and dosimetry models for incorporated radionuclides as well as the dose and dose rate effectiveness factor.

Influence of Light Emitting Diode-Derived Blue Light Overexposure on Mouse Ocular Surface.

PURPOSE: To investigate the influence of overexposure to light emitting diode (LED)-derived light with various wavelengths on mouse ocular surface. METHODS: LEDs with various wavelengths were used to irradiate C57BL/6 mice at an energy dose of 50 J/cm2, twice a day, for 10 consecutive days. The red, green, and blue groups represented wavelengths of 630 nm, 525 nm, and 410 nm, respectively. The untouched group (UT) was not exposed to LED light and served as the untreated control. Tear volume, tear film break-up time (TBUT), and corneal fluorescein staining scores were measured on days 1, 3, 5, 7, and 10. Levels of interferon (IFN)-γ, interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α were measured in the cornea and conjunctiva using a multiplex immunobead assay at day 10. Levels of malondialdehyde (MDA) were measured with an enzyme-linked immunosorbent assay. Flow cytometry, 2'7'-dichlorofluorescein diacetate (DCF-DA) assay, histologic analysis, immunohistochemistry with 4-hydroxynonenal, and terminal deoxynucleotidyl transferase-mediated dUTP-nick end labeling (TUNEL) staining were also performed. RESULTS: TBUT of the blue group showed significant decreases at days 7 and 10, compared with the UT and red groups. Corneal fluorescein staining scores significantly increased in the blue group when compared with UT, red, and green groups at days 5, 7, and 10. A significant increase in the corneal levels of IL-1ß and IL-6 was observed in the blue group, compared with the other groups. The blue group showed significantly increased reactive oxygen species production in the DCF-DA assay and increased inflammatory T cells in the flow cytometry. A significantly increased TUNEL positive cells was identified in the blue group. CONCLUSIONS: Overexposure to blue light with short wavelengths can induce oxidative damage and apoptosis to the cornea, which may manifest as increased ocular surface inflammation and resultant dry eye.

Effects of monochromatic light stimuli on the development and Muc2 expression of goblet cells in broiler small intestines during embryogenesis.

The effects of monochromatic light on the ontogeny, differentiation, and Muc2 expression level in goblet cells were studied in the small intestines of late-stage broiler embryos. The embryos were exposed to blue light (B group), green light (G group), red light (R group), or darkness (D group) throughout the incubation period. On d 15 of incubation (E15), a few acidic goblet cells (only the sulfated subtype) were observed, and Muc2 mRNA expression was detected. On E18, however, neutral, acidic, and intermediate types, as well as the sulfated subtype, were observed in the small intestine, and a decreasing gradient of goblet cell density was found along the duodenum to ileum axis. Up to E21, 3 types of goblet cells and 3 acidic cell subtypes were found in all the small intestines. The goblet cell density increased along the duodenum to ileum axis. Monochromatic light stimulation resulted in no significant differences in the density and types of goblet cells between the different treatment groups on E15 and E18, but an increased Muc2 mRNA expression level was detected on E18 in the G group compared with the other treatment groups. On E21, the goblet cell density, proportion of acidic goblet cells, and Muc2 mRNA expression level increased in the G group compared with other treatment groups. These results suggest that the ontogeny and differentiation of goblet cells in broiler embryos display temporal and spatial differences. Green monochromatic light may have the potential to promote the proliferation and maturation of as well as the expression of Muc2 mRNA in goblet cells of broiler embryos.

Protective effects of curcumin against gamma radiation-induced ileal mucosal damage.

The major objective of this study was to test curcumin as a potential radioprotectant for the ileum goblet cells of the rat. Wistar albino rats were used in the study. Group A was the control group and group B was the single dose radiation group. Group C was the two dose radiation group (4 days interval). The rats in groups D and E were given a daily dose of 100 mg/kg of curcumin for 14 and 18 days, respectively. During the curcumin administration period, the rats in group D were exposed to abdominal area gamma (gamma)-ray dose of 5 Gy on the 10th day and group E was exposed to same dose radiation on the 10th and 14th day. Irradiation and treatment groups were decapitated on the 4th day after exposure to single or two-dose irradiation and ileum tissues were removed for light and electron microscopic investigation. Single or two dose 5 Gy gamma-irradiation caused a marked intestinal mucosal injury in rats on the 4th day. Radiation produced increases in the number of goblet cells. Curcumin appears to have protective effects against radiation-induced damage, suggesting that clinical transfer is feasible.

