Non-irradiated Tissue Research Articles

Lower ACLR Failure Rates in Bone–Soft Tissue Versus Soft Tissue–Only Allografts in Adults: A Systematic Review and Meta-analysis

Background: While allografts are commonly used for anterior cruciate ligament reconstruction (ACLR), evidence to guide specific allograft selection is lacking. Purpose: To compare clinical and graft failure rates after ACLR using soft tissue–only allografts and bone–soft tissue allografts in adults. Study Design: Systematic review and meta-analysis; Level of evidence, 4. Methods: English-language studies with clinical outcome data on primary and revision ACLR in adults with nonirradiated soft tissue–only and bone–soft tissue grafts were identified in the search. Data extracted included allograft type, patient characteristics, follow-up time, and failure rates. The cumulative failure rate was defined as International Knee Documentation Committee grade C/D, graft retear, grade ≥2+ Lachman, grade ≥2+ pivot shift, and/or side-to-side KT-1000 laxity of >5 mm. The graft rupture rate was defined solely by the proportion of patients who had a graft rupture. Meta-analyses using the inverse variance method were used to estimate the pooled rates with 95% CIs. Subgroup analysis was conducted to compare allograft types and determine whether age, sex, and follow-up time influenced the estimates. Results: A total of 14 studies met the inclusion criteria: 7 investigated bone–soft tissue allografts, 6 investigated soft tissue–only allografts, and 1 investigated both. The comparative study showed a difference in the cumulative failure rate between bone–patellar tendon–bone and soft tissue–only allografts. The pooled cumulative failure rates for bone–soft tissue and soft tissue–only allografts were 11% (95% CI, 7-17) and 20% (95% CI, 14-29), respectively ( P = .05). The pooled graft rupture rates for bone–soft tissue and soft tissue–only allografts were 6% (95% CI, 4-9) and 13% (95% CI, 7-23), respectively ( P = .07). Conclusion: The meta-analysis results showed that bone–soft tissue allografts have lower cumulative failure rates than soft tissue–only allografts. Bone–soft tissue allografts may be the preferred allograft choices for ACLR.

Mandibular revascularization using a humeral periosteal free flap: A technical note

The vascularized periosteal free flap transposes a non-irradiated soft tissue with neoangiogenesis, bone induction, and osteogenesis qualities. A surgical technique using a humeral periosteal free flap is described for the treatment of recurrent osteoradionecrosis of the lower jaw. The humeral periosteal free flap is a technique associated with low morbidity. The procedure described avoids sacrificing major vessels as seen in other common flap procedures. Hence, this revascularization approach is equivalent to a prevention technique that should be considered early in the development of osteoradionecrosis to avoid further damage and challenging reconstruction.

Radiation-Induced DNA Damage in Uveal Melanoma Is Influenced by Dose Delivery and Chromosome 3 Status.

The purpose of this study was to analyze the extent of DNA breaks in primary uveal melanoma (UM) with regard to radiotherapy dose delivery (single-dose versus fractionated) and monosomy 3 status. A total of 54 patients with UM were included. Stereotactic radiotherapy (SRT) was performed in 23 patients, with 8 undergoing single-dose SRT (sdSRT) treatment and 15 receiving fractionated SRT (fSRT). DNA breaks in the enucleated or endoresected tumors were visualized by a TUNEL assay and quantified by measuring the TUNEL-positive area. Protein expression was analyzed by immunohistochemistry. Co-detection of chromosome 3 with proteins was performed by immuno-fluorescent in situ hybridization. The amount of DNA breaks in the total irradiated group was increased by 2.7-fold (P < 0.001) compared to non-irradiated tissue. Tumors treated with fSRT were affected more severely, showing 2.1-fold more DNA damage (P = 0.007) compared to the cases after single (high) dose irradiation (sdSRT). Monosomy 3 tumors showed less DNA breaks compared to disomy 3 samples (P = 0.004). The presence of metastases after radiotherapy correlated with monosomy 3 and less DNA breaks compared to patients with non-metastatic cancer in the combined group with fSRT and sdSRT (P < 0.05). Fractionated irradiation led to more DNA damage than single-dose treatment in primary UM. As tumors with monosomy 3 showed less DNA breaks than those with disomy 3, this may indicate that they are less radiosensitive, which may influence the efficacy of irradiation.

Niraparib efficacy in patients with newly-diagnosed glioblastoma: Clinical readout of a phase 0/2 "trigger" trial.

