Erythrocytes are devoid of nuclei and mitochondria which are the crucial elements of apoptosis, so their programmed suicidal death is called eryptosis. Eryptosis is characterized by cell shrinkage, membrane blebbing, activation of proteases, and phosphatidylserine exposure. Prostaglandin E(2) (PGE(2)) activates nonselective cation channels that increase cytosolic Ca(2+) activity and platelet-activating factor (PAF) activates a sphingomyelinase which lead to formation of ceramide. Either can lead to membrane scrambling with subsequent phosphatidylserine exposure. Exposed phosphatidylserine is recognized by macrophages that engulf and degrade the injured cells. As such, eryptosis can clear the injured red blood cells and avoid the release of hemoglobin. The signaling of eryptosis includes PGE(2), cation channels, PAF, ceramide, protein kinase C, and in some instances, caspases. In this review, the PGE(2), PAF and protein kinase pathways, erythrocyte surface receptor-mediated effects, oxidative stress and caspase effects, the inhibitory factors of eryptosis and the clinical eryptosis-related diseases are discussed.
Apoptosis ; physiology ; Dinoprostone ; metabolism ; Erythrocytes ; metabolism ; physiology ; Humans ; Platelet Activating Factor ; metabolism ; Signal Transduction

OBJECTIVE: To investigate the relationship between platelet activating factor (PAF) and occurrence of hepatorenal syndrome (HRS). METHODS: A total of 57 cases of patients with liver cirrhosis or hepatitis gravis were enrolled. The serum concentrations of PAF, lipopolysaccharide (LPS) and prothrombin activity (PTA), total bilirubin, and serum creatinine were detected in patients combined with HRS and in patients without HRS in hospital at the term. The correlations among the PAF, LPS, and the function of liver and kidney were analyzed. RESULTS: The concentrations of PAF and LPS in the patients combined with HRS were significantly higher than those patients without HRS. There were linear correlations between the PAF and LPS level, the total bilirubin level and PAF level, the PAF level and serum creatinine level. CONCLUSION The PAF associates with the occurrence of HRS. The PAF may mediate the occurrence of HRS induced by LPS. The PAF level may forecast whether patients with liver failure will take place HRS.
Biomarkers ; metabolism ; Female ; Hepatorenal Syndrome ; metabolism ; Humans ; Male ; Platelet Activating Factor ; metabolism

OBJECTIVETo investigate the expression changes and regulation of pituitary adenylate cyclase-activating polypeptide (PACAP) mRNA in corpus luteum during pregnancy.

METHODSPregnant rats' ovaries were collected at different time points. The techniques of RT-PCR and in situ hybridization were used to observe expression changes of PACAP mRNA in rat ovaries during pregnancy. To further explore the regulation mechanism of PACAP mRNA expression in corpus luteum, luteal cells were cultured in vitro. Immature (25 - 28 days old) female Sprague-Dawley rats were injected subcutaneously with 50IU pregnant mare serum gonadotrophin (PMSG), and 25IU human chorionic gonadotrophin (hCG) 48 h later, to induce follicular development and luteum formation. On day 6 after hCG administration (the day of hCG administration was the first day), the rats were killed by guillotine and the ovarian luteal cells were collected. After incubation for 24 h, luteal cells were administration with various factors for 24 h. And then expression changes of PACAP mRNA in luteal cells after administration with different factors were detected by RT-PCR, and radioimmunoassay was used to analyze progesterone levels.

RESULTSWith the development of pregnancy, the expression of PACAP mRNA increased gradually, reached the peak at pregnancy 19 d, and then decreased. Compared with control group, platelet activating factor (PAF), forskolin and PMA could obviously stimulate PACAP mRNA expression in luteal cells which were cultured with corresponding factors for 24 h. At the same time, progesterone levels in culture media were also elevated.

CONCLUSIONPACAP, acting as a local ovary regulator, was closely related to the maintenance of medium-term and late pregnancy. PAF could directly stimulate PACAP mRNA expression in luteal cells, and protein kinase C (PKC) and protein kinase A (PKA) signal pathways could both participate in this process.

Animals ; Cells, Cultured ; Corpus Luteum ; metabolism ; Female ; Pituitary Adenylate Cyclase-Activating Polypeptide ; genetics ; metabolism ; Platelet Activating Factor ; metabolism ; Pregnancy ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the inhibitory effect and mechanism of rutin against platelet activating factor (PAF) induced platelet aggregation, 5-HT release and intra-platelet free calcium concentration.

METHODSThe rate of washed rabbit platelet (WRP) aggregation was measured by turbidimetry and O-phthaldialdehyde (OPT) fluoro-spectrophotometry (FSPM) was used to determine 5-HT content. The intraplatelet free calcium concentration was measured with Fura-2/AM FSPM assay.

RESULTSRutin in vitro was concentration-dependently inhibiting PAF (9.55 x 10(-9) mol/L) induced WRP aggregation, the IC50 of 5-HT release was 0.73, 1.13 mmol/L respectively and the intraplatelet free calcium concentration elevation evoked by PAF (4.78 x 10(-10) mol/L) were inhibited by 68.3, 136, 274, 545 mumol/L of rutin dose-dependently.

CONCLUSIONRutin could inhibit PAF induced platelet aggregation, 5-HT release and the increase of intraplatelet free calcium.

