MASP2 inhibition by narsoplimab suppresses endotheliopathies characteristic of transplant-associated thrombotic microangiopathy: in vitro and ex vivo evidence

Transplant-associated thrombotic microangiopathy (TA-TMA) is an endotheliopathy complicating up to 30% of allogeneic hematopoietic stem cell transplants (alloHSCT). Positive feedback loops among complement, pro-inflammatory, pro-apoptotic, and coagulation cascade likely assume dominant roles at different disease stages. We hypothesized that mannose-binding lectin-associated serine protease 2 (MASP2), principal activator of the lectin complement system, is involved in the microvascular endothelial cell (MVEC) injury characteristic of TA-TMA through pathways that are susceptible to suppression by anti-MASP2 monoclonal antibody narsoplimab. Pre-treatment plasmas from 8 of 9 TA-TMA patients achieving a complete TMA response in a narsoplimab clinical trial activated caspase 8, the initial step in apoptotic injury, in human MVEC. This was reduced to control levels following narsoplimab treatment in 7 of the 8 subjects. Plasmas from 8 individuals in an observational TA-TMA study, but not 8 alloHSCT subjects without TMA, similarly activated caspase 8, which was blocked in vitro by narsoplimab. mRNA sequencing of MVEC exposed to TA-TMA or control plasmas with and without narsoplimab suggested potential mechanisms of action. The top 40 narsoplimab-affected transcripts included upregulation of SerpinB2, which blocks apoptosis by inactivating procaspase 3; CHAC1, which inhibits apoptosis in association with mitigation of oxidative stress responses; and pro-angiogenesis proteins TM4SF18, ASPM, and ESM1. Narsoplimab also suppressed transcripts encoding pro-apoptotic and pro-inflammatory proteins ZNF521, IL1R1, Fibulin-5, aggrecan, SLC14A1, and LOX1, and TMEM204, which disrupts vascular integrity. Our data suggest benefits to narsoplimab use in high-risk TA-TMA and provide a potential mechanistic basis for the clinical efficacy of narsoplimab in this disorder.

Defibrotide mitigates endothelial cell injury induced by plasmas from patients with COVID-19 and related vasculopathies

Background and objectives

COVID-19 progression is characterized by systemic small vessel arterial and venous thrombosis. Microvascular endothelial cell (MVEC) activation and injury, platelet activation, and histopathologic features characteristic of acute COVID-19 also describe certain thrombotic microangiopathies, including atypical hemolytic-uremic syndrome (aHUS), thrombotic thrombocytopenic purpura (TTP), and hematopoietic stem cell transplant (HSCT)-associated veno-occlusive disease (VOD). We explored the effect of clinically relevant doses of defibrotide, approved for HSCT-associated VOD, on MVEC activation/injury.

Methods

Human dermal MVEC were exposed to plasmas from patients with acute TMAs or acute COVID-19 in the presence and absence of defibrotide (5 μg/ml) and caspase 8, a marker of EC activation and apoptosis, was assessed. RNAseq was used to explore potential mechanisms of defibrotide activity.

Results

Defibrotide suppressed TMA plasma-induced caspase 8 activation in MVEC (mean 60.2 % inhibition for COVID-19; p = 0.0008). RNAseq identified six major cellular pathways associated with defibrotide's alteration of COVID-19-associated MVEC changes: TNF-α signaling; IL-17 signaling; extracellular matrix (ECM)-EC receptor and platelet receptor interactions; ECM formation; endothelin activity; and fibrosis. Communications across these pathways were revealed by STRING analyses. Forty transcripts showing the greatest changes induced by defibrotide in COVID-19 plasma/MVEC cultures included: claudin 14 and F11R (JAM), important in maintaining EC tight junctions; SOCS3 and TNFRSF18, involved in suppression of inflammation; RAMP3 and transgelin, which promote angiogenesis; and RGS5, which regulates caspase activation and apoptosis.

Conclusion

Our data, in the context of a recent clinical trial in severe COVID-19, suggest benefits to further exploration of defibrotide and these pathways in COVID-19 and related endotheliopathies.

Premortem Skin Biopsy Assessing Microthrombi, Interferon Type I Antiviral and Regulatory Proteins, and Complement Deposition Correlates with Coronavirus Disease 2019 Clinical Stage

Apart from autopsy, tissue correlates of coronavirus disease 2019 (COVID-19) clinical stage are lacking. In the current study, cutaneous punch biopsy specimens of 15 individuals with severe/critical COVID-19 and six with mild/moderate COVID-19 were examined. Evidence for arterial and venous microthrombi, deposition of C5b-9 and MASP2 (representative of alternative and lectin complement pathways, respectively), and differential expression of interferon type I-driven antiviral protein MxA (myxovirus resistance A) versus SIN3A, a promoter of interferon type I-based proinflammatory signaling, were assessed. Control subjects included nine patients with sepsis-related acute respiratory distress syndrome (ARDS) and/or acute kidney injury (AKI) pre-COVID-19. Microthrombi were detected in 13 (87%) of 15 patients with severe/critical COVID-19 versus zero of six patients with mild/moderate COVID-19 (P < 0.001) and none of the nine patients with pre-COVID-19 ARDS/AKI (P < 0.001). Cells lining the microvasculature staining for spike protein of severe acute respiratory syndrome coronavirus 2, the etiologic agent of COVID-19, also expressed tissue factor. C5b-9 deposition occurred in 13 (87%) of 15 patients with severe/critical COVID-19 versus zero of six patients with mild/moderate COVID-19 (P < 0.001) and none of the nine patients with pre-COVID-19 ARDS/AKI (P < 0.001). MASP2 deposition was also restricted to severe/critical COVID-19 cases. MxA expression occurred in all six mild/moderate versus two (15%) of 13 severe/critical cases (P < 0.001) of COVID-19. In contrast, SIN3A was restricted to severe/critical COVID-19 cases co-localizing with severe acute respiratory syndrome coronavirus 2 spike protein. SIN3A was also elevated in plasma of patients with severe/critical COVID-19 versus control subjects (P ≤ 0.02). In conclusion, the study identified premortem tissue correlates of COVID-19 clinical stage using skin. If validated in a longitudinal cohort, this approach could identify individuals at risk for disease progression and enable targeted interventions.

