Claudin-3 expression in radiation-exposed rat models: a potential marker for radiation-induced intestinal barrier failure.

The molecular events leading to radiation-induced intestinal barrier failure are not well known. The influence of the expression of claudin proteins in the presence and absence of neurotensin was investigated in radiation-exposed rat intestinal epithelium. Wistar rats were randomly divided into control, irradiation, and irradiation+neurotensin groups, and bacterial translocation to the mesenteric lymph node and expression of claudins were determined. Irradiation led to intestinal barrier failure as demonstrated by significant bacterial translocation. In irradiated terminal ilea, expression of claudin-3 and claudin-4 was significantly decreased, and claudin-2 expression was increased. Administration of neurotensin significantly reduced bacterial translocation and restored the structure of the villi as seen by histologic examination. Among the three subtype of claudins, only claudin-3 expression was restored. These results suggest that the therapeutic effect of neurotensin on the disruption of the intestinal barrier is associated with claudin-3 alteration and that claudin-3 could be used as a marker in evaluating radiation-induced intestinal injury.

Radiation-induced distal ileal obstruction complicating ileostomy closure.

BACKGROUND: Radiation enteropathy is a recognized complication in patients who undergo neoadjuvant radiotherapy for locally advanced rectal cancer. Routine formation of defunctioning loop ileostomy in these patients may mask the development of stricturing, terminal ileal and radiation enteropathy which later may complicate the ileostomy closure. Our aim was to assess the preventive techniques and key warning signs. METHODS: We present two cases of ileostomy closure in patients with occult, radiation-induced, terminal ileal stricture and review the relevant literature. RESULTS: The first case was complicated by dehiscence of the ileal anastomosis due to undiagnosed, downstream stenosis of the irradiated terminal ileum. A similar terminal ileal stricture was diagnosed in the second case by contrast fluoroscopy enabling an elective ileocolic anastomosis. The literature indicates the importance of identifying such problems prior to loop ileostomy closure. CONCLUSIONS: Contrast studies before loop ileostomy closure are valuable in limiting the complications of radiation-induced distal ileal obstruction in selected patients.

Female Mice are More Resistant to the Mixed-Field (67% Neutron + 33% Gamma) Radiation-Induced Injury in Bone Marrow and Small Intestine than Male Mice due to Sustained Increases in G-CSF and the Bcl-2/Bax Ratio and Lower miR-34a and MAPK Activation.

In nuclear and radiological incidents, overexposure to ionizing radiation is life-threatening. It is evident that radiation depletes blood cells and increases circulating cytokine/chemokine concentrations as well as mortality. While microglia cells of female mice have been observed to be less damaged by radiation than in male mice, it is unclear whether sex affects physio-pathological responses in the bone marrow (BM) and gastrointestinal system (GI). We exposed B6D2F1 male and female mice to 0, 1.5, 3, or 6 Gy with mixed-field radiation containing 67% neutron and 33% gamma at a dose rate of 0.6 Gy/min. Blood and tissues were collected on days 1, 4, and 7 postirradiation. Radiation increased cytokines/chemokines in the femurs and ilea of female and male mice in a dose-dependent manner. Cytokines and chemokines reached a peak on day 4 and declined on day 7 with the exception of G-CSF which continued to increase on day 7 in female mice but not in male mice. MiR-34a (a Bcl-2 inhibitor), G-CSF (a miR-34a inhibitor), MAPK activation (pro-cell death), and citrulline (a biomarker of entroepithelial proliferation), active caspase-3 (a biomarker of apoptosis) and caspase-1 activated gasdermin D (a pyroptosis biomarker) were measured in the sternum, femur BM and ileum. Sternum histopathology analysis with H&E staining and femur BM cell counts as well as Flt-3L showed that BM cellularity was not as diminished in females, with males showing a 50% greater decline on day 7 postirradiation, mainly mediated by pyroptosis as indicated by increased gasdermin D in femur BM samples. Ileum injury, such as villus height and crypt depth, was also 43% and 30%, respectively, less damaged in females than in males. The severity of injury in both sexes was consistent with the citrulline and active caspase-3 measurements as well as active caspase-1 and gasdermin D measurements, suggesting apoptosis and pyroptosis occurred. On day 7, G-CSF in the ileum of female mice continued to be elevated by sevenfold, whereas G-CSF in the ileum of male mice returned to baseline. Furthermore, G-CSF is known to inhibit miR-34a expression, which in ileum on day 1 displayed a 3- to 4-fold increase in female mice after mixed-field (67% neutron + 33% gamma) irradiation, as compared to a 5- to 9-fold increase in male mice. Moreover, miR-34a blocked Bcl-2 expression. Mixed-field (60% neutron + 33% gamma) radiation induced more Bcl-2 in females than in males. On day 7, AKT activation was found in the ileums of females and males. However, MAPK activation including ERK, JNK, and p38 showed no changes in the ileum of females (by 0-fold; P > 0.05), whereas the MAPK activation was increased in the ileum of males (by 100-fold; P < 0.05). Taken together, the results suggest that organ injury from mixed-field (67% neutron + 33% gamma) radiation is less severe in females than in males, likely due to increased G-CSF, less MAPK activation, low miR-34a and increased Bcl-2/Bax ratio.

