Haptoglobin administration into the subarachnoid space prevents hemoglobin-induced cerebral vasospasm.

Delayed ischemic neurological deficit (DIND) is a major driver of adverse outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH), defining an unmet need for therapeutic development. Cell-free hemoglobin that is released from erythrocytes into the cerebrospinal fluid (CSF) is suggested to cause vasoconstriction and neuronal toxicity, and correlates with the occurrence of DIND. Cell-free hemoglobin in the CSF of patients with aSAH disrupted dilatory NO signaling ex vivo in cerebral arteries, which shifted vascular tone balance from dilation to constriction. We found that selective removal of hemoglobin from patient CSF with a haptoglobin-affinity column or its sequestration in a soluble hemoglobin-haptoglobin complex was sufficient to restore physiological vascular responses. In a sheep model, administration of haptoglobin into the CSF inhibited hemoglobin-induced cerebral vasospasm and preserved vascular NO signaling. We identified 2 pathways of hemoglobin delocalization from CSF into the brain parenchyma and into the NO-sensitive compartment of small cerebral arteries. Both pathways were critical for hemoglobin toxicity and were interrupted by the large hemoglobin-haptoglobin complex that inhibited spatial requirements for hemoglobin reactions with NO in tissues. Collectively, our data show that compartmentalization of hemoglobin by haptoglobin provides a novel framework for innovation aimed at reducing hemoglobin-driven neurological damage after subarachnoid bleeding.

Risk Factors for Macroscopic Haemoglobinuria After Sclerotherapy Using Ethanolamine Oleate for Venous Malformations.

OBJECTIVES: Sclerotherapy is an essential component of the treatment for venous malformations, and ethanolamine oleate (EO) is known as a useful sclerosing agent. However, macroscopic haemoglobinuria (MH) and subsequent renal impairment are severe complications after sclerotherapy using EO. The present study aimed to clarify the MH risk factors for better peri-operative management of venous malformations. METHODS: Data collected during 130 procedures involving 94 patients who were undergoing sclerotherapy using EO for venous malformation were retrospectively analysed. Pre-operative and operative variables, including sex, age, pre-operative body mass index, location, depth, type of lesion, size, number of procedures, type of drainage vein, ratio of sclerosant to air, and injected total dose of 5% EO per body weight (BW), were examined. Univariable analysis and multivariable logistic regression were performed to determine the possible risk factors for MH. RESULTS: Following sclerotherapy, MH occurred in 27.7% of patients, but no patient developed post-operative renal impairment because of aggressive hydration and haptoglobin administration. On univariable analysis, diffuse lesion, lesion size ≥50 cm2, and total injected dose of 5% EO ≥ 0.18 mL/kg were found to be the MH risk factors. Multivariable logistic regression analysis identified a total injected dose of 5% EO ≥ 0.18 mL/kg as the significant independent factor contributing to MH risk. CONCLUSIONS: Macroscopic haemoglobinuria is a reversible complication if immediate and appropriate interventions with aggressive hydration and haptoglobin administration are performed; therefore, it should be closely monitored following sclerotherapy, especially when using 5% EO ≥ 0.18 mL/kg.

Haemoglobin scavenging in intracranial bleeding: biology and clinical implications.

Haemoglobin is released into the CNS during the breakdown of red blood cells after intracranial bleeding. Extracellular free haemoglobin is directly neurotoxic. Haemoglobin scavenging mechanisms clear haemoglobin and reduce toxicity; these mechanisms include erythrophagocytosis, haptoglobin binding of haemoglobin, haemopexin binding of haem and haem oxygenase breakdown of haem. However, the capacity of these mechanisms is limited in the CNS, and they easily become overwhelmed. Targeting of haemoglobin toxicity and scavenging is, therefore, a rational therapeutic strategy. In this Review, we summarize the neurotoxic mechanisms of extracellular haemoglobin and the peculiarities of haemoglobin scavenging pathways in the brain. Evidence for a role of haemoglobin toxicity in neurological disorders is discussed, with a focus on subarachnoid haemorrhage and intracerebral haemorrhage, and emerging treatment strategies based on the molecular pathways involved are considered. By focusing on a fundamental biological commonality between diverse neurological conditions, we aim to encourage the application of knowledge of haemoglobin toxicity and scavenging across various conditions. We also hope that the principles highlighted will stimulate research to explore the potential of the pathways discussed. Finally, we present a consensus opinion on the research priorities that will help to bring about clinical benefits.

