Endurance Training Provokes Arrhythmogenic Right Ventricular Cardiomyopathy Phenotype in Heterozygous Desmoglein-2 Mutants: Alleviation by Preload Reduction.

Desmoglein-2 mutations are detected in 5-10% of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Endurance training accelerates the development of the ARVC phenotype, leading to earlier arrhythmic events. Homozygous Dsg2 mutant mice develop a severe ARVC-like phenotype. The phenotype of heterozygous mutant (Dsg2mt/wt) or haploinsufficient (Dsg20/wt) mice is still not well understood. To assess the effects of age and endurance swim training, we studied cardiac morphology and function in sedentary one-year-old Dsg2mt/wt and Dsg20/wt mice and in young Dsg2mt/wt mice exposed to endurance swim training. Cardiac structure was only occasionally affected in aged Dsg20/wt and Dsg2mt/wt mice manifesting as small fibrotic foci and displacement of Connexin 43. Endurance swim training increased the right ventricular (RV) diameter and decreased RV function in Dsg2mt/wt mice but not in wild types. Dsg2mt/wt hearts showed increased ventricular activation times and pacing-induced ventricular arrhythmia without obvious fibrosis or inflammation. Preload-reducing therapy during training prevented RV enlargement and alleviated the electrophysiological phenotype. Taken together, endurance swim training induced features of ARVC in young adult Dsg2mt/wt mice. Prolonged ventricular activation times in the hearts of trained Dsg2mt/wt mice are therefore a potential mechanism for increased arrhythmia risk. Preload-reducing therapy prevented training-induced ARVC phenotype pointing to beneficial treatment options in human patients.

Validation of NIAAAm-CRP criteria to predict alcohol-associated steatohepatitis on liver histology.

Background & Aims: In clinical practice, the diagnosis of alcohol-associated hepatitis (AH) is mostly based on non-invasive criteria, which were defined at a consensus conference by the National Institute on Alcohol Abuse and Alcoholism (NIAAA). These criteria were recently modified by adding C-reactive protein (CRP) and termed NIAAAm-CRP criteria, which showed superior diagnostic accuracy for presence of alcohol-associated steatohepatitis (ASH) on liver histology. The aim of our study was to validate the diagnostic accuracy of both original NIAAA criteria and NIAAAm-CRP criteria for presence of ASH on liver histology in an independent cohort. Methods: Data from a large multinational cohort of 445 patients with alcohol-associated liver disease (ALD) that served to establish a novel grading and staging system of alcohol-associated liver disease were analyzed retrospectively. Diagnosis of ASH was based on presence of hepatocyte ballooning plus lobular neutrophil infiltration and established in virtual consensus meetings of multiple expert liver pathologists. Results: Complete data including CRP values were available in 346 patients. Overall diagnostic accuracy for prediction of ASH was 73% for NIAAA criteria and 77% for NIAAAm-CRP criteria. In a subgroup with suspected severe AH (MELD >20, n = 123), overall diagnostic accuracy for prediction of ASH was 69% for NIAAA criteria and 74% for NIAAAm-CRP criteria. Conclusion: Our findings confirm recent data on suboptimal diagnostic accuracy of original NIAAA criteria and validate slightly better but still suboptimal performance of NIAAAm-CRP criteria for presence of ASH. Impact and Implications: Alcohol-associated steatohepatitis (ASH) is diagnosed on liver histology but liver biopsy is not always feasible. Non-invasive diagnosis based on clinical findings has been proposed using the National Institute on Alcohol Abuse and Alcoholism (NIAAA) criteria and recently improved using NIAAAm-CRP criteria. Our findings validate slightly better but still suboptimal performance of NIAAAm-CRP criteria for the presence of histological ASH. Clinical trials of novel drugs should focus on histologically proven ASH.

An Assessment of the Mechanophysical and Hormonal Impact on Human Endometrial Epithelium Mechanics and Receptivity.

