Discovery of novel phosphodiesterase-1 inhibitors for curing vascular dementia: Suppression of neuroinflammation by blocking NF-κB transcription regulation and activating cAMP/CREB axis

Vascular dementia (VaD) is the second commonest type of dementia which lacks of efficient treatments currently. Neuroinflammation as a prominent pathological feature of VaD, is highly involved in the development of VaD. In order to verify the therapeutic potential of PDE1 inhibitors against VaD, the anti-neuroinflammation, memory and cognitive improvement were evaluated in vitro and in vivo by a potent and selective PDE1 inhibitor 4a. Also, the mechanism of 4a in ameliorating neuroinflammation and VaD was systematically explored. Furthermore, to optimize the drug-like properties of 4a, especially for metabolic stability, 15 derivatives were designed and synthesized. As a result, candidate 5f, with a potent IC50 value of 4.5 nmol/L against PDE1C, high selectivity over PDEs, and remarkable metabolic stability, efficiently ameliorated neuron degeneration, cognition and memory impairment in VaD mice model by suppressing NF-κB transcription regulation and activating cAMP/CREB axis. These results further identified PDE1 inhibition could serve as a new therapeutic strategy for treatment of VaD.

Effect and mechanism of amphiregulin on acute respiratory distress syndrome in mice / 中华危重病急救医学

OBJECTIVE@#To explore the protective effect of amphiregulin (Areg) on acute respiratory distress syndrome (ARDS) in mice and its underlying mechanism.@*METHODS@#(1) Male C57BL/6 mice aged 6-8 weeks were selected for animal experiments and divided into 3 groups (n = 10) according to the random number table method, which includes sham-operated group (Sham group), ARDS model group [ARDS model in mice was established by intratracheal instillation of lipopolysaccharide (LPS) 3 mg/kg] and ARDS+Areg intervention group [recombinant mice Areg (rmAreg) 5 μg was injected intraperitoneally 1 hour after LPS modeling]. The mice were sacrificed at 24 h after LPS injection lung histopathological changes were observed under hematoxylin-eosin (HE) staining and scored for lung injury; oxygenation index and wet/dry ratio of lung tissue were measured; the content of protein in bronchoalveolar lavage fluid (BALF) was detected by bicinchoninic acid (BCA) method, the level of inflammatory factors interleukins (IL-1β, IL-6) and tumor necrosis factor-α (TNF-α) in BALF were measured by enzyme-linked immunosorbent assay (ELISA). (2) Mice alveolar epithelial cell line MLE12 cells were obtained and cultured for experiment in vitro. Blank control group (Control group), LPS group (LPS 1 mg/L) and LPS+Areg group (rmAreg 50 μg/L was added 1 hour after LPS stimulation) were set. The cells and culture fluid were collected at 24 hours after LPS stimulation, and the apoptosis level of MLE12 cells was detected by flow cytometry; the activation level of phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) and the expressions of apoptosis-related proteins Bcl-2 and Bax in MLE12 cells were detected by Western blotting.@*RESULTS@#(1) Animal experiments: compared with the Sham group, the lung tissue structure of ARDS model group was destroyed, the lung injury score was significantly increased, the oxygenation index was significantly decreased, the wet/dry weight ratio of lung was significantly increased, and the levels of protein and inflammatory factors in BALF were significantly increased. Compared with ARDS model group, lung tissue structure damage was reduced, pulmonary interstitial congestion, edema and inflammatory cell infiltration were significantly reduced, and lung injury score was significantly decreased (scores: 0.467±0.031 vs. 0.690±0.034) in ARDS+Areg intervention group. In addition, oxygenation index in ARDS+Areg intervention group was significantly increased [mmHg (1 mmHg ≈ 0.133 kPa): 380.00±22.36 vs. 154.00±20.74]. Lung wet/dry weight ratio (5.40±0.26 vs. 6.63±0.25), protein and inflammatory factors levels in BALF [protein (g/L): 0.42±0.04 vs. 0.86±0.05, IL-1β (ng/L): 30.00±2.00 vs. 40.00±3.65, IL-6 (ng/L): 190.00±20.30 vs. 581.30±45.76, TNF-α (ng/L): 30.00±3.65 vs. 77.00±4.16], and the differences were statistically significant (all P < 0.01). (2) Cell experiments: compared with the Control group, the number of apoptotic MLE12 cells was significantly increased in the LPS group, and the levels of PI3K phosphorylation, anti-apoptotic gene Bcl-2 level and pro-apoptotic gene Bax level were increased in MLE12 cells. Compared with the LPS group, the number of apoptosis in MLE12 cells was significantly reduced in the LPS+Areg group after administration of rmAreg treatment [(17.51±2.12)% vs. (36.35±2.84)%], and the levels of PI3K/AKT phosphorylation and Bcl-2 expression in MLE12 cells were significantly increased (p-PI3K/PI3K: 2.400±0.200 vs. 0.550±0.066, p-AKT/AKT: 1.647±0.103 vs. 0.573±0.101, Bcl-2/GAPDH: 0.773±0.061 vs. 0.343±0.071), and Bax expression was significantly suppressed (Bax/GAPDH: 0.810±0.095 vs. 2.400±0.200). The differences were statistically significant (all P < 0.01).@*CONCLUSIONS@#Areg could alleviate ARDS in mice by inhibiting the apoptosis of alveolar epithelial cells through activating PI3K/AKT pathway.