Haptoglobin Administration in Cardiovascular Surgery Patients: Its Association With the Risk of Postoperative Acute Kidney Injury.

BACKGROUND: Acute kidney injury (AKI) often occurs after cardiac surgery. During cardiac surgery, plasma free hemoglobin (fHb) would increase due to hemolysis. Since plasma fHb is thought to be nephrotoxic, haptoglobin, which is an fHb scavenger, may have the potential to prevent postoperative AKI (pAKI). However, there have been few studies in which the association of intraoperative administration of haptoglobin with the incidence of AKI after cardiac surgery was assessed. METHODS: This study was a retrospective observational study to assess the independent association of intraoperative administration of haptoglobin with the incidence pAKI in cardiac surgery patients. We screened cardiac surgery patients who required cardiopulmonary bypass from 2008 to 2015. We excluded patients who required renal replacement therapy preoperatively. We also excluded patients in whom descending aortic replacement was performed. pAKI was defined according to AKI Network criteria. A propensity score-matched model was used to adjust confounders. For sensitive analysis, we further developed a logistic regression model. RESULTS: We included 1326 patients in this study. The incidence of AKI in the total cohort was 25.5% (338 patients). Haptoglobin was administered in 260 patients (19.6%). In the crude cohort, the incidence of AKI in patients with haptoglobin administration was 24.6%, which was not significantly different from the incidence of 25.7% in those without haptoglobin administration (P = .72; odds ratio, 0.94 [95% confidence interval, 0.69-1.29]). After propensity score matching, we had 249 patients in each group (for a total of 498 patients). In this propensity score-matched cohort, the incidence of AKI in patients with haptoglobin administration was 22.5%, which was significantly lower than the incidence of 30.9% in those without haptoglobin administration (P = .033; odds ratio, 0.65 [0.43-0.97]). In our logistic regression model for the risk of pAKI, haptoglobin administration was independently associated with decreased risk of AKI (P = .029; adjusted odds ratio, 0.54 [0.31, 0.93]). CONCLUSIONS: In this hypothesis-generating, single-center retrospective observational study, intraoperative administration of haptoglobin was independently associated with lower risk of AKI after cardiovascular surgery.

Endothelial dysfunction inhibits the ability of haptoglobin to prevent hemoglobin-induced hypertension.

Intravascular hemolysis produces injury in a variety of human diseases including hemoglobinopathies, malaria, and sepsis. The adverse effects of increased plasma hemoglobin are partly mediated by depletion of nitric oxide (NO) and result in vasoconstriction. Circulating plasma proteins haptoglobin and hemopexin scavenge extracellular hemoglobin and cell-free heme, respectively. The ability of human haptoglobin or hemopexin to inhibit the adverse effects of NO scavenging by circulating murine hemoglobin was tested in C57Bl/6 mice. In healthy awake mice, the systemic hemodynamic effects of intravenous coinfusion of cell-free hemoglobin and exogenous haptoglobin or of cell-free hemoglobin and hemopexin were compared with the hemodynamic effects of infusion of cell-free hemoglobin or control protein (albumin) alone. We also studied the hemodynamic effects of infusing hemoglobin and haptoglobin as well as injecting either hemoglobin or albumin alone in mice fed a high-fat diet (HFD) and in diabetic (db/db) mice. Coinfusion of a 1:1 weight ratio of haptoglobin but not hemopexin with cell-free hemoglobin prevented hemoglobin-induced systemic hypertension in healthy awake mice. In mice fed a HFD and in diabetic mice, coinfusion of haptoglobin mixed with an equal mass of cell-free hemoglobin did not reverse hemoglobin-induced hypertension. Haptoglobin retained cell-free hemoglobin in plasma, but neither haptoglobin nor hemopexin affected the ability of hemoglobin to scavenge NO ex vivo. In conclusion, in healthy C57Bl/6 mice with normal endothelium, coadministration of haptoglobin but not hemopexin with cell-free hemoglobin prevents acute hemoglobin-induced systemic hypertension by compartmentalizing cell-free hemoglobin in plasma. In murine diseases associated with endothelial dysfunction, haptoglobin therapy appears to be insufficient to prevent hemoglobin-induced vasoconstriction.NEW & NOTEWORTHY Coadministraton of haptoglobin but not hemopexin with cell-free hemoglobin prevents hemoglobin-induced systemic hypertension in mice with a normal endothelium. In contrast, treatment with the same amount of haptoglobin is unable to prevent hemoglobin-induced vasoconstriction in mice with hyperlipidemia or diabetes mellitus, disorders that are associated with endothelial dysfunction.

