Properties of Plasma Clots in Adult Patients Following Fontan Procedure: Relation to Clot Permeability and Lysis Time—Multicenter Study

Objectives: thromboembolic complications are a major cause of morbidity and mortality following Fontan (FO) surgery. It is also well established that altered FO circulation results in systemic complications, including liver and endothelium damage. We sought to evaluate whether dysfunctions of these sources of hemostatic factors may result in changes of fibrin clot properties. Methods: a permeation coefficient (Ks) and clot lysis time (CLT) were assessed in 66 FO patients, aged 23.0 years [IQR 19.3–27.0], and 59 controls, aged 24.0 years [IQR 19.0–29.0]. Ks was determined using a pressure-driven system. CLT value was measured according to assay described by Pieters et al. Endothelium and liver-derived hemostatic factors along with liver function parameters were evaluated. The median time between FO operation and investigation was 20.5 years [IQR 16.3–22.0]. Results: FO patients had lower Ks (p = 0.005) and prolonged CLT (p < 0.001) compared to that of controls. Ks correlated with CLT (r = −0.28), FVIII (r = −0.30), FIX (r = −0.38), fibrinogen (r = −0.41), ALT (r = −0.25), AST (r = −0.26), GGTP (r = −0.27) and vWF antigen (r = −0.30), (all p < 0.05). CLT correlated with the time between FO operation and investigation (r = 0.29) and FIX (r = 0.25), (all p < 0.05). After adjustment for potential cofounders, TAFI antigen and GGTP were independent predictors of reduced Ks (OR 1.041 per 1% increase, 95% CI 1.009–1.081, p = 0.011 and OR 1.025 per 1 U/L increase, 95% CI 1.005–1.053, p = 0.033, respectively). Protein C and LDL cholesterol predicted prolonged CLT (OR 1.078 per 1% increase, 95% CI 1.027–1.153, p = 0.001 and OR 6.360 per 1 μmol/L increase, 95% CI 1.492–39.894, p = 0.011, respectively). Whereas elevated tPA was associated with lower risk of prolonged CLT (OR 0.550 per 1 ng/mL, 95% CI 0.314–0.854, p = 0.004). GGTP correlated positively with time between FO surgery and investigation (r = 0.25, p = 0.045) and patients with abnormal elevated GGTP activity (n = 28, 42.4%) had decreased Ks, compared to that of the others (5.9 × 10−9 cm2 vs. 6.8 × 10−9 cm2, p = 0.042). Conclusion: our study shows that cellular liver damage and endothelial injury were associated with prothrombotic clot phenotype reflected by Ks and CLT.

Shiga Toxin 2a Induces NETosis via NOX-Dependent Pathway

Shiga toxin (Stx)-producing Escherichia coli (STEC) infection is the most common cause of hemolytic uremic syndrome (HUS), one of the main causes of acute kidney injury in children. Stx plays an important role in endothelium damage and pathogenesis of STEC-HUS. However, the effects of Stx on neutrophils and neutrophil extracellular trap (NET) formation are not well understood. In this study, we investigated how Stx2a affects NET formation and NETotic pathways (NADPH or NOX-dependent and -independent) using neutrophils isolated from healthy donors and patients with STEC-HUS, during the acute and recovery phase of the disease. Stx2a dose-dependently induced NETosis in neutrophils isolated from both healthy controls and STEC-HUS patients. NETosis kinetics and mechanistic data with pathway-specific inhibitors including diphenyleneiodonium (DPI)-, ERK-, and P38-inhibitors showed that Stx2a-induced NETosis via the NOX-dependent pathway. Neutrophils from STEC-HUS patients in the acute phase showed less ROS and NETs formation compared to neutrophils of the recovery phase of the disease and in healthy controls. NETs induced by Stx2a may lead to the activation of endothelial cells, which might contribute to the manifestation of thrombotic microangiopathy in STEC-HUS.

