Scalable plasma and digital cognitive markers for diagnosis and prognosis of Alzheimer's disease and related dementias.

INTRODUCTION: With emergence of disease-modifying therapies, efficient diagnostic pathways are critically needed to identify treatment candidates, evaluate disease severity, and support prognosis. A combination of plasma biomarkers and brief digital cognitive assessments could provide a scalable alternative to current diagnostic work-up. METHODS: We examined the accuracy of plasma biomarkers and a 10-minute supervised tablet-based cognitive assessment (Tablet-based Cognitive Assessment Tool Brain Health Assessment [TabCAT-BHA]) in predicting amyloid ß positive (Aß+) status on positron emission tomography (PET), concurrent disease severity, and functional decline in 309 older adults with subjective cognitive impairment (n = 49), mild cognitive impairment (n = 159), and dementia (n = 101). RESULTS: Combination of plasma pTau181, Aß42/40, neurofilament light (NfL), and TabCAT-BHA was optimal for predicting Aß-PET positivity (AUC = 0.962). Whereas NfL and TabCAT-BHA optimally predicted concurrent disease severity, combining these with pTau181 and glial fibrillary acidic protein was most accurate in predicting functional decline. DISCUSSION: Combinations of plasma and digital cognitive markers show promise for scalable diagnosis and prognosis of ADRD. HIGHLIGHTS: The need for cost-efficient diagnostic and prognostic markers of AD is urgent. Plasma and digital cognitive markers provide complementary diagnostic contributions. Combination of these markers holds promise for scalable diagnosis and prognosis. Future validation in community cohorts is needed to inform clinical implementation.

Multifaceted Roles of Mitochondrial Components and Metabolites in Metabolic Diseases and Cancer.

Mitochondria are essential cellular components that ensure physiological metabolic functions. They provide energy in the form of adenosine triphosphate (ATP) through the electron transport chain (ETC). They also constitute a metabolic hub in which metabolites are used and processed, notably through the tricarboxylic acid (TCA) cycle. These newly generated metabolites have the capacity to feed other cellular metabolic pathways; modify cellular functions; and, ultimately, generate specific phenotypes. Mitochondria also provide intracellular signaling cues through reactive oxygen species (ROS) production. As expected with such a central cellular role, mitochondrial dysfunctions have been linked to many different diseases. The origins of some of these diseases could be pinpointed to specific mutations in both mitochondrial- and nuclear-encoded genes. In addition to their impressive intracellular tasks, mitochondria also provide intercellular signaling as they can be exchanged between cells, with resulting effects ranging from repair of damaged cells to strengthened progression and chemo-resistance of cancer cells. Several therapeutic options can now be envisioned to rescue mitochondria-defective cells. They include gene therapy for both mitochondrial and nuclear defective genes. Transferring exogenous mitochondria to target cells is also a whole new area of investigation. Finally, supplementing targeted metabolites, possibly through microbiota transplantation, appears as another therapeutic approach full of promises.

Efficacy of Autologous Platelet Concentrates as Adjuvant Therapy to Surgical Excision in the Treatment of Keloid Scars Refractory to Conventional Treatments: A Pilot Prospective Study.

BACKGROUND: After conventional treatments, keloid scars show varying degrees of recurrence. The aim of this study was to assess the efficacy and safety of platelet-rich plasma in the treatment of postoperative keloid scars refractory to conventional treatments. METHODS: This pilot prospective study was conducted in 17 patients with keloid scars who did not respond to 4 injections of cortisone or radiotherapy after extralesional resection of keloid. Platelet-rich plasma was injected intraoperatively and then 3 times with a 1-month interval. The primary end point was the complete remission of keloid scars 2 years posttreatment. Scar pruritus severity was scored before and after treatment. The study protocol was approved by the ethics committee and authorized by the French National Agency. This trial was registered at ClinicalTrials.gov, identifier NCT02922972. RESULTS: Nine keloid scars (53%) were completely resolved at 2 years, and 5 (29%) completely relapsed after treatment. Pruritus severity score was significantly lower at 2 years compared with baseline (1.33 ± 0.97 before treatment and 0.40 ± 0.63 at 2 years, P < 0.003). The mean Vancouver Scar Scale score significantly improved (8.18 ± 2.38 before treatment and 3.82 ± 1.98 at 2 years, P < 0.001). CONCLUSIONS: Injecting platelet-rich plasma is an effective and safe method as adjunctive therapy to resection for treating keloid scars refractory to conventional therapy.