Animals ; Biological Transport, Active ; Blood Platelets ; metabolism ; Calcium ; metabolism ; Male ; Platelet Activating Factor ; antagonists & inhibitors ; Platelet Activation ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; Rabbits ; Rutin ; pharmacology ; Serotonin ; metabolism

Enterocolitis, Necrotizing ; metabolism ; pathology ; Female ; Humans ; Immunohistochemistry ; Infant, Newborn ; Intestinal Mucosa ; metabolism ; pathology ; Male ; Platelet Activating Factor ; metabolism

Animals ; Cells, Cultured ; Female ; Granulosa Cells ; metabolism ; Pituitary Adenylate Cyclase-Activating Polypeptide ; genetics ; metabolism ; Platelet Activating Factor ; pharmacology ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley

AIMTo study the antagonistic effect of myricetin on platelet activing factor (PAF).

METHODSThe specific binding of [3H] PAF to rabbit platelet receptor was investigated using radio ligand binding assay (RLBA). Platelet adhesion induced by PAF was measured with spectrophotometry. The elevation of inner free calcium concentration in rabbit polymorphonuclear leukocytes (PMNs) induced by PAF was assayed by Fura-2 fluorescent technique.

RESULTSThe specific binding inhibition potency of Myr was found to be concentration-dependent. The IC50 of Myr in [3H] PAF 1, 2 and 4 nmol.L-1 were 34.8, 85.7 and 118.6 mumol.L-1, respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration increase were inhibited by Myr in a dose-dependent manner. The IC50 of Myr to inhibit platelet adhesion was 13.1 mumol.L-1.

CONCLUSIONThe specific receptor binding of PAF can be antagonized by myricetin.

Animals ; Calcium ; metabolism ; Flavonoids ; pharmacology ; Male ; Neutrophils ; metabolism ; Platelet Activating Factor ; antagonists & inhibitors ; metabolism ; Platelet Activation ; drug effects ; Platelet Adhesiveness ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; Platelet Membrane Glycoproteins ; metabolism ; Rabbits ; Receptors, G-Protein-Coupled ; metabolism

This study was aimed to investigate the changes of the platelet particle membrane protein (GMP-140), platelet activating factor (PAF) and platelet parametes in the patients with hyperuricemia (HUA), ELISA was used to detect the levels of GMP-140 and PAF in 55 patients with HUA and 30 healthy individuals. Platelet parameters were measured with automatic blood cell analyzer, and the biochemical indexes were detected at the same time. The results showed that the levels of serum uric acid, triglycerides (TG) and low density lipoprotein cholesterol (LDL-C) in HUA patients were higher than that in the normal group (P < 0.01). Serum uric acid level of HUA group was higher in men than that in women. The levels of GMP-140 and PAF in HUA patients were much higher than that in the normal group (P < 0.01), the indexes of platelet distribution width (PDW) and platelet-large cell ratio (P-LCR) in HUA patients were higher than that in the normal group (P < 0.01), there was no statistically significant difference in platelet count, plateletcrit (PCT), mean platelet volume (MPV) between the two groups. There was positive correlation between serum uric acid and levels of GMP-140, PAF, P-LCR and PDW, respectively (r = 0.667, 0.879, 0.310, 0.460, P < 0.01 or P < 0.05). Multivariate stepwise regression analysis revealed that serum uric acid, creatinine, P-LCR, urea nitrogen contributed to GMP-140 level (adjusted R(2) = 0.822). Serum uric acid and LDL-C also contributed to PAF level (adjusted R(2) = 0.451). It is concluded that a close relationship exists between HUA and the change of platelet function, and HUA plays a certain role in cardiovascular disease thrombosis complications.
Adult ; Aged ; Blood Platelets ; metabolism ; Case-Control Studies ; Female ; Humans ; Hyperuricemia ; blood ; Male ; Middle Aged ; P-Selectin ; metabolism ; Platelet Activating Factor ; metabolism ; Platelet Count

AIMTo observe the levels of interleukin-12 (IL-12) and platelet activating factor (PAF) in severe acute pancreatitis (SAP) in rats and the efficacy of Ginkgolide B (BN52021) in treating SAP.

METHODSWistar rats were randomly divided into 3 groups: model group (SAP), treatment group (BN) and negative control group (NC). SAP was induced by retrograde infusion of 5% sodium taurocholate into the pancreatic duct in Wistar rats. NC rats only receive abdominal incision. In groups of SAP and NC rats received the femoral vein injection of isotonic Na chloride 15 minutes after induction of SAP; in BN group,rats received BN52021 instead. After operation rats were sacrificed at 1, 6 and 12 hour for plasma IL-12 and PAF determined with ELISA.

RESULTSAn increase of IL-12 in group BN was observed VS group SAP or group NC at 1 h stage (p = 0.011, P < 0.01). At 6 h or 12 h stage,an increase of IL-12 in group SAP was observed VS group NC (P < 0.01, P < 0.05). The plasma level of PAF in group SAP or group BN was increased significantly at 1 h time stage VS group NC (P < 0.001). At 6 h or 12 h stage, a decrease of PAF in group BN or group NC was observed VS group SAP (P < 0.05, P < 0.01).

CONCLUSIONIt confirmed that the plasma level of cytokine IL-12 in SAP group was decreased significantly in early stage and it witnessed a remarkable increase of cytokine PAF. The plasma level of IL-12 was increased in early stage but PAF was decreased in rats treatment by BN52021 which inhibited the development of SAP.

Acute Disease ; Animals ; Ginkgolides ; pharmacology ; Interleukin-12 ; blood ; Lactones ; pharmacology ; Male ; Pancreatitis ; blood ; Platelet Activating Factor ; metabolism ; Rats ; Rats, Wistar

Animals ; Diet ; Enterocolitis, Necrotizing ; etiology ; metabolism ; Humans ; Infant, Newborn ; NF-kappa B ; physiology ; Platelet Activating Factor ; chemistry ; metabolism ; Risk Factors ; Tumor Necrosis Factor-alpha ; physiology