Defining and targeting tumor-associated macrophages in malignant mesothelioma.

Defining the ontogeny of tumor-associated macrophages (TAM) is important to develop therapeutic targets for mesothelioma. We identified two distinct macrophage populations in mouse peritoneal and pleural cavities, the monocyte-derived, small peritoneal/pleural macrophages (SPM), and the tissue-resident large peritoneal/pleural macrophages (LPM). SPM rapidly increased in tumor microenvironment after tumor challenge and contributed to the vast majority of M2-like TAM. The selective depletion of M2-like TAM by conditional deletion of the Dicer1 gene in myeloid cells (D-/-) promoted tumor rejection. Sorted SPM M2-like TAM initiated tumorigenesis in vivo and in vitro, confirming their capacity to support tumor development. The transcriptomic and single-cell RNA sequencing analysis demonstrated that both SPM and LPM contributed to the tumor microenvironment by promoting the IL-2-STAT5 signaling pathway, inflammation, and epithelial-mesenchymal transition. However, while SPM preferentially activated the KRAS and TNF-α/NFkB signaling pathways, LPM activated the IFN-γ response. The importance of LPM in the immune response was confirmed by depleting LPM with intrapleural clodronate liposomes, which abrogated the antitumoral memory immunity. SPM gene signature could be identified in pleural effusion and tumor from patients with untreated mesothelioma. Five genes, TREM2, STAB1, LAIR1, GPNMB, and MARCO, could potentially be specific therapeutic targets. Accordingly, Trem2 gene deletion led to reduced SPM M2-like TAM with compensatory increase in LPM and slower tumor growth. Overall, these experiments demonstrate that SPM M2-like TAM play a key role in mesothelioma development, while LPM more specifically contribute to the immune response. Therefore, selective targeting of monocyte-derived TAM may enhance antitumor immunity through compensatory expansion of tissue-resident TAM.

Foxp3+ Regulatory T Cell Depletion after Nonablative Oligofractionated Irradiation Boosts the Abscopal Effects in Murine Malignant Mesothelioma.

Increasing evidence indicates that local hypofractionated radiotherapy (LRT) can elicit both immunogenic and immunosuppressive local and systemic immune responses. We thus hypothesized that blockade of LRT-induced immunosuppressive responses could augment the antitumor effects and induce an abscopal response. In this study, we found that the upregulation of Foxp3+ regulatory T cells (Tregs) in the mesothelioma tumor microenvironment after nonablative oligofractionated irradiation significantly limited the success of irradiation. Using DEREG mice, which allow conditional and efficient depletion of Foxp3+ Tregs by diphtheria toxin injection, we observed that transient Foxp3+ Treg depletion immediately after nonablative oligofractionated irradiation provided synergistic local control and biased the T cell repertoire toward central and effector memory T cells, resulting in long-term cure. Furthermore, this combination therapy showed significant abscopal effect on the nonirradiated tumors in a concomitant model of mesothelioma through systemic activation of cytotoxic T cells and enhanced production of IFN-γ and granzyme B. Although local control was preserved with one fraction of nonablative irradiation, three fractions were required to generate the abscopal effect. PD-1 and CTLA-4 were upregulated on tumor-infiltrating CD4+ and CD8+ T cells in irradiated and nonirradiated tumors, suggesting that immune checkpoint inhibitors could be beneficial after LRT and Foxp3+ Treg depletion. Our findings are applicable to the strategy of immuno-radiotherapy for generating optimal antitumor immune responses in the clinical setting. Targeting Tregs immediately after a short course of irradiation could have a major impact on the local response to irradiation and its abscopal effect.

An Updated Review of Lysophosphatidylcholine Metabolism in Human Diseases.