Sustained treatment of sickle cell mice with haptoglobin increases HO-1 and H-ferritin expression and decreases iron deposition in the kidney without improvement in kidney function.

There is growing evidence that extracellular haemoglobin and haem mediate inflammatory and oxidative damage in sickle cell disease. Haptoglobin (Hp), the scavenger for free haemoglobin, is depleted in most patients with sickle cell disease due to chronic haemolysis. Although single infusions of Hp can ameliorate vaso-occlusion in mouse models of sickle cell disease, prior studies have not examined the therapeutic benefits of more chronic Hp dosing on sickle cell disease manifestations. In the present study, we explored the effect of Hp treatment over a 3-month period in sickle mice at two dosing regimens: the first at a moderate dose of 200 mg/kg thrice weekly and the second at a higher dose of 400 mg/kg thrice weekly. We found that only the higher dosing regimen resulted in increased haem-oxygenase-1 and heavy chain ferritin (H-ferritin) expression and decreased iron deposition in the kidney. Despite the decreased kidney iron deposition following Hp treatment, there was no significant improvement in kidney function. However, there was a nearly significant trend towards decreased liver infarction.

Haptoglobin or Hemopexin Therapy Prevents Acute Adverse Effects of Resuscitation After Prolonged Storage of Red Cells.

BACKGROUND: Extracellular hemoglobin and cell-free heme are toxic breakdown products of hemolyzed erythrocytes. Mammals synthesize the scavenger proteins haptoglobin and hemopexin, which bind extracellular hemoglobin and heme, respectively. Transfusion of packed red blood cells is a lifesaving therapy for patients with hemorrhagic shock. Because erythrocytes undergo progressive deleterious morphological and biochemical changes during storage, transfusion of packed red blood cells that have been stored for prolonged intervals (SRBCs; stored for 35-40 days in humans or 14 days in mice) increases plasma levels of cell-free hemoglobin and heme. Therefore, in patients with hemorrhagic shock, perfusion-sensitive organs such as the kidneys are challenged not only by hypoperfusion but also by the high concentrations of plasma hemoglobin and heme that are associated with the transfusion of SRBCs. METHODS: To test whether treatment with exogenous human haptoglobin or hemopexin can ameliorate adverse effects of resuscitation with SRBCs after 2 hours of hemorrhagic shock, mice that received SRBCs were given a coinfusion of haptoglobin, hemopexin, or albumin. RESULTS: Treatment with haptoglobin or hemopexin but not albumin improved the survival rate and attenuated SRBC-induced inflammation. Treatment with haptoglobin retained free hemoglobin in the plasma and prevented SRBC-induced hemoglobinuria and kidney injury. In mice resuscitated with fresh packed red blood cells, treatment with haptoglobin, hemopexin, or albumin did not cause harmful effects. CONCLUSIONS: In mice, the adverse effects of transfusion with SRBCs after hemorrhagic shock are ameliorated by treatment with either haptoglobin or hemopexin. Haptoglobin infusion prevents kidney injury associated with high plasma hemoglobin concentrations after resuscitation with SRBCs. Treatment with the naturally occurring human plasma proteins haptoglobin or hemopexin may have beneficial effects in conditions of severe hemolysis after prolonged hypotension.