Left atrial appendage remodeling following percutaneous closure with WATCHMAN 2.5 and FLX: insights from the WATCH-DUAL registry

Background

Percutaneous left atrial appendage closure (LAAC) has emerged as a valid option for prevention of thromboembolic events in patients with non-valvular atrial fibrillation and contraindications for oral anticoagulation. The most recent devices have been created to improve the intervention efficiency and to allow the procedure in a wider range of anatomies. The new-generation Watchman FLX (WMFLX) features a new design but its in vivo performances have not been compared to the previous WATCHMAN 2.5 (WM2.5) prosthesis. Hence, the data regarding conformability, compression and device-related LAA remodeling are scarce.

Purpose

To compare the anatomical results of WM2.5 and WMFLX implantation and impact on LAA dimensions.

Methods

This study included LAAC patients from the WATCH-DUAL registry who benefited from a pre- and post-intervention CT scan. The WATCH-DUAL study was a dual center observational study including all the LAAC procedures prospectively collected in local registries from two high-volume centres between November 2017 and December 2020. The LAA and device dimensions were measured in a centralized core lab by 3D CT scan reconstruction methods, focusing on the device landing zone (LZ/defined as the cross section of the appendage that was perpendicular to its axis and connected the circumflex artery to a point 1 to 2 cm inside the LAA).

Results

This analysis included n=107 patients (n=58 WMFLX, n=49 WM2.5). The patients clinical profiles didn't differ, except for a higher proportion of coronary artery disease in WM2.5 group. The LAA dimensions were comparable between groups. There was a significantly higher proportion of chickenwing shapes in the WMFLX patients. The mean device baseline diameter was in the WMFLX compared to the WM2.5 patients (28.8±0.5 vs. 25.7±0.4 mm, p&lt;0.001).

The median delay for CT control was 48 (43–62) days. The LZ area (451 (363–521) vs. 366 (260–459) mm2, p&lt;0.001) and minimal diameter (23.0 (20.7–24.8) vs. 18.7 (15.9–21.8) mm, p&lt;0.001) significantly increased after implantation among patients. The LZ area increase absolute value and percentage were 101 (18–151) mm2 and 28 (4–54) % respectively. The LZ dimensions increase was more pronounced in the WMFLX group: these patients exhibited post LAAC larger LZ area and dimensions compared to the WM2.5 cases. The LAA eccentricity was reduced after implantation: the ratio LZ maximal/LZ minimal diameter significantly decreased for all patients (r=1.28 (1.18–1.40) vs. 1.06 (1.05–1.09), p&lt;0.001). Comparable results were observed in WMFLX and WM2.5 patients.

A multivariable regression analysis demonstrated that baseline LAA length, baseline LZ eccentricity and WM FLX use were independent predictors of LAA remodeling/dimensions increase.

Conclusion

LAA dimensions increased over time at the site of WM prosthesis implantation suggesting a local positive appendage remodeling after procedure. This phenomenon appears to be more pronounced with the WMFLX device.

Funding Acknowledgement

Type of funding sources: None.

MASP2 levels are elevated in thrombotic microangiopathies: association with microvascular endothelial cell injury and suppression by anti-MASP2 antibody narsoplimab

Involvement of the alternative complement pathway (AP) in microvascular endothelial cell (MVEC) injury characteristic of a thrombotic microangiopathy (TMA) is well documented. However, the role of the lectin pathway (LP) of complement has not been explored. We examined mannose-binding lectin associated serine protease (MASP2), the effector enzyme of the LP, in thrombotic thrombocytopenic purpura, atypical hemolytic uremic syndrome and post-allogeneic hematopoietic stem cell transplantation (alloHSCT) TMAs. Plasma MASP2 and terminal complement component sC5b-9 levels were assessed by enzyme-linked immunosorbent assay (ELISA). Human MVEC were exposed to patient plasmas, and the effect of the anti-MASP2 human monoclonal antibody narsoplimab on plasma-induced MVEC activation was assessed by caspase 8 activity. MASP2 levels were highly elevated in all TMA patients versus controls. The relatively lower MASP2 levels in alloHSCT patients with TMAs compared to levels in alloHSCT patients who did not develop a TMA, and a significant decrease in variance of MASP2 levels in the former, may reflect MASP2 consumption at sites of disease activity. Plasmas from 14 of the 22 TMA patients tested (64%) induced significant MVEC caspase 8 activation. This was suppressed by clinically relevant levels of narsoplimab (1·2 μg/ml) for all 14 patients, with a mean 65·7% inhibition (36.8-99.4%; P < 0·0001). In conclusion, the LP of complement is activated in TMAs of diverse etiology. Inhibition of MASP2 reduces TMA plasma-mediated MVEC injury in vitro. LP inhibition therefore may be of therapeutic benefit in these disorders.