The endometrial epithelium and underlying stroma undergo profound changes to support and limit embryo adhesion and invasion, which occur in the secretory phase of the menstrual cycle during the window of implantation. This coincides with a peak in progesterone and estradiol production. We hypothesized that the interplay between hormone-induced changes in the mechanical properties of the endometrial epithelium and stroma supports this process. To study it, we used hormone-responsive endometrial adenocarcinoma-derived Ishikawa cells growing on substrates of different stiffness. We showed that Ishikawa monolayers on soft substrates are more tightly clustered and uniform than on stiff substrates. Probing for mechanical alterations, we found accelerated stress-relaxation after apical nanoindentation in hormone-stimulated monolayers on stiff substrates. Traction force microscopy furthermore revealed an increased number of foci with high traction in the presence of estradiol and progesterone on soft substrates. The detection of single cells and small cell clusters positive for the intermediate filament protein vimentin and the progesterone receptor further underscored monolayer heterogeneity. Finally, adhesion assays with trophoblast-derived AC-1M-88 spheroids were used to examine the effects of substrate stiffness and steroid hormones on endometrial receptivity. We conclude that the extracellular matrix and hormones act together to determine mechanical properties and, ultimately, embryo implantation.

Effect of albumin infusion on oxidative albumin modification and albumin binding capacity in chronic liver failure.

Oxidative albumin modification and impaired albumin binding function have been described both in chronic liver failure and for therapeutic albumin solutions. The aim of the present study was to evaluate the effect of albumin infusion on redox state and binding function of circulating albumin. We studied 20 patients with cirrhosis who routinely received albumin infusions for prevention of post-paracentesis circulatory dysfunction or treatment of hepatorenal syndrome. We measured albumin fractions by redox state of cysteine-34 and albumin binding properties using dansylsarcosine as site II ligand. Therapeutic albumin solutions showed high contents of human nonmercaptalbumin-1 and human nonmercaptalbumin-2, exceeding the respective values in our patients with decompensated cirrhosis. An initial protocol for the first nine patients sampled at baseline, 24 h and 48 h after albumin infusion revealed no significant changes of oxidized albumin species or albumin binding properties. However, a modified protocol for the remaining 11 patients sampled at baseline, <1 h after and 24 h after albumin infusion revealed short-lived changes of oxidized albumin species while no changes in albumin binding properties were observed. In conclusion, therapeutic albumin infusion transiently changed albumin redox state but did not improve binding function of circulating albumin in chronic liver failure.

Plasticity of cytoplasmic intermediate filament architecture determines cellular functions.

Cytoplasmic intermediate filaments endow cells with mechanical stability. They are subject to changes in morphology and composition if needed. This remodeling encompasses entire cells but can also be restricted to specific intracellular regions. Intermediate filaments thereby support spatially and temporally defined cell type-specific functions. This review focuses on recent advances in our understanding of how intermediate filament dynamics affect the underlying regulatory pathways. We will elaborate on the role of intermediate filaments for the formation and maintenance of surface specializations, cell migration, contractility, organelle positioning, nucleus protection, stress responses and axonal conduction velocity. Together, the selected examples highlight the modulatory role of intermediate filament plasticity for multiple cellular functions.

A keratin code defines the textile nature of epithelial tissue architecture.

We suggest that the human body can be viewed as of textile nature whose fabric consists of interconnected fiber systems. These fiber systems form highly dynamic scaffolds, which respond to environmental changes at different temporal and spatial scales. This is especially relevant at sites where epithelia border on connective tissue regions that are exposed to dynamic microenvironments. We propose that the enormous heterogeneity and adaptability of epithelia are based on a "keratin code", which results from the cell-specific expression and posttranslational modification of keratin isotypes. It thereby defines unique cytoskeletal intermediate filament networks that are coupled across cells and to the correspondingly heterogeneous fibers of the underlying extracellular matrix. The resulting fabric confers unique local properties.

Desmosomes in Cell Fate Determination: From Cardiogenesis to Cardiomyopathy.

