Indoleamine 2,3-dioxygenase 1 (Ido1) is involved in the control of mouse caput epididymis immune environment

The epididymis maintains a state of immune tolerance towards spermatozoa while also protecting them and itself against infection and acute inflammation. The immunosuppressive enzyme indoleamine 2,3-dioxygenase 1 (Ido1) participates in this delicate local equilibrium. Using the mouse Ido1−/− model, we show here that the absence of IDO1 expression leads in the epididymis but not in serum to (1) an increase in the inflammatory state as evidenced by changes in the content of cytokines and chemokines, (2) the engagement of a Th1-driven inflammatory response as evidenced by changes in the Th17/Treg as well as Th1/Th2 equilibria, as well as (3) differences in the content of lipid intermediates classically involved in inflammation. Despite this more pronounced inflammatory state, Ido1−/− animals succeed in preserving the local epididymal immune situation due to the activation of compensatory mechanisms that are discussed

Enzymatic Assays for the Diagnosis of Bradykinin-Dependent Angioedema

<div><p>Background</p><p>The kinins (primarily bradykinin, BK) represent the mediators responsible for local increase of vascular permeability in hereditary angioedema (HAE), HAE I-II associated with alterations of the <i>SERPING1</i> gene and HAE with normal C1-Inhibitor function (HAE-nC1INH). Besides C1-Inhibitor function and concentration, no biological assay of kinin metabolism is actually available to help physicians for the diagnosis of angioedema (AE). We describe enzymatic tests on the plasma for diagnosis of BK-dependent AE.</p><p>Methods</p><p>The plasma amidase assays are performed using the Pro-Phe-Arg-<i>p</i>-nitroanilide peptide substrate to evaluate the spontaneous amidase activity and the proenzyme activation. We analyzed data of 872 patients presenting with BK-dependent AE or BK-unrelated diseases, compared to 303 controls. Anti-high MW kininogen (HK) immunoblot was achieved to confirm HK cleavage in exemplary samples. Reproducibility, repeatability, limit of blank, limit of detection, precision, linearity and receiver operating characteristics (ROC) were used to calculate the diagnostic performance of the assays.</p><p>Results</p><p>Spontaneous amidase activity was significantly increased in all BK-dependent AE, associated with the acute phase of disease in HAE-nC1INH, but preserved in BK-unrelated disorders. The increase of the amidase activity was associated to HK proteolysis, indicating its relevance to identify kininogenase activity. The oestrogens, known for precipitating AE episodes, were found as triggers of enzymatic activity. Calculations from ROC curves gave the optimum diagnostic cut-off for women (9.3 nmol⋅min⁻¹⋅mL⁻¹, area under curve [AUC] 92.1%, sensitivity 80.0%, and specificity 90.1%) and for men (6.6 nmol·min⁻¹⋅mL⁻¹, AUC 91.0%, sensitivity 87.0% and specificity 81.2%).</p><p>Conclusion</p><p>The amidase assay represents a diagnostic tool to help physicians in the decision to distinguish between BK-related and –unrelated AE.</p></div

Diagnostic outcomes for spontaneous amidase assay in the diagnosis of BK-dependent AE.

<p>(A) Receiving operator characteristic (ROC) curves of male and female individuals. (B) Diagnostic values for spontaneous amidase activity. Data were generated from women (n = 678: HAE I-II, n = 155; HAE-nC1INH carriers of the <i>F12</i> mutation, n = 53; HAE-nC1INH non-carriers, n = 186; AAE, n = 12; asymptomatic HAE-I, n = 5; asymptomatic HAE-nC1INH non-carriers of the <i>F12</i> mutation, n = 63; IgE-mediated AE, n = 50; HD-AE, n = 39; chronic inflammatory disorders, n = 14; healthy donors, n = 101) and from men (n = 394: HAE I-II, n = 95; HAE-nC1INH carriers of the <i>F12</i> T928K mutation, n = 7; HAE-nC1INH non-carriers, n = 82; AAE, n = 8; asymptomatic HAE-I, n = 2; asymptomatic HAE-nC1INH non-carriers of the <i>F12</i> mutation, n = 55; IgE-mediated AE, n = 14; HD-AE, n = 23; chronic inflammatory disorders, n = 9; healthy donors, n = 99).</p

HK cleavage demonstrated by anti-HK L chain immunoblot.

<p>Plasma samples were collected from a healthy control, an IgE-dependent angioedema individual (IgE-AE) and patients presenting with HAE I, HAE-nC1INH non-carrier of <i>F12</i> mutation (during an attack and the remission period), and with HAE-nC1INH non-carrier of <i>F12</i> mutation during OC (+ OC) and after stopping OC pill (– OC) intakes. The values of the corresponding spontaneous amidase activities are indicated.</p

Oestrogen intake and spontaneous amidase activity.

<p>(A) Plasma spontaneous amidase activities in female blood donors not taking oestrogen combined contraceptive pill (Healthy – OC, n = 37), taking OC (Healthy+OC, n = 49), HAE-nC1INH women with OC (HAE-nC1INH+OC, n = 93) or during pregnancy (HAE-nC1INH Pregnancy, n = 40). ns, not significant; ***, <i>P</i><0.0001 <i>vs</i> Healthy – OC. (B) Plasma spontaneous amidase activities in HAE-nC1INH women during OC contraception (+ OC) and after stopping OC pill (– OC); n = 55. ***, <i>P</i><0.0001 <i>vs</i> Healthy – OC. The horizontal bars show the median values.</p