Ultrastructure of the microvessels in skeletal muscle in a case of systemic capillary leak syndrome

Unlocking endothelial barrier restoration: FX06 in systemic capillary leak syndrome and beyond

Increased vascular permeability is a prevalent feature in a wide spectrum of clinical conditions, but no effective treatments to restore the endothelial barrier are available. Idiopathic systemic capillary leak syndrome (ISCLS) is a life-threatening Paroxysmal Permeability Disorder characterized by abrupt, massive plasma extravasation. This condition serves as a robust model for investigating therapeutic approaches targeting interendothelial junctions. We conducted a single-center, interventional in vitro study at the Referral Center for ISCLS in Italy, involving four diagnosed ISCLS patients, aiming at investigating the effects of FX06, a Bβ15-42 fibrin-derived peptide binding to VE-Cadherin, on endothelial barrier exposed to intercritical and acute ISCLS sera. The Transwell Permeability Assay was used to assess the permeability of human umbilical vein endothelial cells (HUVECs) exposed to ISCLS sera with or without FX06 (50 µg/ml). Acute ISCLS serum was also tested in a three-dimensional microfluidic device. Nitric oxide (NO), VE-Cadherin localization, and cytoskeletal organization were also assessed. In two and three-dimensional systems, ISCLS sera increased endothelial permeability, with a more pronounced effect for acute sera. Furthermore, acute sera altered VE-Cadherin localization and cytoskeletal organization. NO levels remained unchanged. FX06 restored the endothelial barrier function by influencing cellular localization rather than VE-Cadherin levels. In conclusion, FX06 prevents and reverts the hyperpermeability induced by ISCLS sera. These preliminary yet promising results provide initial evidence of the in vitro efficacy of a drug targeting the underlying pathophysiological mechanisms of ISCLS. Moreover, this approach may hold potential for addressing hyperpermeability in a spectrum of clinical conditions beyond ISCLS.

Chronic systemic capillary leak syndrome with lymphatic capillaries involvement and MYOF mutation: case report and literature review

Introduction: Idiopathic systemic capillary leak syndrome (SCLS) is a rare disorder characterized by hemoconcentration, hypoproteinemia and edema. Chronic SCLS (cSCLS) presents as intractable edema, distinguishing it from the classic acute form, and only about 10 cases were reported worldwide. Nevertheless, the underlying pathogenesis of both types is obscure. Case presentation: We report a case of a 58-year-old man with chronic edema persisting for 8 years, complicated by unique chylous polyserous effusions and hypotrichosis, which was successfully relieved by treatment with dexamethasone, intravenous immunoglobulin, and thalidomide. Furthermore, a variant c.5594A>G (p.K1865R) in the MYOF gene was identified as a potentially pathogenic mutation through whole-exome genetic sequencing. The proposed mechanism involves its impact on VEGF signaling, leading to increased capillary permeability. Conclusion: Our case illustrates possible lymphatic capillaries involvement in SCLS, which may plays a potential role in immune disorder, and revealed a possible causative genetic mutation of SCLS.

Systemic Capillary Leak Syndrome (Clarkson Syndrome) in Cancer Patients: A Systematic Review

Systemic capillary leak syndrome (SCLS) is a rare disease characterized by shock caused by capillary hyperpermeability. The disease can occur in cancer patients and effective therapeutic strategies have not been established yet. The aim of the study was to analyze the clinical and laboratory data, treatment modalities, and mortality rate of patients and to identify contributing factors leading to mortality of SCLS in cancer. We searched MEDLINE (inception to July 2018) and of 4612 articles, we identified 62 case reports on SCLS associated with cancer or cancer-related drugs in a total of 53 articles. SCLS was associated with cancer itself in 43.6%, with anti-cancer agents in 51.6% and bone marrow transplantation (BMT) in 4.8%. Among anti-cancer agents, granulocyte-colony stimulating factor (G-CSF) was the most frequently associated drug (14.6%), followed by interleukin (IL)-2 (11.4%). The most common associated malignancies were hematologic (61.3%) with non-Hodgkin lymphoma (22.7%) and multiple myeloma (12.9%) being the leading causes. Common symptoms and signs included dyspnea (27.4%), edema (67.7%), hypotension (32.2%), pleural effusion (29.0%), ascites (22.7%), oliguria (22.7%), and weight gain (21.0%). Patients with SCLS were treated with steroids (59.7%), volume replacement (33.8%), diuretics (24.2%), inotropes (9.6%), methylxanthines (12.8%), β2 agonists (4.8%), while intravenous immunoglobulins (IVIG) were administered in 2 patients (3.2%) only. Among sixteen deaths during follow-up, four were directly attributed to SCLS. Hematologic malignancies were associated with an increased risk for mortality (hazard ratio (HR) 8.820, 95% confidence interval (CI) 1.126–69.063, p = 0.038). Taken together, SCLS can be one important adverse event in cancer patients and careful monitoring of fluid volume is required in the management of SCLS.