Matrilysin expression related to radiation and microflora changes in murine bowel.

BACKGROUND: Matrilysin (MMP-7) elevation after radiotherapy is shown in humans. Matrilysin regulates certain cytokines and the production of bactericidal proteins when the mucosa is exposed to bacterial antigens. We investigate the effect of irradiation on matrilysin and microflora in murine bowel, after modulation with antibiotics. METHODS: Animals were divided into two different groups a radiation group (72 animals) and sham radiation group (36 animals). Animals were divided into smaller groups of six according to radiation dose (19 or 38 Gy or sham). Seven days before radiotherapy ampicillin 500 mg/kg/d was administered intramuscularly, in the antibiotic groups. An exteriorized segment of ileum was subjected to single high dose radiation (19 or 38 Gy). Samples were collected 2, 24, and 48 h and analyzed for microflora, MIP-2, TGF-ß, and MMP-7. RESULTS: The combination of antibiotics and irradiation leads to an early significant reduction of bacteria, down-regulates MIP-2, up-regulates TGF-ß and elevation of MMP-7 to levels achieved by antibiotics or irradiation alone. Lactobacilli were reduced to non-existent levels after antibiotics. CONCLUSIONS: Pretreatment with Ampicillin before irradiation and laparotomy in a murine model leads to Matrilysin over-expression as achieved by radiotherapy alone. Microfloral regulation does not affect MMP-7 stimulation after surgical or radiological trauma. Radiotherapy overrides the effect of antibiotics leading to an up-regulation of MMP-7, TGF-ß and MIP-2 expression between 24 h and 48 h.

Differential Recovery of Small Intestinal Segments after Partial-Body Irradiation in Non-Human Primates.

In the event of a radiological attack or accident, it is more likely that the absorbed radiation dose will be heterogeneous, rather than uniformly distributed throughout the body. This type of uneven dose distribution is known as partial-body irradiation (PBI). Partial exposure of the vital organs, specifically the highly radiosensitive intestines, may cause death, if the injury is significant and the post-exposure recovery is considerably compromised. Here we investigated the recovery rate and extent of recovery from PBI-induced intestinal damage in large animals. Rhesus macaques (Macaca mulatta) were randomly divided into four groups: sham-irradiated (0 Gy), 8 Gy PBI, 11 Gy PBI and 14 Gy PBI. A single dose of ionizing radiation was delivered in the abdominal region using a uniform bilateral anteroposterior and posteroanterior technique. Irradiated animals were scheduled for euthanasia on days 10, 28 or 60 postirradiation, and sham-irradiated animals on day 60. Intestinal structural injuries were assessed via crypt depth, villus height, and mucosal surface length in the four different intestinal regions (duodenum, proximal jejunum, distal jejunum and ileum) using H&E staining. Higher radiation doses corresponded with more injury at 10 days post-PBI and a faster recovery rate. However, at 60 days post-PBI, damage was still evident in all regions of the intestine. The proximal and distal ends (duodenum and ileum, respectively) sustained less damage and recovered more fully than the jejunum.

Protection from Radiation-induced Damage in Rat's Ileum and Colon by Combined Regimens of Melatonin and Metformin: A Histopathological Study.