2002 Background: Poly (ADP-ribose) polymerase (PARP) mediates DNA damage response; niraparib is an investigational PARP1/2-selective inhibitor. This Phase 0 study evaluates newly-diagnosed glioblastoma (GBM) tumor pharmacokinetics (PK) and pharmacodynamics (PD), graduating patients with O6-methylguanine methyltransferase (MGMT) unmethylated tumors into a therapeutic regimen of niraparib plus fractionated radiotherapy when PK threshold is met. Methods: Presumed newly-diagnosed GBM patients received 4 days of niraparib (300/200 mg QD) prior to planned resection 3-5 (cohort 1) or 8-10 hours (cohort2) following the last dose. Tumor tissue (Gadolinium enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after ex vivo irradiation of surgical vs non-irradiated tissue. A PK ‘trigger’ determined eligibility for the Phase 2 component of the study and was defined as unbound [niraparib] &gt; 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. Patients with MGMT unmethylated tumors in excess of the PK threshold were eligible for Phase 2 dosing of niraparib plus radiotherapy followed by a maintenance phase of niraparib monotherapy. Results: All Phase 0 patients (n=46) met the PK threshold. In non-enhancing tumor regions, the mean unbound concentration of niraparib was 335.1 nM (n=43) for cohort 1 and 331.9 nM (n=3) for cohort 2. PAR suppression after ex vivo radiation was observed in 73% of the patients (24/33). Nineteen of 27 (70.3%) patients with unmethylated tumors were enrolled into Phase 2. Five patients in Phase 2 experienced Grade 4 thrombocytopenia related to niraparib. All adverse events resolved without sequelae. At time of data cutoff, median progression-free survival was 11.7 months. Mature overall survival (OS) data will be reported for the first time. Conclusions: Niraparib achieves pharmacologically relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor. Accompanying PD effects were observed in patient tumor tissue. For the first time, we report on the clinical efficacy of the study. A global Phase 3, open-label, randomized 2-arm study comparing niraparib versus temozolomide in adult patients with newly diagnosed, MGMT unmethylated glioblastoma is being planned. Clinical trial information: NCT05076513 .

Accuracy of patient-specific CT organ doses from Monte Carlo simulations: influence of CT-based voxel models

Monte Carlo simulations using patient CT images as input are the gold standard to perform patient-specific dosimetry. However, in standard clinical practice patient’s CT images are limited to the reconstructed CT scan range. In this study, organ dose calculations were performed with ImpactMC for chest and cardiac CT using whole-body and anatomy-specific voxel models to estimate the accuracy of CT organ doses based on the latter model. When the 3D patient model is limited to the CT scan range, CT organ doses from Monte Carlo simulations are the most accurate for organs entirely in the field of view. For these organs only the radiation dose related to scatter from the rest of the body is not incorporated. For organs lying partially outside the field of view organ doses are overestimated by not accounting for the non-irradiated tissue mass. This overestimation depends strongly on the amount of the organ volume located outside the field of view. To get a more accurate estimation of the radiation dose to these organs, the ICRP reference organ masses and densities could form a solution. Except for the breast, good agreement in dose was found for most organs. Voxel models generated from clinical CT examinations do not include the overscan in the z-direction. The availability of whole-body voxel models allowed to study this influence as well. As expected, overscan induces slightly higher organ doses.

PUM1 and PGK1 are Favorable Housekeeping Genes over Established Biodosimetry-related Housekeeping Genes such as HPRT1, ITFG1, DPM1, MRPS5, 18S rRNA and Others after Radiation Exposure.

In gene expression (GE) studies, housekeeping genes (HKGs) are required for normalization purposes. In large-scale inter-laboratory comparison studies, significant differences in dose estimates are reported and divergent HKGs are employed by the teams. Among them, the 18S rRNA HKG is known for its robustness. However, the high abundance of 18S rRNA copy numbers requires dilution, which is time-consuming and a possible source of errors. This study was conducted to identify the most promising HKGs showing the least radiation-induced GE variance after radiation exposure. In the screening stage of this study, 35 HKGs were analyzed. This included selected HKGs (ITFG1, MRPS5, and DPM1) used in large-scale biodosimetry studies which were not covered on an additionally employed pre-designed 96-well platform comprising another 32 HKGs used for different exposures. Altogether 41 samples were examined, including 27 ex vivo X-ray irradiated blood samples (0, 0.5, 4 Gy), six X-irradiated samples (0, 0.5, 5 Gy) from two cell lines (U118, A549), as well as eight non-irradiated tissue samples to encompass multiple biological entities. In the independent validation stage, the most suitable candidate genes were examined from another 257 blood samples, taking advantage of already stored material originating from three studies. These comprise 100 blood samples from ex vivo X-ray irradiated (0-4 Gy) healthy donors, 68 blood samples from 5.8 Gy irradiated (cobalt-60) Rhesus macaques (RM) (LD29/60) collected 0-60 days postirradiation, and 89 blood samples from chemotherapy-(CTx) treated breast tumor patients. CTx and radiation-induced GE changes in previous studies appeared comparable. RNA was isolated, converted into cDNA, and GE was quantified employing TaqMan assays and quantitative RT-PCR. We calculated the standard deviation (SD) and the interquartile range (IQR) as measures of GE variance using raw cycle threshold (Ct) values and ranked the HKGs accordingly. Dose, time, age, and sex-dependent GE changes were examined employing the parametrical t-test and non-parametrical Kruskal Wallis test, as well as linear regression analysis. Generally, similar ranking results evolved using either SD or IQR GE measures of variance, indicating a tight distribution of GE values. PUM1 and PGK1 showed the lowest variance among the first ten most suitable genes in the screening phase. MRPL19 revealed low variance among the first ten most suitable genes in the screening phase only for blood and cells, but certain comparisons indicated a weak association of MRPL19 with dose (P = 0.02-0.09). In the validation phase, these results could be confirmed. Here, IQR Ct values from, e.g., X-irradiated blood samples were 0.6 raw Ct values for PUM1 and PGK1, which is considered to represent GE differences as expected due to methodological variance. Overall, when compared, the GE variance of both genes was either comparable or lower compared to 18S rRNA. Compared with the IQR GE values of PUM1 and PGKI, twofold-fivefold increased values were calculated for the biodosimetry HKG HPRT1, and comparable values were calculated for biodosimetry HKGs ITFG1, MRPS5, and DPM1. Significant dose-dependent associations were found for ITFG1 and MRPS5 (P = 0.001-0.07) and widely absent or weak (P = 0.02-0.07) for HPRT1 and DPM1. In summary, PUM1 and PGK1 appeared most promising for radiation exposure studies among the 35 HKGs examined, considering GE variance and adverse associations of GE with dose.