Idiopathic systemic capillary leak syndrome presenting as septic shock: A case report

BACKGROUND

Idiopathic capillary leak syndrome (Clarkson's Disease) is a rare angiopathy with a heterogenous phenotype that may present as distributive shock refractory to resuscitative management.

OBJECTIVE

We report a case of idiopathic systemic capillary leak syndrome presenting as septic shock.

METHODS

Structured case report and review of the literature.

RESULTS

A 27-year old man admitted to our institution with coryzal symptoms rapidly deteriorated with presumed sepsis, leading to intensive care unit admission. Following further deterioration, Idiopathic systemic capillary leak syndrome was considered and intravenous immunoglobulin administered, resulting in rapid improvement in the patient's clinical status.

CONCLUSIONS

Idiopathic systemic capillary leak syndrome is a rare and potentially life-threatening angiopathy that may present as, and should be considered in, refractory distributive shock. Administration of intravenous immunglobulin resulted in rapid recovery in this patient, and has been associated with positive outcomes in previous cases.

Recognition and management of idiopathic systemic capillary leak syndrome: an evidence-based review

INTRODUCTION

Idiopathic systemic capillary leak syndrome (SCLS) is a unique disorder characterized by episodes of massive systemic leak of intravascular fluid leading to volume depletion and shock. A typical attack of SCLS consists of prodromal, leak and post-leak phases. Complications, such as compartment syndrome and pulmonary edema, usually develop during the leak and post-leak phases respectively. Judicious intravenous hydration and early use of vasopressors is the cornerstone of management in such cases. Areas covered: The purpose of the present review is to provide an up-to-date, evidence-based review of our understanding of SCLS and its management in the light of currently available evidence.

COMMENTARY

Idiopathic SCLS was first described in 1960 and, since then, more than 250 cases have been reported. A large number of cases have been reported over the past one decade, most likely due to improved recognition. In the acute care setting, most patients with SCLS are managed as per the Surviving Sepsis guidelines and receive aggressive volume resuscitation - which is not the optimal management strategy for such patients. There is a need to raise awareness amongst physicians and clinicians in order to improve recognition of this disorder and ensure its appropriate management.

Inflammatory Markers of the Systemic Capillary Leak Syndrome (Clarkson Disease)

OBJECTIVES

The Systemic Capillary Leak Syndrome (SCLS) is a rare and potentially fatal disorder resembling systemic anaphylaxis that is characterized by transient episodes of hypotensive shock and peripheral edema. The pathogenesis of SCLS is unknown, and triggers for attacks are apparent only in a minority of patients. We introduce a clinical algorithm for the diagnosis of SCLS, and we investigated potential serum biomarkers of acute SCLS episodes.

METHODS

We analyzed serum cytokines in a cohort of 35 patients with an established diagnosis of SCLS and characterized the effects of SCLS sera on endothelial cell function. We investigated the cellular source(s) of CXCL10, a chemokine that was significantly elevated in both basal and acute SCLS sera, by flow cytometry.