BACKGROUND: Radiation-induced enteritis and proctitis are common side effects of abdominopelvic cancers among patients that undergo radiotherapy for prostate, colorectal or urinary cancers. Exposure of these tissues to high doses of radiation leads to damage to villous, inflammation, pain, ulcer and bleeding, which may cause malabsorption and gastrointestinal disorders. To date, several procedures such as pharmaceutical treatment have been proposed for protection and mitigation of gastrointestinal toxicity following radiotherapy. AIMS: In the current study, we aimed to investigate the possible radioprotection of ileum and colon in rats using a combination of melatonin and metformin. METHODS: In this experimental study, 30 male Wistar rats were randomly assigned to six groups: control, melatonin (100 mg/kg) treatment, melatonin (100 mg/kg) plus metformin (100 mg/kg) treatment, radiation (10 Gy to whole body) group, radiation + melatonin (100 mg/kg) treatment, and radiation + melatonin (100 mg/kg) plus metformin (100 mg/kg) treatment. After 3.5 days, rats were sacrificed and their ileum and colon tissues carefully removed. Histopathological evaluations were conducted on these tissue samples. RESULTS: Histological evaluations reported moderate to severe damages to ileum and colon following whole body irradiation. Melatonin administration was able to protect the ileum remarkably, while the combination of melatonin and metformin was less effective. Interestingly, for the colon, melatonin was less effective while its combination with metformin was able to protect against radiation toxicity completely. CONCLUSION: For the ileum, melatonin was a more effective radioprotector compared to its combination with metformin. However, the combination of melatonin and metformin can be proposed as an ideal radioprotector for the colon.

Anti-Ferroptosis Drug Enhances Total-Body Irradiation Mitigation by Drugs that Block Apoptosis and Necroptosis.

Mitigation of total-body irradiation (TBI) in C57BL/6 mice by two drugs, which target apoptosis and necroptosis respectively, increases survival compared to one drug alone. Here we investigated whether the biomarker (signature)directed addition of a third anti-ferroptosis drug further mitigated TBI effects. C57BL/6NTac female mice (30-33 g) received 9.25 Gy TBI, and 24 h or later received JP4-039 (20 mg/kg), necrostatin-1 (1.65 mg/kg) and/or lipoxygenase-15 inhibitor (baicalein) (50 mg/kg) in single-, dual- or three-drug regimens. Some animals were sacrificed at days 0, 1, 2, 3, 4 or 7 postirradiation, while the majority in each group were maintained beyond 30 days. For those mice sacrificed at the early time points, femur bone marrow, intestine (ileum), lung and blood plasma were collected and analyzed for radiation-induced and mitigator-modified levels of 33 pro-inflammatory and stress response proteins. Each single mitigator administered [JP4-039 (24 h), necrostatin-1 (48 h) or baicalein (24 h)] improved survival at day 30 after TBI to 25% (P = 0.0432, 0.2816 or 0.1120, respectively) compared to 5% survival of 9.25 Gy TBI controls. Mice were administered the drug individually based on weight (mg/kg). Drug vehicles comprised 30% cyclodextrin for JP4-039 and baicalein, and 10% Cremphor-EL/10% ethanol/80% water for necrostatin-1; thus, dual-vehicle controls were also tested. The dual-drug combinations further enhanced survival: necrostatin-1 (delayed to 72 h) with baicalein 40% (P = 0.0359); JP4-039 with necrostatin-1 50% (P = 0.0062); and JP4-039 with baicalein 60% (P = 0.0064). The three-drug regimen, timed to signature directed evidence of onset after TBI of each death pathway in marrow and intestine, further increased the 30-day survival to 75% (P = 0.0002), and there was optimal normalization to preirradiation levels of inflammatory cytokine and stress response protein levels in plasma, intestine and marrow. In contrast, lung protein levels were minimally altered by 9.25 Gy TBI or mitigators over 7 days. Significantly, elevated intestinal proteins at day 7 after TBI were reduced by necrostatin-1-containing regimens; however, normalization of plasma protein levels at day 7 required the addition of JP4-039 and baicalein. These findings indicate that mitigator targeting to three distinct cell death pathways increases survival after TBI.

Oral PEG 15-20 protects the intestine against radiation: role of lipid rafts.