Clinical case of thrombotic microangiopathy in obstetric practice.

Тромботическая микроангиопатия (ТМА) – клинико-морфологический синдром, в основе которого лежит повреждение эндотелия сосудов микроциркуляторного русла, вызванное разными причинами, но проявляющееся сходной клинической симптоматикой и гистологическими признаками. Одним из важнейших триггеров возникновения ТМА является беременность. Во время беременности возможно развитие вторичной ТМА – при тяжелой преэклампсии и HELLP-синдроме или после тяжелой кровопотери, осложнившейся синдромом диссеминированного внутрисосудистого свертывания крови (ДВС-синдромом). Первый клинический пример иллюстрирует роль в индукции атипичного гемолитико-уремического синдрома (аГУС) многочисленных акушерских осложнений и ДВС-синдрома, возникшего в результате своевременно некомпенсированной кровопотери. Их можно рассматривать как дополнительные комплемент-активирующие состояния. Представленное наблюдение иллюстрирует классическое течение вторичного аГУС с характерными признаками ТМА. Прекращение трансфузий свежезамороженной плазмы (СЗП) и начало таргетной комплемент-блокирующей терапии (экулизумаб) привело к значительному улучшению состояния и обратному развитию ТМА. Во втором наблюдении клинико-лабораторные признаки указывали на наличие вторичной ТМА, вызванной преэклампсией, HELLP-синдромом при отсутствии острого повреждения почек. Назначенная базовая терапия преэклампсии, а также введение СЗП и антикоагулянта позволили прервать внутрисосудистый гемолиз. Thrombotic microangiopathy (TMA) is a clinical morphological syndrome developing as a result of microvascular endothelium damage caused by various reasons but manifesting similar clinical symptoms and histological signs. Pregnancy is one of the most critical TMA triggers. Pregnancy may be accompanied with secondary TMA development in case of severe preeclampsia and HELLP-syndrome or after massive blood loss complicated with disseminated intravascular coagulation (DIC). The first clinical case demonstrates the role of multiple obstetric complications and DIC emerged as a result of failure to timely compensate blood loss in atypical haemolytic-uremic syndrome (aHUS) induction. They may be viewed as additional complement-activating conditions. The described observation illustrates classic progress of secondary aHUS with typical TMA signs. Stopping of fresh frozen plasma (FFP) transfusions and beginning of a target complement blocking therapy (eculizumab) led to significant improvement of condition and TMA involution. In the second observation clinical laboratory signs indicated secondary TMA caused by preeclampsia and HELLP-syndrome without acute renal injury. Prescribed basic therapy of preeclampsia, as well as administration of FFP and anticoagulant, allowed to interrupt intravascular hemolysis.

THROMBOSE-FIBROUS COMPLICATIONS OF SYSTEMIC ENDOTHELIUM DAMAGE AT COVID-19

The analysis of literature data and our own research of lungs tissues of the persons who died owing to COVID-19 caused fibrosis testify to participation in this pathology of a cascade of disturbances of molecular and cellular levels. Viral damage to endothelial cells causes systemic damage to the vascular glycocalyx, which loses its clotting properties and releases significant amounts of blood clotting factors. The fibrin clot formed under such conditions is characterized by resistance to fibrinolysis and locally blocks blood vessels with the systemic development of endogenous intoxication. Destabilized proteins of the latter form micro- and nano-sized aggregates with a significant content of β-folded structures. This contributes to the increase of fibrin resistance to the proteolytic action of plasmin, causes the development of fibrosis of the tissues affected in this way, and leads to the failure of the functions of the relevant organs.

"Bonded by one chain, related to one purpose": what is primary in the development of thrombotic complications in COVID-19 — mechanisms of inflammation or endothelium damage?