P1476Global longitudinal strain assessed by 2-D speckle tracking echocardiography identifies myocardial viability and predicts LV function and remodeling after acute MI with systolic dysfunction

Aims

To assess whether two-dimensional speckle-tracking echocardiography (2D-STE) could (1) identify myocardial viability in comparison with late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR); (2) predict global left ventricular (LV) functional recovery and remodeling and (3) assess prognosis after acute myocardial infarction (MI) with LV systolic dysfunction.

Methods

Seventy one first STEMI patients with LVEF ≤45%, treated with acute percutaneous coronary intervention, underwent 2D-echocardiography for 2D-STE analysis and LGE CMR between 2 and 45 days after STEMI. Segments were defined as viable when transmural LGE extension was <50% and non viable when transmural LGE extension was ≥50%. At 8-month follow-up, transthoracic echocardiography was repeated to determine global LV functional recovery (increase in LVEF ≥5%) and LV remodeling (increase in end-systolic volume >15%) (n=30) and clinical outcomes were obtained (n=46).

Results

Global longitudinal strain (GLS) was lower in non viable than in viable infarct segments (−6.6±6.1% vs −10.3±5.9%, p<0.0001) and in viable infarct segments than in normal segments (−10.3±5.9% vs −14.5±6.4%, p<0.0001). GLS >−12% had sensitivity of 78% and specificity of 69% to identify non viable segments (area under the curve (AUC), 0.79; 95% confidence interval (CI), 0.77–0.81, p<0.0001). GLS >−11.3% had sensitivity of 53% and specificity of 100% to predict the absence of global functional improvement (AUC=0.73 (CI: 0.55–0.87) p=0.01) at 8-month follow-up. GLS <−12.5% predicted the absence of adverse LV remodeling at 8-month follow-up with a sensitivity of 100% and a specificity of 54% (AUC=0.83 (CI: 0.66–0.94) p<0.0001). GLS >−11.5% was associated with a poor prognosis.

Conclusions

In patients with recent first acute MI with LV systolic dysfunction, GLS assessed by 2D-STE: (1) is able to identify non viable segments in comparison with LGE CMR, (2) allows prediction of LV global functional recovery and LV remodeling at 8-month follow-up and (3) provides strong prognostic information, independently of LVEF.

P3725Impact of left atrial appendage closure on circulating microvesicles levels: the MICROPLUG study

Background

Percutaneous left atrial appendage occlusion (LAAO) has emerged as a valid alternative to oral anticoagulation therapy for the prevention of systemic embolism in patients with non-valvular atrial fibrillation (AF). Microvesicles (MVs) are shed-membrane particles generated during various cellular types activation/ apoptosis that carry out diverse biological effects, including procoagulant effects. Left atrial appendage has been suspected to be a potential source of MVs during AF, but the effects of LAAO on MVs production and circulating levels are unknown.The aim of this work study was to assess the variations of circulating MVs levels following LAAO.

Methods

The study includedn=25 LAAO patients and n=25 control patients who underwent coronary angiography. LAAO and control patients were treated by clopidogrel+ aspirin loading doses before procedures. Blood samples were drawn before antiplatelets therapy & 2 days after for all. A third sample was collected 6 weeks after procedure in LAAO patients. In N=10 extra patients, blood samples were collected from right atrium, left appendage and pulmonary vein during LAAO procedure. Circulating procoagulant (AnnV+), endothelial (CD62e+), platelets (CD41+), red blood cells/RBC (CD235+), leukocytes (CD11+) derived-MVs were measured using flow cytometry methods.

Results

Control and LAAO groups baseline characteristics were comparable, except for the higher age & incidence of previous stroke and lower incidence of coronary artery disease in LAAO patients. Baseline levels of the different microvesicles were comparable in both groups. In the LAAO group, we observed a significant increase of AnnV+ MVs (4355 [1712–8478] vs. 1798 [1006–2759] ev/μL, p=0.001), platelets (1615 [833–4772] vs. 802 [358–1376] ev/, p=0.005), RBC (207 [85–708] vs. 35 [5–84] ev/μL, p<0.001), and leukocytes MVs (1368 [783–2319] vs. 1067 [827–1564] ev/μL, p=0.02) following intervention, whereas only AnnV+ MVs levels significantly rose in controls (3701 [2043–7017] vs. 1506 [1033–4899] ev/μL, p=0.03). The 6-w analysis showed that RBC-MVs (55 [8–182 ev/μL]and AnnV+ MVs levels (2468 [1813–5576 ev/μL]were still significantly increased compared to baseline values in LAAO patients (p<0.05). The in-site analysis revealed that leukocyte MVs and CD62e+ endothelial-MVs were significantly higher in left atrial appendage compared to pulmonary vein (respectively 430 [26–700 vs. 161 [0–426] and 344 [22–723] vs. 200 [120–326] ev/μL, p<0.05), suggesting a local increased production. No major adverse ischemic or bleeding event was observed in any patient post procedural course.

Conclusions

LAAO impact circulating MVs and could create mild pro-coagulant status, inflammation and potential erythrocytes activation due to device presence during the first 6 weeks following intervention. These results suggest that careful attention should be paid in the anti-platelet/anti-coagulant therapy in the post procedural course.

Acknowledgement/Funding

This work was funded by a research grant from the French Society of Cardiology and a research grant from St Jude/Abbott

[Left atrial appendage occlusion in elderly]

Left atrial appendage occlusion (LAAO) is an alternative option to oral anticoagulation therapy in patients with non-valvular atrial fibrillation. According to French regulations, this procedure is currently reserved for patients with formal contraindications to VKA and direct thrombin inhibitors. LAAO procedures reduce ischemic and stroke risks compared to no treatment and also reduce bleeding events compared to VKA therapy in eligible patients. The peri-procedural complications risk has been reported to be limited in the different series published so far. Although elderly patients (>75 years) have either higher ischemic and bleeding risk than younger subjects, they hardly benefit from optimal anticoagulation. Thus, these subjects might greatly benefit from LAAO. Published studies reported excellent feasibility and efficiency of LAAO procedure in elderly patients. Yet there is a trend towards a higher incidence of peri-procedural complications (including tamponade), long-term safety is excellent and comparable to what is observed in patients<75 years. Therefore, interventional percutaneous LAAO is an attractive strategy in elderly patients with atrial fibrillation that should be incorporated in a multidisciplinary management.

