Prostacyclin Mitigates Renal Fibrosis by Activating Fibroblast Prostaglandin I 2 Receptor.

SIGNIFICANCE STATEMENT: Renal fibrosis is a common pathologic process of progressive CKD. We have provided strong evidence that PGI 2 is an important component in the kidney injury/repairing process by reducing fibrosis and protecting renal function from declining. In our study, administration of a PGI 2 analog or selective PTGIR agonist after the acute injury ameliorated renal fibrosis. Our findings provide new insights into the role of PGI 2 in kidney biology and suggest that targeting PGI 2 /PTGIR may be a potential therapeutic strategy for CKD. BACKGROUND: Prostanoids have been demonstrated to be important modulators to maintain tissue homeostasis in response to physiologic or pathophysiologic stress. Prostacyclin (PGI 2 ) is a member of prostanoids. While limited studies have shown that PGI 2 is involved in the tissue injury/repairing process, its role in renal fibrosis and CKD progression requires further investigation. METHODS: Prostacyclin synthase ( Ptgis )-deficient mice, prostaglandin I 2 receptor ( Ptgir )-deficient mice, and an oral PGI 2 analog and selective PTGIR agonist were used to examine the role of PGI 2 in renal fibrosis in mouse models. We also analyzed the single-cell RNA-Seq data to examine the PTGIR -expressing cells in the kidneys of patients with CKD. RESULTS: Increased PTGIS expression has been observed in fibrotic kidneys in both humans and mice. Deletion of the PTGIS gene aggravated renal fibrosis and decline of renal function in murine models. A PGI 2 analog or PTGIR agonist that was administered after the acute injury ameliorated renal fibrosis. PTGIR, the PGI 2 receptor, deficiency blunted the protective effect of the PGI 2 analog. Fibroblasts and myofibroblasts were the major cell types expressing PTGIR in the kidneys of patients with CKD. Deletion of PTGIR in collagen-producing fibroblastic cells aggravated renal fibrosis. The protective effect of PGI 2 was associated with the inhibition of fibroblast activation through PTGIR-mediated signaling. CONCLUSIONS: PGI 2 is an important component in the kidney injury/repairing process by preventing the overactivation of fibroblasts during the repairing process and protecting the kidney from fibrosis and decline of renal function. Our findings suggest that PGI 2 /PTGIR is a potential therapeutic target for CKD.

Diverse effects of prostacyclin on angiogenesis-related processes in the porcine endometrium.

Angiogenesis is important for endometrial remodeling in mature females. The endometrium synthesizes high amounts of prostacyclin (PGI2) but the role of PGI2 in angiogenesis-related events in this tissue was not fully described. In the present study, porcine endometrial endothelial (pEETH) cells and/or a swine umbilical vein endothelial cell line (G1410 cells) were used to determine the regulation of PGI2 synthesis and PGI2 receptor (PTGIR) expression by cytokines and to evaluate the effect of PGI2 on pro-angiogenic gene expression, intracellular signaling activation, cell proliferation and migration, cell cycle distribution, and capillary-like structure formation. We found that IL1ß, IFNγ, and/or TNFα increased PGI2 secretion and PTGIR expression in pEETH cells. Iloprost (a PGI2 analogue) acting through PTGIR enhanced the transcript abundance of KDR, FGFR2, and ANGPT2 and increased proliferation of pEETH cells. This latter was mediated by PI3K and mTOR activation. In support, transfection of G1410 cells with siRNA targeting PGI2 synthase decreased pro-angiogenic gene expression and cell proliferation. Furthermore, iloprost accelerated the gap closure and promoted cell cycle progression. Intriguingly, the formation of capillary-like structures was inhibited but not completely blocked by iloprost. These findings point to a complex pleiotropic role of PGI2 in angiogenesis-related events in the porcine uterus.

Association between serum prostacyclin and cerebrovascular reactivity in healthy young and older adults.