The ongoing COVID-19 pandemic has caused significant morbidity and mortality worldwide, as well as a profound impact on society. Among the nosologies that increase the risk of a severe course of COVID-19, coronary heart disease, chronic heart failure, cardiomyopathy. The main complications caused by coronavirus infection include thrombotic ones. Spike protein SARS-CoV-2 can interact directly with platelets and fibrin, causing blood hypercoagulation and obstructing blood flow. The presence of the spike protein in circulation leads to structural changes in fibrin, complement 3 and prothrombin, which can contribute to hypercoagulability in COVID-19 positive patients and cause a significant violation of fibrinolysis. Endothelial damage and systemic inflammation, being interrelated triggers of coagulopathy characteristic of COVID-19, trigger a cascade of reactions resulting in thrombotic complications against the background of endothelial dysfunction and hyperinflammation, which may be of clinical importance in the treatment of hypercoagulability in patients with COVID-19 (bibliography: 14 refs).

Status of corneal endothelial cells in the presence of silicone oil in the anterior chamber

To evaluate corneal endothelium damage with silicone oil (SO) presence in the anterior chamber after pars plana vitrectomy. We investigated the medical records of consecutive 54 eyes of 53 patients undergoing SO removal after pars plana vitrectomy with SO tamponade at Saitama Medical Center, Jichi Medical University, Japan. We recorded SO tamponade retention period, anterior chamber SO with gonioscope, area of SO attachment to the corneal endothelium before SO removal surgery, and the lens status. We then retrospectively investigated the correlation between SO presence in the anterior chamber and the decrease rate of corneal endothelial cell (CEC) density during SO tamponade. The average decrease rate of CEC density was 7.6 (0–38.1) %. The correlation between SO tamponade retention period and decrease rate of CEC density was high (p = 0.0001). However, there was no correlation between anterior chamber SO under gonioscope, SO attaching area, and lens status with the decrease rate of CEC density (p = 0.11, p = 0.93, p = 0.16). No correlation was observed between CEC loss and the existence of anterior chamber SO, although CEC decrease rate was relatively high after a long SO tamponade period. These findings suggest that SO presence in the anterior chamber may not directly injure CEC.

Antiphospholipid antibodies and anticoagulant therapy: capillaroscopic findings

Background Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by specific vascular and obstetric manifestations and by antiphospholipid antibodies (aPL) positivity. Microvascular damage in the course of APS and “aPL carrier” patients without symptoms is poorly investigated. Objectives This study aims to compare nailfold videocapillaroscopy (NVC) microvascular parameters in APS patients and non-symptomatic "aPL carriers" and to investigate their possible correlations with different aPL subtypes. Methods NVC was performed during standard evaluations in 18 APS patients (mean age 50 ± 13.8 years), 24 "aPL carriers" without symptoms (mean age 46.4 ± 16.4 years), and 18 control patients (CTR) (mean age 74 ± 12.5 years) taking oral anticoagulants for non-immunological indications (i.e., cardiovascular accidents). All patients were investigated for the presence of dilated capillaries, giant capillaries, microhemorrhages, capillary loss, and further non-specific/specific abnormalities (i.e., branched “bushy” capillaries, sign of neoangiogenesis) by NVC. Every alteration was also classified according to a semi-quantitative score. Lupus anticoagulant, anticardiolipin antibodies, and antibeta2 glycoprotein I antibodies were tested in each patient. Results APS patients showed at NVC increased frequency of microhemorrhages (p = 0.039)—particularly a “comb-like” pattern (parallel hemorrhages) (p = 0.002)—than "aPL carriers". Of note, there were no significant differences concerning the isolated number of microhemorrhages between APS and the CTR group (p = 0.314), but “comb-like” hemorrhages were significantly more frequent in the APS group (p = 0.034). Not any significant correlation was found between the aPL subtypes and NVC parameters. Conclusions APS patients showed significantly a greater number of non-specific NVC abnormalities than "aPL carriers", particularly the “comb-like” NVC pattern. Oral anticoagulants may represent a confounding factor for isolated microhemorrhages. Not any correlation was found between aPL subtypes and NVC parameters. Further investigations are needed to better characterize the microvascular endothelium damage induced by aPL.