Lysophosphatidylcholine (LPC) is increasingly recognized as a key marker/factor positively associated with cardiovascular and neurodegenerative diseases. However, findings from recent clinical lipidomic studies of LPC have been controversial. A key issue is the complexity of the enzymatic cascade involved in LPC metabolism. Here, we address the coordination of these enzymes and the derangement that may disrupt LPC homeostasis, leading to metabolic disorders. LPC is mainly derived from the turnover of phosphatidylcholine (PC) in the circulation by phospholipase A2 (PLA2). In the presence of Acyl-CoA, lysophosphatidylcholine acyltransferase (LPCAT) converts LPC to PC, which rapidly gets recycled by the Lands cycle. However, overexpression or enhanced activity of PLA2 increases the LPC content in modified low-density lipoprotein (LDL) and oxidized LDL, which play significant roles in the development of atherosclerotic plaques and endothelial dysfunction. The intracellular enzyme LPCAT cannot directly remove LPC from circulation. Hydrolysis of LPC by autotaxin, an enzyme with lysophospholipase D activity, generates lysophosphatidic acid, which is highly associated with cancers. Although enzymes with lysophospholipase A1 activity could theoretically degrade LPC into harmless metabolites, they have not been found in the circulation. In conclusion, understanding enzyme kinetics and LPC metabolism may help identify novel therapeutic targets in LPC-associated diseases.

Putative cancer stem cells may be the key target to inhibit cancer cell repopulation between the intervals of chemoradiation in murine mesothelioma.

BACKGROUND: Cancer cell repopulation during chemotherapy or radiotherapy is a major factor limiting the efficacy of treatment. Cancer stem cells (CSC) may play critical roles during this process. We aim to demonstrate the role of mesothelioma stem cells (MSC) in treatment failure and eventually to design specific target therapies against MSC to improve the efficacy of treatment in malignant mesothelioma. METHODS: Murine mesothelioma AB12 and RN5 cells were used to compare tumorigenicity in mice. The expression of CSC-associated genes was evaluated by quantitative real-time PCR in both cell lines treated with chemo-radiation. Stemness properties of MSC-enriched RN5-EOS-Puro2 cells were characterized with flow cytometry and immunostaining. A MSC-specific gene profile was screened by microarray assay and confirmed thereafter. Gene Ontology analysis of the selected genes was performed by GOMiner. RESULTS: Tumor growth delay of murine mesothelioma AB12 cells was achieved after each cycle of cisplatin treatment, however, tumors grew back rapidly due to cancer cell repopulation between courses of chemotherapy. Strikingly, a 10-times lower number of irradiated cells in both cell lines led to a similar tumor incidence and growth rate as with untreated cells. The expression of CSC-associated genes such as CD24, CD133, CD90 and uPAR was dramatically up-regulated, while others did not change significantly after chemoradiation. Highly enriched MSC after selection with puromycin displayed an increasing GFP-positive population and showed typical properties of stemness. Comparatively, the proportion of MSC significantly increased after RN5-EOS parental cells were treated with either chemotherapy, γ-ray radiation, or a combination of the two, while MSC showed more resistance to the above treatments. A group of identified genes are most likely MSC-specific, and major pathways related to regulation of cell growth or apoptosis are involved. Upregulation of the gene transcripts Tnfsf18, Serpinb9b, Ly6a, and Nppb were confirmed. CONCLUSION: Putative MSC possess the property of stemness showing more resistance to chemoradiation, suggesting that MSC may play critical roles in cancer cell repopulation. Further identification of selected genes may be used to design novel target therapies against MSC, so as to eliminate cancer cell repopulation in mesothelioma.

Impact of Perineural Invasion and Preexisting Type 2 Diabetes on Patients with Esophageal Squamous Cell Carcinoma Receiving Neoadjuvant Chemoradiotherapy.