Delivery of human mesenchymal adipose-derived stem cells restores multiple urological dysfunctions in a rat model mimicking radical prostatectomy damages through tissue-specific paracrine mechanisms.

Urinary incontinence (UI) and erectile dysfunction (ED) are the most common functional urological disorders and the main sequels of radical prostatectomy (RP) for prostate cancer. Mesenchymal stem cell (MSC) therapy holds promise for repairing tissue damage due to RP. Because animal studies accurately replicating post-RP clinical UI and ED are lacking, little is known about the mechanisms underlying the urological benefits of MSC in this setting. To determine whether and by which mechanisms MSC can repair damages to both striated urethral sphincter (SUS) and penis in the same animal, we delivered human multipotent adipose stem cells, used as MSC model, in an immunocompetent rat model replicating post-RP UI and ED. In this model, we demonstrated by using noninvasive methods in the same animal from day 7 to day 90 post-RP injury that MSC administration into both the SUS and the penis significantly improved urinary continence and erectile function. The regenerative effects of MSC therapy were not due to transdifferentiation and robust engraftment at injection sites. Rather, our results suggest that MSC benefits in both target organs may involve a paracrine process with not only soluble factor release by the MSC but also activation of the recipient's secretome. These two effects of MSC varied across target tissues and damaged-cell types. In conclusion, our work provides new insights into the regenerative properties of MSC and supports the ability of MSC from a single source to repair multiple types of damage, such as those seen after RP, in the same individual.

Hydroperoxide Measurements During Low-Temperature Gas-Phase Oxidation of n-Heptane and n-Decane.

A wide range of hydroperoxides (C1-C3 alkyl hydroperoxides, C3-C7 alkenyl hydroperoxides, C7 ketohydroperoxides, and hydrogen peroxide (H2O2)), as well as ketene and diones, have been quantified during the gas-phase oxidation of n-heptane. Some of these species, as well as C10 alkenyl hydroperoxides and ketohydroperoxides, were also measured during the oxidation of n-decane. These experiments were performed using an atmospheric-pressure jet-stirred reactor at temperatures from 500 to 1100 K and one of three analytical methods, time-of-flight mass spectrometry combined with tunable synchrotron photoionization with a molecular beam sampling: time-of-flight mass spectrometry combined with laser photoionization with a capillary tube sampling, continuous wave cavity ring-down spectroscopy with sonic probe sampling. The experimental temperature at which the maximum mole fraction is observed increases significantly for alkyl hydroperoxides, alkenyl hydroperoxides, and then more so again for hydrogen peroxide, compared to ketohydroperoxides. The influence of the equivalence ratio from 0.25 to 4 on the formation of these peroxides has been studied during n-heptane oxidation. The up-to-date detailed kinetic oxidation models for n-heptane and for n-decane found in the literature have been used to discuss the possible pathways by which these peroxides, ketene, and diones are formed. In general, the model predicts well the reactivity of the two fuels, as well as the formation of major intermediates.

Study of the Formation of the First Aromatic Rings in the Pyrolysis of Cyclopentene.