RESULTS

Several cytokines were elevated in acute SCLS sera compared to baseline or sera from healthy controls, including CXCL10, CCL2, IL-1β, IL-6, IL-8, IL-12 and TNFα. The majority of acute sera failed to activate endothelial cells as assessed by surface adhesion marker expression. Monocytes appear to be the major source of serum CXCL10, and the percentage of CXLC10+ monocytes in response to IFNγ stimulation was increased in SCLS subjects compared to controls.

CONCLUSIONS

The presence of proinflammatory cytokines in acute SCLS sera suggests that inflammation or infection may have a role in triggering episodes. The enhanced capacity of monocytes from SCLS patients to produce CXCL10 suggests a new therapeutic avenue for SCLS.

Vascular endothelial hyperpermeability induces the clinical symptoms of Clarkson disease (the systemic capillary leak syndrome)

The systemic capillary leak syndrome (SCLS) is a rare disorder characterized by transient episodes of hypotensive shock and anasarca thought to arise from reversible microvascular barrier dysfunction. Although the high prevalence of a monoclonal gammopathy of unknown significance in SCLS suggests a pathogenic contribution of endogenous immunoglobulins, the mechanisms of vascular hyperpermeability remain obscure. Herein, we report clinical and molecular findings on 23 patients, the largest SCLS case series to date. Application of episodic SCLS sera, but neither the purified immunoglobulin fraction nor sera obtained from patients during remission, to human microvascular endothelial cells caused vascular endothelial cadherin internalization, disruption of interendothelial junctions, actin stress fiber formation, and increased permeability in complementary functional assays without inducing endothelial apoptosis. Intravenous immunoglobulin, one promising therapy for SCLS, mitigated the permeability effects of episodic sera. Consistent with the presence of endogenous, nonimmunoglobulin, circulating permeability factor(s) constrained to SCLS episodes, we found that vascular endothelial growth factor (VEGF) and angiopoietin 2 (Ang2), were elevated in episodic SCLS sera but not in remission sera. Ab-based inhibition of Ang2 counteracted permeability induced by episodic SCLS sera. Comparable experiments with anti-VEGF Ab (bevacizumab) yielded less interpretable results, probably because of endothelial toxicity of VEGF withdrawal. Our results support a model of SCLS pathogenesis in which nonimmunoglobulin humoral factors such as VEGF and Ang2 contribute to transient endothelial contraction, suggesting a molecular mechanism for this highly lethal disorder.

[Idiopathic capillary leak syndrome]

Idiopathic capillary leak syndrome (ICLS) is a rare and poorly known condition. Since the first description in 1960, about hundred cases have been reported. A French register that was initiated in 1997 provides a better knowledge of the natural course of the disease and highlights some therapeutic issues. ICLS mainly affects middle-aged adults. The prognosis is poor with a 10-year mortality rate around 34%. Severe crisis and complications occurring in intensive care units account for 80% of the mortality. Diagnosis relies on an almost pathognomonic association: recurrent attacks of hypotension and hemoconcentration with paradoxical hypoalbuminemia. A monoclonal gammopathy is found in about 80% of patients. Physiopathology still remains unclear. Paraprotein toxicity has never been demonstrated. As a result, no evidence-based treatment is available neither for acute crisis nor for prophylaxis. Management of acute episodes is mainly symptomatic. Fluid infusion must be cautious because it can induce complications during the recovery phase. Patient education is a major measure to prevent recurrent attacks. Beta-2 stimulants were reported to reduce the frequency and severity of episodes and were considered as the recommended prophylactic measure. However, early data from the French register suggest that intravenous immunoglobulins are more effective in reducing both frequency and severity of the attacks. Inclusion of patients with ICLS in a register is crucial to improve the knowledge about aetiology and treatment of this disorder.

Systemic capillary leak syndrome with monoclonal IgG and complement alterations. A case report on an episodic syndrome

A case of the rare systemic capillary leak syndrome (SCLS) is described. The patient suffered 9 attacks with muscle pain, weakness and profuse sweating. He showed increased Hct values up to 79 percent and a decreasing plasma volume to about 50 percent of normal. During the attacks the patient was in a state of shock and BP was unmeasurable. Studies with 131I-labelled albumin during attack showed an increased transcapillary escape rate to about 20 percent/hour, compared to 6 percent when he was without symptoms. A monoclonal IgG with a constant concentration of about 5g/l was found. Studies of the complement system during attack showed low C4 values, disproportions among the C1 subcomponents and C1r-C1s-C1IA complexes, suggesting a complement activation via the classic pathway. Hereditary angio-edema was excluded by normal C1IA values. The complement activation might be part of the pathogenesis of the increased macromolecular permeability in this syndrome. A short review of cases described earlier is given.

