Inflammatory Bowel Disease-Associated Colorectal Cancer: Translational and Transformational Risks Posed by Exogenous Free Hemoglobin Alpha Chain, A By-Product of Extravasated Erythrocyte Macrophage Erythrophagocytosis.

Colonic inflammatory bowel disease (IBD) encompasses ulcerative colitis (UC) and Crohn's colitis (CC). Patients with IBD are at increased risk for colitis-associated colorectal cancer (CACRC) compared to the general population. CACRC is preceded by IBD, characterized by highly heterogenous, pharmacologically incurable, pertinacious, worsening, and immune-mediated inflammatory pathologies of the colon and rectum. The molecular and immunological basis of CACRC is highly correlated with the duration and severity of inflammation, which is influenced by the exogenous free hemoglobin alpha chain (HbαC), a byproduct of infiltrating immune cells; extravasated erythrocytes; and macrophage erythrophagocytosis. The exogenous free HbαC prompts oxygen free radical-arbitrated DNA damage (DNAD) through increased cellular reactive oxygen species (ROS), which is exacerbated by decreased tissue antioxidant defenses. Mitigation of the Fenton Reaction via pharmaceutical therapy would attenuate ROS, promote apoptosis and DNAD repair, and subsequently prevent the incidence of CACRC. Three pharmaceutical options that attenuate hemoglobin toxicity include haptoglobin, deferoxamine, and flavonoids (vitamins C/E). Haptoglobin's clearance rate from plasma is inversely correlated with its size; the smaller the size, the faster the clearance. Thus, the administration of Hp1-1 may prove to be beneficial. Further, deferoxamine's hydrophilic structure limits its ability to cross cell membranes. Finally, the effectiveness of flavonoids, natural herb antioxidants, is associated with the high reactivity of hydroxyl substituents. Multiple analyses are currently underway to assess the clinical context of CACRC and outline the molecular basis of HbαC-induced ROS pathogenesis by exposing colonocytes and/or colonoids to HbαC. The molecular immunopathogenesis pathways of CACRC herein reviewed are broadly still not well understood. Therefore, this timely review outlines the molecular and immunological basis of disease pathogenesis and pharmaceutical intervention as a protective measure for CACRC.

Engineering Therapeutics to Detoxify Hemoglobin, Heme, and Iron.

Hemolysis (i.e., red blood cell lysis) can increase circulatory levels of cell-free hemoglobin (Hb) and its degradation by-products, namely heme (h) and iron (Fe). Under homeostasis, minor increases in these three hemolytic by-products (Hb/h/Fe) are rapidly scavenged and cleared by natural plasma proteins. Under certain pathophysiological conditions, scavenging systems become overwhelmed, leading to the accumulation of Hb/h/Fe in the circulation. Unfortunately, these species cause various side effects such as vasoconstriction, hypertension, and oxidative organ damage. Therefore, various therapeutics strategies are in development, ranging from supplementation with depleted plasma scavenger proteins to engineered biomimetic protein constructs capable of scavenging multiple hemolytic species. In this review, we briefly describe hemolysis and the characteristics of the major plasma-derived protein scavengers of Hb/h/Fe. Finally, we present novel engineering approaches designed to address the toxicity of these hemolytic by-products.

Fucosylated haptoglobin is a novel predictive marker of hepatocellular carcinoma after hepatitis C virus elimination in patients with advanced liver fibrosis.

BACKGROUND: Patients with advanced fibrosis are at risk for developing hepatocellular carcinoma (HCC) even after hepatitis C virus (HCV) elimination. We previously reported that serum fucosylated haptoglobin (Fuc-Hp) levels increase as the disease progresses from chronic hepatitis to cirrhosis and then HCC. However, it remains unclear whether serum Fuc-Hp levels can stratify the risk of HCC occurrence after a sustained virological response (SVR) is achieved with direct-acting antivirals (DAAs) in patients with advanced liver fibrosis. METHODS: Among 3,550 patients with chronic hepatitis C treated with DAAs at Osaka University Hospital and related hospitals, the stored sera of 140 patients who were diagnosed with F3 or F4 by liver biopsy before DAA treatment, achieved SVR, and had no history of HCC were available at both baseline and the end of treatment (EOT). We measured the Fuc-Hp levels in these samples. RESULTS: The median serum levels of Fuc-Hp at EOT were significantly lower than those at baseline. During the 54.4-month follow-up period, 16 of 140 patients developed HCC. Multivariate Cox proportional hazards analysis revealed that high Fuc-Hp at EOT, high body mass index (BMI), and low albumin at EOT were independent risk factors for HCC occurrence. Patients with all three factors-high Fuc-Hp, high BMI, and low albumin-had a higher incidence of HCC than patients without these factors. CONCLUSIONS: High serum Fuc-Hp levels at EOT were an independent risk factor for HCC occurrence after SVR. Combined with BMI and albumin, Fuc-Hp can stratify the risk of HCC occurrence among those with advanced fibrosis.