Comparison of a prepCheck-supported self-assessment concept with conventional faculty supervision in a pre-clinical simulation environment

OBJECTIVES

This study aimed to evaluate the educational outcome of a digitally based self-assessment concept (prepCheck; DentsplySirona, Wals, Austria) for pre-clinical undergraduates in the context of a regular phantom-laboratory course.

MATERIALS AND METHODS

A sample of 47 third-year dental students participated in the course. Students were randomly divided into a prepCheck-supervised (self-assessment) intervention group (IG; n = 24); conventionally supervised students constituted the control group (CG; n = 23). During the preparation of three-surface (MOD) class II amalgam cavities, each IG participant could analyse a superimposed 3D image of his/her preparation against the "master preparation" using the prepCheck software. In the CG, several course instructors performed the evaluations according to pre-defined assessment criteria. After completing the course, a mandatory (blinded) practical examination was taken by all course participants (both IG and CG students), and this assessment involved the preparation of a MOD amalgam cavity. Then, optical impressions by means of a CEREC-Omnicam were taken to digitalize all examination preparations, followed by surveying and assessing the latter using prepCheck.

RESULTS

The statistical analysis of the digitalized samples (Mann-Whitney U test) revealed no significant differences between the cavity dimensions achieved in the IG and CG (P = .406). Additionally, the sum score of the degree of conformity with the "master preparation" (maximum permissible 10% of plus or minus deviation) was comparable in both groups (P = .259).

CONCLUSION

The implemented interactive digitally based, self-assessment learning tool for undergraduates appears to be equivalent to the conventional form of supervision. Therefore, such digital learning tools could significantly address the ever-increasing student to faculty ratio.

HIV-associated cardiovascular disease: importance of platelet activation and cardiac fibrosis in the setting of specific antiretroviral therapies

HIV infection is a risk factor for cardiovascular disease (CVD). This risk is accentuated by certain combination antiretroviral therapies (cARTs), independent of their effects on lipid metabolism and insulin sensitivity. We sought to define potential mechanisms for this association through systematic review of clinical and preclinical studies of CVD in the setting of HIV/cART from the English language literature from 1989 to March 2018. We used PubMed, Web of Knowledge and Google Scholar, and conference abstracts for the years 2015-March 2018. We uncovered three themes: (1) a critical role for the HIV protease inhibitor (PI) ritonavir and certain other PI-based regimens. (2) The importance of platelet activation. Virtually all PIs, and one nucleoside reverse transcriptase inhibitor, abacavir, activate platelets, but a role for this phenomenon in clinical CVD risk may require additional postactivation processes, including: release of platelet transforming growth factor-β1; induction of oxidative stress with production of reactive oxygen species from vascular cells; suppression of extracellular matrix autophagy; and/or sustained proinflammatory signalling, leading to cardiac fibrosis and dysfunction. Cardiac fibrosis may underlie an apparent shift in the character of HIV-linked CVD over the past decade from primarily left ventricular systolic to diastolic dysfunction, possibly driven by cART. (3) Recognition of the need for novel interventions. Switching from cART regimens based on PIs to contemporary antiretroviral agents such as the integrase strand transfer inhibitors, which have not been linked to clinical CVD, may not mitigate CVD risk assumed under prior cART. In conclusion, attention to the effects of specific antiretroviral drugs on platelet activation and related profibrotic signalling pathways should help: guide selection of appropriate anti-HIV therapy; assist in evaluation of CVD risk related to novel antiretrovirals; and direct appropriate interventions.

Thrombotic Microangiopathy in the Setting of HIV Infection: A Case Report and Review of the Differential Diagnosis and Therapy

Before the modern era of HIV/AIDS therapeutics, which enabled a cascade of early recognition of infection, prompt initiation of effective antiretroviral therapies, and close follow-up, severe forms of microvascular clotting disorders known as thrombotic microangiopathies (TMAs) were frequent in the setting of advanced HIV disease. Their incidence was as high as 7% in the period 1984-1999, but fell dramatically, to <0.5%, by 2002. This profound change was predicated on one critical development: availability of new classes of anti-HIV drugs, enabling reduction and maintenance of HIV viral loads to undetectable levels. Another development in the period 1999-2002 related to TMA therapy: with recognition of autoantibodies against the von Willebrand factor cleaving protease ADAMTS13 as the etiology of most cases of one major form of TMA, thrombotic thrombocytopenic purpura, it permitted appropriate use of life-saving interventions based on plasma exchange and immune suppression. A more recent factor in TMA therapeutics was the 2011 approval by the US FDA and European EMA of eculizumab, a humanized monoclonal antibody against complement component C5, for the treatment of atypical hemolytic uremic syndrome, another major form of TMA. Despite these milestones, life- and organ-threatening TMAs still occur in untreated HIV disease and, to a much lesser extent, in those patients with suppressed viral loads. Confusion in terms of the differential diagnosis of these TMAs also impedes use of directed treatments. This report utilizes a case study of a young woman with advanced AIDS who presented with a severe TMA, characterized by coma and renal failure, to highlight the diagnostic and therapeutic challenges raised by complex hematologic conditions occurring in the setting of HIV.