Intestinal injury following abdominal radiation therapy or accidental exposure remains a significant clinical problem that can result in varying degrees of mucosal destruction such as ulceration, vascular sclerosis, intestinal wall fibrosis, loss of barrier function, and even lethal gut-derived sepsis. We determined the ability of a high-molecular-weight polyethylene glycol-based copolymer, PEG 15-20, to protect the intestine against the early and late effects of radiation in mice and rats and to determine its mechanism of action by examining cultured rat intestinal epithelia. Rats were exposed to fractionated radiation in an established model of intestinal injury, whereby an intestinal segment is surgically placed into the scrotum and radiated daily. Radiation injury score was decreased in a dose-dependent manner in rats gavaged with 0.5 or 2.0 g/kg per day of PEG 15-20 (n = 9-13/group, P < 0.005). Complementary studies were performed in a novel mouse model of abdominal radiation followed by intestinal inoculation with Pseudomonas aeruginosa (P. aeruginosa), a common pathogen that causes lethal gut-derived sepsis following radiation. Mice mortality was decreased by 40% in mice drinking 1% PEG 15-20 (n = 10/group, P < 0.001). Parallel studies were performed in cultured rat intestinal epithelial cells treated with PEG 15-20 before radiation. Results demonstrated that PEG 15-20 prevented radiation-induced intestinal injury in rats, prevented apoptosis and lethal sepsis attributable to P. aeruginosa in mice, and protected cultured intestinal epithelial cells from apoptosis and microbial adherence and possible invasion. PEG 15-20 appeared to exert its protective effect via its binding to lipid rafts by preventing their coalescence, a hallmark feature in intestinal epithelial cells exposed to radiation.

Deoxyribonuclease I is essential for DNA fragmentation induced by gamma radiation in mice.

Gamma radiation is known to induce cell death in several organs. This damage is associated with endonuclease-mediated DNA fragmentation; however, the enzyme that produces the latter and is likely to cause cell death is unknown. To determine whether the most abundant cytotoxic endonuclease DNase I mediates gamma-radiation-induced tissue injury, we used DNase I knockout mice and zinc chelate of 3,5-diisopropylsalicylic acid (Zn-DIPS), which, as we show, has DNase I inhibiting activity in vitro. The study demonstrated for the first time that inactivation or inhibition of DNase I ameliorates radiation injury to the white pulp of spleen, intestine villi and bone marrow as measured using a quantitative TUNEL assay. The spleen and intestine of DNase I knockout mice were additionally protected from radiation by Zn-DIPS, perhaps due to the broad radioprotective effect of the zinc ions. Surprisingly, the main DNase I-producing tissues such as the salivary glands, pancreas and kidney showed no effect of DNase I inactivation. Another unexpected observation was that even without irradiation, DNA fragmentation and cell death were significantly lower in the intestine of DNase I knockout mice than in wild-type mice. This points to the physiological role of DNase I in normal cell death in the intestinal epithelium. In conclusion, our results suggested that DNase I-mediated mechanism of DNA damage and subsequent tissue injury are essential in gamma-radiation-induced cell death in radiosensitive organs.

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.

Proteomic Evaluation of the Acute Radiation Syndrome of the Gastrointestinal Tract in a Murine Total-body Irradiation Model.

Radiation exposure to the gastrointestinal system contributes to the acute radiation syndrome in a dose- and time-dependent manner. Molecular mechanisms that lead to the gastrointestinal acute radiation syndrome remain incompletely understood. Using a murine model of total-body irradiation, C57BL/6J male mice were irradiated at 8, 10, 12, and 14 Gy and assayed at day 1, 3, and 6 after exposure and compared to nonirradiated (sham) controls. Tryptic digests of gastrointestinal tissues (upper ileum) were analyzed by liquid chromatography-tandem mass spectrometry on a Waters nanoLC coupled to a Thermo Scientific Q Exactive hybrid quadrupole-orbitrap mass spectrometer. Pathway and gene ontology analysis were performed with Qiagen Ingenuity, Panther GO, and DAVID databases. A number of trends were identified in our proteomic data including pronounced protein changes as well as protein changes that were consistently up regulated or down regulated at all time points and dose levels interrogated. Time- and dose-dependent protein changes, canonical pathways affected by irradiation, and changes in proteins that serve as upstream regulators were also identified. Additionally, proteins involved in key processes including inflammation, radiation, and retinoic acid signaling were identified. The proteomic profiling conducted here represents an untargeted systems biology approach to identify acute molecular events that will be useful for a greater understanding of animal models and may be potentially useful toward the development of medical countermeasures and/or biomarkers.

dTMP-GH Fusion Protein Therapy Improves Survival after Radiation Injury Combined with Skin-Burn Trauma in Mice.

