Pre-eclampsia affects approximately 5% of pregnancies and remains a leading cause of maternal and neonatal mortality and morbidity in the United States and the world1,2. The clinical hallmarks of this maternal disorder include hypertension, proteinuria, endothelial dysfunction and placental defects. Advanced-stage clinical symptoms include cerebral hemorrhage, renal failure and the HELLP (hemolysis, elevated liver enzymes and low platelets) syndrome. An effective treatment of pre-eclampsia is unavailable owing to the poor understanding of the pathogenesis of the disease. Numerous recent studies3–5 have shown that women with pre-eclampsia possess autoantibodies, termed AT1-AAs, that bind and activate the angiotensin II receptor type 1a (AT1 receptor). We show here that key features of pre-eclampsia, including hypertension, proteinuria, glomerular endotheliosis (a classical renal lesion of pre-eclampsia), placental abnormalities and small fetus size appeared in pregnant mice after injection with either total IgG or affinity-purified AT1-AAs from women with pre-eclampsia. These features were prevented by co-injection with losartan, an AT1 receptor antagonist, or by an antibody neutralizing seven–amino-acid epitope peptide. Thus, our studies indicate that pre-eclampsia may be a pregnancy-induced autoimmune disease in which key features of the disease result from autoantibody-induced angiotensin receptor activation. This hypothesis has obvious implications regarding pre-eclampsia screening, diagnosis and therapy.

Aim: Thalassaemia is a good candidate disease for control by preventive genetic programmes in developing countries. Accurate population frequency data are needed for planning the control of thalassaemia in the high risk Guangdong Province of southern China. Methods: In total, 13 397 consecutive samples from five geographical areas of Guangdong Province were analysed for both haematological and molecular parameters.Results: There was a high prevalence of carriers of a thalassaemia (8.53%), b thalassaemia (2.54%), and both a and b thalassaemia (0.26%). Overall, 11.07% of the population in this area were heterozygous carriers of a and b thalassaemia. The mutation spectrum of a and b thalassaemia and its constitution were fully described in this area. This study reports the true prevalence of silent a thalassaemia in the southern China population for the first time. In addition, two novel mutations that give rise to a thalassaemia, one deletion resulting in b thalassaemia, and a rare deletion (22 THAI allele) previously unreported in mainland China were detected. The frequency of the most common mutation, the Southeast Asian type of deletion (22 SEA , accounting for 48.54% of all a thalassaemias) was similar to the total of two a + thalassaemia deletions (2a 3.7 and 2a 4.2 , accounting for 47.49% of a thalassaemia). Conclusion: Both a and b thalassaemia are widely distributed in Guangdong Province of China. The knowledge gained in this study will enable the projected number of pregnancies at risk to be estimated and a screening strategy for control of thalassaemia to be designed in this area.

Priapism, abnormally prolonged penile erection in the absence of sexual excitation, is associated with ischemia-mediated erectile tissue damage and subsequent erectile dysfunction. It is common among males with sickle cell disease (SCD), and SCD transgenic mice are an accepted model of the disorder. Current strategies to manage priapism suffer from a poor fundamental understanding of the molecular mechanisms underlying the disorder. Here we report that mice lacking adenosine deaminase (ADA), an enzyme necessary for the breakdown of adenosine, displayed unexpected priapic activity. ADA enzyme therapy successfully corrected the priapic activity both in vivo and in vitro, suggesting that it was dependent on elevated adenosine levels. Further genetic and pharmacologic evidence demonstrated that A 2B adenosine receptor-mediated (A 2B R-mediated) cAMP and cGMP induction was required for elevated adenosine-induced prolonged penile erection. Finally, priapic activity in SCD transgenic mice was also caused by elevated adenosine levels and A 2B R activation. Thus, we have shown that excessive adenosine accumulation in the penis contributes to priapism through increased A 2B R signaling in both Ada -/-and SCD transgenic mice. These findings provide insight regarding the molecular basis of priapism and suggest that strategies to either reduce adenosine or block A 2B R activation may prove beneficial in the treatment of this disorder.

