Inhibition of activated hepatic stellate cells (HSCs) is essential for treating fibrotic liver disease, while the capillarized hepatic sinusoidal barrier extremely hinders HSC-targeted drug delivery and early intervention. Herein, we developed a dual-phase barrier-penetrating nanomedicine (SFR-RA@lip) based on the coassembly of silibinin (SIL) and riociguat (RIO), with retinoic acid (RA) for HSCs targeting and a lipid shell to facilitate multipathway transcellular transport. In the initial phase, SFR-RA@lip exploits caveolin-mediated endocytosis and endoplasmic reticulum-Golgi apparatus trafficking to rapidly traverse liver sinusoidal endothelial cells (LSECs) and reach HSCs for an early intervention. Meanwhile, clathrin-mediated endocytosis facilitates the normalization of LSECs, restoring fenestrae through the NO-sGC-cGMP pathway activation. This fenestrae restoration facilitates a second-phase delivery, further enhancing the drug transport and accumulation in HSCs. In a thioacetamide-induced fibrotic liver model, SFR-RA@lip demonstrated significantly improved hepatic distribution and antifibrotic efficacy. This dual-phase nanosystem enhances trans-sinusoidal drug delivery and improves antifibrotic efficacy, offering a promising strategy for the treatment of liver fibrosis.

ABSTRACTPleural effusions (PLEF) in pulmonary arterial hypertension (PAH), particularly in patients with isolated right heart failure, are associated with poor prognosis and increased mortality. This study investigates changes in alveolar fluid clearance (AFC) transporter expression in relation to lung fluid accumulation and PLEF formation during PAH progression, as well as the effects of terbutaline (TER) and riociguat (RIO) treatment. Using a monocrotaline (MCT)‐induced pulmonary hypertension (PH) rat model, we performed a detailed molecular analysis of AFC transporter expression at different disease stages, both before and after PH development. Although only minor changes were observed in the early stages prior to PH onset, a downregulation of key transporters, γ‐ENaC and Na+/K+‐ATPase subunits Atp1a2 and Atp1b1, was evident in the later stages. This reduction may have contributed to pulmonary oedema, as indicated by histological analysis. TER treatment modestly increased Atp1a2 expression, aligning with the stimulatory effects of β2‐agonist on oedema clearance. Conversely, RIO showed trends towards fluid accumulation, indicated by perivascular oedema in control animals and reduced oxygen saturation in MCT‐treated rats. These findings support a potential role of impaired AFC in the pathogenesis of PLEF in PAH and suggest that pharmacological interventions may differentially affect lung fluid homeostasis in this setting.

Lung ischemia and reperfusion (LIR) injury can lead to systemic and neurological complications, potentially exacerbating Alzheimer's disease (AD). Riociguat (RIO) has shown promise in reducing ischemia-reperfusion injuries. LIR-induced neuroinflammation in brain tissue contributes to beta amyloid (Aβ) accumulation. This study hypothesizes that RIO could mitigate AD progression by reducing brain damage, neuroinflammation, and Aβ accumulation secondary to LIR. Forty Wistar Albino male rats were randomly divided into 4 groups: sham, LIR, LIR+RIO, and RIO. LIR was induced using a vascular clamp on the hilus for 60 minutes, followed by 60 minutes of reperfusion. RIO was administered 30 minutes before ischemia. Brain tissues were analyzed histopathologically and immunohistochemically. Histopathology revealed marked hyperemia, degenerative changes, neuronal loss, gliosis, and inflammatory cell infiltrations in the LIR group. Immunohistochemical analysis showed increased Aβ, Cas-3, and TNF-α levels. RIO treatment effectively reversed these changes, indicating its potential in reducing brain damage, neuroinflammation, and Aβ accumulation. The results suggest that brain changes following lung ischemia-reperfusion in a rat model may predispose to Alzheimer's disease, but RIO may be effective in preventing this condition.

A simple HPLC-UV method for monitoring therapeutic adherence in pulmonary arterial hypertension.