Exposure to ionizing radiation combined with traumatic tissue injury is an important life-threatening condition found in the civilian populations after nuclear and radiological events. The significance feature of radiation combined injury (RCI) is the severe combined effect, which makes the injury more complicated. At present, there are limited measures available to treat RCI. Here we show that a chimeric protein dTMP-GH, fusing human growth hormone (hGH) with a tandem dimer of thrombopoietin mimetic peptide (dTMP), could be an effective therapy agent for RCI in a mice model. In this study, using a RCI mouse model exposed to 60Co γ-ray photons (6.0 Gy, 0.3 Gy/min) followed by a 20% total-body-surface-area burns (henceforth called: RB-CI) was established. Administration of dTMP-GH (200 ug/kg) for 10 consecutive days beginning at 24 h after injury improved survival rate during a 30-day observation period compared with the control vehicle group. dTMP-GH treatment also showed enhanced bone marrow hematopoiesis recovery determined by peripheral blood analysis and bone marrow histopathology. Meanwhile, dTMP-GH treatment accelerated skin wound closure and mitigated ileum injury in the RCI model. These results suggest that dTMP-GH may prove to be an effective therapeutic drug for RCI.

Gamma-radiation induces apoptosis via sarcoplasmatic reticulum in guinea pig ileum smooth muscle cells.

We investigated the effects of gamma-radiation on cells isolated from the longitudinal smooth muscle layer of the guinea pig ileum, a relatively radioresistant tissue. Single doses (up to 50 Gy) reduced the amount of sarcoplasmatic reticulum and condensed the myofibrils, as shown by electron microscopy 3 days post-irradiation. After that, contractility of smooth muscle strips was reduced. Ca(2+) handling was altered after irradiation, as shown in fura-2 loaded cells, with elevated basal intracellular Ca(2+), reduced amount of intrareticular Ca(2+), and reduced capacitive Ca(2+) entry. Radiation also induced apoptosis, judged from flow cytometry of cells loaded with proprium iodide. Electron microscopy showed that radiation caused condensation of chromatin in dense masses around the nuclear envelope, the presence of apoptotic bodies, fragmentation of the nucleus, detachment of cells from their neighbors, and reductions in cell volume. Radiation also caused activation of caspase 12. Apoptosis was reduced by the administration of the caspase inhibitor Z-Val-Ala-Asp-fluoromethyl-ketone methyl ester (Z-VAD-FMK) during the 3 day period after irradiation, and by the chelator of intracellular Ca(2+), 1,2-bis(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA), from 1 h before until 2 h after irradiation. BAPTA also reduced the effects of radiation on contractility, basal intracellular Ca(2+), amount of intrareticular Ca(2+), capacitative Ca(2+) entry, and apoptosis. In conclusion, the effects of gamma radiation on contractility, Ca(2+) handling, and apoptosis appear due to a toxic action of intracellular Ca(2+). Ca(2+)-induced damage to the sarcoplasmatic reticulum seems a key event in impaired Ca(2+) handling and apoptosis induced by gamma-radiation.

Effect of gamma radiation on the structural and biological properties of angiotensin II.

PURPOSE: The vasoactive octapeptide hormone angiotensin II (DRVYIHPF, AngII) was selected as the target of this2investigation, which was aimed at determining the effect of gamma radiation on peptide structure and biological activity. MATERIALS AND METHODS: Radiation doses ranging from 1-15 kGy were applied to samples of purified AngII. RESULTS: The measured amount of remaining native hormone decreased non-linearly as the gamma radiation dose increases. Amino acid analysis of these irradiated peptide solutions demonstrated similar, simultaneous modifications of Phe8 and His6 residues along with the increase in the radiation dose. This structural variation of the vasoactive peptide closely resembled the decreasing process of the biological potencies of irradiated peptide solutions in rat uterus and guinea pig ileum muscle preparations. CONCLUSIONS: These findings suggest that investigating the effect of gamma radiation on small model molecules such as peptides could be of value for further extending this type of study to other physiologically relevant macromolecules such as proteins. Of note, this unique approach could also be useful in generating different types of peptide analogs (after purification) for application in future classical structure-function studies.

Pathological changes in the gastrointestinal tract of a heavily radiation-exposed worker at the Tokai-mura criticality accident.