Radiotherapy Enhances Metastasis Through Immune Suppression by Inducing PD-L1 and MDSC in Distal Sites.

Radiotherapy (RT) is a widely employed anticancer treatment. Emerging evidence suggests that RT can elicit both tumor-inhibiting and tumor-promoting immune effects. The purpose of this study is to investigate immune suppressive factors of radiotherapy. We used a heterologous two-tumor model in which adaptive concomitant immunity was eliminated. Through analysis of PD-L1 expression and myeloid-derived suppressor cells (MDSC) frequencies using patient peripheral blood mononuclear cells and murine two-tumor and metastasis models, we report that local irradiation can induce a systemic increase in MDSC, as well as PD-L1 expression on dendritic cells and myeloid cells, and thereby increase the potential for metastatic dissemination in distal, nonirradiated tissue. In a mouse model using two distinct tumors, we found that PD-L1 induction by ionizing radiation was dependent on elevated chemokine CXCL10 signaling. Inhibiting PD-L1 or MDSC can potentially abrogate RT-induced metastasis and improve clinical outcomes for patients receiving RT. Blockade of PD-L1/CXCL10 axis or MDSC infiltration during irradiation can enhance abscopal tumor control and reduce metastasis.

CTNI-22. A PHASE 0/2 ‘TRIGGER’ TRIAL OF NIRAPARIB IN PATIENTS WITH NEWLY-DIAGNOSED GLIOBLASTOMA

Abstract BACKGROUND Poly (ADP-ribose) polymerase (PARP) mediates DNA damage response; niraparib is an investigational PARP1/2-selective inhibitor. This Phase 0 study evaluates newly-diagnosed glioblastoma (GBM) tumor pharmacokinetics (PK) and pharmacodynamics (PD), graduating patients with O6-methylguanine methyltransferase (MGMT) unmethylated tumors into a therapeutic regimen of niraparib plus fractionated radiotherapy when PK threshold is met. METHODS Presumed newly-diagnosed GBM patients received 4 days of niraparib (300/200 mg QD) prior to planned resection 3-5 or 8-12 hours following the last dose. Tumor tissue (enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after ex vivo irradiation of surgical vs non-irradiated tissue. A PK ‘trigger’ determined eligibility for the therapeutic expansion phase and was defined as unbound [niraparib] &amp;gt; 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. Patients with MGMT unmethylated tumors and positive PK were eligible for phase 2 dosing of niraparib plus radiotherapy followed by a maintenance phase of niraparib. RESULTS All phase 0 patients (n = 44) met the PK threshold. In non-enhancing tumor regions, the mean unbound concentration of niraparib was 226.7 nM (n = 38). PAR suppression after ex vivo radiation was observed in 71% of the patients (20/28). Eighteen out of 26 patients with unmethylated tumors enrolled in phase 2. Five of the 18 initial patients in phase 2 experienced grade 4 thrombocytopenia related to niraparib. All adverse events were resolved without sequelae. For patients who completed at least 6 months of follow-up, PFS6 was 64% (n = 11) with 9.2-month median follow-up. Median follow-up for all patients (n = 18) was 4.2 months with 8 patients remaining on treatment and 2 patients ongoing PFS6 follow-up. CONCLUSIONS Niraparib achieves pharmacologically-relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor.