Neoadjuvant chemoradiotherapy (neoCRT) followed by surgery is the cornerstone treatment strategy in locally advanced esophageal squamous cell carcinoma (ESCC). Despite this high- intensity multimodality therapy, most patients still experience recurrences and metastases, especially those who do not achieve a pathological complete response (pCR) after neoCRT. Here, we focused on identifying poor prognostic factors. In this retrospective cohort study; we enrolled 140 patients who completed neoCRT plus surgery treatment sequence with no interval metastasis. Overall, 45 of 140 patients (32.1%) achieved a pCR. The overall survival, disease-free survival (DFS), and metastasis-free survival was significantly better in patients with a pCR than in patients with a non-pCR. In the non-pCR subgroup, the presence of perineural invasion (PNI) and preexisting type 2 diabetes (T2DM) were two factors adversely affecting DFS. After adjusting for other factors, multivariate analysis showed that the hazard ratio (HR) was 2.354 (95% confidence interval [CI] 1.240-4.467, p = 0.009) for the presence of PNI and 2.368 (95% CI 1.351-4.150, p = 0.003) for preexisting T2DM. Patients with a combination of both factors had the worst survival. In conclusion, PNI and preexisting T2DM may adversely affect the prognosis of patients with ESCC receiving neoadjuvant chemoradiotherapy.

Exosomal miR-21 determines lung-to-brain metastasis specificity through the DGKB/ERK axis within the tumor microenvironment.

BACKGROUND: Brain metastasis affects 20-40 % of lung cancer patients, severely diminishing their quality of life. This research focuses on miR-21, overexpressed in these patients and inversely associated with DGKB in the ERK/STAT3 pathway, suggesting a dysregulated pathway with therapeutic potential. AIMS: The objective was to investigate miR-21's role in lung cancer patients with brain metastases and whether targeting this pathway could improve treatment outcomes. We also examined the miR-21 content in tumor spheres-derived extracellular vesicles (EVs) and their influence on ERK/STAT3 signaling and metastasis. MATERIALS AND METHODS: Tumor spheres were created from metastatic lung cancer cells. We studied miR-21 levels in these spheres, their impact on macrophage polarization, and the transition of nonmetastatic lung cancer cells. Furthermore, we analyzed miR-21 content in EVs derived from these spheres and their effect on ERK/STAT3 signaling and metastasis potential. KEY FINDINGS: We found tumor spheres had high miR-21 levels, promoting macrophage polarization and, epithelial-mesenchymal transition. These spheres-derived EVs, enriched with miR-21, accelerated ERK/STAT3 signaling and metastasis. Silencing miR-21 and inhibiting ERK signaling with ulixertinib notably mitigated these effects. Moreover, ulixertinib reduced brain metastasis incidence and increased survival in a mouse model and led to reduced tumor sphere generation and miR-21 levels in EVs. SIGNIFICANCE: Our study highlights the exacerbation of lung-to-brain metastasis via miR-21-rich EV secretion. This underlines the therapeutic promise of targeting the miR-21/ERK/STAT3 pathway with ulixertinib for managing brain metastasis from lung cancer.

Triple-modality therapy maximizes antitumor immune responses in a mouse model of mesothelioma.

Malignant pleural mesothelioma (MPM) is an intractable disease with an extremely poor prognosis. Our clinical protocol for MPM of subablative radiotherapy (RT) followed by radical surgery achieved better survival compared to other multimodal treatments, but local relapse and metastasis remain a problem. This subablative RT elicits an antitumoral immune response that is limited by the immunosuppressive microenvironment generated by regulatory T (Treg) cells. The antitumor effect of immunotherapy to simultaneously modulate the immune activation and the immune suppression after subablative RT has not been investigated in MPM. Herein, we demonstrated a rationale to combine interleukin-15 (IL-15) superagonist (IL-15SA) and glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) agonist (DTA-1) with subablative RT in mesothelioma. IL-15SA boosted the systemic expansion of specific antitumoral memory CD8+ T cells that were induced by RT in mice. Their effect, however, was limited by the up-regulation and activation of Treg cells in the radiated tumor microenvironment. Hence, selective depletion of intratumoral Treg cells through DTA-1 enhanced the benefit of subablative RT in combination with IL-15SA. The addition of surgical resection of the radiated tumor in combination with IL-15SA and DTA-1 maximized the benefit of RT and was accompanied by a reproducible abscopal response in a concomitant tumor model. These data support the development of clinical trials in MPM to test such treatment options for patients with locally advanced or metastatic tumors.