Desmosomes play a vital role in providing structural integrity to tissues that experience significant mechanical tension, including the heart. Deficiencies in desmosomal proteins lead to the development of arrhythmogenic cardiomyopathy (AC). The limited availability of preventative measures in clinical settings underscores the pressing need to gain a comprehensive understanding of desmosomal proteins not only in cardiomyocytes but also in non-myocyte residents of the heart, as they actively contribute to the progression of cardiomyopathy. This review focuses specifically on the impact of desmosome deficiency on epi- and endocardial cells. We highlight the intricate cross-talk between desmosomal proteins mutations and signaling pathways involved in the regulation of epicardial cell fate transition. We further emphasize that the consequences of desmosome deficiency differ between the embryonic and adult heart leading to enhanced erythropoiesis during heart development and enhanced fibrogenesis in the mature heart. We suggest that triggering epi-/endocardial cells and fibroblasts that are in different "states" involve the same pathways but lead to different pathological outcomes. Understanding the details of the different responses must be considered when developing interventions and therapeutic strategies.

Steatotic Liver Disease: Metabolic Dysfunction, Alcohol, or Both?

Non-alcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD), both of them accounting for fatty liver disease (FLD), are among the most common chronic liver diseases globally, contributing to substantial public health burden. Both NAFLD and ALD share a similar picture of clinical presentation yet may have differences in prognosis and treatment, which renders early and accurate diagnosis difficult but necessary. While NAFLD is the fastest increasing chronic liver disease, the prevalence of ALD has seemingly remained stable in recent years. Lately, the term steatotic liver disease (SLD) has been introduced, replacing FLD to reduce stigma. SLD represents an overarching term to primarily comprise metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), as well as alcohol-related liver disease (ALD), and MetALD, defined as a continuum across which the contribution of MASLD and ALD varies. The present review discusses current knowledge on common denominators of NAFLD/MASLD and ALD in order to highlight clinical and research needs to improve our understanding of SLD.

Infectious diseases in migrant pregnant women from an area of the Colombian Caribbean.

INTRODUCTION: Human migration is an activity that affects society in economic and political aspects and as a social determinant because of its differential impact on individual's health. OBJECTIVE: To describe the situation of health and infectious diseases of vertical transmission risk in migrant pregnant women from an area of the Colombian Caribbean from 2019 to 2021. METHODS: A descriptive cross-sectional study was carried out on pregnant irregular migrants in the Riohacha and Santa Marta municipalities in Colombia. Hemogram, uranalysis, toxoplasma, FTA-ABS, VDRL, rubella, hepatitis B, HIV (TORCHs), vaginal swab, basal glycemia, and transaminases, among other paraclinical tests, were done on pregnant women. Data was arranged, tabulated, and analyzed in SPSS v.23.0. A descriptive statistical analysis with measures of central tendency and dispersion for quantitative variables, and proportions analysis was done for qualitative variables. RESULTS: A total of 555 clinical records were analyzed. Of the infectious agents with a risk of vertical transmission, syphilis was the most frequent with 3.6%. Regarding toxoplasmosis, 2.5% were IgM-positive. 4.2% of the pregnant women had IgG antibodies against Rubella and 2 women showed antibodies against HIV. CONCLUSIONS: Our results reflect the need for the implementation of educational, prevention, and detection health programs with the aim to decrease the number of prenatal infections in the pregnant migrant population for preventing fatal complications both in mothers and newborns.

Determination of binding characteristics as a measure for effective albumin using different methods.

BACKGROUND & AIMS: Transport functions of albumin are of clinical and pharmacological interest and are determined by albumin's properties like posttranslational modifications or bound ligands. Both are affected in pathological conditions and in therapeutic grade albumin solutions. The term effective albumin concentration was introduced as a measure of functionally intact albumin. Our aim was to evaluate the impact of ligands and modifications with different approaches as a measure of effective albumin. APPROACH & RESULTS: We used a spin labelled fatty acid and dansylsarcosine to characterize binding properties of albumin i) prepared from plasma of patients and healthy control donors, ii) measured directly out of plasma, iii) research grade albumin, iv) in vitro modified albumin, and v) therapeutic infusion solutions before and after removal of stabilizers. Bilirubin is the main determinant for binding function in patients' albumin. In in vitro prepared albumin bound fatty acids correlated with impaired binding. Human nonmercaptalbumin1, not human nonmercaptalbumin2, showed reduced binding properties. Binding and transport function of therapeutic albumin was severely impaired and restored by filtration. Glycation of research grade albumin had no effect on the binding of dansylsarcosine and only a minor effect on fatty acid binding. CONCLUSIONS: Our results suggest that effective albumin -in terms of binding properties- is primarily determined by bound ligands and only to a minor extent by posttranslational modifications. Characterizing albumin directly from plasma better reflects the physiological situation whereas in the case of therapeutic grade albumin stabilizers should be removed to make its binding properties accessible.