Helper T cell differentiation and regulation of inflammatory lymphangiogenesis (IRC10P.468)

Lymph node lymphangiogenesis (LNL) is a critical regulator of inflammation. Although it is clear that pro lymphangiogenic factors VEGF-A and C play a central role in the regulation of this process, recent studies showed that these effects are balanced with anti-lymphangiogenic forces like IFN-g. However, although it is clear that T cells play a negative regulatory role in LNL, the effect of T cell differentiation remains unknown. We analyzed the effects of T cell differentiation on LNL in a mouse model of inflammation and analyzed draining lymph nodes at various time point by flow cytometry, histology, and RT-PCR. We found that induced inflammation, resulted in a robust inflammatory response in the draining lymph nodes beginning 7 days after injection and lasting until day 21. This process was associated with generation of a mixed Th1,Th2 responses, decreased expression of IFN-g, and increased expression of VEGF-A/C. Loss of CD4 or CD8 T cells resulted in augmentation of lymphangiogenesis, increased expression of IFN-g, and VEGF-C. Treatment of mice with IFN-g, IL13, or IL17A neutralizing antibodies resulted in augmented LNL and increased expression of VEGF-C and IFN-g. Loss of either CD4 or CD8 T cells resulted in augmentation of LNL as a result of increased VEGF-A/C expression. Similarly, inhibition of Th1, Th2, or Th17 cytokines increase LNL and increased VEGF-A/C expression. In conclusion, we showed that T cell differentiation modulates inflammatory LNL.

Th2 differentiation is necessary for soft tissue fibrosis and lymphatic dysfunction resulting from lymphedema

Lymphedema is a dreaded complication of cancer treatment. However, despite the fact that >5 million Americans are affected by this disorder, the development of effective treatments is limited by the fact that the pathology of lymphedema remains unknown. The purpose of these studies was to determine the role of inflammatory responses in lymphedema pathology. Using mouse models of lymphedema, as well as clinical lymphedema specimens, we show that lymphatic stasis results in a CD4 T-cell inflammation and T-helper 2 (Th2) differentiation. Using mice deficient in T cells or CD4 cells, we show that this inflammatory response is necessary for the pathological changes of lymphedema, including fibrosis, adipose deposition, and lymphatic dysfunction. Further, we show that inhibition of Th2 differentiation using interleukin-4 (IL-4) or IL-13 blockade prevents initiation and progression of lymphedema by decreasing tissue fibrosis and significantly improving lymphatic function, independent of lymphangiogenic growth factors. We show that CD4 inflammation is a critical regulator of tissue fibrosis and lymphatic dysfunction in lymphedema and that inhibition of Th2 differentiation markedly improves lymphatic function independent of lymphangiogenic cytokine expression. Notably, preventing and/or reversing the development of pathological tissue changes that occur in lymphedema may be a viable treatment strategy for this disorder.

CD4(+) cells regulate fibrosis and lymphangiogenesis in response to lymphatic fluid stasis

Introduction

Lymphedema is a chronic disorder that occurs commonly after lymph node removal for cancer treatment and is characterized by swelling, fibrosis, inflammation, and adipose deposition. Although previous histological studies have investigated inflammatory changes that occur in lymphedema, the precise cellular make up of the inflammatory infiltrate remains unknown. It is also unclear if this inflammatory response plays a causal role in the pathology of lymphedema. The purpose of this study was therefore to characterize the inflammatory response to lymphatic stasis and determine if these responses are necessary for the pathological changes that occur in lymphedema.

Methods

We used mouse-tail lymphedema and axillary lymph node dissection (ANLD) models in order to study tissue inflammatory changes. Single cell suspensions were created and analyzed using multi-color flow cytometry to identify individual cell types. We utilized antibody depletion techniques to analyze the causal role of CD4+, CD8+, and CD25+ cells in the regulation of inflammation, fibrosis, adipose deposition, and lymphangiogenesis.

Results

Lymphedema in the mouse-tail resulted in a mixed inflammatory cell response with significant increases in T-helper, T-regulatory, neutrophils, macrophages, and dendritic cell populations. Interestingly, we found that ALND resulted in significant increases in T-helper cells suggesting that these adaptive immune responses precede changes in macrophage and dendritic cell infiltration. In support of this we found that depletion of CD4+, but not CD8 or CD25+ cells, significantly decreased tail lymphedema, inflammation, fibrosis, and adipose deposition. In addition, depletion of CD4+ cells significantly increased lymphangiogenesis both in our tail model and also in an inflammatory lymphangiogenesis model.

Conclusions

Lymphedema and lymphatic stasis result in CD4+ cell inflammation and infiltration of mature T-helper cells. Loss of CD4+ but not CD8+ or CD25+ cell inflammation markedly decreases the pathological changes associated with lymphedema. In addition, CD4+ cells regulate lymphangiogenesis during wound repair and inflammatory lymphangiogenesis.