Recurrent microangiopathic hemolysis after recovery from complement-mediated hemolytic uremia syndrome during chemotherapy for a CFH-mutated patient with T-lymphoblastic lymphoma.

Complement-mediated hemolytic uremic syndrome (CM-HUS) following chemotherapy for pediatric acute lymphoid neoplasms has rarely been reported. We report the case of an 8-year-old boy with T-lymphoblastic lymphoma (T-LBL) who developed CM-HUS with complement factor H (CFH) mutations (S1191L, V1197A) during induction therapy. Safe administration of chemotherapy after CM-HUS recovery was challenging. By closely monitoring hemolytic and renal parameters during the 2-year treatment period, we observed four episodes of microangiopathic hemolytic anemia (MAHA) with hypocomplementemia and low haptoglobin but no renal dysfunction or thrombocytopenia. Here, we describe the MAHA and CM-HUS episodes in the hopes of elucidating the complex pathophysiology of disorders associated with CFH mutation.

The Role of Circulating Cell-Free Hemoglobin in Sepsis-Associated Acute Kidney Injury.

Sepsis is a heterogeneous clinical syndrome that is complicated commonly by acute kidney injury (sepsis-AKI). Currently, no approved pharmacologic therapies exist to either prevent sepsis-AKI or to treat sepsis-AKI once it occurs. A growing body of evidence supports a connection between red blood cell biology and sepsis-AKI. Increased levels of circulating cell-free hemoglobin (CFH) released from red blood cells during hemolysis are common during sepsis and can contribute to sepsis-AKI through several mechanisms including tubular obstruction, nitric oxide depletion, oxidative injury, and proinflammatory signaling. A number of potential pharmacologic therapies targeting CFH in sepsis have been identified including haptoglobin, hemopexin, and acetaminophen, and early phase clinical trials have suggested that acetaminophen may have beneficial effects on lipid peroxidation and kidney function in patients with sepsis. Bedside measurement of CFH levels may facilitate predictive enrichment for future clinical trials of CFH-targeted therapeutics. However, rapid and reliable bedside tests for plasma CFH will be required for such trials to move forward.

Haptoglobin improves shock, lung injury, and survival in canine pneumonia.

During the last half-century, numerous antiinflammatory agents were tested in dozens of clinical trials and have proven ineffective for treating septic shock. The observation in multiple studies that cell-free hemoglobin (CFH) levels are elevated during clinical sepsis and that the degree of increase correlates with higher mortality suggests an alternative approach. Human haptoglobin binds CFH with high affinity and, therefore, can potentially reduce iron availability and oxidative activity. CFH levels are elevated over approximately 24-48 hours in our antibiotic-treated canine model of S. aureus pneumonia that simulates the cardiovascular abnormalities of human septic shock. In this 96-hour model, resuscitative treatments, mechanical ventilation, sedation, and continuous care are translatable to management in human intensive care units. We found, in this S. aureus pneumonia model inducing septic shock, that commercial human haptoglobin concentrate infusions over 48-hours bind canine CFH, increase CFH clearance, and lower circulating iron. Over the 96-hour study, this treatment was associated with an improved metabolic profile (pH, lactate), less lung injury, reversal of shock, and increased survival. Haptoglobin binding compartmentalized CFH to the intravascular space. This observation, in combination with increasing CFHs clearance, reduced available iron as a potential source of bacterial nutrition while decreasing the ability for CFH and iron to cause extravascular oxidative tissue injury. In contrast, haptoglobin therapy had no measurable antiinflammatory effect on elevations in proinflammatory C-reactive protein and cytokine levels. Haptoglobin therapy enhances normal host defense mechanisms in contrast to previously studied antiinflammatory sepsis therapies, making it a biologically plausible novel approach to treat septic shock.