Intravenous infusion of haptoglobin for the prevention of adverse clinical outcome in Sickle Cell Disease.

Sickle Cell Disease (SCD) is a genetic condition which manifests as altered hemoglobin (Hb) protein that can aggregate under hypoxic conditions. The resultant sickled erythrocytes experience premature hemolysis, releasing an estimated 10g of free Hb (fHb) into the intravascular space. FHb participates in redox reactions creating various reactive oxygen species which rapidly and irreversibly scavenge nitric oxide, thereby attenuating its vasodilatory, antithrombotic, and anti-inflammatory properties. FHb also induces endothelial expression of adhesion molecules, triggering leukocyte margination at the vessel wall. These mechanisms participate in diverse SCD-associated clinical events including nephropathy, pulmonary hypertension, chronic leg ulceration, and ischemic events. FHb also exerts a direct reno-toxic effect contributing to albuminuria which is an early, frequent manifestation of glomerular injury. Under normal conditions, fHb is effectively scavenged by the Hb-scavenging mechanism (HSM); this involves binding to haptoglobin (Hp), uptake via the Hb-scavenging receptor (CD163) on monocytes and metabolism by heme-oxygenase-1. This culminates in increased CD163 expression and release of anti-inflammatory by-products e.g. interleukin-10 (IL-10). In SCD, the Hb-binding capacity is overwhelmed by chronic hemolysis; our previous research shows serum Hp as the depleted component. This deficiency could result in the harmful consequences of circulating fHb going unbridled. The hypothesis we explore here is that Hp infusions, in excess of fHb concentration, will allow the HSM to remain functional, and thereby achieve improved clinical outcomes, tracking albuminuria as a sentinel. Albuminuria was selected because of its high prevalence in SCD and its relative ease of diagnosis and monitoring. The hypothesis may be evaluated in four phases: Phase 1 will determine the concentration of Hp needed to trigger the HSM as measured by induction of CD163 and IL-10 and the recovery of hemopexin. Phase 2 will investigate the half-life of HSM induction by analyzing the time-course of CD163 expression and IL-10 and hemopexin serum concentration. Phase 3 will determine patient eligibility for therapy, whether as treatment or prevention. Phase 4 will test the efficacy of Hp transfusions in a randomized control trial as measured by correction of albuminuria. Angiotensin converting enzyme inhibitors (ACEi) are currently the first-line treatment for SCD nephropathy, however hyperkalemia limits its use. Hydroxyurea, which has therapeutic value in many SCD adverse events, has yielded inconsistent effects on albuminuria. We are proposing the addition of an intervention more proximal in the hemolytic cascade. Boosting the exhausted Hb-scavenging capacity via Hp replacement therapy has the potential to modify multiple downstream clinical events.

Haptoglobina como indicador de estrés en vacas de lidia / Haptoglobin as an indicator of stress in lidia breeding cows

Se ha estudiado la influencia del estrés físico y psicológico sobre las concentraciones plasmáticas de la proteína de fase aguda haptoglobina (Hp) en 20 vacas de raza bovina de lidia de 3 a 6 años de edad. Los animalesse dividieron en 4 grupos, el primero, utilizado como control, corresponde a vacas en la ganadería sin estimulación aparente, los tres grupos restantes corresponden a vacas que se utilizaron en encierros tradicionales y que fueron sacrificados a las 30, 54 y 78 horas de la celebración del espectáculo. Las concentraciones medias de Hp en suero para las vacas control fueron 0,093 g/l y 0,13 g/l a las 30h, 0,19 g/l a las 54 h y 0,5 g/l a las 78 h de la celebración del encierro. Estos resultados indican que en los encierros tradicionales se estimula la producciónde Hp en vacas de lidia, presentando valores estadísticamente significativos a partir de las 54 horas de larealización del mismo y situándose los valores máximos a las 78 horas. Como conclusión, hemos de considerarque en situaciones de estrés en vacas de lidia los niveles de Hp en plasma son superiores a los normales y estosparámetros podrían ser utilizados como un indicador del nivel de estrés sufrido por el animal

