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Abstract Background Resistance to chemotherapy continues to be a challenge when treating epithelial ovarian cancer (EOC), contributing to low patient survival rates. While CA125, the conventional EOC biomarker, has been useful in monitoring patients’ response to therapy, there are no biomarkers used to predict treatment response prior to chemotherapy. Previous work in vitro showed that plasma gelsolin (pGSN) is highly expressed in chemoresistant EOC cell lines, where it is secreted in small extracellular vesicles (sEVs). Whether sEVs from tumour cells are secreted into the circulation of EOC patients and could be used to predict patient chemoresponsiveness is yet to be determined. This study aims to identify if sEV-pGSN in the circulation could be a predictive biomarker for chemoresistance in EOC. Methods Sandwich ELISA was used to measure pGSN concentrations from plasma samples of 96 EOC patients (primarily high grade serous EOC). sEVs were isolated using ExoQuick ULTRA and characterized using western blot, nanoparticle tracking analysis, and electron microscopy after which pGSN was measured from the sEVs. Patients were stratified as platinum sensitive or resistant groups based on first progression free interval (PFI) of 6 or 12 months. Results Total circulating pGSN was significantly decreased and sEV-pGSN increased in patients with a PFI ≤ 12 months (chemoresistant) compared to those with a PFI > 12 months (chemosensitive). The ratio of total pGSN to sEV-pGSN further differentiated these groups and was a strong predictive marker for chemoresistance (sensitivity: 73.91%, specificity: 72.46%). Predetermined CA125 was not different between chemosensitive and chemoresistant groups and was not predictive of chemoresponsiveness prior to treatment. When CA125 was combined with the ratio of total pGSN/sEV-pGSN, it was a significant predictor of chemoresponsiveness, but the test performance was not as robust as the total pGSN/sEV-pGSN alone. Conclusions Total pGSN/sEV-pGSN was the best predictor of chemoresponsiveness prior to treatment, outperforming the individual biomarkers (CA125, total pGSN, and sEV-pGSN). This multianalyte predictor of chemoresponsiveness could help to inform physicians’ treatment and follow up plan at the time of EOC diagnosis, thus improving patients’ outcomes.

Silicon nitride membranes were experimentally obtained as substrates for biological samples, which are examined using a microscope with an operating wavelength of 13.8 nm. The free-hanging films obtained have a size of up to 1.5 × 1.5 mm2, which makes it possible to select an area of interest for investigation on the sample on the order of tens to hundreds of microns. The mechanical strength of the membranes satisfies that the samples do not tear the membranes and withstand transportation. The results obtained are an import-substituting technology for the manufacture of Si3N4 membranes. The resulting membranes have a transparency of more than 40% in the range of the "water transparency window" (2.3–4.4 nm) and EUV (13–15 nm). The developed technology will become the basis for creating cuvettes for living biological samples for soft X-ray microscopy studies. [ABSTRACT FROM AUTHOR]

Fifty years ago, it was reported that individuals of the Pacific boreal limpet Problacmaea (= Erginus) bear a penis for copulation and brood their young in the pallial cavity. These observations were based on light microscopy, but now we reveal new details of the reproductive biology of Erginus (Problacmaea) puniceus with electron microscopy. Gametogenesis is fundamentally similar to other Patellogastropoda, but there are some key differences. Oocytes develop in the ovary, dorsal to the foot in the posterior half of the body, before passing through the oviduct to the pallial cavity, where they are fertilized and brooded. Development is direct with embryos being brooded to the crawl-away juvenile stage. However, sometimes fertilization occurs internally with embryos beginning development in or near the gonad. Free sperm, which were likely autosperm (self) but could have been allosperm (cross), were found near developing oocytes in the gonad. Spermiogenesis results in the formation of an enta-quasperm with a cap-like acrosome, a bullet-shaped nucleus and spherical mitochondria in the midpiece. Copulation was not observed, but we confirm the presence of a penis with a dorsal penial groove that lies below the right cephalic tentacle in males, which is typical of functional penises of some molluscs. Males were always smaller, but intermediate-sized individuals were hermaphroditic to different extents. The largest individuals were entirely female, and their penises were smaller and often lacked the penial groove. Thus, E. (Problacmaea) puniceus appears to be a protandrous hermaphrodite, passing from male to female phase. Remnants of the testis persist into the female phase, suggesting that they are protandrous hermaphrodites with overlap, possibly allowing for self-fertilization to occur on occasion. However, the largest females lacked any testis remnants, suggesting instead that the species may be protandrous sequential hermaphrodites. [ABSTRACT FROM AUTHOR]

Biomeshes based on decellularized bovine pericardium (DBP) are widely used in reconstructive surgery due to their wide availability and the attractive biomechanical properties. However, their efficacy in clinical applications is often affected by the uncontrolled immunogenicity and proteolytic degradation. To address this issue, we present here in vivo multiparametric imaging analysis of epoxy crosslinked DBPs to reveal their fate after implantation. We first analyzed the structure of the crosslinked DBP using scanning electron microscopy and evaluated proteolytic stability and cytotoxicity. Next, using combination of fluorescence and hypoxia imaging, X-ray computed microtomography and histology techniques we studied the fate of DBPs after subcutaneous implantation in animals. Our approach revealed high resistance to biodegradation, gradual remodeling of a surrounding tissue forming the connective tissue capsule and calcification of crosslinked DBPs. These changes were concomitant to the development of hypoxia in the samples within 3 weeks after implantation and subsequent induction of angiogenesis and vascularization. Collectively, presented approach provides new insights on the transplantation of the epoxy crosslinked biomeshes, the risks associated with its applications in soft-tissue reconstruction and can be transferred to studies of other types of implants.