In Vivo Sonoporation Effect Under the Presence of a Large Amount of Micro-Nano Bubbles in Swine Liver.

Sonoporation as a method of intracellular drug and gene delivery has not yet progressed to being used in vivo. The aim of this study was to prove the feasibility of sonoporation at a level practical for use in vivo by using a large amount of carbon dioxide micro-nano bubbles. The carbon dioxide micro-nano bubbles and 100 mg of cisplatin were intra-arterially injected to the swine livers, and ultrasound irradiation was performed from the surface of the liver under laparotomy during the intra-arterial injection. After the intra-arterial injection, ultrasound-irradiated and nonirradiated liver tissues were immediately excised. Tissue platinum concentration was measured using inductively coupled plasma mass spectrometry. Liver tissue platinum concentrations were compared between the irradiated tissue and nonirradiated tissue using the Wilcoxon signed rank test. The mean (SD) liver tissue platinum concentration was 6.260*103 (2.070) ng/g in the irradiated liver tissue and 3.280*103 (0.430) ng/g in the nonirradiated liver tissue, showing significantly higher concentrations in the irradiated tissue ( P = 0.004). In conclusion, increasing the tissue concentration of administered cisplatin in the livers of living swine through the effect of sonoporation was possible in the presence of a large amount of micro-nano bubbles.

Exploring the Efficacy and Molecular Mechanism of Systemic Therapy-Based Split-Course Stereotactic Body Radiation Therapy for Solid Tumors

Considering the therapeutic toxicity, the question of how to administer adequate chemotherapy to synchronize Stereotactic body radiation therapy (SBRT) treatment strategy for maximizing the benefits of neoadjuvant therapy to improve prognosis is a challenging and debatable issue. This study explores the feasibility and theoretical advantages of the simultaneous implementation of split-course SBRT with systemic treatment. We evaluated the effect of three irradiation regimens (conventional radiotherapy (C-R, 15×2 Gy, (D1-5, D8-12, D15-19)), continuous SBRT (C-S, 3×7 Gy, (D1-3)), split SBRT (S-S, 3×7 Gy, (D1, D10, D19)) in combination with systemic therapy (chemotherapy (gemcitabine), PD-1 inhibitor (Anti-mouse PD-1 antibody) and angiogenesis-targeting agent (Anlotinib)) on tumor growth and survival by using the immunologically active C57BL/6 bilateral subcutaneous model with different cancer cells. At different time points after treatment, we monitored changes in the tumor microenvironment and explored the possible mechanisms. In the case of radiotherapy alone, we found similar tumor control in all groups but the best survival in the S-S group. When combined with systemic therapy, the S-S group has shown advantages in tumor control and survival. And the S-S combination group induced more CD4+ and CD8+ T lymphocyte infiltration in the tumor, which had the highest number of tumor vessels and the smallest area of hypoxia. Tumor cell PD-L1 expression was increased after radiotherapy in all but the most elevated and persistent S-S combination treatment group. CD3+ T cells, CD4+ T cells and CD8+ T cells peaked at weeks 2-3 after treatment, and all remained at the highest level for 6 weeks in the S-S combination group. Meanwhile, PD-L1 expression was significantly higher in all tumors in the third week than in other groups. The most significant reduction in the hypoxic area and increase in perfusion level was observed in the S-S group in the third week. RNA sequencing analysis revealed that immune response-related pathways were upregulated on the irradiated and non-irradiated side, tumor proliferation and invasion on the non-irradiated side, and angiogenesis-related pathways were down-regulated in the fractionated SBRT combination treatment group. In both irradiated side and non-irradiated side tumor tissues where the abscopal effect was observed, immune response-related pathways were upregulated in the S-S group relative to the C-R group, and tumor proliferation and invasion and angiogenesis-related pathways were found to be downregulated in the non-irradiated side. In preclinical models, the combination of split SBRT with systemic therapy has been shown to be more advantageous than conventional segmentation, possibly by affecting immune cell infiltration in the tumor microenvironment and reducing tumor hypoxia.

A Combined Phase 0/2 "Trigger" Trial of Niraparib in Combination with Radiation in Patients with Newly-Diagnosed Glioblastoma