New progress of pathogenesis in ventilator-induced lung injury / 中华危重病急救医学

Mechanical ventilation is not only an important treatment method of acute respiratory distress syndrome (ARDS),but also one of the basic treatments in the intensive care unit (ICU).However,mechanical ventilation itself can cause or aggravate acute lung injury,which is called ventilator-induced lung injury (VILI).Currently,clinical pathogenesis of VILI includes four categories such as barotrauma,volutrauma,atelectrauma and hiotrauma.The pathogenesis of mechanical injury has been widely accepted,but the biological injury pathogenesis is unclear.With further research,we found that in the late stage VILI patients occured proliferation of puhnonary fibrosis,which may be formed by partial epithelial-mesenchymal transdifferentiation (EMT).Further study of specific pathogenesis of biotrauma and ARDS pulmonary fibrosis proliferation could provide new ideas for the clinical treatment of VILI.

Effect of exogenous protectin DX on acute lung injury in septic mice / 中华麻醉学杂志

Objective To investigate the effect of exogenous protectin DX (PDX) on acute lung injury in septic mice.Methods Thirty male C57BL/6 mice,aged 6-8 weeks,weighing 20-25 g,were randomly divided into 3 groups (n =10 each) using a random number table:sham operation group (Sham group),sepsis group (S group) and PDX group.Sepsis was produced by cecum ligation and puncture (CLP) in the mice anesthetized with pentobarbital sodium.At 1 h after CLP,PDX 300 ng was injected intraperitoneally in PDX group,and the equal volume of normal saline was given in Sham and S groups.At 24 h after CLP,the mice were sacrificed,and the broncho-alveolar lavage fluid (BALF) was collected for determination of interleukin-1beta (IL-1β),tumor necrosis factor-alpha (TNF-α),IL-6 and IL-10 concentrations,and the lungs were removed for microscopic examination and for determination of the myeloperoxidase (MPO) activity,wet/dry lung weight ratio (W/D ratio) and phosphorylation of nuclear factor-kappa B (NF-κB) p65.Lung injury scores were calculated.Results Compared with Sham group,the lung injury score,MPO activity,W/D ratio,phosphorylation of NF-κB p65,and concentrations of protein and inflammatory factors in BALF were significantly increased in S and PDX groups (P＜0.05).Compared with S group,the lung injury score,MPO activity,W/D ratio,phosphorylation of NF-κB p65,and concentrations of protein,IL-1β,TNF-α and IL-6 in BALF were significantly decreased,and the concentration of IL-10 in BALF was significantly increased in PDX group (P＜0.05).Conclusion Exogenous PDX can alleviate acute lung injury through inhibiting NF-κB activity in the lung tissues of septic mice.

Effect of sivelestat sodium on the prognosis of patients with acute lung injury and acute respiratory distress syndrome：a meta-analysis / 中华危重病急救医学

ObjectiveTo investigate the effect of sivelestat sodium on the prognosis in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS).Methods Databases including PubMed, EBSCO, Springer, Ovid, Wanfang data, CNKI and China Biology Medicine (CBM) were searched to identify randomized controlled trials (RCTs) regarding sivelestat sodium treatment for ALI/ARDS published from 1985 to December 2014. The patients in treatment group received intravenous infusion of sivelestat sodium, and those in control group received normal saline. The items for analysis were 28-day mortality, duration of mechanical ventilation, length of intensive care unit (ICU) stay, and oxygenation index on day 3. According to the evaluation method of Cochrane system, data extraction and quality assessment from the literature were carried out. Meta-analysis was performed using RevMan 5.3. The publication bias was analyzed with funnel plot.Results Five RCTs with a total of 780 participants were included, with 389 patients in sivelestat sodium group, and 391 in control group. Meta analysis showed: compared with control group, sivelestat sodium could not lower the 28-day mortality [odds ratio (OR) = 0.91, 95% confidence interval (95%CI) =0.66-1.26,P = 0.58], or shorten the duration of mechanical ventilation or length of ICU stay [duration of mechanical ventilation: mean difference (MD) = -0.02, 95%CI = -0.29 to 0.24,P = 0.87; length of ICU stay:MD = -9.63, 95%CI =-23.34 to 4.08,P = 0.17], but it could improve oxygenation index on day 3 (MD = 0.88, 95%CI = 0.39 to 1.36, P = 0.000 4). Heterogeneity was not significant for the main analysis and no publication bias was shown on funnel plot. Conclusion Sivelestat sodium gave rise to a better oxygenation on day 3, but did not change the length of mechanical ventilation and ICU stay, and it did not improve 28-day mortality in ALI and ARDS.