Investigation of electrochemical behaviour and determination of Riociguat with bare GCE and molecularly imprinted polymer-based electrochemical sensor

Objective: Pleural effusions (PLEF) in patients with pulmonary arterial hypertension (PAH) co-diagnosed with isolated right-sided heart failure (RHF) have been reported to be associated with increased mortality. We hypothesized that alterations of transporters responsible for alveolar fluid clearance contributes to fluid accumulation in lungs and secondary formation of PLEF. This was examined in a model of PAH including administration of riociguat (RIO) that as a stimulator of sGC may be responsible for cGMP-dependent inhibition of epithelial sodium channel (ENaC) and might affect alveolar epithelial sodium transport. Design and method: Wistar rats were injected with monocrotaline (MCT; 60 mg/kg, s.c.) or vehicle (CON). 2 weeks after MCT administration, RIO treatment (10 mg/kg/d, p.o.) was started (CON+RIO, MCT+RIO). MCT groups were subdivided: MCT4W - sacrificed 4 weeks after MCT application and prematurely terminated MCT (ptMCT) - sacrificed after PAH deterioration. Expressions of ENaC alpha, beta, gama subunits, Na-K-Cl cotransporter (NKCC1), sodium-glucose linked transporter (SGLT1), sodium-coupled neutral amino acid transporters (SNAT2, SNAT5), aquaporin 3 (AQP3) were determined by RT-qPCR in lungs. Lung samples were subjected to histological analysis. Results: Increased lung weight was observed in MCT4W (2.331g vs.CON, p<0.05) and ptMCT (2.778g, vs.MCT4W, p<0.05). Similar situation was observed in RIO treated groups, however, more profound compared to MCT4W (ptMCT+RIO = 3.086g, p<0.05). Expression of ENaC, SNAT5 was decreased in ptMCT and ptMCT+RIO. Expression of NKCC1 decreased in ptMCT+RIO (by 30%) and simultaneously expression of SNAT2 in MCT4W+RIO, ptMCT+RIO (by 58%), both p<0.05 vs.CON, without any changes in MCT4W and ptMCT. 15-fold increase in AQP3 expression was observed in ptMCT, ptMCT+RIO (p<0.05 vs.CON). The presence of fluid in alveoli was observed in MCT4W and ptMCT with incidence of PLEF 20% and 30% respectively (ns). Incidence of PLEF in MCT4W+RIO and ptMCT+RIO was 22% and 44% (p<0.05), however, with interstitial swelling present. Conclusions: Downregulation of ENaC in MCT-induced PAH may represent a predisposing factor for alveolar fluid clearance impairment contributing to accumulation of fluid in lungs manifested as lung weight increase. Incidence of PLEF is probably related to lung weight increase. Riociguat rather worsened the incidence of PLEF and downregulation of ENaC.

Impairment of the nitric oxide/soluble guanylate cyclase (NO)/sGC) signalling cascade is associated with many forms of cardiovascular disease, resulting not only in compromised vasodilatation but also loss of anti-aggregatory homeostasis. Myocardial ischaemia, heart failure, and atrial fibrillation are associated with moderate impairment of NO/sGC signalling, and we have recently demonstrated that coronary artery spasm (CAS) is engendered by severe impairment of platelet NO/sGC activity resulting in combined platelet and vascular endothelial damage. We therefore sought to determine whether sGC stimulators or activators might normalise NO/sGC homeostasis in platelets. ADP-induced platelet aggregation and its inhibition by the NO donor sodium nitroprusside (SNP), the sGC stimulator riociguat (RIO), and the sCG activator cinaciguat (CINA) alone or in addition to SNP were quantitated. Three groups of individuals were compared: normal subjects (n = 9), patients (Group 1) with myocardial ischaemia, heart failure and/or atrial fibrillation (n = 30), and patients (Group 2) in the chronic stage of CAS (n = 16). As expected, responses to SNP were impaired (p = 0.02) in patients versus normal subjects, with Group 2 patients most severely affected (p = 0.005). RIO alone exerted no anti-aggregatory effects but potentiated responses to SNP to a similar extent irrespective of baseline SNP response. CINA exerted only intrinsic anti-aggregatory effects, but the extent of these varied directly (r = 0.54; p = 0.0009) with individual responses to SNP. Thus, both RIO and CINA tend to normalise anti-aggregatory function in patients in whom NO/sGC signalling is impaired. The anti-aggregatory effects of RIO consist entirely of potentiation of NO, which is not selective of platelet NO resistance. However, the intrinsic anti-aggregatory effects of CINA are most marked in individuals with initially normal NO/sGC signalling, and thus their magnitude is at variance with extent of physiological impairment. These data suggest that RIO and other sGC stimulators should be evaluated for clinical utility in both prophylaxis and treatment of CAS.