The thermal decomposition of cyclopentene was studied in a jet-stirred reactor operated at constant pressure and temperature to provide new experimental information about the formation of the first aromatic rings from cyclic C5 species. Experiments were carried out at a residence time of 1 s, a pressure of 106.7 kPa, temperatures ranging from 773 to 1073 K and under diluted conditions (cyclopentene inlet mole fraction of 0.04). Species were quantified using three analytical methods: gas chromatography, synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS), and single photon laser ionization mass spectrometry (SPI-MS). Several species could be quantified using both methods allowing comparison of experimental data obtained with the three apparatuses. Discrepancies observed in mole fraction profiles of some large aromatics suggest that the direct sampling in the gas phase (with a molecular beam or a capillary tube) provide more reliable results. The main reaction products are 1,3-cyclopentadiene and hydrogen. The formation of many unsaturated C2-C6 olefins, diolefins and alkynes was also observed but in smaller amounts. Benzene, toluene, styrene, indene, and naphthalene were detected from 923 K. SVUV-PIMS data allowed the identification of another C6H6 isomer which is 1,5-hexadien-3-yne rather than fulvene. The quantification of the cyclopentadienyl radical was obtained from SVUV-PIMS and SPI-MS data with some uncertainty induced by the possible contribution to the signal for m/z 65 of a fragment from the decomposition of a larger ion. This is the first time that a radical is quantified in a jet-stirred reactor using non-optical techniques. SPI-MS analyses allowed the detection of species likely being combination products of allyl and cyclopentadienyl radicals. A model was developed for the pyrolysis of cyclopentene. This model includes routes of formation of aromatics from the cyclopentadienyl radical. The comparison of experimental and computed data is overall satisfactory for primary reaction products whereas discrepancies are still observed for aromatics.

Nanotubular crosstalk with distressed cardiomyocytes stimulates the paracrine repair function of mesenchymal stem cells.

Mesenchymal stem cells (MSC) are known to repair broken heart tissues primarily through a paracrine fashion while emerging evidence indicate that MSC can communicate with cardiomyocytes (CM) through tunneling nanotubes (TNT). Nevertheless, no link has been so far established between these two processes. Here, we addressed whether cell-to-cell communication processes between MSC and suffering cardiomyocytes and more particularly those involving TNT control the MSC paracrine regenerative function. In the attempt to mimic in vitro an injured heart microenvironment, we developed a species mismatch coculture system consisting of terminally differentiated CM from mouse in a distressed state and human multipotent adipose derived stem cells (hMADS). In this setting, we found that crosstalk between hMADS and CM through TNT altered the secretion by hMADS of cardioprotective soluble factors such as VEGF, HGF, SDF-1α, and MCP-3 and thereby maximized the capacity of stem cells to promote angiogenesis and chemotaxis of bone marrow multipotent cells. Additionally, engraftment experiments into mouse infarcted hearts revealed that in vitro preconditioning of hMADS with cardiomyocytes increased the cell therapy efficacy of naïve stem cells. In particular, in comparison with hearts treated with stem cells alone, those treated with cocultured ones exhibited greater cardiac function recovery associated with higher angiogenesis and homing of bone marrow progenitor cells at the infarction site. In conclusion, our findings established the first relationship between the paracrine regenerative action of MSC and the nanotubular crosstalk with CM and emphasize that ex vivo manipulation of these communication processes might be of interest for optimizing current cardiac cell therapies.

Experimental and Modeling Investigation of the Low-Temperature Oxidation of Dimethyl Ether.

The oxidation of dimethyl ether (DME) was studied using a jet-stirred reactor over a wide range of conditions: temperatures from 500 to 1100 K; equivalence ratios of 0.25, 1, and 2; residence time of 2 s; pressure of 106.7 kPa (close to the atmospheric pressure); and an inlet fuel mole fraction of 0.02 (with high dilution in helium). Reaction products were quantified using two analysis methods: gas chromatography and continuous wave cavity ring-down spectroscopy (cw-CRDS). cw-CRDS enabled the quantification of formaldehyde, which is one of the major products from DME oxidation, as well as that of hydrogen peroxide, which is an important branching agent in low-temperature oxidation chemistry. Experimental data were compared with data computed using models from the literature with important deviations being observed for the reactivity at low-temperature. A new detailed kinetic model for the oxidation of DME was developed in this study. Kinetic parameters used in this model were taken from literature or calculated in the present work using quantum calculations. This new model enables a better prediction of the reactivity in the low-temperature region. Under the present JSR conditions, error bars on predictions were given. Simulations were also successfully compared with experimental flow reactor, jet-stirred reactor, shock tube, rapid compression machine, and flame data from literature. The kinetic analysis of the model enabled the highlighting of some specificities of the oxidation chemistry of DME: (1) the early reactivity which is observed at very low-temperature (e.g., compared to propane) is explained by the absence of inhibiting reaction of the radical directly obtained from the fuel (by H atom abstraction) with oxygen yielding an olefin + HO2·; (2) the low-temperature reactivity is driven by the relative importance of the second addition to O2 (promoting the reactivity through branching chain) and the competitive decomposition reactions with an inhibiting effect.