Toll-like receptor deficiency worsens inflammation and lymphedema after lymphatic injury

Mechanisms regulating lymphedema pathogenesis remain unknown. Recently, we have shown that lymphatic fluid stasis increases endogenous danger signal expression, and these molecules influence lymphatic repair (Zampbell JC, et al. Am J Physiol Cell Physiol 300: C1107-C1121, 2011). Endogenous danger signals activate Toll-like receptors (TLR) 2, 4, and 9 and induce homeostatic or harmful responses, depending on physiological context. The purpose of this study was to determine the role of TLRs in regulating tissue responses to lymphatic fluid stasis. A surgical model of lymphedema was used in which wild-type or TLR2, 4, or 9 knockout (KO) mice underwent tail lymphatic excision. Six weeks postoperatively, TLR KOs demonstrated markedly increased tail edema compared with wild-type animals (50-200% increase; P < 0.01), and this effect was most pronounced in TLR4 KOs (P < 0.01). TLR deficiency resulted in decreased interstitial and lymphatic transport, abnormal lymphatic architecture, and fewer capillary lymphatics (40-50% decrease; P < 0.001). Lymphedematous tissues of TLR KOs demonstrated increased leukocyte infiltration (P < 0.001 for TLR4 KOs), including higher numbers of infiltrating CD3+ cells (P < 0.05, TLR4 and TLR9 KO), yet decreased infiltrating F4/80+ macrophages (P < 0.05, all groups). Furthermore, analysis of isolated macrophages revealed twofold reductions in VEGF-C (P < 0.01) and LYVE-1 (P < 0.05) mRNA from TLR2-deficient animals. Finally, TLR deficiency was associated with increased collagen type I deposition and increased transforming growth factor-β1 expression (P < 0.01, TLR4 and TLR9 KO), contributing to dermal fibrosis. In conclusion, TLR deficiency worsens tissue responses to lymphatic fluid stasis and is associated with decreased lymphangiogenesis, increased fibrosis, and reduced macrophage infiltration. These findings suggest a role for innate immune responses, including TLR signaling, in lymphatic repair and lymphedema pathogenesis.

A functional impairment of Foxp3+CD4+ regulatory T cell may lead to the exacerbated inflammation in ARDS. (47.2)

Acute Respiratory Distress Syndrome (ARDS) is a clinical syndrome characterized by an intense host inflammatory response to an infectious, non-infectious, or extrapulmonary insult. It is associated with the development of lung damage, the rapid onset of severe respiratory and organ failure. Neutrophils and lymphocytes have been shown to accumulate in the airways. However, the mechanisms that lead to this aberrant inflammation and the nature of the lymphocyte subsets involved in the recruitment of neutrophils to the lung and in their activation are not yet clearly defined. Using a unique mouse model of virus-induced ARDS that recapitulates the histopathology observed in patients with ARDS, we hypothesized, that the inflammation observed in ARDS is the result of (i) a defective regulatory Foxp3+CD4+ T cell population (T-reg), and (ii) an imbalance in the modulation of T-regs and the proinflammatory TH17 population. Therefore, we evaluated the presence of Foxp3+CD4+ T-regs in the lungs and BAL fluid of infected mice. We observed a difference in the phenotype of the regulatory T cell population in the lungs at different stages of the disease from progression to recovery in our virus-induced ARDS model. We concluded that the inflammation observed in our model, does not result from the absence of regulatory T cells, but may result from an impairment of the function of the Foxp3+CD4+ regulatory T cells, which may contribute to the uncontrolled inflammation observed in ARDS.

[High-risk left main coronary stenting supported by percutaneous Impella Recover LP 2.5 assist device]

Percutaneous coronary interventions (PCI) of complex coronary lesions in patients with severely depressed left ventricular (LV) function may increasingly constitute an alternative to surgical revascularization. The availability of hemodynamic support devices offers a promising option to reduce PCI-related complications in such high-risk procedures. We report the case of a successful distal left main coronary artery T-stenting supported by the Impella Recover LP 2.5 assist device in a patient with severe LV dysfunction.

[Clinical and angiographic outcomes after implantation of drug-eluting stents in bifurcation lesions with the crush stent technique]

The most common approach in the treatment of bifurcation lesions is stenting only the main branch (MB) with provisional T-stenting of the side branch (SB). However, some bifurcation lesions may have extensive disease within a large SB requiring stenting of this vessel. The "crush" technique, which has been proposed as an alternative approach to other strategies to treat complex bifurcations, is a relatively simple technique that ensures complete coverage of the SB ostium. Previous series have reported its safety and feasibility, but limited data are available about the long-term outcomes. We report our experience on 21 consecutive patients (pts) treated with the "crush" technique with drug-eluting stents (DES) between November 2005 and March 2007. Clinical follow-up was 18+/-7 months for 19 pts (90%), and angiographic follow-up was completed in 66% of pts (N=14), at a mean time of 8.5+/-4 months. Mean pt age was 70+/-11 years; 33% (N=7) had diabetes mellitus, and mean preoperative logistic EUROSCORE predicted 11% mortality rate. The left anterior descending artery/diagonal and the distal left main were the most frequent bifurcation locations (52 and 43% of cases respectively), with a type 1,1,1 of the Medina classification of bifurcation lesions in 62% of pts, and an angulation MB-SB below 50 degrees in 66% of cases. Final kissing balloon dilation was performed in 90% of pts (N=20). Stent diameter and length were similar between MB and SB. The procedure was successfull in 100% of cases in the MB and 95% of cases in the SB. Procedure-related CK elevation above 2 ULN was seen in two pts (9.5%), without ECG modification. One pt had subacute stent thrombosis 5 days after his procedure. At the end of follow-up, target vessel revascularization (TVR) was required in four pts (19%), and target lesion revascularisation (TLR) in three pts (14%) whom had focal restenosis in the SB ostium (one pt) and in the MB and SB ostia (one pt). Sudden death occurred in one pt 14 months after his procedure. In conclusion, when an effective strategy for stenting both branches is planned, the "crush" technique with final kissing balloon can be safely used by experienced operators to treat complex bifurcation lesions with DES. The safety profile and TLR rate in our small series of "crush" stenting were similar to that of other studies reported thus far.

