Pregnancy success rate and response to heparins and/or aspirin differ in women with antiphospholipid antibodies according to their Global AntiphosPholipid Syndrome Score.

BACKGROUND: The current treatment to prevent pregnancy morbidity (PM) associated with antiphospholipid antibodies (aPL) is based on the use of low dose aspirin and low molecular weight heparin (henceforth defined as standard of care (SoC) treatment). Despite the SoC, up to 30% of women with aPL continue to have pregnancy complications. The global antiphospholipid syndrome (APS) score (GAPSS) is a tool to quantify the risk for the aPL-related clinical manifestations. In this study, we investigated the individual clinical response to SoC in women with aPL after stratifying them according to their GAPSS. METHODS: One-hundred-fourty-three women (352 pregnancies) with aPL ever pregnant treated with SoC therapy were included. The patients GAPSS was then grouped according to the patients' GAPSS into low risk (< 6), medium risk (6-11), and high risk (≥12). RESULTS: The live birth rate was 70.5% (248 out of the 352 pregnancies), 45 patients (31%) experienced at least one event of PM, defined as early or late. Patients were stratified according to GAPSS values, in order to identify a low risk group (GAPSS <6, n = 72), a medium risk group (GAPSS 6-11, n = 66) and a high risk group (GAPSS ≥12, n = 5). When considering patients who ever experienced any PM while treated with SoC, all patients in the high risk group experienced PM, while patients in the medium group had a significant higher rate of PM when compared to the low risk group [29 (43.9%) patients V.s. 11 (15.3%), respectively; p < 0.001]. When analysing the number of pregnancies in the three groups, patients in the high risk group had significantly lower live birth rates, when compared to the other groups [11 (40.7%) live births vs. 100 (62.1%) and 137 (82.5%), respectively; p < 0.05]. Furthermore, patients with medium risk group also had significantly lower live birth rates, when compared to the lower risk group (p < 0.001). CONCLUSIONS: GAPSS might be a valuable tool for to identify patients with a higher likelihood of response to SoC.

Synthesis of partially modified retro-inverso substance P analogues and their biological activity.

Partial retro-inverso modification of a single peptide bond was applied to pGlu-Phe-Phe-Gly-Leu-Met-NH2 (I), a C-terminal hexapeptide analogue of the neuropeptide substance P. Two analogues with reversed peptide bonds, between the pGlu-Phe and Phe-Gly residues, were prepared, purified and characterized. The analogue gpGlu-(RS)-mPhe-Phe-Gly-Leu-Met-NH2 (II) was devoid of either agonistic or antagonistic activity. The second pseudopeptide analogue, i.e., pGlu-Phe-gPhe-mGly-Leu-Met-NH2 (III), was found to be a full agonist with 22% of the potency of I in the guinea pig ileum assay.

Desensitization of substance P-induced K+ release in rat parotid.

Challenge of rat parotid slices with substance P or its analogs, at concentrations which cause less than maximal response resulted in the transient release of K+ into the medium. Reuptake of the released K+ into the cell was accompanied by a parallel decrease in the biologically active concentration of the peptide in the medium, indicating that at low concentrations inactivation of the peptide is a mechanism for termination of the substance P response. At concentrations of substance P and its analogs which are higher than needed for a maximal response, a second mechanism for the termination of the response enters into play, resulting in desensitization of the response to substance P. Desensitization was specific for substance P and was not influenced by activation of the cholinergic or alpha-adrenoceptors. Inactivation of the peptide by proteolytic breakdown does not take part in the development of desensitization to substance P.

Metabolically stable analogues of substance P: persistent action of partially modified retro-inverso analogues of substance P on rat parotid and hypothalamic slices.

In a search for metabolically stable analogues of substance P (SP) the hexapeptide [pGlu6]SP-(6-11) was modified by reversal of the direction of a single amide bond. This novel peptide modification reverses the direction of the amide bonds at the peptide backbone but attempt to retain the topology of the amino acid side-chains at the peptide surface. The partial retro-inverso modification was successfully applied in a previous study for enkephalin analogues which were found to have potent and protracted morphinomimetic activity both in vivo and in vitro. The partially modified retro-inverso analogues: [pGlu6 psi(NH-CO)(RS)-Phe7]SP-(6-11) (analogue II) and [pGlu6,Phe8 psi(NH-CO)Gly9]SP-(6-11) (analogue III) were tested on guinea-pig ileum and for K+ release from rat parotid slices. Metabolic stability of the analogues was measured by their ability to produce persistent K+ release from parotid slices, their half life time (t1/2) in the rat parotid and hypothalamic slice systems and their resistance to proteolytic cleavage by chymotrypsin, pepsin, papain and pronase. Analogue II was devoid of biological activity and was slowly degraded in the parotid system and by several proteases. Analogue II was a full agonist of the SP-P receptor with a potency of 22 and 15% of the parent compound I, in the guinea-pig ileum and parotid slice system respectively. Pretreatment of the guinea-pig ileum with atropine (0.3 microM) had no effect on the potency of analogue III. On the other hand, when tested on rat vas deferens (an SP-E system), analogue III was about 20-fold more potent than the parent compound I.(ABSTRACT TRUNCATED AT 250 WORDS)