Glutaredoxin 2 (GRX2), a mitochondrial glutathione-dependent oxidoreductase, is central to glutathione homeostasis and mitochondrial redox, which is crucial in highly metabolic tissues like the heart. Previous research showed that absence of Grx2, leads to impaired mitochondrial complex I function, hypertension and cardiac hypertrophy in mice but the impact on mitochondrial structure and function in intact cardiomyocytes and in humans has not been explored. We hypothesized that Grx2 controls cardiac mitochondrial dynamics and function in cellular and mouse models, and that low expression is associated with human cardiac dysfunction. Here we show that Grx2 absence impairs mitochondrial fusion, ultrastructure and energetics in primary cardiomyocytes and cardiac tissue. Moreover, provision of the glutathione precursor, N-acetylcysteine (NAC) to Grx2-/- mice did not restore glutathione redox or prevent impairments. Using genetic and histopathological data from the human Genotype-Tissue Expression consortium we demonstrate that low GRX2 is associated with fibrosis, hypertrophy, and infarct in the left ventricle. Altogether, GRX2 is important in the control of cardiac mitochondrial structure and function, and protects against human cardiac pathologies. Keywords: Human heart, Mitochondria, Oxidative stress, Redox, Cardiac metabolism, Cardiac hypertrophy

Current peroxisome proliferator-activated receptor (PPAR)-targeted drugs, such as the PPARγ-directed diabetes drug rosiglitazone, are associated with undesirable side effects due to robust agonist activity in non-target tissues. To find new PPAR ligands with fewer toxic effects, we generated transgenic zebrafish that can be screened in high throughput for new tissue-selective PPAR partial agonists. A structural analog of coenzyme Q10 (idebenone) that elicits spatially restricted partial agonist activity for both PPARα and PPARγ was identified. Coenzyme Q10 was also found to bind and activate both PPARs in a similar fashion, suggesting an endogenous role in relaying the states of mitochondria, peroxisomes and cellular redox to the two receptors. Testing idebenone in a mouse model of type 2 diabetes revealed the ability to reverse fatty liver development. These findings indicate new mechanisms of action for both PPARα and PPARγ, and new potential treatment options for nonalcoholic fatty liver disease (NAFLD) and steatosis. This article has an associated First Person interview with the first author of the paper.

A brief description of the concept of a soft X-ray microscope for the Nanoscope station, which is planned to be installed at the SKIF fourth-generation synchrotron, is given. The microscope is designed to study the structure of cells and dynamic processes in them with nanometer spatial resolution. It will use a unique absorption contrast of ~15 between carbon-containing structures and water in the spectral range of the water window, λ = 2.3–4.3 nm, which eliminates the need for contrasting and the use of fluorophores and minimizes the doses of ionizing radiation absorbed in the samples to obtain high-quality 3D images. The scanning and projection schemes of the microscope, their main technical characteristics, including the calculated spectra and parameters of the undulator source are presented, and an estimate of the absorbed doses depending on the resolution is obtained. The main advantage of the proposed concept lies in the use of an objective lens of high-aperture multilayer X-ray mirrors, which makes it possible to clearly visualize the focal section of the sample. Technically simple axial tomography will also be used to reconstruct the three-dimensional structure of frozen or dried samples. In the scanning scheme, due to a low dose of radiation, it will be possible to study living plant cells with a resolution of up to 10 nm, animals with a resolution of up to 80 nm, and cryofixed samples with a resolution of up to 5 nm. In the projection scheme, due to simultaneous observation of the entire focal XY section, the time for obtaining three-dimensional images is significantly reduced, but due to a large dose, it will be oriented mainly on the study of fixed samples. [ABSTRACT FROM AUTHOR]

Background: Injury to the mesothelial layer of the peritoneal membrane during peritoneal dialysis (PD) is implicated in loss of ultrafiltration capacity, but there are no validated biomarkers for mesothelial cell injury. Microparticles (MPs) are 0.1 to 1.0 µm membrane vesicles shed from the cell surface following injury and are sensitive markers of tissue damage. Formation of MPs in the peritoneal cavity during PD has not been reported to date. Methods: We designed a single-center, proof of concept study to assess whether peritoneal solution exposure induces formation of mesothelial MPs suggestive of PD membrane injury. We examined MP levels in PD effluents by electron microscopy, nanoparticle tracking analysis (NTA), flow cytometry, procoagulant activity, and Western blot. Results: NTA identified particles in the size range of 30 to 900 nm, with a mean of 240 (SE: 10 nm). MP levels increased in a progressive manner during a 4-hour PD dwell. Electron microscopy confirmed size and morphology of vesicles consistent with characteristics of MPs as well as the presence of mesothelin on the surface. Western blot analysis of the MP fraction also identified the presence of mesothelin after 4 hours, suggesting that MPs found in PD effluents may arise from mesothelial cells. Conclusions: Our results suggest that MPs are formed and accumulate in the peritoneal cavity during PD, possibly as a stress response. Assessing levels of MPs in PD effluents may be useful as a biomarker for peritoneal membrane damage.