NEW FINDINGS: What is the central question of this study? What is the relationship between prostacyclin and cerebrovascular reactivity to hypercapnia before and after administration of a cyclooxygenase inhibitor, indomethacin, in healthy young and older adults? What is the main finding and importance? Serum prostacyclin was not related to cerebrovascular reactivity to hypercapnia before or after administration of indomethacin. However, in older adults, serum prostacyclin was related to the magnitude of change in cerebrovascular reactivity from before to after indomethacin administration. This suggests that older adults with higher serum prostacyclin may rely more on cyclooxygenase products to mediate cerebrovascular reactivity. ABSTRACT: Platelet activation may contribute to age-related cerebrovascular dysfunction by interacting with the endothelial cells that regulate the response to vasodilatory stimuli. This study evaluated the relationship between a platelet inhibitor, prostacyclin, and cerebrovascular reactivity (CVR) in healthy young (n = 35; 25 ± 4 years; 17 women, 18 men) and older (n = 12; 62 ± 2 years; 8 women, 4 men) adults, who were not daily aspirin users, before and after cyclooxygenase inhibition. Prostacyclin was determined by levels of 6-keto-prostaglandin F1α (6-keto PGF1α) in the blood. CVR was assessed by measuring the middle cerebral artery blood velocity response to hypercapnia using transcranial Doppler ultrasound before (CON) and 90 min after cyclooxygenase inhibition with indomethacin (INDO). In young adults, there were no associations between prostacyclin and middle cerebral artery CVR during CON (r = -0.14, P = 0.415) or INDO (r = 0.27, P = 0.118). In older adults, associations between prostacyclin and middle cerebral artery CVR during CON (r = 0.53, P = 0.075) or INDO (r = -0.45, P = 0.136) did not reach the threshold for significance. We also evaluated the relationship between prostacyclin and the change in CVR between conditions (ΔCVR). We found no association between ΔCVR and prostacyclin in young adults (r = 0.27, P = 0.110); however, in older adults, those with higher baseline prostacyclin levels demonstrated significantly greater ΔCVR (r = -0.74, P = 0.005). In conclusion, older adults with higher serum prostacyclin, a platelet inhibitor, may rely more on cyclooxygenase products for cerebrovascular reactivity to hypercapnia.

Platelet zinc status regulates prostaglandin-induced signaling, altering thrombus formation.

BACKGROUND: Approximately 17.3% of the global population exhibits an element of zinc (Zn2+) deficiency. One symptom of Zn2+ deficiency is increased bleeding through impaired hemostasis. Platelets are crucial to hemostasis and are inhibited by endothelial-derived prostacyclin (prostaglandin I2 [PGI2]), which signals via adenylyl cyclase (AC) and cyclic adenosine monophosphate signaling. In other cell types, Zn2+ modulates cyclic adenosine monophosphate concentrations by changing AC and/or phosphodiesterase activity. OBJECTIVES: To investigate if Zn2+ can modulate platelet PGI2 signaling. METHODS: Platelet aggregation, spreading, and western blotting assays with Zn2+ chelators and cyclic nucleotide elevating agents were performed in washed platelets and platelet-rich plasma conditions. In vitro thrombus formation with various Zn2+ chelators and PGI2 was assessed in whole blood. RESULTS: Incubation of whole blood or washed platelets with Zn2+ chelators caused either embolization of preformed thrombi or reversal of platelet spreading, respectively. To understand this effect, we analyzed resting platelets and identified that incubation with Zn2+ chelators elevated pVASPser157, a marker of PGI2 signaling. In agreement that Zn2+ affects PGI2 signaling, addition of the AC inhibitor SQ22536 blocked Zn2+ chelation-induced platelet spreading reversal, while addition of Zn2+ blocked PGI2-mediated platelet reversal. Moreover, Zn2+ specifically blocked forskolin-mediated AC reversal of platelet spreading. Finally, PGI2 inhibition of platelet aggregation and in vitro thrombus formation was potentiated in the presence of low doses of Zn2+ chelators, increasing its effectiveness in inducing platelet inhibition. CONCLUSION: Zn2+ chelation potentiates platelet PGI2 signaling, elevating PGI2's ability to prevent effective platelet activation, aggregation, and thrombus formation.