The influence of physical and psychological stress on the concentration in plasma of the acute phase proteinhaptoglobin (Hp) was studied in 20 fi ghting cows aged 3 to 6 years. Four groups were prepared, the first one orcontrol group comprised live stock with no apparent stimulation. The other groups corresponded to animals oftraditional bull running that were sacrificed at 30, 54 and 78 h after the end of the spectacle. The mean serum Hpconcentration from control fighting cows was 0,093 g/l, while it was 0,13 g/l at 30h, 0,19 g/l at 54 h and 0,5 g/lat 78 h after the end of the spectacle. These results show that in the traditional bull running, Hp concentration is elevated and significant differences are observed at 54 h, although the maximum levels appeared at 78 h. In conclusion, in fighting cows the serum hp concentration was more elevated due to a situation of physical and psychological stress and may be a useful indicator of stress levels in the animal

Endovascular obliteration of bleeding duodenal varices in patients with liver cirrhosis.

The purpose of this paper is to describe our experience with endovascular obliteration of duodenal varices in patients with liver cirrhosis and portal hypertension. Balloon-occluded transvenous retrograde and percutaneous transhepatic anterograde embolizations were performed for duodenal varices in five patients with liver cirrhosis, portal hypertension, and decreased liver function. All patients had undergone previous endoscopic treatments that failed to stop bleeding and were poor surgical candidates. Temporary balloon occlusion catheters were used to achieve accumulation of an ethanolamine oleate-iopamidol mixture inside the varices. Elimination of the varices was successful in all patients. Retrograde transvenous obliteration via efferent veins to the inferior vena cava was enough to achieve adequate sclerosant accumulation in three patients. A combined anterograde-retrograde embolization was used in one patient with balloon occlusion of afferent and efferent veins. Transhepatic embolization through the afferent vein was performed in one patient under balloon occlusion of both efferent and afferent veins. There was complete variceal thrombosis and no bleeding was observed at follow-up. No major complications were recorded. Endovascular obliteration of duodenal varices is a feasible and safe alternative procedure for managing patients with portal hypertension and hemorrhage from this source.

Conservative treatment of hemolytic complication following coil embolization in two adult cases of patent ductus arteriosus.

Two adult cases of relatively large patent ductus arteriosus (PDA) were treated by coil embolization, but were complicated by hemolysis that was successfully managed by medical treatment. Case 1 was a 67-year-old woman and Case 2 was a 71-year-old woman with a PDA of minimal diameter of 5.3 mm and 5.5 mm, respectively. The approach was via the pulmonary artery and 2 coils were delivered simultaneously into the ductus, known as the 'kissing coil technique'. Although immediately after the procedure only a small residual shunt was revealed by aortogram, hemolysis occurred for several hours after the procedure in both cases. A hemolytic complication usually needs additional coil embolization or surgical treatment, but in these 2 cases it was successfully treated by haptoglobin infusion to prevent nephropathy and by antiplasmin infusion to promote thrombus formation. Hemolytic complications of coil embolization of PDA can managed by medication when the residual shunt is minimal and the degree of hemolysis is mild.

Administration of haptoglobin during cardiopulmonary bypass surgery.

A study was undertaken to evaluate hemolysis and subsequent renal damage in 14 patients undergoing cardiopulmonary bypass (CPB) surgery. In all patients, free haptoglobin disappeared completely 30 to 90 minutes into CPB, while free hemoglobin (Hb) levels increased progressively. The NAG index and alpha 1M index also increased progressively, indicating renal tubular injury due to hemolysis (Study 1). An additional 20 patients were monitored intraoperatively for plasma free Hb levels by a newly developed colorimetric method using a haptoglobin coated strip. Free Hb levels during CPB exceeded 30 mg/dl in 14 patients, who were immediately given haptoglobin. This treatment eliminated plasma free Hb within 30 minutes, and effectively prevented hemoglobinuria. Haptoglobin treatment brought significant decreases in the NAG index and alpha 1M index, suggesting a protective effect on renal function (Study 2).

[Study on the usefulness of haptoglobin used on endoscopic injection sclerotherapy].

