Mirjana Bećarević

The IgG and IgM isotypes of anti-annexin A5 antibodies: relevance for primary antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease that is characterized by the presence of thromboses and/or recurrent pregnancy losses (RPL). The persistent presence of antiphospholipid antibodies (aPL Abs): IgG and/or IgM isotypes of the anticardiolipin and/or anti-β2 glycoprotein I antibodies and lupus anticoagulant is mandatory for the laboratory diagnosis of APS. Due to the heating debate on the relevance of the IgM isotype of aPL Abs as a laboratory criterion defining APS, the focus of this article was to analyze whether both the IgG and IgM isotype of anti-annexin A5 Abs have equal relevance for clinical and serological features of patients with primary APS (PAPS). The IgG isotype of anti-annexin A5 Abs is associated with RPL in PAPS patients, although it is not elucidated whether these Abs are the cause or the consequence of RPL in PAPS. No data that could substantiate the association of the IgG and/or the IgM isotypes of anti-annexin A5 Abs with the presence of arterial and/or venous thromboses and/or their main complications in PAPS is available so far. However, the presence of clinical manifestations of the PAPS is increasing with the multiple positivity for aPL Abs and the IgM isotype of anti-annexin A5 Abs. The importance of the IgM isotype of anti-annexin A5 Abs in PAPS needs further elucidation due to the facts that majority of the available articles did not differentiate between both isotypes or only investigated the IgG isotype of anti-annexin A5 Abs.

Adiponectin, Non-Esterified Fatty Acids and Antiphospholipid Antibodies in Type II Diabetes Mellitus

Adiponectin, Non-Esterified Fatty Acids and Antiphospholipid Antibodies in Type II Diabetes Mellitus The importance of the association of antiphospholipid antibodies (aPL Abs) with the features of type II diabetes mellitus has not yet been elucidated. The aim of this work was to investigate the association of aPL Abs with adiponectin and non-esterified fatty acids (NEFA) in type II diabetes mellitus patients without micro and/or macrovascular complications, and to analyze the differences between the male and female patients with regard to the abovementioned parameters. Male patients with type II diabetes mellitus showed a positive correlation between NEFA concentrations and anti-oxLDL antibodies (r=0.334, p=0.019). A weak, but statistically significant correlation between adiponectin concentrations and the IgM isotype of anti-annexin A5 antibodies was found in type II diabetes mellitus patients (r=0.285, p=0.011). The presence of a positive correlation between NEFA and anti-oxLDL antibodies might be useful in the detection of patients with premature atherosclerosis in type II diabetes mellitus patients without any micro and/or macrovascular complications among type II diabetes mellitus patients. Adiponektin, Neesterifikovane Masne Kiseline i Antifosfolipidna Antitela u Dijabetesu Tip II Značaj povezanosti antifosfolipidnih antitela (aPL Abs) sa odlikama dijabetesa tip II još nije razjašnjen. Cilj rada bilo je ispitivanje povezanosti aPL Abs sa adiponektinom i neesterifikovanim masnim kiselinama (NEFA) kod pacijenata sa dijabetesom tip II bez mikro i/ili makrovaskularnih komplikacija i analiziranje razlika u navedenim parametrima između muškaraca i žena sa dijabetesom. Kod muškaraca sa dijabetesom tip II pokazana je pozitivna korelacija između koncentracija NEFA i anti-oxLDL antitela (r=0,334, p=0,019). Slaba ali statistički značajna korelacija između koncentracija adiponektina i IgM izotipa anti-aneksin A5 antitela pronađena je kod pacijenata sa dijabetesom tip II (r=0,285, p=0,011). Pozitivna korelacija između NEFA i anti-oxLDL antitela mogla bi da bude korisna u detekciji pacijenata sa prevremenom aterosklerozom u dijabetesu tip II bez mikro i/ili makrovaskularnih komplikacija.