Anti-inflammatory effects of the prostacyclin analogue iloprost in an in vitro model of inflamed human dental pulp cells.

Iloprost's anti-inflammatory effects on human dental pulp stem cells (HDPCs) are currently unknown. We hypothesized that iloprost could downregulate the expression of inflammatory-related genes and protein in an inflamed HDPC in vitro model. To induce inflammation, the HDPCs were treated with a cocktail of interleukin-1 beta, interferon-gamma, and tumour necrosis alpha, at a ratio of 1:10:100. Iloprost (10-6  M) was then added or not to the cultures. Interleukin-6 (IL-6) and interleukin-12 (IL-12) mRNA expression were assessed by real-time polymerase chain reaction. IL-6 protein expression was assessed by enzyme-linked immunosorbent assay. The results were analysed using one-way ANOVA or the Kruskal-Wallis test. The cytokine cocktail induced more robust IL-6 expression than LPS treatment. Iloprost slightly, yet significantly, downregulated IL-6 and IL-12 mRNA expression. These findings suggest that iloprost might be used as a beneficial component in vital pulp therapy.

Assessment of Inhaled Treprostinil Palmitil, Inhaled and Intravenous Treprostinil, and Oral Selexipag in a Sugen/Hypoxia Rat Model of Pulmonary Arterial Hypertension.

Treprostinil palmitil (TP), a long-acting inhaled pulmonary vasodilator prodrug of treprostinil (TRE), has beneficial effects in a Sugen5416/hypoxia (Su/Hx) rat model of pulmonary arterial hypertension (PAH) that compare favorably to the oral phosphodiesterase 5 inhibitor (PDE5) sildenafil. In this study in male Sprague-Dawley rats, a dry powder formulation of TP (TPIP) was compared with inhaled and intravenous TRE and oral selexipag to evaluate inhibition of hemodynamic and pathologic changes in the lungs and heart induced by Su/Hx challenge. Su (20 mg/kg) was injected subcutaneously followed by 3 weeks of Hx (10% O2/balance N2) and then initiation of test article administration over 5 weeks with room air breathing. Hemodynamics and histopathology were measured at the end of the study. Su/Hx challenge approximately doubled the mean pulmonary arterial blood pressure (mPAP) and the Fulton index, decreased cardiac output (CO), doubled the wall thickness and muscularization of the small (10-50 µm) and medium (51-100 µm) sized pulmonary arteries, and increased the percentage of obliterated pulmonary blood vessels. Even though inhaled TRE (65 µg/kg, 4× daily), intravenous TRE (810 ng/kg/min), and oral selexipag (30 mg/kg, twice daily) provided some beneficial effects against the Su/Hx challenge, the overall benefit was generally greater with TPIP at high dose (117 µg/kg, once daily). These results demonstrate that TPIP compares favorably to inhaled and intravenous TRE and oral selexipag with respect to inhibition of the pathophysiological changes induced by Su/Hx challenge in rats. SIGNIFICANCE STATEMENT: Treprostinil palmitil (TP) is a long-acting pulmonary vasodilator prodrug of treprostinil (TRE) formulated for inhaled administration by dry powder [treprostinil palmitil inhalation powder (TPIP)]. Comparison of the activity of TPIP, inhaled and intravenous TRE, and oral selexipag in a Sugen5416/hypoxia (Su/Hx) rat model of pulmonary arterial hypertension demonstrated that each of these drugs exert protection against the hemodynamic and histopathological changes induced by the Su/Hx challenge, with the greatest effect on these changes produced by TPIP.

Role of Prostaglandins in Nitric Oxide-Induced Glial Cell-Mediated Vasodilation in Rat Retina.