Blocking the GITR-GITRL pathway to overcome resistance to therapy in sarcomatoid malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is an aggressive neoplasm originating from the pleura. Non-epithelioid (biphasic and sarcomatoid) MPM are particularly resistant to therapy. We investigated the role of the GITR-GITRL pathway in mediating the resistance to therapy. We found that GITR and GITRL expressions were higher in the sarcomatoid cell line (CRL5946) than in non-sarcomatoid cell lines (CRL5915 and CRL5820), and that cisplatin and Cs-137 irradiation increased GITR and GITRL expressions on tumor cells. Transcriptome analysis demonstrated that the GITR-GITRL pathway was promoting tumor growth and inhibiting cell apoptosis. Furthermore, GITR+ and GITRL+ cells demonstrated increased spheroid formation in vitro and in vivo. Using patient derived xenografts (PDXs), we demonstrated that anti-GITR neutralizing antibodies attenuated tumor growth in sarcomatoid PDX mice. Tumor immunostaining demonstrated higher levels of GITR and GITRL expressions in non-epithelioid compared to epithelioid tumors. Among 73 patients uniformly treated with accelerated radiation therapy followed by surgery, the intensity of GITR expression after radiation negatively correlated with survival in non-epithelioid MPM patients. In conclusion, the GITR-GITRL pathway is an important mechanism of autocrine proliferation in sarcomatoid mesothelioma, associated with tumor stemness and resistance to therapy. Blocking the GITR-GITRL pathway could be a new therapeutic target for non-epithelioid mesothelioma.

Neoadjuvant Chemoradiotherapy and Larynx-Preserving Surgery for Cervical Esophageal Cancer.

Neoadjuvant concurrent chemoradiotherapy (CCRT) followed by surgery is widely used for treating locally advanced esophageal cancer in the thorax. This study evaluated the feasibility of neoadjuvant CCRT as a larynx preservation strategy for treating cervical esophageal squamous cell carcinoma (SCC) by a multidisciplinary team. Fifteen patients with cervical esophageal SCC who received neoadjuvant CCRT and radical surgery at our institution were reviewed. All patients received CCRT using the intensity-modulated radiation therapy with 48 Gy to gross tumor and 43.2 Gy to regional lymphatic basin in 24 fractions. Side effects, clinical tumor responses, pathological responses, and surgical margin status were analyzed. Pathological T down-staging was noted in seven patients (46.7%); pathological complete response was achieved in three patients (20%). Fourteen patients (93.3%) had larynx preservation; eight patients (53.3%) achieved negative surgical margins. The 2-year overall survival, local relapse-free survival, and regional relapse-free survival were 50.6%, 62.2%, and 47.5%, respectively. Neoadjuvant CCRT and larynx-sparing surgery are feasible and tolerable in patients with cervical esophageal SCC. Prospectively designed studies for large patient groups and long-term follow-up results are needed for validating this multimodality therapy.

Prognostic influence of tumor microenvironment after hypofractionated radiation and surgery for mesothelioma.