Products from the oxidation of linear isomers of hexene.

The experimental study of the oxidation of the three linear isomers of hexene was performed in a quartz isothermal jet-stirred reactor (JSR) at temperatures ranging from 500 to 1100 K including the negative temperature coefficient (NTC) zone, at quasi-atmospheric pressure (1.07 bar), at a residence time of 2 s and with dilute stoichiometric mixtures. The fuel and reaction product mole fractions were measured using online gas chromatography. In the case of 1-hexene, the JSR has also been coupled through a molecular-beam sampling system to a reflectron time-of-flight mass spectrometer combined with tunable synchrotron vacuum ultraviolet photoionization. A difference of reactivity between the three fuels, which varies with the temperature range has been observed and is discussed according to the changes in the possible reaction pathways when the double bond is displaced. An enhanced importance of the reactions via the Waddington mechanism and of those of allylic radicals with HO2 radicals can be noted for 2- and 3-hexenes compared to 1-hexene.

SIRT-1/RHOT-1/PGC-1α loop modulates mitochondrial biogenesis and transfer to offer resilience following endovascular stem cell therapy in ischemic stroke.

Current clinical interventions for stroke majorly involve thrombolysis or thrombectomy, however, cessation of the progressive deleterious cellular cascades post-stroke and long-term neuroprotection are yet to be explored. Mitochondria are highly vulnerable organelles and their dysfunction is one of the detrimental consequences following stroke. Mitochondria dysregulation activate unfavourable cellular events over a period of time that leads to the collapse of neuronal machinery in the brain. Hence, strategies to protect and replenish mitochondria in injured neurons may be useful and needs to be explored. Stem cell therapy in ischemic stroke holds a great promise. Past studies have shown beneficial outcomes of endovascularly delivered stem cells in both pre-clinical and clinical settings. Intra-arterial (IA) administration can provide more cells to the stroke foci and affected brain regions than intravenous administration. Supplying new mitochondria to the stroke-compromised neurons either in the core or penumbra by infused stem cells can help increase their survival and longevity. Previously, our lab has demonstrated that IA 1∗105 mesenchymal stem cells (MSCs) in rats were safe, efficacious and rendered neuroprotection by regulating neuronal calcineurin, modulating sirtuin1(SIRT-1) mediated inflammasome signaling, ameliorating endoplasmic reticulum-stress, alleviation of post-stroke edema and reducing cellular apoptosis. To explore further, our present study aims to investigate the potential of IA MSCs in protecting and replenishing mitochondria in the injured neurons post-stroke and the involvement of SIRT-1/RHOT-1/PGC-1α loop towards mitochondria transfer, biogenesis, and neuroprotection. This study will open new avenues for using stem cells for ischemic stroke in clinics as one of the future adjunctive therapies.

Critical contribution of mitochondria in the development of cardiomyopathy linked to desmin mutation.