We previously identified that NO derived from neuronal cells acts on glial cells and causes vasodilation in the healthy rat retina via the release of epoxyeicosatrienoic acids (EETs) and prostaglandins (PGs) by activation of the arachidonic acid cascade. However, it is not clear which PG types are involved in these responses. The aim of the present study was to identify prostanoid receptors involved in glial cell-derived vasodilation induced by NO in rat retina. Male Wistar rats were used to examine the effects of intravitreal pretreatment with indomethacin, a cyclooxygenase inhibitor; PF-04418948, a prostanoid EP2 receptor antagonist; and CAY10441, a prostanoid IP receptor antagonist, on the changes in the retinal arteriolar diameter induced by intravitreal administration of NOR3, an NO donor. Retinal arteriolar diameters were measured using ocular fundus images captured with a high-resolution digital camera in vivo. The increase in the retinal arteriolar diameter induced by intravitreal injection of NOR3 was significantly suppressed by intravitreal pretreatment with indomethacin and PF-04418948, but not by CAY10441. The dose of PF-04418948 and CAY10441 injected intravitreally in the present study significantly reduced the increase in the retinal arteriolar diameter induced by prostaglandin E2 (PGE2) and prostaglandin I2 (PGI2), respectively. These results suggest that activation of the arachidonic acid cascade and subsequent stimulation of prostanoid EP2 receptors are involved in rat retinal vasodilatory responses evoked by NO-induced glial cell stimulation. Therefore, glial cell-derived PGE2, similar to EETs, may play an important role in retinal vasodilatory mechanisms.

High-Intensity Exercise Training Improves Basal Platelet Prostacyclin Sensitivity and Potentiates the Response to Dual Anti-Platelet Therapy in Postmenopausal Women.

The risk of thrombotic events dramatically increases with age and may be accelerated in women by the cessation of endogenous estrogen production at menopause. Patients at risk of thrombosis are prescribed dual anti-platelet therapy (DAPT; aspirin and a P2Y12 antagonist) and are encouraged to participate in regular physical activity, as these modalities improve nitric oxide and prostacyclin-mediated inhibition of platelet aggregation. METHODS: We assessed prostacyclin sensitivity as well as basal platelet reactivity with and without in vitro DAPT before and after an 8-week high-intensity exercise training program in 13 healthy, sedentary postmenopausal women. The training intervention consisted of three 1 h sessions per week. Isolated platelets were analyzed for thromboxane A2 receptor, thromboxane A2 synthase, cyclooxygenase-1, and prostacyclin receptor protein expression. Additionally, plasma 6-keto prostaglandin F1α and thromboxane B2 levels were determined. RESULTS: Exercise training made platelets more sensitive to the inhibitory effects of prostacyclin on thromboxane-, collagen-, and adenosine 5'-diphosphate (ADP)-induced aggregation, as well as thrombin-receptor activator peptide 6- and ADP-induced aggregation with DAPT. However, there was no change in protein expression from isolated platelets or plasma thromboxane B2 and prostacyclin levels following training. CONCLUSION: Together, these findings emphasize the importance of promoting physical activity as a tool for reducing thrombotic risk in postmenopausal women and suggest that training status should be considered when prescribing DAPT in this cohort.

The Antifibrotic Effects of Inhaled Treprostinil: An Emerging Option for ILD.

Interstitial lung diseases (ILD) encompasses a heterogeneous group of parenchymal lung diseases characterized by variable amounts of inflammation and fibrosis. The targeting of fibroblasts and myofibroblasts with antifibrotic treatments is a potential therapeutic target for these potentially fatal diseases. Treprostinil is unique among the prostacyclin mimetics in that it has distinct actions at additional prostaglandin receptors. Preclinical and clinical evidence suggests that treprostinil has antifibrotic effects through the activation of the prostaglandin E receptor 2 (EP2), the prostaglandin D receptor 1 (DP1), and peroxisome proliferator-activated receptors (PPAR). In vivo studies of EP2 and the DP1 have found that administration of treprostinil resulted in a reduction in cell proliferation, reduced collagen secretion and synthesis, and reduced lung inflammation and fibrosis. In vitro and in vivo studies of PPARß and PPARγ demonstrated that treprostinil inhibited fibroblast proliferation in a dose-dependent manner. Clinical data from a post hoc analysis of the INCREASE trial found that inhaled treprostinil improved forced vital capacity in the overall population as well as in idiopathic interstitial pneumonia and idiopathic pulmonary fibrosis subgroups. These preclinical and clinical findings suggest a dual benefit of treprostinil through the amelioration of both lung fibrosis and pulmonary hypertension.

