2-AMINOETHYLDIPHENYLBORINATE MODIFIES THE PULMONARY CIRCULATION IN PULMONARY HYPERTENSIVE NEWBORN LAMBS WITH PARTIAL GESTATION AT HIGH ALTITUDE

Calcium signaling through store operated channels (SOC) is involved in hypoxic pulmonary hypertension. We determined whether a treatment with 2-aminoethyldiphenylborinate (2-APB), a compound with SOC blocker activity, reduces pulmonary hypertension and vascular remodeling. Twelve newborn lambs exposed to perinatal chronic hypoxia were studied, 6 of them received a 2-APB treatment and the other 6 received vehicle treatment, for 10 days in both cases. Throughout this period, we recorded cardiopulmonary variables and on day 11 we evaluated the response to an acute hypoxic challenge. Additionally, we assessed the vasoconstrictor and vasodilator function in isolated pulmonary arteries as well as their remodeling in lung slices. 2-APB reduced pulmonary arterial pressure at the third and tenth days, cardiac output between the fourth and eighth days, and pulmonary vascular resistance at the tenth day of treatment. The pulmonary vasoconstrictor response to acute hypoxia was reduced by the end of treatment. 2-APB also decreased maximal vasoconstrictor response to the thromboxane mimetic U46619 and endothelin-1 and increased maximal relaxation to 8-Br-cGMP. The maximal relaxation and potency to phosphodiesterase-5 and Rho-kinase inhibition with sildenafil and fasudil respectively, were also increased. Finally, 2-APB reduced the medial and adventitial layers' thickness, the expression of α-actin and the percentage of Ki67+ nuclei of small pulmonary arteries. Taken together, our results indicate that 2-APB reduces pulmonary hypertension, vasoconstrictor responses and pathological remodeling in pulmonary hypertensive lambs. We conclude that SOC targeting may be a useful strategy for the treatment of neonatal pulmonary hypertension, however, further testing of specific blockers is needed.

Store-operated channels in the pulmonary circulation of high- and low-altitude neonatal lambs

We determined whether store-operated channels (SOC) are involved in neonatal pulmonary artery function under conditions of acute and chronic hypoxia, using newborn sheep gestated and born either at high altitude (HA, 3,600 m) or low altitude (LA, 520 m). Cardiopulmonary variables were recorded in vivo, with and without SOC blockade by 2-aminoethyldiphenylborinate (2-APB), during basal or acute hypoxic conditions. 2-APB did not have effects on basal mean pulmonary arterial pressure (mPAP), cardiac output, systemic arterial blood pressure, or systemic vascular resistance in both groups of neonates. During acute hypoxia 2-APB reduced mPAP and pulmonary vascular resistance in LA and HA, but this reduction was greater in HA. In addition, isolated pulmonary arteries mounted in a wire myograph were assessed for vascular reactivity. HA arteries showed a greater relaxation and sensitivity to SOC blockers than LA arteries. The pulmonary expression of two SOC-forming subunits, TRPC4 and STIM1, was upregulated in HA. Taken together, our results show that SOC contribute to hypoxic pulmonary vasoconstriction in newborn sheep and that SOC are upregulated by chronic hypoxia. Therefore, SOC may contribute to the development of neonatal pulmonary hypertension. We propose SOC channels could be potential targets to treat neonatal pulmonary hypertension.

Efficacy of ursodeoxycholic acid in treating intrahepatic cholestasis of pregnancy: a meta-analysis

BACKGROUND & AIMS

We performed a meta-analysis to evaluate the effects of ursodeoxycholic acid (UDCA) on pruritus, liver test results, and outcomes of babies born to women with intrahepatic cholestasis of pregnancy (ICP).

METHODS

We performed a systematic review of 9 published, randomized controlled trials (3 double blinded) that compared the effects of UDCA to other drugs, placebo, or no specific treatment (controls) in patients with ICP. We analyzed data from 454 patients: 207 received only UDCA, 70 received only placebo, 42 received cholestyramine, 36 received dexamethasone for 1 week and then placebo for 2 weeks, 65 received S-adenosyl-methionine, and 34 received no specific treatment. To achieve consistency among end points, a standard questionnaire was sent to all corresponding authors. For each end point, we performed pooled analysis that compared the effects of UDCA with those of all controls and UDCA with those of placebos.