High-sensitivity C-reactive protein: Discriminator between patients with primary and secondary antiphospholipid syndrome

OBJECTIVE It is not clear whether primary (PAPS) or secondary (SAPS) antiphospholipid syndrome represent distinct clinical entities or whether they are the same syndrome seen against different background. Therefore we examined whether hsCRP, C3, C4 and anti-oxLDL antibodies could discriminate between PAPS and SAPS patients. DESIGN AND METHODS This study included: 44 patients with PAPS and 20 patients with SAPS associated with SLE and 37 control subjects. Antibody levels were estimated by ELISA, while C3, C4 and hsCRP were determined by immunonephelometric method. RESULTS SAPS patients had significantly elevated hsCRP (mg/L) concentrations in comparison to PAPS patients (8.00 (7.00-15.00) vs. 2.27 (0.68-6.89), Mann-Whitney, p=0.000). CONCLUSION Measurement of hsCRP should be mandatory in the follow-up of SAPS patients in order to identify a subset with a high cardiovascular risk and in PAPS in order to identify patients with a risk of evolving to SLE.

Detrimental roles of TNF-alpha in the antiphospholipid syndrome and de novo synthesis of antiphospholipid antibodies induced by biopharmaceuticals against TNF-alpha

Antiphospholipid syndrome (APS) is an autoimmune disease that is characterized by arterial and/or venous thrombosis and/or recurrent pregnancy losses. Obstetric APS (OAPS) is considered as a distinct entity from vascular APS (VAPS). In the absence of any additional disease, APS is designated as primary (PAPS), while the term secondary APS (SAPS) is used when other diseases are associated. Catastrophic APS (CAPS) is characterized by the rapid development of multiple thrombosis in various vital organs. The presence of antiphospholipid antibodies (aPL Abs) is considered as a laboratory criterion for APS diagnosis. aPL Abs cause an increase in systemic and decidual TNF-alpha levels in experimental model of APS (eAPS), while paradoxically, administration of TNF-alpha blockers has been associated with de novo synthesis of aPL Abs in patients with various autoimmune diseases. While eAPS provides evidence for the fact that application of TNF-alpha blockers has beneficial effects, lack of randomized prospective studies is the main obstacle for consideration of TNF-alpha blockers administration as a therapeutic option not for all, but at least for selected cases of APS patients despite compelling evidence for detrimental roles of TNF-alpha for both VASP and OAPS. This article represents a review of previously published reports on detrimental roles of TNF-alpha in APS, reports on the application of anti-TNF-alpha agents in eAPS and articles that reported de novo synthesis of aPL Abs induced by biopharmaceuticals against TNF-alpha.

TNF-alpha and annexin A2: inflammation in thrombotic primary antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is characterized by thromboses and/or pregnancy losses. Laboratory criterion for the diagnosis of APS is the presence of antiphospholipid antibodies (anticardiolipin, anti-beta2-glycoprotein I (aβ2gpI) and lupus anticoagulant). On the one hand, the latest classification criteria for the diagnosis of APS emphasized that thrombotic manifestations of the syndrome should be without any signs of an inflammatory process, while on the other hand, some recent reports have suggested that APS is a “pro-inflammatory state.” This article is focused on the importance of TNF-alpha and annexin A2 (anxA2) for patients with vascular (thrombotic) manifestations of the primary APS. The classic antithrombotic and antiplatelet therapy does not protect APS patients from the development of recurrent thrombosis. Therefore, an urgent need for the introduction of new therapeutic approaches in the treatment of APS patients is obvious. This review provides a rationale for the necessity for the use of immunomodulatory medications that could interfere with β2gpI binding to its receptor(s), such as anxA2, and/or inhibit TNF-alpha activity.