Poly ADP-ribose (PAR) polymerase (PARP) mediates DNA damage response. Niraparib is an investigational PARP1/2-selective inhibitor. We conducted a combined phase 0/2 study to evaluate niraparib pharmacokinetics (PK) and pharmacodynamics (PD) in patients with newly-diagnosed glioblastoma (GBM), graduating patients to a phase 2 study evaluating a therapeutic regimen of niraparib with concurrent conventionally-fractionated radiotherapy (RT) in O6-methylguanine methyltransferase (MGMT) unmethylated tumors exceeding a prespecified PK threshold in non-enhancing tumor. Patients with presumed newly-diagnosed GBM were enrolled in a phase 0 study receiving 4 days of niraparib (300 or 200 mg QD) prior to planned resection 3-5 or 8-12 hours following the last dose. Tumor tissue (enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after 10 Gy ex vivo irradiation in surgical tissue compared to non-irradiated control tissue. A PK 'trigger' determined eligibility for the therapeutic phase 2 expansion portion of the study. This was defined as unbound [niraparib] > 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. Patients with MGMT unmethylated tumors exceeding this PK threshold were eligible for expansion phase dosing of niraparib with concurrent RT followed by a maintenance phase of niraparib. Patients with MGMT methylated tumors were not eligible for the expansion phase and proceeded with temozolomide (TMZ) plus RT followed by maintenance TMZ. RT dose was 60 Gy in 30 fractions using volumetric-modulated arc therapy (VMAT). All 29 patients enrolled in the phase 0 portion of the study met the PK threshold. In non-enhancing regions, the mean unbound concentration of niraparib was 258.2 nM. The suppression of PAR levels after ex vivo RT was observed in 79% of the patients (17/22). Sixteen patients had unmethylated tumors, and of those, 11 patients enrolled in phase 2. Five of the 6 initial patients enrolled in phase 2 experienced thrombocytopenia related to niraparib, and 3/5 cases were deemed serious and life-threatening. Consequently, starting dose in both phases was lowered to 200 mg, and no serious AEs were observed thereafter. At a median follow-up of 8.1 months [range: 6.0-12.9 months], 6-month PFS was 64% with 4 patients remaining on treatment and 5 patients ongoing survival follow-up. Niraparib achieves pharmacologically-relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor. When delivered with concurrent RT, niraparib was well-tolerated, with low rates of grade 3+ toxicity. Initial clinical efficacy data are encouraging.

A phase 0/2 trigger trial of niraparib in patients with newly diagnosed glioblastoma.

2069 Background: Poly (ADP-ribose) polymerase (PARP) mediates DNA damage response; niraparib is an investigational PARP1/2-selective inhibitor. This Phase 0 study evaluates newly-diagnosed glioblastoma (GBM) tumor pharmacokinetics (PK) and pharmacodynamics (PD), graduating patients with O6-methylguanine methyltransferase (MGMT) unmethylated tumors into a therapeutic regimen of niraparib plus fractionated radiotherapy when high unbound drug concentrations are present in gadolinium-nonenhancing tumor. Methods: Patients with presumed newly-diagnosed GBM were enrolled in a phase 0 study receiving 4 days of niraparib (300/200 mg QD) prior to planned resection 3-5 or 8-12 hours following the last dose. Tumor tissue (enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after 10 Gy ex vivo irradiation in surgical tissue compared to non-irradiated control tissue. A PK ‘trigger’ determined eligibility for the therapeutic expansion phase and was defined as unbound [niraparib] &gt; 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. Patients with MGMT unmethylated tumors exceeding this PK threshold were eligible for expansion phase dosing of niraparib plus radiotherapy followed by a maintenance phase of niraparib. Results: All patients (n=35) enrolled in the phase 0 portion of the study met the PK threshold. In non-enhancing tumor regions, the mean unbound concentration of niraparib was 253.2 nM in 32 evaluable GBM patients. The suppression of PAR levels after ex vivo radiation was observed in 75% of the patients (18/24). Eleven out of 18 patients with unmethylated tumors enrolled in phase 2. Five of the 6 initial patients enrolled in phase 2 experienced thrombocytopenia related to niraparib, and 3/5 cases were deemed serious and life-threatening. Consequently, starting dose in both phases was lowered to 200 mg, and no serious AEs were observed thereafter. At a median follow-up of 8.1 months [range: 6.0-12.9 months], PFS6 was 64% (n=11) with 4 patients remaining on treatment and 5 patients ongoing survival follow-up. Conclusions: Niraparib achieves pharmacologically-relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor. Clinical trial information: NCT05076513 .

In situ synchrotron radiation µCT indentation of cortical bone: Anisotropic crack propagation, local deformation, and fracture