Performance of non-invasive tests and histology for the prediction of clinical outcomes in patients with non-alcoholic fatty liver disease: an individual participant data meta-analysis.

BACKGROUND: Histologically assessed liver fibrosis stage has prognostic significance in patients with non-alcoholic fatty liver disease (NAFLD) and is accepted as a surrogate endpoint in clinical trials for non-cirrhotic NAFLD. Our aim was to compare the prognostic performance of non-invasive tests with liver histology in patients with NAFLD. METHODS: This was an individual participant data meta-analysis of the prognostic performance of histologically assessed fibrosis stage (F0-4), liver stiffness measured by vibration-controlled transient elastography (LSM-VCTE), fibrosis-4 index (FIB-4), and NAFLD fibrosis score (NFS) in patients with NAFLD. The literature was searched for a previously published systematic review on the diagnostic accuracy of imaging and simple non-invasive tests and updated to Jan 12, 2022 for this study. Studies were identified through PubMed/MEDLINE, EMBASE, and CENTRAL, and authors were contacted for individual participant data, including outcome data, with a minimum of 12 months of follow-up. The primary outcome was a composite endpoint of all-cause mortality, hepatocellular carcinoma, liver transplantation, or cirrhosis complications (ie, ascites, variceal bleeding, hepatic encephalopathy, or progression to a MELD score ≥15). We calculated aggregated survival curves for trichotomised groups and compared them using stratified log-rank tests (histology: F0-2 vs F3 vs F4; LSM: <10 vs 10 to <20 vs ≥20 kPa; FIB-4: <1·3 vs 1·3 to ≤2·67 vs >2·67; NFS: <-1·455 vs -1·455 to ≤0·676 vs >0·676), calculated areas under the time-dependent receiver operating characteristic curves (tAUC), and performed Cox proportional-hazards regression to adjust for confounding. This study was registered with PROSPERO, CRD42022312226. FINDINGS: Of 65 eligible studies, we included data on 2518 patients with biopsy-proven NAFLD from 25 studies (1126 [44·7%] were female, median age was 54 years [IQR 44-63), and 1161 [46·1%] had type 2 diabetes). After a median follow-up of 57 months [IQR 33-91], the composite endpoint was observed in 145 (5·8%) patients. Stratified log-rank tests showed significant differences between the trichotomised patient groups (p<0·0001 for all comparisons). The tAUC at 5 years were 0·72 (95% CI 0·62-0·81) for histology, 0·76 (0·70-0·83) for LSM-VCTE, 0·74 (0·64-0·82) for FIB-4, and 0·70 (0·63-0·80) for NFS. All index tests were significant predictors of the primary outcome after adjustment for confounders in the Cox regression. INTERPRETATION: Simple non-invasive tests performed as well as histologically assessed fibrosis in predicting clinical outcomes in patients with NAFLD and could be considered as alternatives to liver biopsy in some cases. FUNDING: Innovative Medicines Initiative 2.

Intermediate filament network perturbation in the C. elegans intestine causes systemic dysfunctions.

Intermediate filaments (IFs) are major components of the metazoan cytoskeleton. A long-standing debate concerns the question whether IF network organization only reflects or also determines cell and tissue function. Using Caenorhabditis elegans, we have recently described mutants of the mitogen-activated protein kinase (MAPK) SMA-5 which perturb the organization of the intestinal IF cytoskeleton resulting in luminal widening and cytoplasmic invaginations. Besides these structural phenotypes, systemic dysfunctions were also observed. We now identify the IF polypeptide IFB-2 as a highly efficient suppressor of both the structural and functional deficiencies of mutant sma-5 animals by removing the aberrant IF network. Mechanistically, perturbed IF network morphogenesis is linked to hyperphosphorylation of multiple sites throughout the entire IFB-2 molecule. The rescuing capability is IF isotype-specific and not restricted to sma-5 mutants but extends to mutants that disrupt the function of the cytoskeletal linker IFO-1 and the IF-associated protein BBLN-1. The findings provide strong evidence for adverse consequences of the deranged IF networks with implications for diseases that are characterized by altered IF network organization.