The impact of nebulized epoprostenol and iloprost on hemoglobin oxygen affinity: an ex vivo experiment.

Inhalational prostacyclins act as strong vasodilators, potentially improving oxygenation by reducing shunt fraction and ventilation-perfusion mismatch. As prostacyclin receptors are known to be present on human erythrocytes, possible direct effects on hemoglobin oxygen transport were further explored by examining the sole in vitro influence of prostacyclins on hemoglobin oxygen (Hb-O2) affinity. Venous blood samples from 20 healthy volunteers were exposed in vitro to supramaximal doses of epoprostenol, iloprost, and compared with control. By high-throughput measurements, hemoglobin oxygen dissociation curves (ODCs) were derived. Hb-O2 affinity, expressed by P50 and Hill coefficient, was determined and analyzed for three subgroups: males (n = 10), females not taking oral contraceptives (n = 4), and females taking oral contraceptives (n = 6). Epoprostenol significantly decreased P50 in all (males, females without contraceptives, and females taking oral contraceptives) [27.5 (26.4-28.6) mmHg (control) vs. 24.2 (22.7-25.3) mmHg; P < 0.001. median (interquartile range, IQR)] thereby increasing Hb-O2 affinity. Inversely, iloprost only showed significant effects in females taking oral contraceptives where P50 was markedly increased and therefore Hb-O2 affinity decreased [28.4 (27.9-28.9) mmHg (control) vs. 34.4 (32.2-36.0) mmHg; P < 0.001]. Prostacyclin-receptor stimulation and subsequent cAMP-mediated ATP release from erythrocytes are discussed as a possible underlying mechanism for the effect of epoprostenol on Hb-O2 affinity. The reason for the sex hormone-modified iloprost effect remains unclear. Being aware of potentially differing effects on Hb-O2 affinity might help select the right prostacyclin (epoprostenol vs. iloprost) depending on the patient and the underlying disease (e.g., acute respiratory distress syndrome vs. peripheral arterial disease).

Differential effects of cyclo-oxygenase 1 and 2 inhibition on angiogenesis inhibitor-induced hypertension and kidney damage.

Vascular endothelial growth factor antagonism with angiogenesis inhibitors in cancer patients induces a 'preeclampsia-like' syndrome including hypertension, proteinuria and elevated endothelin (ET)-1. Cyclo-oxygenase (COX) inhibition with aspirin is known to prevent the onset of preeclampsia in high-risk patients. In the present study, we hypothesised that treatment with aspirin would prevent the development of angiogenesis inhibitor-induced hypertension and kidney damage. Our aims were to compare the effects of low-dose (COX-1 inhibition) and high-dose (dual COX-1 and COX-2 inhibition) aspirin on blood pressure, vascular function, oxidative stress, ET-1 and prostanoid levels and kidney damage during angiogenesis-inhibitor therapy in rodents. To this end, Wistar Kyoto rats were treated with vehicle, angiogenesis inhibitor (sunitinib) alone or in combination with low- or high-dose aspirin for 8 days (n=5-7/group). Our results demonstrated that prostacyclin (PGI2) and ET-1 were increased during angiogenesis-inhibitor therapy, while thromboxane (TXA2) was unchanged. Both low- and high-dose aspirin blunted angiogenesis inhibitor-induced hypertension and vascular superoxide production to a similar extent, whereas only high-dose aspirin prevented albuminuria. While circulating TXA2 and prostaglandin F2α levels were reduced by both low- and high-dose aspirin, circulating and urinary levels PGI2 were only reduced by high-dose aspirin. Lastly, treatment with aspirin did not significantly affect ET-1 or vascular function. Collectively our findings suggest that prostanoids contribute to the development of angiogenesis inhibitor-induced hypertension and renal damage and that targeting the prostanoid pathway could be an effective strategy to mitigate the unwanted cardiovascular and renal toxicities associated with angiogenesis inhibitors.