Are High Doses of Corticosteroids Protective in COVID-19 Patient With Panhypopituitarism?

Introduction: Clinical course of COVID-19 infection is diverse and the best therapeutical guidelines are still lacking. Case Presentation: We present a case of 73 year old male COVID-19 positive patient. In 2017 transnasal hypophysectomy was performed due to prolactinoma. He receives therapy (hydrocortisone 20 + 10 mg/day, levothyroxine 75/50 µg/day, bromocriptine 2.5 mg twice/day). He suffers also from arterial hypertension. Present illness started with intensive dry cough, fever (37.5◦C), diarrhoea and loss of smell. On the first day patient was febrile up to 38.4◦C and later afebrile. Laboratory parameters showed abnormalities in several parameters: D-dimers 13.45 (RR:&lt; 0.50) mg/L, creatinine 110 (49-90) µmol/L, ALT 73 (12-28) U/L, LDH 531 (25-241) U/L, creatine kinase 549 (&lt;177) U/L, GGT 277 (9-35) U/L, CRP 38 (&lt;5 mg/L), sedimentation rate 40 (5-28) mm/3.6ks, procalcitonine 0.07 (&lt;0.05) ng/ml, sodium 128 (137-146) mmol/L, hs-TroponinT 18 (&lt; 14) ng/L, neutrophils 8.56 (2.06-6.49 x109/L), lymphocytes 0.52 (1.19-3.35 x109/L) and pO2 6.1 (11.0-14.4) kPa. At the admission X-ray showed normal presentation, while four days later on the right side pneumonia was noticed as spotty inhomogeneous shading. He was treated with azithromycin, hydrocortisone (50 mg twice/day) and oxygen supplementation. At the beginning of hospitalization he was addicted to O2 10-12 L/min. After 22 days of hospitalization he was discharged without any symptom but with still positive SARS-CoV2 swabs. After a 30 days of follow-up, his swabs are now negative with no laboratory abnormalities. In the meantime, his two brothers, born in 1945 and 1940 died due to COVID-19 infection. They did not receive substitutional corticosteroid therapy. Conclusion: The main pathophysiological mechanism of infection is explained by cytokine storm. Hypercytokinemia causes myelosuppression and vascular endothelium damage. Corticosteroids are potent anti-inflammatory agents. High-doses of corticosteroids might beneficially modulate the host immune response to SARS-CoV2 virus and have protective role in this patient.

Histopathological analysis of incompetent great saphenous veins after mechanochemical ablation treatment – An ex-vivo experiment

Background The endovascular technique of mechanochemical ablation (MOCA) has become popular in treating patients with saphenous reflux. We reported the histopathological findings in human ex-vivo incompetent great saphenous veins following treatment with saline, polidocanol, mechanical ablation and MOCA using ClariVein device. Methods Twenty-four vein GSV specimens were obtained via traditional surgery and treated with four methods: Group A: 0.9% normal saline (NS); Group B: 3% polidocanol; Group C: mechanical ablation + 0.9% NS; Group D: mechanical ablation + 3% polidocanol (MOCA). Hematoxylin and eosin (HE), Masson’s trichrome and immunohistochemical staining were performed on each specimen and integrated optical densities were measured with vWF and a-SMA stains and statistically evaluated. vWF staining was used to assess endothelial damage and a a-SMA staining was used to assess media injury. Results HE and Masson’s trichrome staining of Groups C and D revealed severe damage to the endothelium and media compared to Groups A and B. The statistical result of vWF staining showed the damage of endothelium was significantly increased by Group D compared to Groups A, B and C. The statistical result of a-SMA staining showed the damage of media was significantly increased by Groups C and D compared to Groups A and B. Conclusions The mechanism of MOCA was caused by both endothelium damage and media tearing. The damage of endothelium was significantly increased by MOCA when compared with mechanical ablation alone.