Synaptoporin and parathyroid hormone 2 as markers of multimodal inputs to the auditory brainstem.

The distribution of the synaptic vesicle protein synaptoporin was investigated by immunofluorescence in the central auditory system of the mouse brainstem. Synaptoporin immunostaining displayed region-specific differences. High and moderate accumulations of were seen in the superficial layer of the dorsal cochlear nucleus, dorsal and external regions of the inferior colliculus, the medial and dorsal divisions of the medial geniculate body and in periolivary regions of the superior olivary complex (SOC). Low or absent labeling was observed in the more central parts of these structures such as the principal nuclei of the SOC. It was conspicuous that dense synaptoporin immunoreactivity was detected predominantly in areas, which are known to be synaptic fields of multimodal, extra-auditory inputs. Target neurons of synaptoporin-positive synapses in the SOC were then identified by double-labelling immunofluorescence microscopy. We thereby detected synaptoporin puncta perisomatically at nitrergic, glutamatergic and serotonergic neurons but none next to neurons immunoreactive for choline-acetyltransferase and calcitonin-gene related peptide. These results leave open whether functionally distinct neuronal groups are accessed in the SOC by synaptoporin-containing neurons. The last part of our study sought to find out whether synaptoporin-positive neurons originate in the medial paralemniscal nucleus (MPL), which is characterized by expression of the peptide parathyroid hormone 2 (PTH2). Anterograde neuronal tracing upon injection into the MPL in combination with synaptoporin- and PTH2-immunodetection showed that (1) the MPL projects to the periolivary SOC using PTH2 as transmitter, (2) synaptoporin-positive neurons do not originate in the MPL, and (3) the close juxtaposition of synaptoporin-staining with either the anterograde tracer or PTH2 reflect concerted action of the different inputs to the SOC.

Bioprinting-associated pulsatile hydrostatic pressure elicits a mild proinflammatory response in epi- and endothelial cells.

During nozzle-based bioprinting, like inkjet and microextrusion, cells are subjected to hydrostatic pressure for up to several minutes. The modality of the bioprinting-related hydrostatic pressure is either constant or pulsatile depending on the technique. We hypothesized that the difference in the modality of hydrostatic pressure affects the biological response of the processed cells differently. To test this, we used a custom-made setup to apply either controlled constant or pulsatile hydrostatic pressure on endothelial and epithelial cells. Neither bioprinting procedure visibly altered the distribution of selected cytoskeletal filaments, cell-substrate adhesions, and cell-cell contacts in either cell type. In addition, pulsatile hydrostatic pressure led to an immediate increase of intracellular ATP in both cell types. However, the bioprinting-associated hydrostatic pressure triggered a pro-inflammatory response in only the endothelial cells, with an increase of interleukin 8 (IL-8) and a decrease of thrombomodulin (THBD) transcripts. These findings demonstrate that the settings adopted during nozzle-based bioprinting cause hydrostatic pressure that can trigger a pro-inflammatory response in different barrier-forming cell types. This response is cell-type and pressure-modality dependent. The immediate interaction of the printed cells with native tissue and the immune system in vivo might potentially trigger a cascade of events. Our findings, therefore, are of major relevance in particular for novel intra-operative, multicellular bioprinting approaches.

Genetic variation in TERT modifies the risk of hepatocellular carcinoma in alcohol-related cirrhosis: results from a genome-wide case-control study.