Endothelium-dependent vasorelaxant effects of praeruptorin a in isolated rat thoracic aorta.

Praeruptorin A (PA) is a natural coumarin compound from the roots of Radix Peucedani and is commonly used in the treatment of certain respiratory diseases and hypertension. Although previous studies identified relaxant effects of PA on tracheal and arterial preparations, little is known about its vasodilative effects and underlying mechanisms. Here, an organ bath system and tension recording methods were used to prepare and analyze isolated rat thoracic aorta artery rings. Aorta artery rings were pre-contracted with phenylephrine and then incubated with PA, and the possible mechanism of relaxation was investigated by adding inhibitors of nitric oxide synthase (NG-nitro-L-arginine methyl ester, L-NAME), endothelial nitric oxide synthase (L-NG-nitroarginine, L-NNA), cyclooxygenase (indomethacin), guanylyl cyclase (1 H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one, ODQ), and KCa channels (tetraethylammonium, TEA). Our study showed that PA-induced vasodilation was blocked by L-NAME, L-NNA, and ODQ, while CaCl2-induced vasoconstriction was countered by PA. Thus, PA may exert a vasodilatory effect by influencing the amounts of endothelium-derived relaxing factors through endothelial-dependent NO-cGMP and prostacyclin pathways (such as NO and prostacyclin 2). In the rat thoracic aorta, PA reduces vasoconstriction by inhibiting Ca2+ inflow.

Prostacyclin analogues decrease platelet aggregation but have no effect on thrombin generation, fibrin clot structure, and fibrinolysis in pulmonary arterial hypertension: PAPAYA coagulation.

Prostacyclin (PGI2) analogues (epoprostenol, treprostonil, iloprost) are the cornerstone of pulmonary arterial hypertension (PAH) treatment. PGI2 analogues inhibit platelet reactivity, but their impact on coagulation and fibrinolysis parameters has not been elucidated. We compared platelet reactivity, thrombin generation, clot permeation, and lysis properties in patients with PAH treated with PGI2 analogues (n = 20) and those not receiving PGI2 analogues (n = 20). Platelet reactivity was lower in patients treated with PGI2 analogues, compared to the control group, as evaluated with arachidonic acid (ASPI), adenosine diphosphate (ADP), and thrombin receptor-activating peptide-6 (TRAP) tests (p = .009, p = .02, p = .007, respectively). In the subgroup analysis, both treprostinil and epoprostenol decreased platelet reactivity to the similar extent. There were no differences regarding thrombin generation, clot permeation, and lysis parameters in patients receiving and not receiving PGI2 analogues (p ≥ .60 for all). In the subgroup analysis, there were no differences regarding coagulation and fibrinolysis parameters between treprostinil, epoprostenol, and no PGI2 analogues. To conclude, patients with PAH treated with PGI2 analogues have reduced platelet reactivity, but similar clot formation and lysis parameters, compared to patients not receiving PGI2 analogues. Further randomized clinical trials are required to confirm these findings.

The effect of prostacyclin infusion on markers of endothelial activation and damage in mechanically ventilated patients with SARS-CoV-2 infection.