OBJECTIVE: Cytotoxic CD8+ tumor infiltrating lymphocytes (TILs) can contribute to the benefit of hypofractionated radiation, but programmed cell death pathways (programmed cell death 1 and programmed cell death ligand 1 [PD-1/PD-L1]) may provide a mechanism of tumor immune escape. We therefore reviewed the influence of PD-1/PD-L1 and CD8+ TILs on survival after accelerated hypofractionated hemithoracic radiation followed by extrapleural pneumonectomy for malignant pleural mesothelioma (MPM). METHODS: Sixty-nine consecutive patients undergoing the protocol of Surgery for Mesothelioma after Radiation Therapy (SMART) between November 2008 and February 2016 were analyzed for the presence of PD-L1 on tumor cells, PD-1 on inflammatory cells, and CD8+ TILs. Comparison was made with a cohort of patients undergoing extrapleural pneumonectomy after induction chemotherapy (n = 14) and no induction (n = 2) between March 2005 and October 2008. PD-L1 expression on tumor cells ≥1% was considered positive. CD8+ TILs and PD-1 expression were scored as a percentage of positive cells. RESULTS: PD-L1 was negative in 75% of MPM after completion of SMART. CD8+ TILs ranged between 0.24% and 8.47% (median 2%). CD8+ TILs ≥2% was associated with significantly better survival in epithelioid MPM (median survival 3.7 years vs 2.3 years in CD8+ TILs <2%; P = .02). PD-L1 positivity was associated with worse survival in biphasic MPM (median survival, 0.4 years vs 1.5 years in biphasic PD-L1 negative tumors; P = .07) after SMART. Multivariate analysis demonstrated that epithelioid MPM, nodal disease, and CD8+ TILs were independent predictors of survival after SMART. CONCLUSIONS: The influence of tumor microenvironment on survival differs between epithelioid and nonepithelioid MPM. CD8+ TILs is an independent factor associated with better survival in epithelioid MPM treated with SMART.

Progress of malignant mesothelioma research in basic science: A review of the 14th international conference of the international mesothelioma interest group (iMig2018).

Here we summarize the most recent update of mesothelioma research in basic science presented at the 14th iMig2018 international conference. The symposium of basic science track mainly focused on the drivers of mesothelioma initiation and progression, molecular pathogenesis, and perspectives on potential therapeutic approaches. This review covers several promising fields including strategies efficiently inhibiting YAP/TAZ functions or their critical downstream targets, heparanase inhibitors, RAN depletion, and MIF/CD74 inhibitors that may be developed as novel therapeutic approaches. In addition, targeting mesothelioma stem cells by depleting M2-polarized macrophages in tumor microenvironment or blocking Tnfsf18 (GITRL)-GITR signalling might be translated into therapeutic modalities in mesothelioma treatment.

Frequency-domain birefringence measurement of biological binding to magnetic nanoparticles.

Optical detection of the frequency-dependent magnetic relaxation signal is used to monitor the binding of biological molecules to magnetic nanoparticles in a ferrofluid. Biological binding reactions cause changes in the magnetic relaxation signal due to an increase in the average hydrodynamic diameter of the nanoparticles. To allow the relaxation signal to be detected in dilute ferrofluids, measurements are made using a balanced photodetector, resulting in a 25 µV/√Hz noise floor, within 50% of the theoretical limit imposed by photon shot noise. Measurements of a ferrofluid composed of magnetite nanoparticles coated with anti-IgG antibodies show that the average hydrodynamic diameter increases from 115.2 to 125.4 nm after reaction with IgG.

Surgical outcomes of pulmonary mucoepidermoid carcinoma: A review of 41 cases.