RESULTS

In pooled analyses that compared UDCA with all controls, UDCA was associated with total resolution of pruritus (odds ratio [OR], 0.23; 95% confidence interval [CI], 0.07-0.74; P < .01), reduced pruritis (OR, 0.27; 95% CI, 0.13-0.55; P < .0001), normalization of serum levels of alanine aminotransferase (ALT) (OR, 0.23; 95% CI, 0.10-0.50; P < .001), decreased serum level of ALT (OR, 0.24; 95% CI, 0.11-0.52; P < .0001), reduced serum levels of bile acids (OR, 0.37; 95% CI, 0.19-0.75; P < .001), fewer premature births (OR, 0.44; 95% CI, 0.24-0.79; P < .01), reduced fetal distress (OR, 0.46; 95% CI, 0.25-0.86; P < .01), less frequent respiratory distress syndrome (OR, 0.30; 95% CI, 0.12-0.74; P < .01), and fewer neonates in the intensive care unit (OR, 0.49; 95% CI, 0.25-0.98; P = .046). In pooled analyses that compared the effects of UDCA with placebo, UDCA reduced pruritus (OR, 0.21; 95% CI, 0.07-0.62; P < .01), normalized (OR, 0.18; 95% CI, 0.06-0.52; P < .001) or decreased serum levels of ALT (OR, 0.12; 95% CI, 0.05-0.31; P < .0001), and reduced serum levels of bile acids (OR, 0.30; 95% CI, 0.12-0.73; P < .01).

CONCLUSIONS

Based on a meta-analysis, UDCA is effective in reducing pruritus and improving liver test results in patients with ICP; UDCA therapy might also benefit fetal outcomes.

Therapeutic effect of an altered peptide ligand derived from heat-shock protein 60 by suppressing of inflammatory cytokines secretion in two animal models of rheumatoid arthritis

Rheumatoid arthritis is a systemic autoimmune disease mediated by T cells. Productive engagement of T cell receptors by major histocompatibility complex-peptide leads to proliferation, differentiation and the definition of effector functions. Altered peptide ligands (APL) generated by amino acid substitutions in the antigenic peptide have diverse effects on T cell response. We predicted a novel T cell epitope from human heat-shock protein 60, an autoantigen involved in the pathogenesis of rheumatoid arthritis. Three APLs were designed from this epitope and it was demonstrated that these peptides induce the activation of T cells through their ability to modify cell cycle phase's distribution of CD4+T cells from RA patients. Also, IL-17, TNF-α and IL-10 levels were determined in PBMC from these patients. Unlike the wild-type peptide and the other two APLs, APL2 increased the IL-10 level and suppressed IL-17 secretion in these assays. Therapeutic effect of this APL in adjuvant arthritis (AA) and collagen-induced arthritis (CIA) models was also evaluated. Clinical score, histopathology, inflammatory and regulatory cytokine concentration were monitored in the animals. APL2 efficiently inhibited the progression of AA and CIA with a significant reduction of the clinical and histopathologic score. Therapeutic effect of APL2 on CIA was similar to that obtained with MTX; the standard treatment for RA. This effect was associated with a decrease of TNF-α and IL-17 levels. These results suggest that the therapeutic effect of APL2 is mediated in part by down-regulation of inflammatory cytokines and support the potential use of APL2 as a therapeutic drug in RA patients.

GAB2 gene does not modify the risk of Alzheimer's disease in Spanish APOE 4 carriers

OBJECTIVES

The genetic basis of Alzheimer's disease (AD) is being analyzed in multiple whole genome association studies (WGAS). The GAB2 gene has been proposed as a modifying factor of APOE epsilon 4 allele in a recent case-control WGAS conducted in the US. Given the potential application of these novel results in AD diagnostics, we decided to make an independent replication to examine the GAB2 gene effect in our series.

DESIGN

We are conducting a multicenter population-based study of AD in Spain.

PARTICIPANTS

We analyzed a total of 1116 Spanish individuals. Specifically, 521 AD patients, 475 controls from the general population and 120 neurologically-normal elderly controls (NNE controls).