Haptoglobin and hemopexin inhibit vaso-occlusion and inflammation in murine sickle cell disease: Role of heme oxygenase-1 induction.

During hemolysis, hemoglobin and heme released from red blood cells promote oxidative stress, inflammation and thrombosis. Plasma haptoglobin and hemopexin scavenge free hemoglobin and heme, respectively, but can be depleted in hemolytic states. Haptoglobin and hemopexin supplementation protect tissues, including the vasculature, liver and kidneys. It is widely assumed that these protective effects are due primarily to hemoglobin and heme clearance from the vasculature. However, this simple assumption does not account for the consequent cytoprotective adaptation seen in cells and organs. To further address the mechanism, we used a hyperhemolytic murine model (Townes-SS) of sickle cell disease to examine cellular responses to haptoglobin and hemopexin supplementation. A single infusion of haptoglobin or hemopexin (± equimolar hemoglobin) in SS-mice increased heme oxygenase-1 (HO-1) in the liver, kidney and skin several fold within 1 hour and decreased nuclear NF-ĸB phospho-p65, and vaso-occlusion for 48 hours after infusion. Plasma hemoglobin and heme levels were not significantly changed 1 hour after infusion of haptoglobin or hemopexin. Haptoglobin and hemopexin also inhibited hypoxia/reoxygenation and lipopolysaccharide-induced vaso-occlusion in SS-mice. Inhibition of HO-1 activity with tin protoporphyrin blocked the protections afforded by haptoglobin and hemopexin in SS-mice. The HO-1 reaction product carbon monoxide, fully restored the protection, in part by inhibiting Weibel-Palade body mobilization of P-selectin and von Willebrand factor to endothelial cell surfaces. Thus, the mechanism by which haptoglobin and hemopexin supplementation in hyperhemolytic SS-mice induces cytoprotective cellular responses is linked to increased HO-1 activity.

Undetectable haptoglobin is associated with major adverse kidney events in critically ill burn patients.

BACKGROUND: Intravascular haemolysis has been associated with acute kidney injury (AKI) in different clinical settings (cardiac surgery, sickle cell disease). Haemolysis occurs frequently in critically ill burn patients. The aim of this study was to assess the predictive value of haptoglobin at admission to predict major adverse kidney events (MAKE) and AKI in critically ill burn patients. METHODS: We conducted a retrospective, single-centre cohort study in a burn critical care unit in a tertiary centre, including all consecutive severely burned patients (total burned body surface > 20% and/or shock and/or mechanical ventilation at admission) from January 2012 to April 2017 with a plasmatic haptoglobin dosage at admission. RESULTS: A total of 130 patients were included in the analysis. Their mean age was 49 (34-62) years, their median total body surface area burned was 29% (15-51%) and the intensive care unit (ICU) mortality was 25%. Early haemolysis was defined as an undetectable plasmatic haptoglobin at admission. We used logistic regression to identify MAKE and AKI risk factors. In multivariate analysis, undetectable haptoglobin was associated with MAKE and AKI (respectively, OR 6.33, 95% CI 2.34-16.45, p < 0.001; OR 8.32, 95% CI 2.86-26.40, p < 0.001). CONCLUSIONS: Undetectable plasmatic haptoglobin at ICU admission is an independent risk factor for MAKE and AKI in critically ill burn patients. This study provides a rationale for biomarker-guided therapy using haptoglobin in critically ill burn patients.

The haptoglobin beta subunit sequesters HMGB1 toxicity in sterile and infectious inflammation.