INTRODUCTION: Pulmonary mucoepidermoid carcinoma is a rare cancer that occurs primarily in younger patients. The prognostic factors of pulmonary mucoepidermoid carcinoma are largely undetermined, especially in elderly patients. The aim of this study was to examine the clinical characteristics and prognostic factors influencing survival after surgical resection in patients with pulmonary mucoepidermoid carcinoma and also analyze the clinical manifestations and prognostic factors in elderly patients. MATERIALS AND METHODS: The pathological records of 41 pulmonary mucoepidermoid carcinoma patients (mean age, 61.4 years) who underwent surgical resection at our hospital between January 1991 and July 2015 were retrospectively reviewed. Subjects >65 years of age (n = 22) were considered elderly. RESULTS: The median follow-up duration was 42.9 (interquartile range, 15.0-120.8) months. Sixteen patients (39.0%) experienced tumor relapse, including 13 patients (81.3%) within 2 years. The 5-year disease-free survival rate was 57.9%. Tumor grade did not influence disease-free survival (P = 0.286). In the multivariate analysis, age, tumor size, pathological T3-4 status, and pathological N2 status were independent predictors of disease-free survival. The 5-year overall survival rate was 57.0%. Tumor grade also did not influence overall survival (P = 0.170). Age, tumor size, pathological T status, and pathological N2 status were independent predictors of overall survival. In elderly patients, the 5-year disease-free survival and overall survival rates were 41.4% and 41.5%, respectively. Pathological T status was the only independent predictor of both disease-free survival and overall survival in elderly patients. CONCLUSIONS: Prognostic factors identified for pulmonary mucoepidermoid carcinoma in this study differ from those of previous studies. Principally, tumor grade did not influence either disease-free survival or overall survival. Age, tumor size, and pathological factors were independent predictors of disease-free survival and overall survival. In elderly patients, pathological T status was the only independent predictor of disease-free survival and overall survival.

Modulation of macrophage polarization and lung cancer cell stemness by MUC1 and development of a related small-molecule inhibitor pterostilbene.

Tumor-associated macrophages (TAMs) polarized to the M2 phenotype play key roles in tumor progression in different cancer types, including lung cancer. MUC1 expression in various types of cancer is an indicator of poorer prognosis. Elevated MUC1 expression has been reported in inflammatory lung macrophages and is associated with lung cancer development. Here, we investigated the role of M2-polarized TAMs (M2-TAMs) in the generation of lung cancer stem cells (LCSCs) and tested pterostilbene, a small-molecule agent that modulates MUC1 expression in lung cancer cells, with the goal of subverting the microenvironment toward a favorable anti-tumor impact. We found that MUC1 was overexpressed in lung cancer patients, which was associated with poor survival rates. M2-TAMs and cancer cell lines were co-cultured in an experimental tumor microenvironment model. The expression levels of MUC1 and cancer stemness genes significantly increased in lung cancer cells in the presence of the M2-TAM cells. Intriguingly, pterostilbene dose-dependently suppressed self-renewal ability in M2-TAMs-co-cultured lung cancer cells, and this suppression was accompanied by downregulation of MUC1, NF-κB, CD133, ß-catenin, and Sox2 expression. Moreover, MUC1-silenced M2-TAMs exhibited a significantly lower ability to promote LCSC generation and decreased levels of NF-κB, CD133, and Sox2. The results suggest that MUC1 plays an important role in TAM-induced LCSC progression. Pterostilbene may have therapeutic potential for modulating the unfavorable effects of TAMs in lung cancer progression.

Multiinstitutional analysis of single-port video-assisted thoracoscopic anatomical resection for primary lung cancer.

BACKGROUND: Multiinstitutional analysis of single-port video-assisted thoracic surgery (VATS) for anatomic pulmonary resection is rare. This study aimed to address the technical feasibility and applicability of single-port video-assisted anatomical resection for primary lung cancer. METHODS: A total of 121 patients with primary lung cancer undergoing single-port video-assisted anatomical resection between 2011 and 2014 in 4 hospitals were included. The clinicopathologic variables and perioperative outcomes were collected and analyzed retrospectively. RESULTS: Single-port VATS segmentectomies and lobectomies were performed in 24 (19.8%) and 97 (80.2%) patients, respectively. One hundred seven of 121 (88.4%) patients had adenocarcinoma and 93 of 121 (76.9%) had pathologic stage I lung cancer. The average operative time and estimated blood loss was 198.8 ± 65.4 minutes and 99.1 ± 147.6 mL, respectively. The conversion and complication rates were 2.5% (3 of 121 cases) and 14.0% (17 of 121 cases), respectively. There was no surgical mortality, and the average length of hospital stay was 6.6 ± 2.6 days. The mean resected lymph node was 22.6 ± 12.0. We also identified patient age of 60 years or more, male sex, and tumor size greater than 3 cm as unfavorable perioperative outcome predictors after single-port video-assisted anatomical pulmonary resection. CONCLUSIONS: This first multiinstitutional single-port VATS study demonstrated that anatomical resection for primary lung cancer can be safely and effectively completed through a single-port VATS approach in hospitals experienced in VATS techniques.