Hypoxia can act as an initial trigger to induce erythrocyte sickling and eventual end organ damage in sickle cell disease (SCD). Many factors and metabolites are altered in response to hypoxia and may contribute to the pathogenesis of the disease. Using metabolomic profiling, we found that the steady-state concentration of adenosine in the blood was elevated in a transgenic mouse model of SCD. Adenosine concentrations were similarly elevated in the blood of humans with SCD. Increased adenosine levels promoted sickling, hemolysis and damage to multiple tissues in SCD transgenic mice and promoted sickling of human erythrocytes. Using biochemical, genetic and pharmacological approaches, we showed that adenosine A2B receptor (A2BR)-mediated induction of 2,3-diphosphoglycerate, an erythrocyte-specific metabolite that decreases the oxygen binding affinity of hemoglobin, underlies the induction of erythrocyte sickling by excess adenosine both in cultured human red blood cells and in SCD transgenic mice. Thus, excessive adenosine signaling through the A2BR has a pathological role in SCD. These findings may provide new therapeutic possibilities for this disease.

During normal pregnancy, the renin-angiotensin system (RAS) plays a vitally important role in salt balance and subsequent well-being of mother and fetus. In this balance, one must consider not only the classical renal RAS but also that of the uteroplacental unit, where both maternal and fetal tissues contribute to the signaling cascade. Many studies have shown that in normal pregnancy there is an increase in almost all of the components of the RAS. In derangements of pregnancy this delicate equilibrium can become unbalanced. Preeclampsia is one such case. It is a disorder of pregnancy characterized by hypertension, proteinuria and placental abnormalities associated with shallow trophoblast invasion and impaired spiral artery remodeling. Despite being a leading cause of maternal death and a major contributor to maternal and perinatal morbidity, the mechanisms responsible for the pathogenesis of preeclampsia are poorly understood. Immunological mechanisms and the RAS have been long considered to be involved in the development of preeclampsia. Numerous recent studies demonstrate the presence of the angiotensin II type I receptor agonistic autoantibody (AT1-AA). This autoantibody can induce many key features of the disorder and upregulate molecules involved in the pathogenesis of preeclampsia. Here we review the functional role of the RAS during pregnancy and the impact of AT1-AA on preeclampsia.

Sphingosine-1-phosphate (S1P) is a bioactive signalling lipid highly enriched in mature erythrocytes, with unknown functions pertaining to erythrocyte physiology. Here by employing nonbiased high-throughput metabolomic profiling, we show that erythrocyte S1P levels rapidly increase in 21 healthy lowland volunteers at 5,260 m altitude on day 1 and continue increasing to 16 days with concurrently elevated erythrocyte sphingonisne kinase 1 (Sphk1) activity and haemoglobin (Hb) oxygen (O2) release capacity. Mouse genetic studies show that elevated erythrocyte Sphk1-induced S1P protects against tissue hypoxia by inducing O2 release. Mechanistically, we show that intracellular S1P promotes deoxygenated Hb anchoring to the membrane, enhances the release of membrane-bound glycolytic enzymes to the cytosol, induces glycolysis and thus the production of 2,3-bisphosphoglycerate (2,3-BPG), an erythrocyte-specific glycolytic intermediate, which facilitates O2 release. Altogether, we reveal S1P as an intracellular hypoxia-responsive biolipid promoting erythrocyte glycolysis, O2 delivery and thus new therapeutic opportunities to counteract tissue hypoxia.