OBJECTIVE: Hepatocellular carcinoma (HCC) often develops in patients with alcohol-related cirrhosis at an annual risk of up to 2.5%. Some host genetic risk factors have been identified but do not account for the majority of the variance in occurrence. This study aimed to identify novel susceptibility loci for the development of HCC in people with alcohol related cirrhosis. DESIGN: Patients with alcohol-related cirrhosis and HCC (cases: n=1214) and controls without HCC (n=1866), recruited from Germany, Austria, Switzerland, Italy and the UK, were included in a two-stage genome-wide association study using a case-control design. A validation cohort of 1520 people misusing alcohol but with no evidence of liver disease was included to control for possible association effects with alcohol misuse. Genotyping was performed using the InfiniumGlobal Screening Array (V.24v2, Illumina) and the OmniExpress Array (V.24v1-0a, Illumina). RESULTS: Associations with variants rs738409 in PNPLA3 and rs58542926 in TM6SF2 previously associated with an increased risk of HCC in patients with alcohol-related cirrhosis were confirmed at genome-wide significance. A novel locus rs2242652(A) in TERT (telomerase reverse transcriptase) was also associated with a decreased risk of HCC, in the combined meta-analysis, at genome-wide significance (p=6.41×10-9, OR=0.61 (95% CI 0.52 to 0.70). This protective association remained significant after correction for sex, age, body mass index and type 2 diabetes (p=7.94×10-5, OR=0.63 (95% CI 0.50 to 0.79). Carriage of rs2242652(A) in TERT was associated with an increased leucocyte telomere length (p=2.12×10-44). CONCLUSION: This study identifies rs2242652 in TERT as a novel protective factor for HCC in patients with alcohol-related cirrhosis.

Regionally specific levels and patterns of keratin 8 expression in the mouse embryo visceral endoderm emerge upon anterior-posterior axis determination.

The mechanical properties of the different germ layers of the early mammalian embryo are likely to be critical for morphogenesis. Cytoskeleton components (actin and myosin, microtubules, intermediate filaments) are major determinants of epithelial plasticity and resilience to stress. Here, we take advantage of a mouse reporter for Keratin 8 to record the pattern of the keratin intermediate filaments network in the first epithelia of the developing mouse embryo. At the blastocyst stage, Keratin 8 is strongly expressed in the trophectoderm, and undetectable in the inner cell mass and its derivatives, the epiblast and primitive endoderm. Visceral endoderm cells that differentiate from the primitive endoderm at the egg cylinder stage display apical Keratin 8 filaments. Upon migration of the Anterior Visceral Endoderm and determination of the anterior-posterior axis, Keratin 8 becomes regionally distributed, with a stronger expression in embryonic, compared to extra-embryonic, visceral endoderm. This pattern emerges concomitantly to a modification of the distribution of Filamentous (F)-actin, from a cortical ring to a dense apical shroud, in extra-embryonic visceral endoderm only. Those regional characteristics are maintained across gastrulation. Interestingly, for each stage and region of the embryo, adjacent germ layers display contrasted levels of keratin filaments, which may play a role in their adaptation to growth and morphological changes.

A Ca2+-Mediated Switch of Epiplakin from a Diffuse to Keratin-Bound State Affects Keratin Dynamics.

Keratins exert important structural but also cytoprotective functions. They have to be adaptable to support cellular homeostasis. Epiplakin (EPPK1) has been shown to decorate keratin filaments in epithelial cells and to play a protective role under stress, but the mechanism is still unclear. Using live-cell imaging of epithelial cells expressing fluorescently tagged EPPK1 and keratin, we report here an unexpected dynamic behavior of EPPK1 upon stress. EPPK1 was diffusely distributed throughout the cytoplasm and not associated with keratin filaments in living cells under standard culture conditions. However, ER-, oxidative and UV-stress, as well as cell fixation, induced a rapid association of EPPK1 with keratin filaments. This re-localization of EPPK1 was reversible and dependent on the elevation of cytoplasmic Ca2+ levels. Moreover, keratin filament association of EPPK1 led to significantly reduced keratin dynamics. Thus, we propose that EPPK1 stabilizes the keratin network in stress conditions, which involve increased cytoplasmic Ca2+.

Cortical tension regulates desmosomal morphogenesis.

