Protective Role of R-spondin1, an Intestinal Stem Cell Growth Factor, against Radiation-Induced Gastrointestinal Syndrome in Mice

BACKGROUND:Radiation-induced gastrointestinal syndrome (RIGS) results from a combination of direct cytocidal effects on intestinal crypt and endothelial cells and subsequent loss of the mucosal barrier, resulting in electrolyte imbalance, diarrhea, weight loss, infection and mortality. Because R-spondin1 (Rspo1) acts as a mitogenic factor for intestinal stem cells, we hypothesized that systemic administration of Rspo1 would amplify the intestinal crypt cells and accelerate the regeneration of the irradiated intestine, thereby, ameliorating RIGS. METHODS AND FINDINGS:Male C57Bl/6 mice received recombinant adenovirus expressing human R-spondin1 (AdRspo1) or E.coli Lacz (AdLacz), 1-3 days before whole body irradiation (WBI) or abdominal irradiation (AIR). Post-irradiation survival was assessed by Kaplan Meier analysis. RIGS was assessed by histological examination of intestine after hematoxilin and eosin staining, immunohistochemical staining of BrdU incorporation, Lgr5 and beta-catenin expression and TUNEL staining. The xylose absorption test (XAT) was performed to evaluate the functional integrity of the intestinal mucosal barrier. In order to examine the effect of R-spondin1 on tumor growth, AdRspo1 and AdLacZ was administered in the animals having palpable tumor and then exposed to AIR. There was a significant increase in survival in AdRspo1 cohorts compared to AdLacZ (p<0.003) controls, following WBI (10.4 Gy). Significant delay in tumor growth was observed after AIR in both cohorts AdRspo1 and AdLacZ but AdRspo1 treated animals showed improved survival compared to AdLacZ. Histological analysis and XAT demonstrated significant structural and functional regeneration of the intestine in irradiated animals following AdRspo1 treatment. Immunohistochemical analysis demonstrated an increase in Lgr5+ve crypt cells and the translocation of beta-catenin from the cytosol to nucleus and upregulation of beta-catenin target genes in AdRspo1-treated mice, as compared to AdLacz-treated mice. CONCLUSION:Rspo1 promoted radioprotection against RIGS and improved survival of mice exposed to WBI. The mechanism was likely related to induction of the Wnt-beta-catenin pathway and promotion of intestinal stem cell regeneration. Rspo1 has protective effect only on normal intestinal tissue but not in tumors after AIR and thereby may increase the therapeutic ratio of chemoradiation therapy in patients undergoing abdominal irradiation for GI malignancies

The role of pre- and post-SRS systemic therapy in patients with NSCLC brain metastases

Purpose: We report our experience with stereotactic radiosurgery (SRS) for NSCLC brain metastases. We then assess the prognostic value of pre- and post-SRS systemic therapy (PrSST and PoSST) and evaluate the timing of PoSST.Methods: In this retrospective study, we analyzed 96 patients with lung cancer and ECOG PS ≤ 3 who underwent SRS during 2007-2013. Recorded factors included SRS treatment parameters, systemic status of disease (SDS) at time of SRS, and the use of PrSST and PoSST. SDS was designated as pulmonary disease or extrapulmonary disease. For analysis, the SRS-PoSST interval (SPI) was divided into ≤30 days and &gt;30 days. Univariate and multivariate analyses were performed.Results: 85 patients with NSCLC were included in this analysis. 48% received PrSST and 48% received PoSST. 57% of patients had pulmonary disease while 40% had extrapulmonary disease. 46% of patients had synchronous metastases. At a median follow-up of 6 months, the median survival was 6.4 months and the actuarial overall survival at 3, 6, 12, and 36 months was 80%, 52%, 31%, and 6%. Extrapulmonary disease (p = 0.008) negatively predicted for survival while the receipt of any systemic therapy (p = 0.050) or PoSST alone (p = 0.039) positively predicted for survival. In patients receiving PoSST, an SPI &gt;30 days positively predicted for survival (HR 0.28, 95% CI 0.13-0.62, p = 0.002) regardless of SDS.Conclusion: Our results indicate the prognostic importance of systemic therapy and specifically PoSST. Additionally, delaying the initiation of PoSST to &gt;30 days seems beneficial. This finding was potentially influenced by neurotoxicity after SRS. Further investigation is warranted to define the optimal SPI.</p

The role of pre- and post-SRS systemic therapy in patients with NSCLC brain metastases

Purpose: We report our experience with stereotactic radiosurgery (SRS) for NSCLC brain metastases. We then assess the prognostic value of pre- and post-SRS systemic therapy (PrSST and PoSST) and evaluate the timing of PoSST.Methods: In this retrospective study, we analyzed 96 patients with lung cancer and ECOG PS ≤ 3 who underwent SRS during 2007-2013. Recorded factors included SRS treatment parameters, systemic status of disease (SDS) at time of SRS, and the use of PrSST and PoSST. SDS was designated as pulmonary disease or extrapulmonary disease. For analysis, the SRS-PoSST interval (SPI) was divided into ≤30 days and &gt;30 days. Univariate and multivariate analyses were performed.Results: 85 patients with NSCLC were included in this analysis. 48% received PrSST and 48% received PoSST. 57% of patients had pulmonary disease while 40% had extrapulmonary disease. 46% of patients had synchronous metastases. At a median follow-up of 6 months, the median survival was 6.4 months and the actuarial overall survival at 3, 6, 12, and 36 months was 80%, 52%, 31%, and 6%. Extrapulmonary disease (p = 0.008) negatively predicted for survival while the receipt of any systemic therapy (p = 0.050) or PoSST alone (p = 0.039) positively predicted for survival. In patients receiving PoSST, an SPI &gt;30 days positively predicted for survival (HR 0.28, 95% CI 0.13-0.62, p = 0.002) regardless of SDS.Conclusion: Our results indicate the prognostic importance of systemic therapy and specifically PoSST. Additionally, delaying the initiation of PoSST to &gt;30 days seems beneficial. This finding was potentially influenced by neurotoxicity after SRS. Further investigation is warranted to define the optimal SPI