The development of treatment strategies for skeletal diseases relies on the understanding of bone mechanical properties in relation to its structure at different length scales. At the microscale, indention techniques can be used to evaluate the elastic, plastic, and fracture behaviour of bone tissue. Here, we combined in situ high-resolution SRµCT indentation testing and digital volume correlation to elucidate the anisotropic crack propagation, deformation, and fracture of ovine cortical bone under Berkovich and spherical tips. Independently of the indenter type we observed significant dependence of the crack development due to the anisotropy ahead of the tip, with lower strains and smaller crack systems developing in samples indented in the transverse material direction, where the fibrillar bone ultrastructure is largely aligned perpendicular to the indentation direction. Such alignment allows to accommodate the strain energy, inhibiting crack propagation. Higher tensile hoop strains generally correlated with regions that display significant cracking radial to the indenter, indicating a predominant Mode I fracture. This was confirmed by the three-dimensional analysis of crack opening displacements and stress intensity factors along the crack front obtained for the first time from full displacement fields in bone tissue. The X-ray beam significantly influenced the relaxation behaviour independent of the tip. Raman analyses did not show significant changes in specimen composition after irradiation compared to non-irradiated tissue, suggesting an embrittlement process that may be linked to damage of the non-fibrillar organic matrix. This study highlights the importance of three-dimensional investigation of bone deformation and fracture behaviour to explore the mechanisms of bone failure in relation to structural changes due to ageing or disease. Statement of significanceCharacterising the three-dimensional deformation and fracture behaviour of bone remains essential to decipher the interplay between structure, function, and composition with the aim to improve fracture prevention strategies. The experimental methodology presented here, combining high-resolution imaging, indentation testing and digital volume correlation, allows us to quantify the local deformation, crack propagation, and fracture modes of cortical bone tissue. Our results highlight the anisotropic behaviour of osteonal bone and the complex crack propagation patterns and fracture modes initiating by the intricate stress states beneath the indenter tip. This is of wide interest not only for the understanding of bone fracture but also to understand other architectured (bio)structures providing an effective way to quantify their toughening mechanisms in relation to their main mechanical function.

Surgical Outcomes of VRAM vs Gracilis Flaps in Vulvoperineal Reconstruction following Oncologic Resection: A Proportional Meta-Analysis

Introduction: Pelvic exenteration and abdomino perineal resection are radical techniques commonly used for locally advanced or recurrent pelvic malignancy. Neo-adjuvant chemotherapy and/or radiotherapy has been shown to decrease local recurrence rates and increase cancer-specific survival by allowing resection of locally advanced neoplasm. However, it leads inevitably to increased morbidity rates due to large pelvic defects Healthy, well vascularized, non-irradiated tissues are required to fill the pelvic dead space and minimize complication rates. We conducted a proportional meta-analysis to compare Vertical Rectus Abdominus Myocutaneous flap (VRAM) vs Gracilis flap for vulvo-perineal reconstruction following oncologic resection. Materials and Methods: A systematic review of Embase, PubMed, Cochrane Library, Research gate and Google Scholar was conducted aiming at all articles reporting VRAM and gracilis surgical outcomes after oncologic abdomino-perineal resection. Proportional meta-analysis of surgical outcomes was performed using the Freeman-Tukey transformation and random-effect model. Results are expressed in proportions with a 95%CI. Pooled proportions were compared between VRAM and Gracilis using a two-sided Z-test. Results: Our review yielded 17 eligible studies (11 for VRAM and 6 for Gracilis), involving 898 patients (756 VRAM and 142 Gracilis). Pooled proportion of overall donor site complications for VRAM flap is 0.584 [95% CI 0.521, 0.647], which is significantly higher than Gracilis flap rate (0.154[95% CI 0.066,0.266]). The pooled rate of overall recipient site complications for VRAM is 0.387 [95% CI 0.305, 0.473], similar to that of the Gracilis flap (0.313 [95% CI 0.194, 0.444]). Pooled flap failure rate were low for VRAM (0.025 [95% CI 0.012-0.042]) and Gracilis (0.064 [95% CI 0.003-0.171]). There was no statistically significant difference between the minor and major complications for both flaps. Conclusion: We demonstrate that both flaps can be used safely for vulvo perineal reconstruction following oncologic resection with similar recipient site outcomes, although the VRAM flap will have more donor site complications than the gracilis flap.

Raman spectroscopy and convolutional neural networks for monitoring biochemical radiation response in breast tumour xenografts

Tumour cells exhibit altered metabolic pathways that lead to radiation resistance and disease progression. Raman spectroscopy (RS) is a label-free optical modality that can monitor post-irradiation biomolecular signatures in tumour cells and tissues. Convolutional Neural Networks (CNN) perform automated feature extraction directly from data, with classification accuracy exceeding that of traditional machine learning, in cases where data is abundant and feature extraction is challenging. We are interested in developing a CNN-based predictive model to characterize clinical tumour response to radiation therapy based on their degree of radiosensitivity or radioresistance. In this work, a CNN architecture is built for identifying post-irradiation spectral changes in Raman spectra of tumour tissue. The model was trained to classify irradiated versus non-irradiated tissue using Raman spectra of breast tumour xenografts. The CNN effectively classified the tissue spectra, with accuracies exceeding 92.1% for data collected 3 days post-irradiation, and 85.0% at day 1 post-irradiation. Furthermore, the CNN was evaluated using a leave-one-out- (mouse, section or Raman map) validation approach to investigate its generalization to new test subjects. The CNN retained good predictive accuracy (average accuracies 83.7%, 91.4%, and 92.7%, respectively) when little to no information for a specific subject was given during training. Finally, the classification performance of the CNN was compared to that of a previously developed model based on group and basis restricted non-negative matrix factorization and random forest (GBR-NMF-RF) classification. We found that CNN yielded higher classification accuracy, sensitivity, and specificity in mice assessed 3 days post-irradiation, as compared with the GBR-NMF-RF approach. Overall, the CNN can detect biochemical spectral changes in tumour tissue at an early time point following irradiation, without the need for previous manual feature extraction. This study lays the foundation for developing a predictive framework for patient radiation response monitoring.