Vitamin C protects against ionizing radiation damage to goblet cells of the ileum in rats.

The aim of the present study was to evaluate the radioprotective effect of vitamin C on gamma-radiation-induced damage to goblet cells of the ileum. Thirty male Wistar albino rats weighing between 250 and 300 g were randomized into the following study groups: I, control; II, single dose radiation treated; III, two dose radiation treated with a 4-day interval between doses; IV, single dose radiation treated with vitamin C; V, two dose radiation treated with vitamin C. Each group contained six animals. The rats in groups IV and V were given a daily dose of 100 mg/kg of vitamin C for 14 and 18 days, respectively. During the vitamin C administration period, the rats in group IV were exposed in the abdominal area to a gamma-ray dose of 5 Gy on day 10 and group V was exposed to same dose of radiation on days 10 and 14. Irradiation and treatment groups were decapitated 4 days after exposure to single or two dose irradiation and ileum tissues were removed for light and electron microscopic investigation. Single or two dose gamma-irradiation caused a marked intestinal mucosal injury in rats. Radiation produced increases in the number of goblet cells. Using transmission electron microscopy, extensions in the area between the cells, disorders in the microvilli, mitochondrial damage and endoplasmic reticulum (ER) cisternae dilatation were observed. Antioxidant treatment with vitamin C prior to irradiation provided protection against intestinal damage.

The effect of extremely low frequency magnetic field on the conjunctiva and goblet cells.

PURPOSE: The aim of this study was to examine the effects of extremely low frequency magnetic field (ELF MF) on the conjunctiva and goblet cells density. METHODS: Thirty adult female Spraque Dawley rats were assigned to one of two groups, each containing 15 rats. The experimental group received magnetic field 4 hr/day for 7 days. The second group received standard laboratory care and served as a control. The specimens were evaluated by light microscopy for goblet cell density, conjunctival edema, inflammation, and fibroblast proliferation. RESULTS: In ELF MF exposure group rats, the number of goblet cells was less than the control group. We also observed a significant difference between ELF MF exposure group and control group in terms of goblet cell density (p = 0.010). The ELF MF exposure group manifested conjunctival edema and inflammation compared to the control group (p < 0.001 and p = 0.003). There was no statistical difference between the groups for fibroblast proliferation (p = 0.422). CONCLUSION: This study suggests that ELF MF exposure leads to morphological alterations of the conjunctiva and reductions in the number of goblet cells. We believe that ELF MF may cause dry eye symptoms.

Nuclear factor kappaB (NFkappaB) and cyclooxygenase-2 (Cox-2) expression in the irradiated colorectum is associated with subsequent histopathological changes.

PURPOSE: Recent studies have proposed that mucositis development is the same throughout the gastrointestinal tract (GIT), as it is formed from one structure embryologically. Radiation-induced oral mucositis studies have outlined the key involvement of nuclear factor kappaB (NFkappaB) and cyclooxygenase-2 (Cox-2) in its pathobiology. The purpose of this study was therefore to investigate the expression of NFkappaB and Cox-2 in the irradiated colorectum and to correlate these with the associated histopathologic changes. METHODS AND MATERIALS: Colorectal tissues from 28 colorectal cancer patients treated with preoperative radiotherapy were analyzed for histopathologic changes using a variety of tissue staining methods. The expression of NFkappaB and Cox-2 in these tissues was investigated using immunohistochemistry. Changes in expression of these proteins were then correlated with the histopathologic changes. RESULTS: Radiation therapy caused injury to the normal colorectal tissue surrounding tumor site, particularly around the blood vessels. These changes were reflected in changes in NFkappaB and Cox-2 expression. CONCLUSIONS: We conclude that different regions of the GIT, the colorectum, and oral cavity have similar underlying mechanisms of radiation-induced mucositis. Understanding these mechanisms will allow new approaches to be developed to specifically target steps in the evolution of alimentary mucositis.