METHODS

We have genotyped GAB2 (rs2373115 G/T) and APOE rs429358 (SNP112)/rs7412 (SNP158) polymorphisms using real time-PCR technologies.

RESULTS

As previously reported in Spain, APOE epsilon 4 allele was strongly associated with AD in our series (OR=2.88 [95% C.I. 2.16- 3.84], p=7.38E-11). Moreover, a large effect for epsilone 4/epsilone 4 genotype was also observed (OR=14.45 [95% C.I., 3.34-125.2], p=1.8E-6). No difference between the general population and the NNE controls series were observed for APOE genotypes (P > 0.61). Next, we explored GAB2 rs2373115 SNP singlelocus association using different genetic models and comparing AD versus controls or NNE controls. No evidence of association with AD was observed for this GAB2 marker (p > 0.17). To evaluate GAB2-APOE genegene interactions, we stratified our series according to APOE genotype and case-control status, in accordance with the original studies. Again, no evidence of genetic association with AD was observed in any strata of GAB2-APOE loci pair (p > 0.34).

CONCLUSION

GAB2 rs2373115 marker does not modify the risk of Alzheimer's disease in Spanish APOE epsilon 4 carriers.

Thrombosis risk modification in transgenic mice containing the human fibrinogen thrombin-binding gamma' chain sequence

BACKGROUND AND OBJECTIVES

Thrombin binding activity in murine fibrin (Antithrombin I) is restricted to its E domains inasmuch as murine gamma' chains (mu-gamma') do not bind thrombin. This feature prompted us to produce a 'gain-of-function' transgenic mouse in which the wild-type (WT) C-terminal mu-gamma' chain fibrinogen sequence had been replaced with the C-terminal thrombin-binding human gamma' sequence.

RESULTS

This procedure resulted in a murine fibrinogen species containing chimeric hu-gamma' chains (hu-gamma' fibrinogen). As anticipated, thrombin bound to WT fibrin at a single class of sites, whereas thrombin binding to heterodimeric hu-gamma'-containing fibrin was increased, reflecting its content of hu-gamma' chains. In an electrolytically-induced femoral vein thrombosis injury model, we found no differences in the volume of thrombus generation between WT and heterozygous hu-gamma' mice. However, heterozygous factor (F) V Leiden (FVL(+/-)) mice developed greater thrombus volumes than did WT controls (P < 0.01). In doubly heterozygous FVL(+/-), hu-gamma' mice, thrombus formation was reduced to WT levels (P < 0.05).

CONCLUSIONS

Murine hu-gamma' fibrinogen down-regulates venous thrombosis in the presence of another known thrombosis risk factor, FV Leiden. This finding indicates that hu-gamma' chain-containing fibrinogen is a thrombosis risk modifier.

Evidence that alpha2-antiplasmin becomes covalently ligated to plasma fibrinogen in the circulation: a new role for plasma factor XIII in fibrinolysis regulation

BACKGROUND

Plasma alpha2-antiplasmin (alpha2AP) is a rapid and effective inhibitor of the fibrinolytic enzyme plasmin. Congenital alpha2AP deficiency results in a severe hemorrhagic disorder due to accelerated fibrinolysis. It is well established that in the presence of thrombin-activated factor XIII (FXIIIa), alpha2AP becomes covalently ligated to the distal alpha chains of fibrin or fibrinogen at lysine 303 (two potential sites per molecule). Some time ago we showed that alpha2AP is covalently linked to plasma fibrinogen . That singular observation led to our hypothesis that native plasma factor XIII (FXIII), which is known to catalyze covalent cross-linking of fibrinogen in the presence of calcium ions, can also incorporate alpha2AP into fibrinogen in the circulation.

RESULTS AND CONCLUSIONS

We now provide evidence that FXIII incorporates I 125-labelled alpha2AP into the Aalpha-chain sites on fibrinogen or fibrin. We also measured the content of alpha2AP in isolated plasma fibrinogen fractions by ELISA and found that substantial amounts were present (1.2-1.8 moles per mole fibrinogen). We propose that alpha2AP becomes ligated to fibrinogen while in the circulation through the action of FXIII, and that its immediate presence in plasma fibrinogen contributes to regulation of in vivo fibrinolysis.