BACKGROUND: In a pilot study, we found a significant reduction in mean daily sequential organ failure assessment score in mechanically ventilated patients with COVID-19 who received prostacyclin, compared to placebo. We here investigate the effect on biomarkers of endothelial activation and damage. METHODS: Post-hoc study of a randomized controlled trial in adult patients with confirmed SARS-CoV-2 infection, mechanically ventilated, with soluble thrombomodulin (sTM) plasma levels >4 ng/mL. Patients received prostacyclin infusion (1 ng/kg/min) or placebo. Blood samples were collected at baseline and 24 h. RESULTS: Eighty patients were randomized (41 prostacyclin, 39 placebo). The median changes in syndecan-1 plasma levels at 24 h were -3.95 (IQR: -21.1 to 2.71) ng/mL in the prostacyclin group vs. 3.06 (IQR: -8.73 to 20.5) ng/mL in the placebo group (difference of the medians: -7.01 [95% CI: -22.3 to -0.231] ng/mL, corresponding to -3% [95% CI: -11% to 0%], p = 0.04). Changes in plasma levels of sTM, PECAM-1, p-selectin, and CD40L did not differ significantly between groups. CONCLUSIONS: Prostacyclin infusion, compared to placebo, resulted in a measurable decrease in endothelial glycocalyx shedding (syndecan-1) at 24 h, suggesting a protective effect on the endothelium, which may be related to the observed reduction in organ failure.

Treprostinil palmitil inhibits the hemodynamic and histopathological changes in the pulmonary vasculature and heart in an animal model of pulmonary arterial hypertension.

Treprostinil palmitil (TP) is a long-acting inhaled pulmonary vasodilator prodrug of treprostinil (TRE). In this study, TP was delivered by inhalation (treprostinil palmitil inhalation suspension, TPIS) in a rat Sugen 5416 (Su)/hypoxia (Hx) model of pulmonary arterial hypertension (PAH) to evaluate its effects on hemodynamics, pulmonary vascular remodeling, and cardiac performance and histopathology. Male Sprague-Dawley rats received Su (20 mg/kg, s.c), three weeks of Hx (10% O2) and 5 or 10 weeks of normoxia (Nx). TPIS was given during the 5-10 week Nx period after the Su/Hx challenge. Su/Hx increased the mean pulmonary arterial blood pressure (mPAP) and right heart size (Fulton index), reduced cardiac output (CO), stroke volume (SV) and heart rate (HR), and increased the thickness and muscularization of the pulmonary arteries along with obliteration of small pulmonary vessels. In both the 8- and 13-week experiments, TPIS at inhaled doses ranging from 39.6 to 134.1 µg/kg, QD, dose-dependently improved pulmonary vascular hemodynamics, reduced the increase in right heart size, enhanced cardiac performance, and attenuated most of the histological changes induced by the Su/Hx challenge. The PDE5 inhibitor sildenafil, administered at an oral dose of 50 mg/kg, BID for 10 weeks, was not as effective as TPIS. These results in Su/Hx challenged rats demonstrate that inhaled TPIS may have superior effects to oral sildenafil. We speculate that the improvement of the pathobiology in this PAH model induced by TPIS involves effects on pulmonary vascular remodeling due to the local effects of TRE in the lungs.

The effects of beraprost sodium on renal function and cardiometabolic profile in patients with diabetes mellitus: a systematic review and meta-analysis of clinical trials.

PURPOSE: This systematic review and meta-analysis aimed to assess renal function and cardiometabolic biomarkers after treatment with beraprost sodium in patients with diabetes mellitus. METHODS: We systemically searched PubMed, Embase, Scopus, Web of Science, and Cochrane Library up to August 2020. Statistical heterogeneities were computed using Cochrane's Q test and I2 test. A fixed- or random-effects model was used to calculate the weighted mean difference (WMD) and corresponding 95% confidence intervals (CI). RESULTS: From 341citations, seven trials were included into our meta-analysis. Our findings demonstrated that beraprost sodium intake significantly decreased blood urea nitrogen (BUN) (WMD = -5.62, 95% CI [-8.49, -2.74], P < 0.001) and cystatin C (WMD = -0.57, 95% CI [-0.68, -0.46], P < 0.001). Beraprost sodium intake had no significant effect on fasting blood sugar (FBS), hemoglobin A1c (HbA1c), cholesterol (TC), triglycerides (TG), HDL-C, LDL-C, systolic blood pressure (SBP), diastolic blood pressure (DBP), and creatinine (Cr) in patients with diabetes receiving beraprost sodium in comparison with the controls. CONCLUSION: Our meta-analysis revealed that beraprost sodium administration significantly decreased BUN and cystatin C levels in patients with diabetes. However, no significant effect was observed on the cardiometabolic profile.