Gastrointestinal syndrome after high-dose acute radiation whole body exposure is difficult to treat, although it is a well-known complication. In this report, we describe the clinical and pathological features of a patient who died after the criticality accident which occurred in Japan on 30 September 1999. The patient was estimated to have been exposed to 16-25 Gy equivalent of gamma ray, and died of multiple organ failure after acute radiation syndrome, especially gastrointestinal syndrome, on day 82. The stomach and small intestine contained a large amount of blood clots and the gastrointestinal epithelial cells were almost totally depleted at autopsy. In addition, the degree of the mucosal damage was dependent on the segment of the gastrointestinal tract; the mucosa of stomach, ileum and ascending colon was entirely depleted, but the esophagus, descending and sigmoid colon and rectum retained a small portion of the epithelial cells. From the posture of the patient at the time of exposure, the absorbed dose was presumed to be highest in the right-anterior abdomen. This agreed with the pathological differences in the mucosal damage by the position in the abdomen, which depended presumably on the radiation dose. This is the first report documenting the relationship between the absorbed dose and the severity of gastrointestinal damages in vivo.

Local radiotherapy of exposed murine small bowel: apoptosis and inflammation.

BACKGROUND: Preoperative radiotherapy of the pelvic abdomen presents with complications mostly affecting the small bowel. The aim of this study was to define the features of early radiation-induced injury on small bowel. METHODS: 54 mice were divided into two groups (36 irradiated and 18 sham irradiated). Animals were placed on a special frame and (in the radiated group) the exteriorized segment of ileum was subjected to a single absorbed dose of 19 or 38 Gy radiation using 6 MV high energy photons. Specimens were collected for histology, immunohistochemistry (IHC) and ELISA analysis after 2, 24 and 48 hours. Venous blood was collected for systemic leucocyte count in a Burker chamber. RESULTS: Histology demonstrated progressive infiltration of inflammatory cells with cryptitis and increased apoptosis. MIP-2 (macrophage inflammatory protein) concentration was significantly increased in irradiated animals up to 48 hours. No significant differences were observed in IL-10 (interleukin) and TNF-alpha (tumour necrosis factor) levels. IHC with CD45 showed a significant increase at 2 hours of infiltrating leucocytes and lymphocytes after irradiation followed by progressive decrease with time. Caspase-3 expression increased significantly in a dose dependent trend in both irradiated groups up to 48 hours. CONCLUSION: Acute small bowel injury caused by local irradiation is characterised by increased apoptosis of crypt epithelial cells and by lymphocyte infiltration of the underlying tissue. The severity of histological changes tends to be dose dependent and may affect the course of tissue damage.

Acute exposure to space flight results in evidence of reduced lymph Transport, tissue fluid Shifts, and immune alterations in the rat gastrointestinal system.

Space flight causes a number of alterations in physiological systems, changes in the immunological status of subjects, and altered interactions of the host to environmental stimuli. We studied the effect of space flight on the lymphatic system of the gastrointestinal tract which is responsible for lipid transport and immune surveillance which includes the host interaction with the gut microbiome. We found that there were signs of tissue damage present in the space flown animals that was lacking in ground controls (epithelial damage, crypt morphological changes, etc.). Additionally, morphology of the lymphatic vessels in the tissue suggested a collapsed state at time of harvest and there was a profound change in the retention of lipid in the villi of the ileum. Contrary to our assumptions there was a reduction in tissue fluid volume likely associated with other fluid shifts described. The reduction of tissue fluid volume in the colon and ileum is a likely contributing factor to the state of the lymphatic vessels and lipid transport issues observed. There were also associated changes in the number of MHC-II+ immune cells in the colon tissue, which along with reduced lymphatic competence would favor immune dysfunction in the tissue. These findings help expand our understanding of the effects of space flight on various organ systems. It also points out potential issues that have not been closely examined and have to potential for the need of countermeasure development.

Long term outcomes in the use of ileal ureter for radiation-induced ureteral strictures.