Gap junctional communication in osteocytes is amplified by low intensity vibrations in vitro.

The physical mechanism by which cells sense high-frequency mechanical signals of small magnitude is unknown. During exposure to vibrations, cell populations within a bone are subjected not only to acceleratory motions but also to fluid shear as a result of fluid-cell interactions. We explored displacements of the cell nucleus during exposure to vibrations with a finite element (FE) model and tested in vitro whether vibrations can affect osteocyte communication independent of fluid shear. Osteocyte like MLO-Y4 cells were subjected to vibrations at acceleration magnitudes of 0.15 g and 1 g and frequencies of 30 Hz and 100 Hz. Gap junctional intracellular communication (GJIC) in response to these four individual vibration regimes was investigated. The FE model demonstrated that vibration induced dynamic accelerations caused larger relative nuclear displacement than fluid shear. Across the four regimes, vibrations significantly increased GJIC between osteocytes by 25%. Enhanced GJIC was independent of vibration induced fluid shear; there were no differences in GJIC between the four different vibration regimes even though differences in fluid shear generated by the four regimes varied 23-fold. Vibration induced increases in GJIC were not associated with altered connexin 43 (Cx43) mRNA or protein levels, but were dependent on Akt activation. Combined, the in silico and in vitro experiments suggest that externally applied vibrations caused nuclear motions and that large differences in fluid shear did not influence nuclear motion (<1%) or GJIC, perhaps indicating that vibration induced nuclear motions may directly increase GJIC. Whether the increase in GJIC is instrumental in modulating anabolic and anti-catabolic processes associated with the application of vibrations remains to be determined.

Altered composition of bone as triggered by irradiation facilitates the rapid erosion of the matrix by both cellular and physicochemical processes.

Radiation rapidly undermines trabecular architecture, a destructive process which proceeds despite a devastated cell population. In addition to the 'biologically orchestrated' resorption of the matrix by osteoclasts, physicochemical processes enabled by a damaged matrix may contribute to the rapid erosion of bone quality. 8w male C57BL/6 mice exposed to 5 Gy of Cs(137) γ-irradiation were compared to age-matched control at 2d, 10d, or 8w following exposure. By 10d, irradiation had led to significant loss of trabecular bone volume fraction. Assessed by reflection-based Fourier transform infrared imaging (FTIRI), chemical composition of the irradiated matrix indicated that mineralization had diminished at 2d by -4.3±4.8%, and at 10d by -5.8±3.2%. These data suggest that irradiation facilitates the dissolution of the matrix through a change in the material itself, a conclusion supported by a 13.7±4.5% increase in the elastic modulus as measured by nanoindentation. The decline in viable cells within the marrow of irradiated mice at 2d implies that the immediate collapse of bone quality and inherent increased risk of fracture is not solely a result of an overly-active biologic process, but one fostered by alterations in the material matrix that predisposes the material to erosion.

Devastation of adult stem cell pools by irradiation precedes collapse of trabecular bone quality and quantity.

