What have we learned from two-pore potassium channels? Their molecular configuration and function in the human heart

Two-pore domain potassium channels (K2P) control excitability, stabilize the resting membrane potential below firing threshold, and accelerate repolarisation in different cells. Until now, fifteen different genes for the six K2P channel subfamily were cloned. The pore-forming part is translated from two genes and they are built up from a dimer of two two-unit transmembrane domains functioning with a wide spectrum of physiological profiles. K2P ion channels were discovered in the last two decades and gave novel opportunity to recognize the complex molecular mechanism of the potassium ion flux, and may lead to the design of individual drug targeting in the future. In this review, we summarise the structure, function, channelopathies and pharmacological silhouette of the two-pore potassium channels in the human tissues. In addition, we present the computer model of the partially reconstructed wild type K2P1/TWIK1 lacking the intracellular C and N terminal loop

Smoking in Systemic Sclerosis: a Longitudinal European Scleroderma Trials and Research Group Study

Data on the role of tobacco exposure in systemic sclerosis (SSc) severity and progression are scarce. We aimed to assess the effects of smoking on the evolution of pulmonary and skin manifestations in the EUSTAR database

Dentate total molecular layer interneurons mediate cannabinoid-sensitive inhibition.

Activity of the dentate gyrus, which gates information flow to the hippocampus, is under tight inhibitory regulation by interneurons with distinctive axonal projections, intrinsic and synaptic characteristics and neurochemical identities. Total molecular layer cells (TML-Cs), a class of morphologically distinct GABAergic neurons with axonal projections across the molecular layer, are among the most frequent interneuronal type in the dentate subgranular region. However, little is known about their synaptic and neurochemical properties. We demonstrate that synapses from morphologically identified TML-Cs to dentate interneurons are characterized by low release probability, facilitating short-term dynamics and asynchronous release. TML-Cs consistently show somatic and axonal labeling for the cannabinoid receptor type 1 (CB1 R) yet fail to express cholecystokinin (CCK) indicating their distinctive neurochemical identity. In paired recordings, the release probability at synapses between TML-Cs was increased by the CB1 R antagonist AM251, demonstrating baseline endocannabinoid regulation of TML-C synapses. Apart from defining the synaptic and neurochemical features of TML-Cs, our findings reveal the morphological identity of a class of dentate CB1 R-positive neurons that do not express CCK. Our findings indicate that TML-Cs can mediate cannabinoid sensitive feed-forward and feedback inhibition of dentate perforant path inputs

Tricuspid Annular Plane Systolic Excursion/Systolic Pulmonary Artery Pressure Ratio and Cardiorenal Syndrome Type 2 in the Systemic Sclerosis EUSTAR Cohort

Objective The aim of the study was to evaluate the association between the tricuspid annular plane systolic excursion (TAPSE)/systolic pulmonary artery pressure (sPAP) ratio and estimated glomerular filtration rate (eGFR) and their association with mortality in the European Scleroderma Trials and Research (EUSTAR) cohort. Methods Patients with systemic sclerosis (SSc) from the EUSTAR database with TAPSE, sPAP, and parameters required to calculate eGFR were included. Logistic regression and Cox regression analysis were performed to evaluate TAPSE/sPAP as a risk factor for chronic kidney disease (CKD) and overall survival. Results A total of 2,370 patients with SSc were included; 284 (12%) patients had CKD stage 3a–5. TAPSE/sPAP (odds ratio [OR] 0.479; 95% CI 0.310–0.743; P < 0.001), arterial hypertension (OR 3.118; 95% CI 2.173–4.475; P < 0.001), diastolic dysfunction (OR 1.670; 95% CI 1.148–2.428; P < 0.01), and N-terminal pro-B-type natriuretic peptide (OR 1.165; 95% CI 1.041–1.304; P < 0.01) were associated with CKD stage 3a–5. TAPSE/sPAP ≤0.32 mm/mm Hg (hazard ratio [HR] 3.589; 95% CI 2.236–5.761; P < 0.001), eGFR <60 mL/min per 1.73 m2 (HR 2.818; 95% CI 1.777–4.468; P < 0.001), and age (HR 1.782; 95% CI 1.348–2.356; P < 0.001) were the most significant predictive factors for all-cause mortality. A total of 276 patients with SSc had pulmonary hypertension (PH) confirmed by right heart catheterization, with 69 (25%) having CKD stage 3a–5. No difference was found in eGFR between patients with PH with reduced or normal cardiac index. Conclusion Reduced TAPSE/sPAP ratio is independently associated with CKD. TAPSE/sPAP ratio ≤0.32 mm/mm Hg and eGFR <60 mL/min per 1.73 m2 are prognostic factors for all-cause mortality. In patients with SSc with PH, eGFR is independent by reduced cardiac output

Registry Evaluation of Digital Ulcers in Systemic Sclerosis

Digital ulcers are a very frequent complication of systemic sclerosis affecting about half of the SSc patients, and about 75% of the affected patients have their first DU episode within 5 years from their first non-Raynaud symptom. The lack of adequate classification criteria as well as the lack of knowledge of the development of DU have contributed to the opening of specific registries to better understand the natural history of these lesions. For these reason, specific disease registries play a fundamental role in this field of research. Thanks to the systematic collection of data and their subsequent analysis and comparison between different cohorts, it is possible to improve understanding of the underlying trigger mechanisms of DU development and to determine temporal trends. In the future, the development of recommendations for the management of DU remains of pivotal importance to prevent DU development and obtain rapid healing as well as reduction of pain and disability