PURPOSE: Radiation-induced ureteral stricture disease poses significant surgical challenges. Ureteral substitution with ileum has long been a versatile option for reconstruction. We evaluated outcomes in patients undergoing ileal ureter replacement for ureteral reconstruction due to radiation-induced ureteral stricture versus other causes. METHODS: Between July 1989 and June 2013, 155 patients underwent consecutive ileal ureter creation. The study cohort included 104 patients with complete data sets and at least 7 months of follow up. Records were retrospectively reviewed with regard to demographics, indications, complications, and renal deterioration. RESULTS: Surgical indications included radiation-induced stricture in 23 (22%) and non-radiation-induced stricture in 81 (78%). Comparing ileal ureter substitution due to radiation versus other stricture etiologies, no statistical significance was observed in regard to age (45.6 vs. 51.2, p = 0.141), hospital length of stay in days (8.8 vs. 7.7, p = 0.216), percent GFR loss (MDRD-4 vs. -5%, p = 0.670 and CKD-EPI-7 vs. -6%, p = 0.914), 30-day surgical complications (26.1 vs. 30.1%, p = 0.658), metabolic acidosis (8.7 vs. 1.2%, p = 0.059), and renal failure requiring dialysis (4.3 vs. 1.2%, p = 0.337). Fistula formation (13.0 vs. 3.7%, p = 0.095), partial small bowel obstructions (21.7 vs. 7.4%, p = 0.063), and small bowel obstructions requiring reoperation (13.0 vs. 1.2%, p = 0.033) approached or reached statistical significance. Using Kaplan-Meier methodology, there was no difference in time to worsening renal outcome between the radiation and non-radiation groups (p > 0.05). CONCLUSION: Ureteral substitution with ileum is an effective reconstructive option for radiation-induced ureteral strictures in carefully selected patients.

Protective effect of polydatin on radiation-induced injury of intestinal epithelial and endothelial cells.

This study aimed to examine the radioprotective effect of polydatin (PD) on crypt and endothelial cells of the small intestines of C57BL/6 mice that received abdominal irradiation (IR). Mice were treated with 6 MV X-ray (20 Gy) abdominal IR at a dose rate of 200 cGy/min. Thirty minutes before or after IR, mice were intraperitoneally injected with PD. The rate of survival of the mice at 30 days after IR was determined. The duodenum (upper small intestine), jejunum (middle small intestine), and ileum (lower small intestine) were collected and subjected to hematoxylin and eosin staining. Tissue sample sections were analyzed through light microscopy, and the lengths of at least 20 intestinal villi were measured in each group; the average number of crypts was obtained from 10 intestinal samples in each group. Microvessel density was assessed using CD31-positive (brown) vascular endothelial cells/cell clusters. FHs74Int cell proliferation was measured using the CCK-8 assay. PD administration (25 mg/kg) before IR was the most effective in prolonging the survival of C57BL/6 mice. PD reduced radiation-induced injury of intestinal villi, prevented loss of crypts, increased intestinal crypt growth, protected against IR-induced intestinal injury, and enhanced the proliferative potential and reduced the apoptosis of FHs74Int cells after IR. Moreover, PD increased small intestinal MVD and reduced the apoptosis of intestinal microvascular endothelial cells in mice after IR. Therefore, PD was found to be able to protect the two types of cells from radiation damage and to thus alleviate radiation-induced injury of small intestine.

Successful mitigation of delayed intestinal radiation injury using pravastatin is not associated with acute injury improvement or tumor protection.

PURPOSE: To investigate whether pravastatin mitigates delayed radiation-induced enteropathy in rats, by focusing on the effects of pravastatin on acute cell death and fibrosis according to connective tissue growth factor (CTGF) expression and collagen inhibition. METHODS AND MATERIALS: Mitigation of delayed radiation-induced enteropathy was investigated in rats using pravastatin administered in drinking water (30 mg/kg/day) 3 days before and 14 days after irradiation. The ileum was irradiated locally after surgical exteriorization (X-rays, 19 Gy). Acute apoptosis, acute and late histologic alterations, and late CTGF and collagen deposition were monitored by semiquantitative immunohistochemistry and colorimetric staining (6 h, 3 days, 14 days, 15 weeks, and 26 weeks after irradiation). Pravastatin antitumor action was studied in HT-29, HeLa, and PC-3 cells by clonogenic cell survival assays and tumor growth delay experiments. RESULTS: Pravastatin improved delayed radiation enteropathy in rats, whereas its benefit in acute and subacute injury remained limited (6 h, 3 days, and 14 days after irradiation). Delayed structural improvement was associated with decreased CTGF and collagen deposition but seemed unrelated to acute damage. Indeed, the early apoptotic index increased, and severe subacute structural damage occurred. Pravastatin elicited a differential effect, protecting normal intestine but not tumors from radiation injury. CONCLUSION: Pravastatin provides effective protection against delayed radiation enteropathy without interfering with the primary antitumor action of radiotherapy, suggesting that clinical transfer is feasible.