Hypoxanthine catabolism in vivo is potentially dangerous as it fuels production of urate and, most importantly, hydrogen peroxide. However, it is unclear whether accumulation of intracellular and supernatant hypoxanthine in stored red blood cell units is clinically relevant for transfused recipients. Leukoreduced red blood cells from glucose-6-phosphate dehydrogenase-normal or -deficient human volunteers were stored in AS-3 under normoxic, hyperoxic, or hypoxic conditions (with oxygen saturation ranging from <3% to >95%). Red blood cells from healthy human volunteers were also collected at sea level or after 1–7 days at high altitude (>5000 m). Finally, C57BL/6J mouse red blood cells were incubated in vitro with 13C1-aspartate or 13C5-adenosine under normoxic or hypoxic conditions, with or without deoxycoformycin, a purine deaminase inhibitor. Metabolomics analyses were performed on human and mouse red blood cells stored for up to 42 or 14 days, respectively, and correlated with 24 h post-transfusion red blood cell recovery. Hypoxanthine increased in stored red blood cell units as a function of oxygen levels. Stored red blood cells from human glucose-6-phosphate dehydrogenase-deficient donors had higher levels of deaminated purines. Hypoxia in vitro and in vivo decreased purine oxidation and enhanced purine salvage reactions in human and mouse red blood cells, which was partly explained by decreased adenosine monophosphate deaminase activity. In addition, hypoxanthine levels negatively correlated with post-transfusion red blood cell recovery in mice and – preliminarily albeit significantly - in humans. In conclusion, hypoxanthine is an in vitro metabolic marker of the red blood cell storage lesion that negatively correlates with post-transfusion recovery in vivo. Storage-dependent hypoxanthine accumulation is ameliorated by hypoxia-induced decreases in purine deamination reaction rates.

Abstract-Preeclampsia is a pregnancy-specific hypertensive syndrome that causes substantial maternal and fetal morbidity and mortality. Recent evidence indicates that maternal endothelial dysfunction in preeclampsia results from increased soluble Fms-like tyrosine kinase-1 (sFlt-1), a circulating antiangiogenic protein. Factors responsible for excessive production of sFlt-1 in preeclampsia have not been identified. We tested the hypothesis that angiotensin II type 1 (AT 1 ) receptor activating autoantibodies, which occur in women with preeclampsia, contribute to increased production of sFlt-1. IgG from women with preeclampsia stimulates the synthesis and secretion of sFlt-1 via AT 1 receptor activation in pregnant mice, human placental villous explants, and human trophoblast cells. Using FK506 or short-interfering RNA targeted to the calcineurin catalytic subunit mRNA, we determined that calcineurin/nuclear factor of activated T-cells signaling functions downstream of the AT 1 receptor to induce sFlt-1 synthesis and secretion by AT 1 -receptor activating autoantibodies. AT 1 -receptor activating autoantibody-induced sFlt-1 secretion resulted in inhibition of endothelial cell migration and capillary tube formation in vitro. Overall, our studies demonstrate that an autoantibody from women with preeclampsia induces sFlt-1 production via angiotensin receptor activation and downstream calcineurin/nuclear factor of activated T-cells signaling. These autoantibodies represent potentially important targets for diagnosis and therapeutic intervention. Key Words: preeclampsia Ⅲ renin-angiotensin system Ⅲ angiotensin receptor Ⅲ autoantibody Ⅲ angiogenesis Ⅲ cell signaling P reeclampsia is a pregnancy-specific syndrome of hypertension and proteinuria, resulting in substantial maternal and neonatal morbidity and mortality. 1 Although the underlying pathogenic mechanisms of the disorder are not well understood, preeclampsia is largely believed to be associated with uteroplacental ischemia and maternal endothelial cell dysfunction. [2][3][4][5] It is a widely held view that "toxic factors" secreted by the placenta into the maternal circulation are responsible for systemic endothelial dysfunction, hypertension, and multiorgan damage. 6 -11 Recent research has shown that soluble Fms-like tyrosine kinase-1 (sFlt-1) is 1 of the key "toxic factors" released by the placenta into the maternal circulation and that it contributes to the hypertension, proteinuria, and endothelial cell dysfunction associated with this disorder. 12-15 sFlt-1 is a soluble form of the vascular endothelial growth factor receptor that lacks the cytoplasmic tail and transmembrane domain but retains the extracellular ligand-binding domain (sFlt-1 is also named sVEGFR1).Therefore, sFlt-1 prevents circulating vascular endothelial growth factor and placental growth factor interactions with their proangiogenic receptors and functions as an antiangiogenic factor. The level of sFlt-1 in the plasma of women with preeclampsia is elevated in comparison with that in women...