Potential Markers of Arterial and/or Venous Thromboses and their Complications in Primary Antiphospholipid Syndrome

Potential Markers of Arterial and/or Venous Thromboses and their Complications in Primary Antiphospholipid Syndrome Antiphospholipid syndrome is characterized by venous or arterial thromboses and/or recurrent abortions accompanied by antiphospholipid antibodies and it can be primary (PAPS) or secondary (SAPS) to another disease. Arterial thromboses are less common than venous and most frequently they manifest as ischemia or infarction. Venous thromboses are usually multiple and bilateral and the most common complication of venous thromboses are pulmonary emboli. Considering that laboratory diagnosis of PAPS is currently based on persistently positive aCL, aβ2gpl and/or LA tests, and that neither one of those tests can discriminate between PAPS patients with arterial or venous thromboses or their complications, the aim of this study was to investigate the diagnostical significance of the determination of apo(a), oxLDL, anti-oxLDL antibodies, antianxA5 antibodies, hsCRP, C3 and C4 complement components and HPT for discrimination between PAPS patients with diverse clinical manifestations. Considering that elevated oxLDL and anti-oxLDL antibodies concentrations were found in PAPS patients, and also in subgroups of PAPS patients with MI or PE, it can be concluded that those parameters represent additional risk factors which together with other factors may lead to thromboses and their complications in PAPS. Regarding the fact that C3 and C4 concentrations were decreased in PAPS patients and that a positive correlation was found between hsCRP and C3 concentrations, this finding could indicate potential roles of these parameters as markers of atherosclerosis, which represents the leading cause of morbidity and mortality. HPT and apo(a) concentrations are not independent risk factors for MI in PAPS because lower levels were found in those patients in comparison to MI survivors without PAPS. No significant correlation of anti-anxA5 antibodies and the presence of arterial or venous thromboses or their complications was found, but increased concentrations of the IgG isotype of those antibodies could be a marker for recurrent abortions in PAPS, although this finding should be further investigated on a larger number of patients with this clinical finding. Determination of hsCRP in PAPS patients could not be an adequate parameter which would provide discrimination between patients with increased risk for development and/or recurrence of venous and/or arterial thromboses, nor for their complications, because no statistically significant difference in concentrations of this parameter was found among PAPS, IM, PE and SLE patients who were included in this study. Potencijalni Pokazatelji Arterijskih I/Ili Venskih Tromboza I Njihovih Komplikacija U Primarnom Antifosfolipidnom Sindromu Antifosfolipidni sindrom karakterišu venske ili arterijske tromboze i/ili spontani pobačaji uz prisustvo antifosfolipidnih antitela, a može biti primarni (PAPS) ili sekundarni (SAPS), koji je povezan sa postojanjem drugog oboljenja. Arterijske tromboze su manje uobičajene nego venske i najčešće se ispoljavaju kao ishemija ili infarkt. Venske tromboze su obično multiple i bilateralne, a njihova najčešća komplikacija su plućne embolije. Kako se laboratorijska dijagnostika PAPS trenutno zasniva na perzistentno pozitivnim aCL, aβ2gpl i/ili LA testovima, od kojih nijedan ne može da napravi diskriminaciju između PAPS pacijenata sa arterijskim ili venskim trombozama i njihovim komplikacijama, cilj ovog istraživanja bio je da se ispita dijagnostička značajnost određivanja nivoa apo (a), oxLDL, anti-oxLDL antitela, anti-anxA5 antitela, hsCRP, C3 i C4 komponente komplementa i HPT za razlikovanje PAPS pacijenata sa različitim kliničkim manifestacijama. Na osnovu povišenih koncentracija oxLDL i anti-oxLDL antitela u pacijenata sa PAPS, kao i u podgrupama PAPS pacijenata čije su glavne kliničke manifestacije bili IM ili PE, može se zaključiti da ovi parametri predstavljaju dodatne faktore rizika koji zajedno sa drugim faktorima mogu da dovedu do tromboza i njihovih komplikacija u PAPS. Kako su koncentracije C3 i C4 komponente komplementa bile snižene u PAPS pacijenata i kako je pronađena pozitivna korelacija između koncentracija hsCRP i C3 komponente komplementa, moglo bi se ukazati na eventualnu ulogu ovih parametara kao pokazatelja ateroskleroze, koja predstavlja jedan od vodećih uzročnika morbiditeta i mortaliteta. Koncentracije HPT i apo(a) nisu nezavisan faktor rizika za infarkte miokarda u PAPS jer su dobijene niže vrednosti u poređenju sa IM pacijentima bez PAPS. Za anti-anxA5 antitela nije pronađena nikakva korelacija sa prisustvom arterijskih ili venskih tromboza, niti njihovih komplikacija, ali bi zato povišene koncentracije ovih antitela IgG klase mogle da budu pokazatelj čestih pobačaja u PAPS pacijentkinja, iako bi se ovaj nalaz morao dodatno ispitati na većem broju pacijentkinja sa ovom odlikom PAPS. Određivanje hsCRP u PAPS pacijenata ne može da bude adekvatan parametar koji bi omogućio pravljenje diskriminacije između pacijenata sa povećanim rizikom od razvoja i/ili učestalosti venskih i/ili arterijskih tromboza, kao ni njihovih najčešćih komplikacija, jer nije pronađena statistički značajna razlika u koncentracijama ovog parametra između PAPS, IM, PE i SLE pacijenata koji su obuhvaćeni ovim istraživanjem.