Systemisches Kapillarlecksyndrom als Ursache eines Kompartmentsyndroms beider Unterschenkel und eines Unterarms

Systemic capillary leak syndrome is a rare disorder which causes recurrent episodes of hypovolemic shock due to a markedly increased plasma shift into the interstitium. Hemoconcentration, hypoalbuminemia and a monoclonal gammopathy are characteristic laboratory findings. A rare manifestation of this disease is a compartment syndrome with rhabdomyolysis and acute renal failure. We describe a patient who suffers from a compartment syndrome of both lower legs and the left forearm secondary to systemic capillary leak syndrome, and discuss the pathophysiological background.

Initial evidence of endothelial cell apoptosis as a mechanism of systemic capillary leak syndrome

BACKGROUND

Systemic capillary leak syndrome (SCLS) is a rare disorder of unknown etiology that is characterized by acute recurrent attacks of hypovolemic shock commonly following an inflammatory stimulus such as a viral illness. Prophylactic therapy is generally ineffective, and the outcome is frequently fatal.

METHODS

In order to investigate the cellular mechanisms leading to SCLS, we examined the effects of sera from two patients with active SCLS on microvascular endothelial cell apoptosis in vitro. Apoptosis was determined by morphologic criteria, DNA fragmentation, annexin V stain, and by a quantitative photometric assay. The apoptotic pathway was investigated by Western blot of endothelial cells lysate after exposure to SCLS sera.

RESULTS

The sera from patients with active SCLS mediated profound apoptosis of microvascular endothelial cells shortly after exposure. The exposed microvascular endothelial cells underwent immediate apoptosis as evidenced by morphologic changes, plasma membrane phosphatidylserine exposure, and by DNA fragmentation. Increased Bax/Bcl-2 ratio in endothelial cells exposed to SCLS sera was observed and suggested an oxidation injury as the possible mechanism for endothelial apoptosis. This potential mechanism was further explored by measuring intracellular reactive oxygen species (ROS) following SCLS serum exposure. Sera from both patients caused marked increases in ROS, initially detectable at 1 h and persisted for at least 12 h, with control serum from healthy subjects showing no effect on basal endothelial cell ROS concentrations.

CONCLUSION

Components from the sera of patients with active systemic capillary leak syndrome in contrast to healthy subject sera mediate early and extensive endothelial apoptosis in vitro that is associated with oxidation injury. These data represent compelling initial evidence for oxidation-induced apoptosis as a likely mechanism for endothelial injury leading to SCLS.

Noncardiogenic pulmonary edema: an unusual and serious complication of anticancer therapy

Noncardiogenic pulmonary edema (NCPE) is a rare and less well-recognizable pulmonotoxic syndrome of anticancer therapy than pneumonitis/fibrosis. NCPE is a clinical syndrome characterized by simultaneous presence of severe hypoxemia, bilateral alveolar infiltrates on chest radiograph, and no evidence of left atrial hypertension/congestive heart failure. The diagnosis of drug-related NCPE relies upon documented exclusion of any infectious, metabolic, or cancer-related causes. The time proximity to therapy with drugs that are known to precipitate NCPE, any preceding episodes of flu-like symptoms during previous chemotherapy courses and possible response to corticosteroids may further support such a diagnosis. Cancer therapeutic agents clearly associated with NCPE are cytarabine, gemcitabine, and interleukin-2, as well as all-trans retinoic acid in acute promyelocytic leukemia patients, while a few other compounds have rarely or occasionally been implicated. The pathophysiology of lung injury in drug-induced NCPE remains unclear. There are indications suggesting that both a direct cytotoxic insult to the lung epithelial cells and induction of a cytokine-triggered inflammatory response may be involved in its pathogenesis. By distinction to drug-induced pulmonary pneumonitis that may lead to permanent pulmonary fibrosis, NCPE if not fatal, can be reversed upon prompt recognition, following immediate discontinuation of the offensive drug and start of intensive supportive treatment and intravenous corticosteroids.