BACKGROUND: Beyond the observed alterations in cellular structure and mitochondria, the mechanisms linking rare genetic mutations to the development of heart failure in patients affected by desmin mutations remain unclear due in part, to the lack of relevant human cardiomyocyte models. METHODS: To shed light on the role of mitochondria in these mechanisms, we investigated cardiomyocytes derived from human induced pluripotent stem cells carrying the heterozygous DESE439K mutation that were either isolated from a patient or generated by gene editing. To increase physiological relevance, cardiomyocytes were either cultured on an anisotropic micropatterned surface to obtain elongated and aligned cardiomyocytes, or as a cardiac spheroid to create a micro-tissue. Moreover, when applicable, results from cardiomyocytes were confirmed with heart biopsies of suddenly died patient of the same family harboring DESE439K mutation, and post-mortem heart samples from five control healthy donors. RESULTS: The heterozygous DESE439K mutation leads to dramatic changes in the overall cytoarchitecture of cardiomyocytes, including cell size and morphology. Most importantly, mutant cardiomyocytes display altered mitochondrial architecture, mitochondrial respiratory capacity and metabolic activity reminiscent of defects observed in patient's heart tissue. Finally, to challenge the pathological mechanism, we transferred normal mitochondria inside the mutant cardiomyocytes and demonstrated that this treatment was able to restore mitochondrial and contractile functions of cardiomyocytes. CONCLUSIONS: This work highlights the deleterious effects of DESE439K mutation, demonstrates the crucial role of mitochondrial abnormalities in the pathophysiology of desmin-related cardiomyopathy, and opens up new potential therapeutic perspectives for this disease.

Epidemiologic features of borderline ovarian tumors in California: a population-based study.

PURPOSE: Borderline ovarian tumors (BOT) became no longer reportable in 2001, and few registries still collect information on these still poorly understood tumors. This study's objective was to describe epidemiologic features, trends, and survival of BOTs compared with those of low-grade (LG) and high-grade (HG) epithelial ovarian cancer (EOC) in the large and diverse population of California. METHODS: Data from the California Cancer Registry were used to examine demographic and tumor characteristics among women diagnosed with BOT (n = 9,786), LG-EOC (n = 3,656), and HG-EOC (n = 40,611) from 1988 to 2010. Annual percent changes in BOT and LG-EOC incidence rates were estimated using Joinpoint regression; 5-year relative survival was calculated for both BOTs and LG-EOCs by age, race/ethnicity, and histology. RESULTS: Age-adjusted incidence rates of BOT in 2009 were 3.1, 2.3, 2.2, and 1.4 per 100,000 among whites, Latinas, African Americans, and Asian/Pacific Islanders, respectively. Incidence rates for LG-EOC decreased by 2.2 % per year; rates for BOT increased by 7.3 % per year until 1993, remained unchanged until 2006, and seemed to decline thereafter. Compared with LG-EOCs, BOTs were diagnosed in higher frequency among Latinas, at younger age, and were more likely to affect only one ovary. Overall, 5-year relative survival for BOT was 98.9 %; among women diagnosed with stage IV BOT, survival was 77.1 %. CONCLUSIONS: In this study, differences between BOTs and LG-EOCs were marked but varied substantially by histologic subtype and were far less dramatic than differences between BOTs and HG-EOCs. Findings underscore the importance of understanding these enigmatic tumors.

Mitochondria on the move: Horizontal mitochondrial transfer in disease and health.

Mammalian genes were long thought to be constrained within somatic cells in most cell types. This concept was challenged recently when cellular organelles including mitochondria were shown to move between mammalian cells in culture via cytoplasmic bridges. Recent research in animals indicates transfer of mitochondria in cancer and during lung injury in vivo, with considerable functional consequences. Since these pioneering discoveries, many studies have confirmed horizontal mitochondrial transfer (HMT) in vivo, and its functional characteristics and consequences have been described. Additional support for this phenomenon has come from phylogenetic studies. Apparently, mitochondrial trafficking between cells occurs more frequently than previously thought and contributes to diverse processes including bioenergetic crosstalk and homeostasis, disease treatment and recovery, and development of resistance to cancer therapy. Here we highlight current knowledge of HMT between cells, focusing primarily on in vivo systems, and contend that this process is not only (patho)physiologically relevant, but also can be exploited for the design of novel therapeutic approaches.

Transfer of Cardiac Mitochondria Improves the Therapeutic Efficacy of Mesenchymal Stem Cells in a Preclinical Model of Ischemic Heart Disease.