pKa values of hyodeoxycholic and cholic acids in the binary mixed micelles sodium-hyodeoxycholate-Tween 40 and sodium-cholate-Tween 40: Thermodynamic stability of the micelle and the cooperative hydrogen bond formation with the steroid skeleton.

Graphical abstract Figure. No Caption available. HighlightsFor bile acids HD and C pKa values increase in mixed micelles with Tween 40.Increase of &Dgr;pKa of HD and C related to pKa of free HD and C is a measure of mixed micelles stability.H‐bonds between steroids OH‐Tween 40 polyoxyethylene groups: aggregate stability.Cooperative hydrogen bond formation between HD and Tween 40. Abstract Due to a relatively small size of bile acid salts, their mixed micelles with nonionic surfactants are analysed. Of the special interests are real binary mixed micelles that are thermodynamically more stable than ideal mixed micelles. Thermodynamic stability is expressed with an excess Gibbs energy (GE) or over an interaction parameter (&bgr;ij). In this paper sodium salts of cholic (C) and hyodeoxycholic acid (HD) in their mixed micelles with Tween 40 (T40) are analysed by potentiometric titration and their pKa values are determined. Examined bile acids in mixed micelles with T40 have higher pKa values than free bile acids. The increase of &Dgr;pKa acid constant of micellary bound C and HD is in a correlation with absolute values of an interaction parameter. According to an interaction parameter and an excess Gibbs energy, mixed micelle HD–T40 are thermodynamically more stable than mixed micelles C–T40. &Dgr;pKa values are higher for mixed micelles with Tween 40 whose second building unit is HD, related to the building unit C. In both micellar systems, &Dgr;pKa increases with the rise of a molar fraction of Tween 40 in binary mixtures of surfactants with sodium salts of bile acids. This suggests that, &Dgr;pKa can be a measure of a thermodynamic stabilization of analysed binary mixed micelles as well as an interaction parameter. &Dgr;pKa values are confirmed by determination of a distribution coefficient of HD and C in systems: water phase with Tween 40 in a micellar concentration and 1‐octanol, with a change of a pH value of a water phase. Conformational analyses suggests that synergistic interactions between building units of analysed binary micelles originates from formation of hydrogen bonds between steroid OH groups and polyoxyethylene groups of the T40. Relative similarity and spatial orientation of C3 and C6 OH group allows cooperative formation of hydrogen bonds between T40 and HD – excess entropy in formation of mixed micelle. If a water solution of analysed binary mixtures of surfactants contains urea in concentration of 4 M significant decreases of an interaction parameter value happens which confirms the importance of hydrogen bonds in synergistic interactions (urea compete in hydrogen bonds).

Antibodies Against Complement Components: Relevance for the Antiphospholipid Syndrome-Biomarkers of the Disease and Biopharmaceuticals.