Effects of Irradiation on Brain Tumors Using MR-Based Electrical Conductivity Imaging

Ionizing radiation delivers sufficient energy inside the human body to create ions, which kills cancerous tissues either by damaging the DNA directly or by creating charged particles that can damage the DNA. Recent magnetic resonance (MR)-based conductivity imaging shows higher sensitivity than other MR techniques for evaluating the responses of normal tissues immediately after irradiation. However, it is still necessary to verify the responses of cancer tissues to irradiation by conductivity imaging for it to become a reliable tool in evaluating therapeutic effects in clinical practice. In this study, we applied MR-based conductivity imaging to mouse brain tumors to evaluate the responses in irradiated and non-irradiated tissues during the peri-irradiation period. Absolute conductivities of brain tissues were measured to quantify the irradiation effects, and the percentage changes were determined to estimate the degree of response. The conductivity of brain tissues with irradiation was higher than that without irradiation for all tissue types. The percentage changes of tumor tissues with irradiation were clearly different than those without irradiation. The measured conductivity and percentage changes between tumor rims and cores to irradiation were clearly distinguished. The contrast of the conductivity images following irradiation may reflect the response to the changes in cellularity and the amounts of electrolytes in tumor tissues.

CTNI-14. A PHASE 0 ‘TRIGGER’ TRIAL OF NIRAPARIB IN NEWLY-DIAGNOSED GLIOBLASTOMA PATIENTS

Abstract BACKGROUND Poly (ADP-ribose) polymerase (PARP) mediates DNA damage response; niraparib is an investigational PARP1/2-selective inhibitor. This Phase 0 study evaluates newly-diagnosed glioblastoma (GBM) tumor pharmacokinetics (PK) and pharmacodynamics (PD), graduating patients to a therapeutic regimen of niraparib plus fractionated radiotherapy when high unbound drug concentrations are present in gadolinium-nonenhancing tumor. METHODS Presumed newly-diagnosed GBM patients received 4 days of niraparib (300 mg QD) prior to planned resection at 3-5 or 8-12 hours following the last dose. Tumor tissue (enhancing and nonenhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. A PK ‘trigger’ determined eligibility for the therapeutic expansion phase and was defined as unbound [niraparib] &amp;gt; 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. PARP inhibition was assessed by quantification of PAR induction after 10 Gy ex vivo irradiation in surgical tissue compared to non-irradiated control tissue. Patients with unmethylated MGMT tumors exceeding the PK threshold were eligible for expansion phase dosing of niraparib plus radiotherapy followed by a maintenance phase of niraparib. RESULTS Nineteen patients were enrolled into the Phase 0 study; all tumors met the study’s PK threshold and five unmethylated patients continued onto the expansion phase. One expansion phase patient experienced treatment-related Grade 3 serious adverse event (ALT and AST elevation) and four remain on treatment (median 4.2 months). In nonenhancing regions, the mean unbound concentrations of niraparib were 353.4 nM and 331.9 nM in the 3-5 hr cohort (n= 17) and the 8-12 hr (n = 3) cohort, respectively. The suppression of PAR levels after ex vivo radiation was observed in 69% of the patients (11/16). CONCLUSIONS Niraparib achieves pharmacologically-relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor.

Capsular inflammation after immediate breast reconstruction – Gene expression patterns and inflammatory cell infiltration in irradiated and non-irradiated breasts

Capsular contracture following post-mastectomy radiotherapy (PMRT) is commonly seen in patients undergoing implant-based immediate breast reconstruction (IBR). Further understanding of the underlying biology is needed for the development of preventive or therapeutic strategies. Therefore, we conducted a comparative study of gene expression patterns in capsular tissue from breast cancer patients who had received versus those who had not received PMRT after implant-based IBR. Biopsies from irradiated and healthy non-irradiated capsular tissue were harvested during implant exchange following IBR. Biopsies from irradiated (n=13) and non-irradiated (n=12) capsules were compared using Affymetrix microarrays to identify the most differentially regulated genes. Further analysis using immunohistochemistry was performed in a subset of materials to compare the presence of T cells, B cells, and macrophages. Enrichment testing using Gene Ontology (GO) analysis revealed that the 227 most differentially expressed genes were mainly involved in an inflammatory response. Twenty-one GO biological processes were identified [p < 0.05, false discovery rate (FDR) < 5%], several with B-cell-associated inflammation. Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) analysis identified macrophages as the most common inflammatory cell type in both groups, further supported by immunostaining of CD68. Radiation remarkably increased B-cell infiltration in the capsular region of biopsies, as quantified by immunostaining of CD20 (p=0.016). Transcript analysis and immunohistochemistry revealed inflammatory responses in capsular biopsies regardless of radiotherapy. However, the radiation response specifically involved B-cell-associated inflammatory responses.