BACKGROUND: The use of mesenchymal stem cells (MSCs) appears to be a promising therapeutic approach for cardiac repair after myocardial infarction. However, clinical trials have revealed the need to improve their therapeutic efficacy. Recent evidence demonstrated that mitochondria undergo spontaneous transfer from damaged cells to MSCs, resulting in the activation of the cytoprotective and pro-angiogenic functions of recipient MSCs. Based on these observations, we investigated whether the preconditioning of MSCs with mitochondria could optimize their therapeutic potential for ischemic heart disease. METHODS: Human MSCs were exposed to mitochondria isolated from human fetal cardiomyocytes. After 24 h, the effects of mitochondria preconditioning on the MSCs' function were analyzed both in vitro and in vivo. RESULTS: We found that cardiac mitochondria-preconditioning improved the proliferation and repair properties of MSCs in vitro. Mechanistically, cardiac mitochondria mediate their stimulatory effects through the production of reactive oxygen species, which trigger their own degradation in recipient MSCs. These effects were further confirmed in vivo, as the mitochondria preconditioning of MSCs potentiated their therapeutic efficacy on cardiac function following their engraftment into infarcted mouse hearts. CONCLUSIONS: The preconditioning of MSCs with the artificial transfer of cardiac mitochondria appears to be promising strategy to improve the efficacy of MSC-based cell therapy in ischemic heart disease.

Brillouin Scattering Selection Rules in Polarization-Sensitive Photonic Resonators.

Spontaneous Brillouin scattering in bulk crystalline solids is governed by the intrinsic selection rules locking the relative polarization of the excitation laser and the Brillouin signal. In this work, we independently manipulate the polarization of the two by employing polarization-sensitive optical resonances in elliptical micropillars to induce a wavelength-dependent rotation of the polarization states. Consequently, a polarization-based filtering technique allows us to measure acoustic phonons with frequencies difficult to access with standard Brillouin and Raman spectroscopies. This technique can be extended to other polarization-sensitive optical systems, such as plasmonic, photonic, or birefringent nanostructures, and finds applications in optomechanical, optoelectronic, and quantum optics devices.

Mitochondria Transfer from Mesenchymal Stem Cells Confers Chemoresistance to Glioblastoma Stem Cells through Metabolic Rewiring.

Glioblastomas (GBM) are heterogeneous tumors with high metabolic plasticity. Their poor prognosis is linked to the presence of glioblastoma stem cells (GSC), which support resistance to therapy, notably to temozolomide (TMZ). Mesenchymal stem cells (MSC) recruitment to GBM contributes to GSC chemoresistance, by mechanisms still poorly understood. Here, we provide evidence that MSCs transfer mitochondria to GSCs through tunneling nanotubes, which enhances GSCs resistance to TMZ. More precisely, our metabolomics analyses reveal that MSC mitochondria induce GSCs metabolic reprograming, with a nutrient shift from glucose to glutamine, a rewiring of the tricarboxylic acid cycle from glutaminolysis to reductive carboxylation and increase in orotate turnover as well as in pyrimidine and purine synthesis. Metabolomics analysis of GBM patient tissues at relapse after TMZ treatment documents increased concentrations of AMP, CMP, GMP, and UMP nucleotides and thus corroborate our in vitro analyses. Finally, we provide a mechanism whereby mitochondrial transfer from MSCs to GSCs contributes to GBM resistance to TMZ therapy, by demonstrating that inhibition of orotate production by Brequinar (BRQ) restores TMZ sensitivity in GSCs with acquired mitochondria. Altogether, these results identify a mechanism for GBM resistance to TMZ and reveal a metabolic dependency of chemoresistant GBM following the acquisition of exogenous mitochondria, which opens therapeutic perspectives based on synthetic lethality between TMZ and BRQ. Significance: Mitochondria acquired from MSCs enhance the chemoresistance of GBMs. The discovery that they also generate metabolic vulnerability in GSCs paves the way for novel therapeutic approaches.

Human mesenchymal stem cells reprogram adult cardiomyocytes toward a progenitor-like state through partial cell fusion and mitochondria transfer.