Purpose of ReviewLaboratory criterion for the diagnosis of antiphospholipid syndrome (APS) is the presence of antiphospholipid antibodies (aPL Abs). Complement system has a role in mediating aPL Abs-induced thrombosis in animal models. The importance of antibodies against complement components (potential biomarkers of APS) and the importance of antibodies with beneficial anti-complement effects in APS (as biopharmaceuticals) are reviewed.Recent FindingsAntibodies against complement components described in APS patients, so far, are anti-C1q and anti-factor H Abs, although anti-factor B Abs and anti-C5a Abs were described in animal models of APS. Clinical studies in APS patients are limited to a small number of case reports.SummaryStudies that would confirm potential role of Abs against complement components (as potential biomarkers of APS) are lacking. Lack of randomized clinical trials (that would provide complete data for confirmation of beneficial effects of biopharmaceuticals in complement inhibition) in APS is alarming.

Double positivity of the IgG isotype of both anticardiolipin and anti-β2gpI antibodies is associated with the highest number of vascular impairment parameters in patients with primary antiphospholipid syndrome: preliminary data

Although numerous studies investigated the association between homocysteine (Hcy), tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP) and apolipoproteins (apos) with thrombosis and/or recurrent pregnancy losses, studies that analyzed the abovementioned parameters and multiple positivity of antiphospholipid antibodies (aPL Abs) in patients with primary antiphospholipid syndrome (PAPS) are lacking. Therefore, the aim of this study was to analyze the presence of various combinations of the abovementioned parameters and their associations with clinical and/or serological features of PAPS. High-pressure liquid chromatography (HPLC) was used for determination of Hcy, while apoAI, apoB, and lipoprotein (Lp) (a) concentrations were estimated by immunonephelometry. High-sensitivity C-reactive protein (hsCRP) was measured by immunoturbidimetry. Apo (a), TNF-α, and aPL Abs were measured by ELISA. Various combinations of analyzed parameters (Hcy/CRP/TNF/apoAI/apoB/apo (a)/Lp (a)) were not associated with a single presence of either aPL Abs. Double positivity for both isotypes of anticardiolipin (aCL) Abs (IgG + IgM) was associated with the increased apoB levels. The presence of the IgG isotype of both aCL + anti-beta2 glycoprotein I (aβ2gpI) Abs was associated with the highest number of analyzed parameters (i.e., increased levels of hsCRP, Lp (a), and apo (a)). The presence of the IgG isotype of both aCL + aβ2gpI Abs was associated with the highest number of vascular impairment parameters in patients with PAPS, and this combination confers the highest risk for the recurrence of thrombotic episodes. This is the first report that analyzed the association between various combinations of vascular impairment parameters with multiple aPL Ab positivity. Our results provide a rationale for further investigations of therapeutic approaches for PAPS patients.

Antiphospholipid Antibodies and Renal Impairment Parameters in Diabetic Nephropathy Preliminary Data

Objective: Antiphospholipid antibodies (aPL Abs) represented an independent factor that was associated with the occurrence and/or progression of nephropathy in patients with antiphospholipid syndrome, but their role in diabetic nephropathy is not elucidated. Therefore, we evaluated the association of aPL Abs with the renal impairment parameters in patients with diabetic nephropathy. Methods: Concentrations of analyzed antibodies were measured by enzyme-linked immunosorbent assay. Results: Cystatin C and anticardiolipin (aCL) antibodies of the immunoglobulin (Ig) G (r = .349, P = .004) and the IgM isotype (r = .316, P = .009) were in positive correlation. The IgG isotype of the aCL Abs was in positive correlation with creatinine (r = .252, P = .038), urea (r = .241, P = .048), and uric acid (r = .271, P = .025). The concentrations of the IgG isotype of the aCL Abs were significantly different between subgroups of patients with diabetic polyneuropathy and patients without this clinical finding (Mann-Whitney, P = .033). Conclusion: This is the first report on positive correlation between aCL Abs and renal impairment parameters. Larger studies are necessary for elucidation whether this association is involved in further progression of the disease.