Kinin B_2 receptor does not exert renoprotective effects on mice with glycerol-induced rhabdomyolysis

AIM： To investigate a potential protective role of the kinin B2 receptor in a glycerol-induced rhabdomyolysis mouse model. METHODS： We separated 28 C57Bl/6 male mice into 4 groups： untreated WT animals, untreated B2 knockout mice, glycerol-treated WT and glycerol-treated B2 knockout mice. Glycerol-treated animals received one intramuscular injections of glycerol solution （50% v/v, 7 mL/kg）. After 48 h, urine and blood samples were collected to measure creatinine and urea levels. Addi-tionally, kidney samples were extracted for histological evaluation, and the mRNA expression levels of kinin B1 and B2 receptors and infammatory mediators were measured by real-time polymerase chain reaction. RESULTS： Serum creatinine and urea levels showed differences between untreated wild-type and glycerol-treated wild-type mice （0.66 ± 0.04 vs 2.61 ± 0.53 mg/dL, P 〈 0.01; and 33.51 ± 2.08 vs 330.2 ± 77.7 mg/dL, P 〈 0.005）, and between untreated B2 knock-out mice and glycerol-treated knockout mice （0.56 ± 0.03 vs 2.23 ± 0.87 mg/dL, P 〈 0.05; and 42.49 ± 3.2 vs 327.2 ± 58.4 mg/dL, P 〈 0.01）, but there was no difference between the glycerol-treated wild-type and glycerol-treated knockout mice. Glycerol was able to in-duce a striking increase in kinin B2 receptor expression （〉 30 times, 31.34 ± 8.9） in kidney. Animals injected with glycerol had a higher degree of tubular injury than untreated animals. Wild-type and knockout mice treat-ed with glycerol intramuscularly present kidney injury, with impairment in renal function. However, B2 knock-out mice treated with glycerol did not show a different phenotype regarding kidney injury markers, when com-pared to the wild-type glycerol-treated group. CONCLUSION： We conclude that the kinin B2 receptordoes not have a protective role in renal injury.

Kallikrein-kinin in stem cell therapy

The tissue kallikrein-kinin system exerts a wide spectrum of biological activities in the cardiovascular, renal and central nervous systems. Tissue kallikrein-kinin modulates the proliferation, viability, mobility and functional activity of certain stem cell populations, namely mesenchymal stem cells(MSCs), endothelial progenitor cells(EPCs), mononuclear cell subsets and neural stem cells. Stimulation of these stem cells by tissue kallikrein-kinin may lead to protection against renal, cardiovascular and neural damage by inhibiting apoptosis, inflammation, fibrosis and oxidative stress and promoting neovascularization. Moreover, MSCs and EPCs genetically modified with tissue kallikrein are resistant to hypoxia- and oxidative stress-induced apoptosis, and offer enhanced protective actions in animal models of heart and kidney injury and hindlimb ischemia. In addition, activation of the plasma kallikrein-kinin system promotes EPC recruitment to the inflamed synovium of arthritic rats. Conversely, cleaved high molecular weight kininogen, a product of plasma kallikrein, reduces the viability and vasculogenic activity of EPCs. Therefore, kallikrein-kinin provides a new approach in enhancing the efficacy of stem cell therapy for human diseases.

Effect of safflower yellow pigment combined with cerebellin on neurological function in patients with ischemic stroke and its mechanism

Objective: To investigate the effects of safflower yellow pigment combined with cerebellin on neurological function in patients with ischemic stroke and analyze its possible mechanism. Methods: A total of 130 patients with ischemic stroke admitted to my hospital from May 2017 to August 2018 were enrolled. The patients were divided into the control group and the study group according to the random number table method, 65 cases in each group. The control group was treated with cerebroside carnosine. And the study group was treated with safflower yellow pigment on the basis of the control group. The changes of neurological function index, oxidative stress index, vascular endothelial function index and inflammatory factor were compared before and after treatment. Results: There were no significant differences in preoperative neurological parameters, oxidative stress, vascular endothelial function and inflammatory factors between the two groups (P>0.05). After treatment, the neurological function indexes S-100β and NSE were significantly lower in both groups, and NGF levels were significantly increased. The S-100β and NSE levels in the study group were (0.91±0.10) ng/L and (12.91±1.33) ng/L, respectively, which were significantly lower than control group. While the NGF level of the study group was (79.52±8.07) μg/L significantly higher than that of the control group (both P<0.05). The levels of Ox-LDL were significantly reduced and GSH-Px levels were significantly elevated in both groups after treatment. The level of oxidative stress index Ox-LDL was (563.51±57.10) μg/dL, which was significantly lower than that of the control group, and the GSH-Px level was (154.55±16.07) U/L, which was significantly higher than the control group (both P<0.05). The levels of vascular endothelial function NT-proBNP, TXB2 and ET-1 were significantly lower in the two groups after treatment. The NT-proBNP, TXB2 and ET-1 in the study group were (95.91±9.77) pg/mL, (245.69±25.06) pg/mL and (64.26±6.65) ng/L, respectively, which were significantly lower than the control group (both P<0.05). The levels of inflammatory factors MMP-9 and TNF-α were significantly lower in the two groups after treatment. The levels of MMP-9 and TNF-α in the study group were (60.64±6.12) ng/mL and (0.33±0.04) ng/mL, respectively, which were significantly lower than those in the control group (both P<0.05). Conclusion: Safflor yellow combined with cerebellin in the treatment of ischemic stroke has higher clinical efficacy and can significantly improve the neurological function of patients. The possible mechanism is related to the improvement of vascular endothelial function and stress response.

AB021.The effect of anti-VEGF on retinal inflammation and its relationship with the Kinin system in a rat model of laser-induced choroidal neovascularization

Background:The neovascular aged-related macular degeneration(AMD)is the leading cause of legal blindness in the elderly.It is presently treated by anti-VEGF intravitreal injection in order to stop the neovascularization.In seeking of more efficient treatments to prevent retinal damage,it has been proposed that the kinin-kallikrein system(KKS),a key player in inflammation,could be involved in AMD etiology.However,the role of kinin receptors and their interaction with VEGF in AMD is poorly understood.Methods:In order to address this question,choroidal neovascularization(CNV)was induced in the left eye of Long-Evans rat.After laser induction,anti-VEGF or IgG control were injected into the vitreal cavity.Gene expression was measured by qRT-PCR,retinal adherent leukocytes were labelled with FITC-Concanavalin A lectin,vascular leakage by the method of Evans blue and cellular localisation by immunohistochemistry.Results:The number of labelled adherent leucocytes was significantly increased in laser-induced CNV compared to the control eye.This was significantly reversed by one single injection of anti-VEGF.Extravasation of Evans blue dye was significantly increased in laser-induced CNV eyes compared to control eyes and partially reversed by one single injection of anti-VEGF or by R954 treatment.The mRNA expression of inflammatory mediators was significantly increased in the retina of CNV rats.Immunodetection of B1R was significantly increased in CNV eyes.B1R immunolabeling was detected on endothelial and ganglion cells.Conclusions:This study is the first to highlight an effect of the kinin/kallikrein system in a model of CNV that could be reduced by both anti-VEGF therapy and topically administered B1R antagonist R-954.