Because stem cells are often found to improve repair tissue including heart without evidence of engraftment or differentiation, mechanisms underlying wound healing are still elusive. Several studies have reported that stem cells can fuse with cardiomyocytes either by permanent or partial cell fusion processes. However, the respective physiological impact of these two processes remains unknown in part because of the lack of knowledge of the resulting hybrid cells. To further characterize cell fusion, we cocultured mouse fully differentiated cardiomyocytes with human multipotent adipose-derived stem (hMADS) cells as a model of adult stem cells. We found that heterologous cell fusion promoted cardiomyocyte reprogramming back to a progenitor-like state. The resulting hybrid cells expressed early cardiac commitment and proliferation markers such as GATA-4, myocyte enhancer factor 2C, Nkx2.5, and Ki67 and exhibited a mouse genotype. Interestingly, human bone marrow-derived stem cells shared similar reprogramming properties than hMADS cells but not human fibroblasts, which suggests that these features might be common to multipotent cells. Furthermore, cardiac hybrid cells were preferentially generated by partial rather than permanent cell fusion and that intercellular structures composed of f-actin and microtubule filaments were involved in the process. Finally, we showed that stem cell mitochondria were transferred into cardiomyocytes, persisted in hybrids and were required for somatic cell reprogramming. In conclusion, by providing new insights into previously reported cell fusion processes, our data might contribute to a better understanding of stem cell-mediated regenerative mechanisms and thus, the development of more efficient stem cell-based heart therapies.

Monitoring of erectile and urethral sphincter dysfunctions in a rat model mimicking radical prostatectomy damage.

INTRODUCTION: Animal models of urinary incontinence and erectile dysfunction following radical prostatectomy (RP) are lacking. AIMS: To develop an animal model of combined post-RP urethral sphincter and erectile dysfunctions, and noninvasive methods to assess erectile function (EF) and urinary sphincter function (USF) during prolonged follow-up. METHODS: In the main experiments, 60 male Sprague Dawley rats were randomized to a sham operation (N = 30) or electrocautery of both sides of the striated urethral sphincter (N = 30). EF and USF were evaluated preoperatively and on postoperative days 7, 15, 30, 60, and 90. Sphincter and penile tissue samples were evaluated histologically on days 7 (N = 10) and 30 (N = 10) to detect apoptosis (TUNEL assays) and fibrosis (Trichrome Masson staining). MAIN OUTCOME MEASURES: To assess EF, we measured systemic and penile blood flow using penile laser Doppler and penile rigidity using a durometer before and after apomorphine injection. USF was assessed based on the retrograde leak point pressure (LPPr). RESULTS: Apomorphine increased baseline Doppler flow by 180% (95% confidence interval, 156-202%) and penile hardness from 3.49 ± 0.5 to 7.16 ± 0.82 Shore A units but did not change systemic arterial flow. Mean LPPr was 76.8 ± 6.18 mm Hg at baseline and decreased by 50% after injury, with no response to apomorphine on day 7. EF and USF impairments persisted up to 90 days post injury. Histology showed penile apoptosis on day 7 and extensive urethral sphincter and penile fibrosis on day 30. Our data did not allow us to determine whether the impairment in erectile response to apomorphine preponderantly reflected arterial penile insufficiency or veno-occlusive dysfunction. CONCLUSION: Electrocautery of the striated urethral sphincter caused severe and lasting impairment of EF and USF that could be monitored repeatedly using minimally invasive methods. This new animal model may hold potential for developing new treatments designed to correct post-RP impairments.

Intercellular Communication in the Brain through Tunneling Nanotubes.

Intercellular communication is essential for tissue homeostasis and function. Understanding how cells interact with each other is paramount, as crosstalk between cells is often dysregulated in diseases and can contribute to their progression. Cells communicate with each other through several modalities, including paracrine secretion and specialized structures ensuring physical contact between them. Among these intercellular specialized structures, tunneling nanotubes (TNTs) are now recognized as a means of cell-to-cell communication through the exchange of cellular cargo, controlled by a variety of biological triggers, as described here. Intercellular communication is fundamental to brain function. It allows the dialogue between the many cells, including neurons, astrocytes, oligodendrocytes, glial cells, microglia, necessary for the proper development and function of the brain. We highlight here the role of TNTs in connecting these cells, for the physiological functioning of the brain and in pathologies such as stroke, neurodegenerative diseases, and gliomas. Understanding these processes could pave the way for future therapies.