The paraproteins in systemic capillary leak syndrome

Systemic capillary leak syndrome (SCLS) is a rare disease characterized by episodes of collapse due to rapid transfer of considerable volumes of plasma from the intravascular to the extravascular compartment. The pathogenesis of this disease is unknown. The diagnosis is made largely on clinical grounds, and investigations are unhelpful. The only consistent abnormality is that an IgG paraprotein is found in most patients, raising the possibility that the paraprotein may be involved in the pathogenesis of the disease. Reduction of the paraprotein level in our patient was associated with remission. Blood samples from three SCLS patients and one probable SCLS have been studied. All patients had monoclonal IgG paraproteins. The purified paraproteins were all of IgG1 subclass and had kappa light chains. However, they differed in size and charge. Antibodies against each of the paraproteins were raised in rabbits. Affinity-purified anti-idiotypic antibodies were tested for cross-reactivity against the other paraproteins using immunoblotting and Ouchterlony assay. These assays showed that the anti-idiotypic antibodies reacted only with the immunizing paraprotein and not with any of the other paraproteins, i.e. that the paraproteins do not share a common idiotype. Paraproteins did not bind to cultured endothelial cells, either unactivated or following activation with interferon-gamma (IFN-gamma), IL-2 or IL-6. In addition, we were unable to demonstrate any cytotoxicity towards cultured human endothelial cells by paraprotein alone, or in the presence of neutrophils (pronounced neutrophilia being a feature of attacks). The relationship between the paraproteins and the disease remains unclear. It is likely that additional, as yet unidentified, factors are required for the paraprotein to lead to capillary leak.

Idiopathic capillary leak syndrome complicated by massive rhabdomyolysis

Idiopathic systemic capillary leak syndrome (Clarkson's disease) is characterized by recurring attacks of increased capillary permeability, resulting in severe hypovolemic shock due to plasma extravasation. Additional laboratory features include association with a monoclonal gammopathy, extreme hemoconcentration, and hypoalbuminemia. Rare manifestations of this syndrome are renal damage and rhabdomyolysis due to increased compartment pressure and ischemic myonecrosis. We present the findings in two patients with capillary leak syndrome complicated by severe rhabdomyolysis, in one case leading to acute renal failure. We review therapeutic aspects of this rare syndrome and emphasize the importance of early diagnosis and of prompt and aggressive fluid replacement.

Control of systemic capillary leak syndrome with aminophylline and terbutaline

PURPOSE

Patients with systemic capillary leak syndrome have a characteristic triad of hypotension, hemoconcentration, and monoclonal gammopathy. They have frequent and severe attacks of hemoconcentration and hypotension accompanied by marked plasma shifts. The exact role of this monoclonal protein is unknown, but it probably leads, in some way, to an increase in capillary permeability. Despite efforts to resuscitate the patients during an acute attack, the syndrome is often fatal. Some success has been obtained in preventing the attacks with the beta-adrenergic-stimulating agent terbutaline. The purpose of this study was to determine the effectiveness of aminophylline and terbutaline in the treatment of systemic capillary leak syndrome.

METHODS

Over a decade, three patients with systemic capillary leak syndrome presented at our institution. All three patients were treated with terbutaline and aminophylline. Prednisone was used during the course of treatment in each of the three patients.

RESULTS

In contrast to previous reports of partial or temporary control of episodes, all three patients are alive with almost complete resolution of their recurrent attacks and have been able to return to their normal lifestyles.

CONCLUSION

The regimen of terbutaline and aminophylline effectively prevents the attacks of hypotension and hemoconcentration that occur in systemic capillary leak syndrome. The role of prednisone is not clear. Until more is known about the pathophysiology of the disorder, treatment must remain empiric and supportive.