[Intracoronary thrombectomy with the Export Aspiration Catheter before angioplasty in patients with ST-segment elevation myocardial infarction]

OBJECTIVES

We aimed to assess the safety and feasibility of thrombectomy with the Export Aspiration Catheter (EAC) before angioplasty, and its ability to improve angiographic results in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Distal embolization of atherothrombotic material often occurs during angioplasty in STEMI, compromising optimal myocardial reperfusion.

METHODS

We performed a thrombus-aspiration with EAC prior to angioplasty in 64 consecutive patients with STEMI. Successful thrombectomy was defined as an improvement of TIMI flow grade > or =1.

RESULTS

Successful thrombectomy (increase of TIMI flow > or =1) was achieved in 40 patients (62.5%). Mean TIMI flow grade increased from 0.7 +/- 1 to 1.9 +/- 1.2 (P < 0.0001) after thrombectomy. TIMI flow grade 3 was observed more frequently after EAC compared with guidewire alone (51.5 vs. 9%, P = 0.0062). Direct stenting was performed in most of patients (N=41, 64%). Distal embolization and noreflow/slowflow phenomenon occurred in 8 patients (12.5%). No vessel injury after EAC thrombectomy was reported. After treatment with balloon angioplasty and/or stenting, final TIMI flow grade 3 was achieved in 54 patients (84.5%). By multivariate analysis, ischemic time <6 h was a significant independent predictor of successful thrombectomy (P = 0.0437).

CONCLUSIONS

Our series suggests that EAC thrombectomy prior to angioplasty in the setting of STEMI is safe and feasible. It might reduce the culprit coronary lesion's thrombus burden, leading to improved flow restoration and myocardial reperfusion. Further large randomized studies are warranted to confirm these preliminary results and to assess the impact of thrombus-aspiration on infarct size as well as on clinical outcomes.

[Iatrogenic lesions of the left main coronary artery]

Reoccurrence of ischemic events several months after a percutaneous transcutaneous coronary angioplasty is usually due to a restenosis. Coronary angiography rarely shows a new stenosis on another site or on the left main coronary artery. In this series, we report 5 cases of left main coronary artery stenosis which have occurred from 3 to 12 months after a prior percutaneous angioplasty. This phenomenon which has previously been described after direct cannulation of the coronaries ostia during aortic valve replacement in the 70'. This complication is related to intimal damage caused by traumatic manipulation of the left main, which can be either already minimally altered or normal. This complication is rare after percutaneous transcutaneous coronary angioplasty (0.2-1.7%) according to various series. We compare our cases to the published cases in the literature.

Platelet glycoprotein IIb/IIIa inhibition with coronary stenting for acute myocardial infarction

BACKGROUND

When administered in conjunction with primary coronary stenting for the treatment of acute myocardial infarction, a platelet glycoprotein IIb/IIIa inhibitor may provide additional clinical benefit, but data on this combination therapy are limited.

METHODS

We randomly assigned 300 patients with acute myocardial infarction in a double-blind fashion either to abciximab plus stenting (149 patients) or placebo plus stenting (151 patients) before they underwent coronary angiography. Clinical outcomes were evaluated 30 days and 6 months after the procedure. The angiographic patency of the infarct-related vessel and the left ventricular ejection fraction were evaluated at 24 hours and 6 months.

RESULTS

At 30 days, the primary end point--a composite of death, reinfarction, or urgent revascularization of the target vessel--had occurred in 6.0 percent of the patients in the abciximab group, as compared with 14.6 percent of those in the placebo group (P=0.01); at 6 months, the corresponding figures were 7.4 percent and 15.9 percent (P=0.02). The better clinical outcomes in the abciximab group were related to the greater frequency of grade 3 coronary flow (according to the classification of the Thrombolysis in Myocardial Infarction trial) in this group than in the placebo group before the procedure (16.8 percent vs. 5.4 percent, P=0.01), immediately afterward (95.1 percent vs. 86.7 percent, P=0.04), and six months afterward (94.3 percent vs. 82.8 percent, P=0.04). One major bleeding event occurred in the abciximab group (0.7 percent); none occurred in the placebo group.

CONCLUSIONS

As compared with placebo, early administration of abciximab in patients with acute myocardial infarction improves coronary patency before stenting, the success rate of the stenting procedure, the rate of coronary patency at six months, left ventricular function, and clinical outcomes.

[Occlusion of a coronary endoprosthesis after a negative stress test]

The frequency of early occlusion of coronary stents has fallen with the use of a powerful association of platelet antiaggregants (ticlopidine and aspirin) in the first month. The authors report the case of coronary stent occlusion after a negative exercise stress test, 11 days after implantation in a centre of cardiac rehabilitation. According to the literature, this type of complication would appear to be rare and related to the small size of the stent and the conditions of implantation (acute phase). It would be useful to compile a registry of complications related to coronary angioplasty during rehabilitation to determine their prevalence and, if necessary, change the protocols of physical training of these patients.

[Why so many stents?]

BETTER THAN ANGIOPLASTY: Prolonging inflation with a perfusion balloon decreases the risk of acute coronary occlusion after angioplasty. The longer the artery remains patent, the greater the chances of 0% residual stenosis. This is what the sent allows. Stent act on both mechanisms of stenosis: elastic recoil and fibrous remodeling of the arterial plaque. TARGETTED ACTION: Stents improve angioplasty prevention of acute stenosis. They have a real action on preventing degeneration of the saphenous graft and lead to a significant reduction in the rate of restenosis of the dilated site. There are however two specific complications: subacute occlusion and greater incidence of vascular events. Stents are particularly indicated for the treatment of restenosis and chronic occlusions. TWO IMPROVEMENTS: Risks related to the implantation of a foreign body in the vascular system have been reduced with the use of ticlopidine and high-pressure stent implantation. POSITIVE RESULTS: Stents have produced better angiographic results. They limit restenosis and the number of revascularizations required in treated patients. Several questions concerning indications remain open.