Mechanical stability is a fundamental and essential property of epithelial cell sheets. It is in large part determined by cell-cell adhesion sites that are tightly integrated by the cortical cytoskeleton. An intimate crosstalk between the adherens junction-associated contractile actomyosin system and the desmosome-anchored keratin intermediate filament system is decisive for dynamic regulation of epithelial mechanics. A major question in the field is whether and in which way mechanical stress affects junctional plasticity. This is especially true for the desmosome-keratin scaffold whose role in force-sensing is virtually unknown. To examine this question, we inactivated the actomyosin system in human keratinocytes (HaCaT) and canine kidney cells (MDCK) and monitored changes in desmosomal protein turnover. Partial inhibition of myosin II by para-nitro-blebbistatin led to a decrease of the cells' elastic modulus and to reduced desmosomal protein turnover in regions where nascent desmosomes are formed and, to a lower degree, in regions where larger, more mature desmosomes are present. Interestingly, desmosomal proteins are affected differently: a significant decrease in turnover was observed for the desmosomal plaque protein desmoplakin I (DspI), which links keratin filaments to the desmosomal core, and the transmembrane cadherin desmoglein 2 (Dsg2). On the other hand, the turnover of another type of desmosomal cadherin, desmocollin 2 (Dsc2), was not significantly altered under the tested conditions. Similarly, the turnover of the adherens junction-associated E-cadherin was not affected by the low doses of para-nitro-blebbistatin. Inhibition of actin polymerization by low dose latrunculin B treatment and of ROCK-driven actomyosin contractility by Y-27632 treatment also induced a significant decrease in desmosomal DspI turnover. Taken together, we conclude that changes in the cortical force balance affect desmosome formation and growth. Furthermore, they differentially modulate desmosomal protein turnover resulting in changes of desmosome composition. We take the observations as evidence for a hitherto unknown desmosomal mechanosensing and mechanoresponse pathway responding to an altered force balance.

Pulmonary vascular disease and exercise hemodynamics in chronic liver disease.

BACKGROUND & AIMS: Portopulmonary hypertension (POPH) and hepatopulmonary syndrome (HPS) are severe pulmonary vascular complications of chronic liver disease and strongly associated with morbidity and mortality. The prevalence of these complications is relatively high in patients evaluated for liver transplantation, however it is virtually unknown in patients with stable chronic liver disease. METHODS: We assessed the pulmonary hypertension (PH) and HPS prevalence in a prospective registry study of our liver out-patient clinic in a tertiary center. Between 2011 and 2016, consecutive patients with cirrhosis or non-cirrhotic portal hypertension were prospectively enrolled after written informed consent. We excluded patients with acute decompensation of liver disease and other causes of PH like severe chronic heart or lung diseases and chronic thromboembolic PH. HPS was diagnosed using contrast enhanced echocardiography and blood gas analysis. Patients were screened for PH using an algorithm implementing severity of dyspnea, echocardiography, cardiopulmonary exercise testing and exercise echocardiography employing a threshold of systolic pulmonary arterial pressure (SPAP) = 50 mmHg at peak exercise. If the algorithm indicated an increased PH risk, patients were invited for invasive investigations by means of right heart and hepatic vein catheter. We defined POPH as resting mPAP≥21 mmHg and PVR>3WU and PAWP<15 mmHg, mild PH as resting mPAP = 21-24 mmHg, and exercise PH as mPAP>30 mmHg and TPR >3 WU at peak exercise. RESULTS: Two-hundred-five patients were enrolled (male 75%; cirrhosis 96%; median age 57 yrs). Sixty-seven patients (33%) fulfilled HPS criteria but only two (1.0%) for severe (PaO2:50-60 mmHg) or very severe HPS (PaO2<50 mmHg). In 18/77 patients (23%) undergoing exercise echocardiography, SPAP at peak exercise exceeded 50 mmHg. Finally, n = 3 (1.5%) patients were invasively diagnosed with POPH, n = 4 (2.9%) with mild PH and n = 2 with exercise PH. CONCLUSION: In chronic liver disease, excluding acute decompensation and other causes of PH, POPH and severe HPS are rare findings while mild to moderate HPS and mild PH or exercise PH are more frequent.