Prospective evaluation of patient-reported outcomes of invisible ink tattoos for the delivery of external beam radiation therapy: the PREFER trial

IntroductionInvisible ink tattoos (IITs) avoid cosmetic permanence of visible ink tattoos (VITs) while serving as more reliable landmarks for radiation setup than tattooless setups. This trial evaluated patient-reported preference and feasibility of IIT implementation.Methods and materialsIn an IRB-approved, single institution, prospective trial, patients receiving proton therapy underwent IIT-based treatment setup. A survey tool assessed patient preference on tattoos using a Likert scale. Matched patients treated using our institutional standard tattooless setup were identified; treatment times and image guidance requirements were evaluated between tattooless and IIT-based alignment approaches. Distribution differences were estimated using Wilcoxon rank-sum tests or Chi-square tests.ResultsOf 94 eligible patients enrolled, median age was 58 years, and 58.5% were female. Most common treatment sites were breast (18.1%), lung (17.0%) and pelvic (14.9%). Patients preferred to receive IITs versus VITs (79.8% pre-treatment and 75.5% post-treatment, respectively). Patients were willing to travel farther from home to avoid VITs versus IITs (p&lt;0.01). Females were willing to travel (45.5% vs. 23.1%; p=0.04) and pay additional money to avoid VITs (34.5% vs. 5.1%; p&lt;0.01). Per-fraction average +treatment time and time from on table/in room to first beam were shorter with IIT-based vs. tattooless setup (12.3min vs. 14.1min; p=0.04 and 24.1min vs. 26.2min; p=0.02, respectively).DiscussionIn the largest prospective trial on IIT-based radiotherapy setup to date, we found that patients prefer IITs to VITs. Additionally, IIT-based alignment is an effective and efficient strategy in comparison with tattooless setup. Standard incorporation of IITs for patient setup should be strongly considered

Bone Marrow Stromal Cell Transplantation Mitigates Radiation-Induced Gastrointestinal Syndrome in Mice

Nuclear accidents and terrorism presents a serious threat for mass casualty. While bone-marrow transplantation might mitigate hematopoietic syndrome, currently there are no approved medical countermeasures to alleviate radiation-induced gastrointestinal syndrome (RIGS), resulting from direct cytocidal effects on intestinal stem cells (ISC) and crypt stromal cells. We examined whether bone marrow-derived adherent stromal cell transplantation (BMSCT) could restitute irradiated intestinal stem cells niche and mitigate radiation-induced gastrointestinal syndrome.Autologous bone marrow was cultured in mesenchymal basal medium and adherent cells were harvested for transplantation to C57Bl6 mice, 24 and 72 hours after lethal whole body irradiation (10.4 Gy) or abdominal irradiation (16-20 Gy) in a single fraction. Mesenchymal, endothelial and myeloid population were characterized by flow cytometry. Intestinal crypt regeneration and absorptive function was assessed by histopathology and xylose absorption assay, respectively. In contrast to 100% mortality in irradiated controls, BMSCT mitigated RIGS and rescued mice from radiation lethality after 18 Gy of abdominal irradiation or 10.4 Gy whole body irradiation with 100% survival (p<0.0007 and p<0.0009 respectively) beyond 25 days. Transplantation of enriched myeloid and non-myeloid fractions failed to improve survival. BMASCT induced ISC regeneration, restitution of the ISC niche and xylose absorption. Serum levels of intestinal radioprotective factors, such as, R-Spondin1, KGF, PDGF and FGF2, and anti-inflammatory cytokines were elevated, while inflammatory cytokines were down regulated.Mitigation of lethal intestinal injury, following high doses of irradiation, can be achieved by intravenous transplantation of marrow-derived stromal cells, including mesenchymal, endothelial and macrophage cell population. BMASCT increases blood levels of intestinal growth factors and induces regeneration of the irradiated host ISC niche, thus providing a platform to discover potential radiation mitigators and protectors for acute radiation syndromes and chemo-radiation therapy of abdominal malignancies

Non-Invasive Targeted Hepatic Irradiation and SPECT/CT Functional Imaging to Study Radiation-Induced Liver Damage in Small Animal Models

Radiation therapy (RT) has traditionally not been widely used in the management of hepatic malignancies for fear of toxicity in the form of radiation-induced liver disease (RILD). Pre-clinical hepatic irradiation models can provide clinicians with better understanding of the radiation tolerance of the liver, which in turn may lead to the development of more effective cancer treatments. Previous models of hepatic irradiation are limited by either invasive laparotomy procedures, or the need to irradiate the whole or large parts of the liver using external skin markers. In the setting of modern-day radiation oncology, a truly translational animal model would require the ability to deliver RT to specific parts of the liver, through non-invasive image guidance methods. To this end, we developed a targeted hepatic irradiation model on the Small Animal Radiation Research Platform (SARRP) using contrast-enhanced cone-beam computed tomography image guidance. Using this model, we showed evidence of the early development of region-specific RILD through functional single photon emission computed tomography (SPECT) imaging