Changes in cMRI parameters following a switch to riociguat from phosphodiesterase type 5 inhibitors (PDE5i) in patients with pulmonary arterial hypertension: a REPLACE substudy

SWITCHING TO RIOCIGUAT IN PATIENTS WITH PULMONARY ARTERIAL HYPERTENSION NOT AT TREATMENT GOAL WITH PHOSPHODIESTERASE TYPE-5 INHIBITORS: SUBGROUP ANALYSIS RESULTS OF THE REPLACE STUDY

Riociguat ameliorates kidney injury and fibrosis in an animal model

Supplemental material, sj-pdf-1-pul-10.1177_2045894020938986 for Safety and effectiveness of riociguat for chronic thromboembolic pulmonary hypertension in real-world clinical practice: interim data from post-marketing surveillance in Japan by Nobuhiro Tanabe, Takeshi Ogo, Masaru Hatano, Ayaka Kigawa, Toshiyuki Sunaya and Shoichiro Sato in Pulmonary Circulation

In cirrhosis, the nitric oxide-soluble guanylyl cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway is impaired, which contributes to increased intrahepatic vascular resistance (IHVR) and fibrogenesis. We investigated if sGC stimulation (riociguat (RIO)), sGC activation (cinaciguat (CINA)) or phosphodiesterase (PDE)-5 inhibition (tadalafil (TADA)) improves portal hypertension (PHT) and liver fibrosis. Fifty male Sprague-Dawley rats underwent bile-duct ligation (BDL) or sham operation. RIO (0.5 mg/kg), CINA (1 mg/kg), TADA (1.5 mg/kg) or vehicle (VEH) was administered from weeks 2 to 4 after BDL. At week 4, invasive haemodynamic measurements were performed, and liver fibrosis was assessed by histology (chromotrope-aniline blue (CAB), Picro-Sirius red (PSR)) and hepatic hydroxyproline content. Cirrhotic bile duct-ligated rats presented with PHT (13.1 ± 1.0 mmHg) and increased IHVR (4.9 ± 0.5 mmHg⋅min/mL). Both RIO (10.0 ± 0.7 mmHg, p = 0.021) and TADA (10.3 ± 0.9 mmHg, p = 0.050) decreased portal pressure by reducing IHVR (RIO: -41%, p = 0.005; TADA: -21%, p = 0.199) while not impacting heart rate, mean arterial pressure and portosystemic shunting. Hepatic cGMP levels increased upon RIO (+239%, p = 0.006) and TADA (+32%, p = 0.073) therapy. In contrast, CINA dosed at 1 mg/kg caused weight loss, arterial hypotension and hyperlactataemia in bile duct-ligated rats. Liver fibrosis area was significantly decreased by RIO (CAB: -48%, p = 0.011; PSR: -27%, p = 0.121) and TADA (CAB: -21%, p = 0.342; PSR: -52%, p = 0.013) compared to VEH-treated bile duct-ligated rats. Hepatic hydroxyproline content was reduced by RIO (from 503 ± 20 to 350 ± 30 µg/g, p = 0.003) and TADA (282 ± 50 µg/g, p = 0.003), in line with a reduction of the hepatic stellate cell activation markers smooth-muscle actin and phosphorylated moesin. Liver transaminases decreased under RIO (AST: -36%; ALT: -32%) and TADA (AST: -24%; ALT: -27%) treatment. Hepatic interleukin 6 gene expression was reduced in the RIO group (-56%, p = 0.053). In a rodent model of biliary cirrhosis, the sGC stimulator RIO and the PDE-5 inhibitor TADA improved PHT. The decrease of sinusoidal vascular resistance was paralleled by a reduction in liver fibrosis and hepatic inflammation, while systemic haemodynamics were not affected.

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are diseases, diagnosed at a late stage with functional class III or IV according to World health organization (WHO). PAH and CTEPH leads to severe right heart failure and ultimately, death. The modern researches aim at exploring the potential therapeutic targets, as at developing new drugs that can affect the previously set target. Riociguat is the first in a new class of soluble guanylatecyclase stimulators. The analysis of main researches, which reflect the evidence of riociguat efficiacy and safety in patients with PAH and inoperable, persistent/recurrent CTEPH, is presented in this rewiew.

Riociguat contraindicated in patients with PH-IIP

Phase II riociguat study terminated

(1001) - Riociguat Significantly Improved SpO2 during Exercise in Patients with CTEPH

Background: In liver cirrhosis nitric oxide (NO) signaling, including function of its receptor soluble guanylyl cyclase (sGC), is distorted. The sGC stimulator riociguat (RIO) is used as treatment for pulmonary hypertension and it has been shown that RIO acts antifibrotic. We thus aimed to investigate effects of RIO on experimental liver cirrhosis and portal hypertension.

Adcirca contraindicated with riociguat

Limited options are available for treating patients with pulmonary hypertension. Initial trials of riociguat, an oral medication that stimulates