Surgical Outcomes of VRAM vs. Gracilis Flaps in Vulvo-Perineal Reconstruction Following Oncologic Resection: A Proportional Meta-Analysis.

Simple SummaryThe rate of perineal complications after abdominoperineal reconstruction for the treatment of cancers ranges from 25% to 60% in the literature. It is well-established in current literature that direct closure has a higher complication rate than closure with a flap. Several reconstructive options have been proposed to fill the dead space with well-vascularized tissue. Every surgeon would like to be comfortable in selecting which flap has superiority in terms of surgical outcome. In the absence of a meta-analysis on the subject due to the scarcity of RCT and comparative studies, we used a proportional meta-analysis to analyze the surgical outcomes after reconstruction with either VRAM flap or gracilis flap following oncologic resection of the vulvo-perineal region.Pelvic exenteration and abdominoperineal resection are radical techniques commonly used for locally advanced or recurrent pelvic malignancy with high morbidity due to large pelvic defects. Flaps can help provide healthy, well-vascularized, non-irradiated tissues to fill pelvic dead space. We conducted a proportional meta-analysis to compare surgical outcomes of vertical rectus abdominus myocutaneous flap (VRAM) vs. gracilis flap for vulvo-perineal reconstruction following oncologic resection. A comprehensive literature search was conducted in the MEDLINE, PubMed, Embase, Google Scholar, and Cochrane Library databases. Proportional meta-analysis was performed to compare the surgical outcomes of using VRAM or gracilis flaps. Our review yielded 16 eligible studies. The pooled resolution rate of overall donor site complications for VRAM flap (pooled proportion = 0.576 [95% CI 0.387, 0.754]) was significantly higher than the pooled rate of overall donor site complications of gracilis flap (pooled proportion = 0.160 [95% CI 0.058, 0.295]). Partial and total flap necrosis were similar in both groups. There was no statistically significant difference between minor and major complications for both flaps. Both flaps can be used safely for vulvo-perineal reconstruction following oncologic resection with similar recipient site outcomes, although the VRAM flap will have more donor site complications than the gracilis flap.

Fenofibrate Attenuates Radiation-Induced Oxidative Damage to the Skin through Fatty Acid Binding Protein 4 (FABP4).

Radiation facilities and radioactive materials have been widely used in military, industry, medicine, science and nuclear facilities, which has significantly increased the potential of large-scale, uncontrolled exposure to radiation. The skin is one of the radiosensitive organ systems and radiation-induced skin injury remains a serious concern after ionizing radiation exposure. Our previous report indicates the involvement of the peroxisome proliferator-activated receptor pathway in the response of skin tissues to ionizing radiation. PPARα is a member of the PPAR nuclear hormone receptor superfamily, which can be activated by fibrate ligands. However, the protection of fenofibrate against ionizing radiation in skin keratinocytes and fibroblasts has not been described. The PPARα mRNA levels in irradiated and nonirradiated skin tissues of rats were determined by real-time assay. The expression of PPARα, and FABP4 were evaluated by western blot and IHC assay. The cell proliferation was detected by colony formation. The γH2AX foci and ROS levels in irradiated WS1 cells with FABP4 overexpression than in control cells were performed by Immunofluorescence assay. We found that PPARα expression was lower in the irradiated skin tissues of mouse, rat, monkey, and human patients than in their nonirradiated counterparts. PPARα fenofibrate significantly decreased radiation-induced ROS and apoptosis in a dose-dependent manner in human keratinocyte HaCaT and skin fibroblast WS1 cells. Moreover, fenofibrate significantly decreased radiation-induced ROS and malondialdehyde (MDA) levels in electron beam irradiated skin tissues of rats. Mechanistically, the proximal promoter of fatty acid binding protein 4 (FABP4) harbored three binding sites of PPARα and fenofibrate stimulated the transcription of FABP4 in skin cells. FABP4 overexpression decreased radiation-induced ROS and γH2AX foci. FABP4 inhibitor BMS309403 abrogated the ROS-eliminating activity as well as the lipid-accumulating role of fenofibrate, indicating that FABP4 mediates the radioprotective role of fenofibrate. In addition, FABP4 overexpression significantly decreased radiation-induced oxidative damage in vivo. These results confirm that fenofibrate attenuated radiation-induced oxidative damage to the skin by stimulating FABP4.