[Medical treatment after implantation of intracoronary stents]

RATIONALE FOR ANTITHROMBOSIS THERAPY: Introducing a foreign body into the coronaries raises the risk of thrombosis in the acute phase and for the 4 following weeks. The objective of antithrombotic therapy is to inhibit platelet adhesion and aggregation or to induce hypocoagulability. AT IMPLANTATION: High-dose heparin is given in a bolus following pretreatment with aspirin. ASPIRIN-TICLOPIDINE COMBINATION: The risk of subacute thrombosis is low, about 1%, and the rate of vascular complications is minimal. Treatment is simple and compatible with short hospitalization.

[Different types of coronary stents]

GENERAL CHARACTERISTICS: Several criteria are used for coronary stent design: biocompatibility, i.e. the capacity to resist thrombotic events and corrosion, flexibility, radial force sufficient to resist elastic recoil, percentage of the lesion covered, radio-opacity, minimal shortening at opening, absence of effect on collateral branches, possibility to use small calibre probe guides, and cost. TWO CATEGORIES: Both tubular stents (self-expanding stents and balloon stents) and filamentary stents (made of stainless steel or tantalum) are used, THE IDEAL STENT: There is no one ideal stent. Choice is dictated by the characteristics of the lesion and by the status of the artery to treat.

[Complete atrioventricular block disclosing Fabry's disease]

Fabry's disease is a hereditary sex-linked sphinglopidosis characterised by abnormal cellular lipid overload in most organs due to deficiencies in enzymes implicated in the catabolism of certain neutral glycolipids. There are two main clinical forms; cardiovascular manifestations usually congestive cardiac failure, and renal manifestations progressing to renal failure and death due to uraemic coma. The authors report a case presenting with juvenile, symptomatic complete infrahisian atrioventricular block. They describe the different cardiovascular complications of Fabry's disease from a review of the medical literature.

[Isolated anomalous origin of a septal artery from a third coronary ostium. Apropos of a case]

The authors report the case of a patient undergoing coronary angiography for angina who had an anomalous origin of the septal perforator artery from a separate ostium. Anomalies of the coronary arteries may consist not only of anomalous trajectories and coronary fistulae but also of anomalous origins of the main coronary arteries. The anomalous origin of a septal artery from a separate ostium is very rare accounting for 0.5% of cases in the medical literature. In some cases, this artery provides a collateral circulation for occluded main coronary vessels, thereby preserving left ventricular contractility.

[Morphological study by transesophageal echocardiography and clinical aspects of ruptured chordae tendineae in the elderly]

Ruptured mitral chordae tendinae is a classical complication of myxomatous mitral valves or Barlow's syndrome. This complication is controversial in non-myxomatous mitral valve. Of 91 consecutive patients with mitral valve prolapse examined over an 18 months period by transthoracic and transesophageal echocardiography, 42 (18 women and 24 men) with an average age of 76 +/- 8 years (60-93 years) had ruptured mitral chordae tendinae. The thickness of the anterior mitral leaflet measured at the distal third of the valve by transesophageal echocardiography enabled the identification of two groups of patients; group I: > 3 mm (24 patients), average 4.8 +/- 0.8 mm and group II: < or = 3 mm (18 patients), average 2.6 +/- 0.3 mm. The diameter of the mitral ring and left atrium, the length of the anterior mitral leaflet, the left ventricular end diastolic dimensions and fractional shortening, were measured by transthoracic 2D echocardiography (mitral ring) and M mode (other parameters). Ruptured chordae were detected in only 13 cases (31%) by transthoracic echocardiography; 38% were asymptomatic and a chance finding at transesophageal echocardiography. No significant difference was observed between the two groups with respect to age, gender presence of hypertension, dimensions of the cardiac chambers, fractional shortening or localisation of the prolapse related to the ruptured chordae. Fifty-eight per cent of patients in group I were in NYHA functional classes 3-4 as compared to 16% in group II (p < 0.02). The size of the left atrium was significantly greater in group I, 51 +/- 8 mm vs 38 +/- 7 mm (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Soluble CD23 potentiates interleukin-1-induced secretion of interleukin-6 and interleukin-1 receptor antagonist by human monocytes

The low-affinity receptor for IgE (CD23) is cleaved into biologically active soluble fragments (sCD23), some of which have been reported to exhibit pleiotropic activities. However, it is not known whether the sCD23 fragments contribute to the induction and/or regulation of pro-inflammatory cytokine production. In this study, this possibility was tested using interleukin (IL)-1-stimulated human whole blood as an ex vivo model of cytokine cascade production. We show that human recombinant 25-kDa sCD23 significantly enhanced the production of IL-6 in whole blood stimulated by IL-1, but had only little or no effect in the absence of IL-1. The potentiating effect of sCD23 was concentration dependent within the range of plasma levels occurring during various inflammatory processes in man. These results prompted us to study whether sCD23 and IL-1 together also enhance the production of regulating factors exhibiting anti-cytokine activities. Our data indicate that sCD23 augments the release of IL-1 receptor antagonist induced by IL-1. Finally, examining the effect of sCD23 on human peripheral monocytes stimulated by IL-1, we confirmed the capacity of sCD23 to potentiate cytokine production. We suggest that sCD23 can modulate monocyte functions, thereby contributing to the amplification and regulation of immune and inflammatory processes.