Stem cell depletion and compromised bone marrow resulting from radiation exposure fosters long-term deterioration of numerous physiologic systems, with the degradation of the skeletal system ultimately increasing the risk of fractures. To study the interrelationship of damaged bone marrow cell populations with trabecular microarchitecture, 8- and 16-week-old C57BL/6 male mice were sublethally irradiated with 5 Gy of (137)Cs γ-rays, and adult stem cells residing in the bone marrow, as well as bone quantity and quality, were evaluated in the proximal tibia after 2 days, 10 days, and 8 weeks compared with age-matched controls. Total extracted bone marrow cells in the irradiated 8-week, young adult mice, including the hematopoietic cell niches, collapsed by 65% ± 11% after 2 days, remaining at those levels through 10 days, only recovering to age-matched control levels by 8 weeks. As early as 10 days, double-labeled surface was undetectable in the irradiated group, paralleled by a 41% ± 12% and 33% ± 4% decline in bone volume fraction (BV/TV) and trabecular number (Tb.N), respectively, and a 50% ± 10% increase in trabecular separation (Tb.Sp) compared with the age-matched controls, a compromised structure that persisted to 8 weeks postirradiation. Although the overall collapse of the bone marrow population and devastation of bone quality was similar between the "young adult" and "mature" mice, the impact of irradiation--and the speed of recovery--on specific hematopoietic subpopulations was dependent on age, with the older animals slower to restore key progenitor populations. These data indicate that, independent of animal age, complications arising from irradiation extend beyond the collapse of the stem cell population and extend toward damage to key organ systems. It is reasonable to presume that accelerating the recovery of these stem cell pools will enable the prompt repair of the skeletal system and ultimately reduce the susceptibility to fractures.

Magnetic scanometric DNA microarray detection of methyl tertiary butyl ether degrading bacteria for environmental monitoring.

A magnetoresistive biosensing platform based on a single magnetic tunnel junction (MTJ) scanning probe and DNA microarrays labeled with magnetic particles has been developed to provide an inexpensive, sensitive and reliable detection of DNA. The biosensing platform was demonstrated on a DNA microarray assay for quantifying bacteria capable of degrading methyl tertiary butyl ether (MTBE), where concentrations as low as 10 pM were detectable. Synthetic probe bacterial DNA was immobilized on a microarray glass slide surface, hybridized with the 48 base pair long biotinylated target DNA and subsequently incubated with streptavidin-coated 2.8 µm diameter magnetic particles. The biosensing platform then makes use of a micron-sized MTJ sensor that was raster scanned across a 3 mm by 5 mm glass slide area to capture the stray magnetic field from the tagged DNA and extract two dimensional magnetic field images of the microarray. The magnetic field output is then averaged over each 100 µm diameter DNA array spot to extract the magnetic spot intensity, analogous to the fluorescence spot intensity used in conventional optical scanners. The magnetic scanning result is compared with results from a commercial laser scanner and particle coverage optical counting to demonstrate the dynamic range and linear sensitivity of the biosensing platform as a potentially inexpensive, sensitive and portable alternative for DNA microarray detection for field applications.

Reconstruction after esophagectomy for esophageal cancer: retrosternal or posterior mediastinal route?

BACKGROUND: The aim of this study is to investigate which reconstructive route is most appropriate for patients undergoing an esophagectomy for esophageal cancer. METHODS: Clinical data on 110 patients were retrospectively collected by reviewing their medical charts. In order to evaluate the effects of adjuvant radiotherapy, patients were interviewed about the adverse side effects they experienced during and after treatment. RESULTS: The leakage rate was significantly lower in group that received posterior mediastinal reconstruction compared with the group that received retrosternal reconstruction (7.1% vs. 39%, p = 0.01). There were no significant differences between groups in terms of side effects related to adjuvant chemoradiotherapy or radiotherapy. The quality-of-life reports of patients who received adjuvant radiotherapy were not significantly different between the two study groups. CONCLUSION: For patients with esophageal cancer who undergo an esophagectomy followed by gastric conduit reconstruction, the posterior mediastinal route is superior to the retrosternal route in regard to anastomotic leakage and hospital mortality. Adjuvant radiotherapy did not influence the postoperative functions of the gastric conduit used for reconstruction in either route.