The effect of haptoglobin (Hp) used on endoscopic injection sclerotherapy (EIS) was evaluated by examining the increase of serum free hemoglobin (FHb) and the changes of renal function. In control group, the increase of serum FHb (delta FHb) was paralleled with the volume of 5% ethanolamine Oleate (EO) injected intravariceally, and free Hp (FHp) was disappered in this group soon after EIS. On the contrary, in the group treated with Hp, neither the increase of FHb nor decrease of FHp were recognized. The significant increase of urine beta 2 microglobulin and NAG was recognized in control group. Therefore, if Hp is used at initial EIS, it would be prevented that serum FHb due to intravascular hemolysis increases, consequently the possibility of renal dysfunction.

[The effects of administration of haptoglobin for hemolysis by extracorporeal circulation].

It is well known that hemolysis by extracorporeal circulation is major cause of renal failure after open heart surgery. The purpose of this study is to investigate the effects of administration of haptoglobin (Hp) during extracorporeal circulation. The patients were divided into two groups: Group I 10 patients underwent open heart surgery for extracorporeal circulation; Group II 10 patients underwent open heart surgery for extracorporeal circulation with the administration of 4,000 IU of Hp. The serum level of total Hp was elevated in group II during bypass, and reduced at 1st day in both groups more than pre-operative level. The serum level of total Hb was elevated in both groups during bypass, and reduced at 1st day within normal limits. Free serum Hb was found in group I at 30 min after start bypass and increased during bypass and urinary Hb was also found. However, in group II free Hb was not found during and after bypass. Urinary NAG and alpha 1 Mg levels of group I were significantly higher than those of group II. The administration of Hp during extracorporeal circulation prevents the increment of serum free Hb and is effective for protection of renal function.

[Clinical experience of autotransfusion system (ATS)--changes in free hemoglobin and haptoglobin].

This study was done to evaluate the usefulness of ATS and the administration of haptoglobin, and is comprised of 15 patients following open heart surgery. Shed mediastinal blood was retransfused during 4-6 hours after open heart surgery. Plasma free Hb (F-Hb) value of the shed blood was 647 mg/dl. But plasma F-Hb of patient did not significantly increase after retransfusion of shed blood without administration of haptoglobin. Plasma F-Hb of patient decreased significantly from 12 mg/dl to 3.3 mg/dl when haptoglobin was given. (p less than 0.05). There was no serious complication associated with the use of ATS, and could save 300 ml of homologous blood. It is concluded that ATS can be used safely for saving homologous blood after open heart surgery and haptoglobin is effective for decreasing of plasma F-Hb.

[A case of A-V fistula with severe hemolysis following internal jugular venipuncture].

Severe hemoglobinuria was observed in a case with abdominal aortic aneurysm on the 23rd postoperative day. The typical continuous murmur was heard on the right upper chest, and IADSA revealed an A-V fistula connecting between the right subclavian artery and the internal jugular vein. This A-V fistula was thought to have been caused by an inadvertent arteriopuncture during the central venous cannulation at the time of the operation. Poloxamer 188 (a non-ionic surfactant) and haptoglobin were given intravenously, and they proved to be quite effective in improving intravascular mechanical hemolysis and hemoglobinuria. A division of the A-V fistula was done successfully, which was facilitated by the median sternotomy combined with the extension of the skin incision to the neck. It cannot be overemphasized that utmost care should be taken to prevent any complication at the time of the central venous cannulation.

Hypohaptoglobinemia associated with familial epilepsy.

In select kindreds afflicted with familial idiopathic epilepsy, most individuals suffering seizures also have low levels of the plasma hemoglobin-binding protein, haptoglobin. This hypohaptoglobinemia may be causally associated with a tendency to develop epilepsy. Our experimental results indicate that artificially-induced hypohaptoglobinemia in mice causes retarded clearance of free hemoglobin from the central nervous system, and that such free hemoglobin may engender the peroxidation of brain lipids. We hypothesize that hypohaptoglobinemia, either inherited, or acquired via traumatic processes, may prevent efficient clearance of interstitial hemoglobin from the central nervous system, thereby predisposing these people to encephalic inflammation and the appearance of seizure disorders.