Sexual dimorphism in prostacyclin-mimetic responses within rat mesenteric arteries: A novel role for KV 7.1 in shaping IP receptor-mediated relaxation.

BACKGROUND AND PURPOSE: Prostacyclin mimetics express potent vasoactive effects via prostanoid receptors that are not unequivocally defined, as to date no study has considered sex as a factor. The aim of this study was to determine the contribution of IP and EP3 prostanoid receptors to prostacyclin mimetic iloprost-mediated responses, whether KV 7.1-5 channels represent downstream targets of selective prostacyclin-IP-receptor agonist MRE-269 and the impact of the oestrus cycle on vascular reactivity. EXPERIMENTAL APPROACH: Within second-order mesenteric arteries from male and female Wistar rats, we determined (1) relative mRNA transcripts for EP1-4 (Ptger1-4 ), IP (Ptgi) and TXA2 (Tbxa) prostanoid receptors via RT-qPCR; (2) the effect of iloprost, MRE-269, isoprenaline and ML277 on precontracted arterial tone in the presence of inhibitors of prostanoid receptors, potassium channels and the molecular interference of KV 7.1 via wire-myograph; (3) oestrus cycle stage via histological changes in cervical cell preparations. KEY RESULTS: Iloprost evoked a biphasic response in male mesenteric arteries, at concentrations ≤100 nmol·L-1 relaxing, then contracting the vessel at concentration ≥300 nmol·L-1 , a process attributed to IP and EP3 receptors respectively. Secondary contraction was absent in the females, which was associated with a reduction in Ptger3. Pharmacological inhibition and molecular interference of KV 7.1 significantly attenuated relaxations produced by the selective IP receptor agonist MRE-269 in male and female Wistar in dioestrus/metoestrus, but not pro-oestrus/oestrus. CONCLUSIONS AND IMPLICATIONS: Stark sexual dimorphisms in iloprost-mediated vasoactive responses are present within mesenteric arteries. KV 7.1 is implicated in IP receptor-mediated vasorelaxation and is impaired by the oestrus cycle.

IPF-Fibroblast Erk1/2 Activity Is Independent from microRNA Cluster 17-92 but Can Be Inhibited by Treprostinil through DUSP1.

Idiopathic pulmonary fibrosis (IPF) is a progressive terminal lung disease, and therapies aim to block fibrosis. Fibroblast proliferation is controlled by C/EBP-ß, microRNA cluster 17-92 (miR17-92), and Erk1/2 mitogen-activated protein kinase. This study assessed the role of miR17-92 in IPF-fibroblast proliferation and its modification by treprostinil. Fibroblasts were isolated from eight IPF patients, five interstitial lung fibrosis patients, and seven control lungs. Fibroblasts were stimulated with TGF-ß1 over 24 h. The miR17-92 expression was analyzed by RT-qPCR, and protein expression by Western blotting. TGF-ß1 upregulated C/EBP-ß in all fibroblasts, which was reduced by treprostinil in control-fibroblasts, but not in IPF-fibroblasts. Compared to controls, the guide strands miR-19a-3p, miR-19b-3p, miR-20a-5p, and miR-92a-3p, as well as the passenger strands miR-17-3p, miR-18-3p, miR-19a-1-5p, and miR-92a-5p were significantly increased in IPF-fibroblasts. In controls, TGF-ß1 and treprostinil significantly reduced specific miR17-92 members. IPF-fibroblast proliferation was inhibited by treprostinil through increased expression of the Erk1/2 inhibitor DUSP1. These data suggest that proliferation control via miR17-92 and C/EBP-ß is disrupted in IPF-fibroblasts. Therefore, the inhibition of early stages of signaling cascades or specific mitogen receptors might be less effective. However, the increased proliferation is sensitive to Erk1/2 inhibition by treprostinil-induced DUSP1.