BACKGROUND: Extra-corpuscular haemoglobin is an endogenous factor enhancing inflammatory tissue damage, a process counteracted by the haemoglobin-binding plasma protein haptoglobin composed of alpha and beta subunits connected by disulfide bridges. Recent studies established that haptoglobin also binds and sequesters another pro-inflammatory mediator, HMGB1, via triggering CD163 receptor-mediated anti-inflammatory responses involving heme oxygenase-1 expression and IL-10 release. The molecular mechanism underlying haptoglobin-HMGB1 interaction remains poorly elucidated. METHODS: Haptoglobin ß subunits were tested for HMGB1-binding properties, as well as efficacy in animal models of sterile liver injury (induced by intraperitoneal acetaminophen administration) or infectious peritonitis (induced by cecal ligation and puncture, CLP, surgery) using wild-type (C57BL/6) or haptoglobin gene-deficient mice. RESULTS: Structural-functional analysis demonstrated that the haptoglobin ß subunit recapitulates the HMGB1-binding properties of full-length haptoglobin. Similar to HMGB1-haptoglobin complexes, the HMGB1-haptoglobin ß complexes also elicited anti-inflammatory effects via CD163-mediated IL-10 release and heme oxygenase-1 expression. Treatment with haptoglobin ß protein conferred significant protection in mouse models of polymicrobial sepsis as well as acetaminophen-induced liver injury, two HMGB1-dependent inflammatory conditions. CONCLUSIONS: Haptoglobin ß protein offers a novel therapeutic approach to fight against various inflammatory diseases caused by excessive HMGB1 release.

Successful CABG in a patient with paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is an uncommon acquired disorder of blood cells characterized by intravascular hemolysis due to an inordinate sensitivity to complement-mediated membrane damage. This report documents coronary artery revascularization in a patient with PNH, which has not been described in the literature so far. We used the on-pump procedure in the present patient and successfully performed revascularization by taking prophylactic measures against hemolysis.

[Renal tubular dysfunction in open pediatric heart surgery--preventive effect of haptoglobin].

Preventive effect of haptoglobin (Hb) for renal tubular dysfunction was studied in 16 pediatric patients undergoing open heart surgery under extracorporeal circulation (ECC). The patients were divided into two groups; Hp(+) group consisting of 7 patients administered haptoglobin (100 U/kg) in priming of ECC, and Hp(-) group of 9 patients not administered haptoglobin. As parameters of renal tubular function, urinary alpha 1-microglobulin-index (U-alpha 1m.I), urinary beta 2-microglobulin-index (U-beta 2m.I), urinary N-acetyl-beta-D-glucosaminidase-index (U-NAG.I), fractional clearance of alpha 1m (Fc-alpha 1m) and beta 2m (Fc-beta 2m), as well as Free-Hb, were measured just before start of ECC and then at periodical time after ECC to the 7th day. The results obtained are as follows. (1) Maximum Free-Hb in Hp(+) group was significantly less (p < 0.05) than that in Hp(-) group. (2) Every parameter of renal tubular function were shown a peak at the end of ECC. Maximum values of U-alpha 1m.I, U-NAG.I and Fc-alpha 1m in Hp(+) group were significantly less (p < 0.05) than those in Hp(-) group. Maximum U-beta 2m.I and Fc-beta 2m in Hp(+) group were less than those in Hp(-) group, although there was no significant difference. These results indicate that administration of haptoglobin suppresses the increase of Free-Hb and is useful for prevention of renal tubular dysfunction during ECC.

The effects of massive transfusion and haptoglobin therapy on hemolysis in trauma patients.

A retrospective study was conducted on 53 patients who suffered severe trauma to determine the severity of intravascular hemolysis, the variations of renal function after trauma, and the effects of transfusion and haptoglobin therapy on these factors. Serum total haptoglobin, total hemoglobin, and urine free hemoglobin were measured 0, 1, 3, and 5 days after the trauma and renal tubular function was evaluated by the urinary N-acetyl-beta-D-glucosaminidase (NAG) index. Patients were divided into two groups depending on whether or not haptoglobin was given: group A (n = 34) did not receive haptoglobin, and group B (n = 19) was administered 4,421 +/- 245 U haptoglobin based on clinical indications. The total transfusion volumes were 3,477 +/- 594 ml and 10,146 +/- 1,794 ml, in groups A and B, respectively (P < 0.01). In group A, total haptoglobin was remarkably decreased to 69.4 +/- 11.6 mg/dl on day 0, but recovered to within the normal range on day 3, while the total hemoglobin was increased and the urine hemoglobin was positive in 61.8% of the patients. In group B, decreases in total haptoglobin and increases in total hemoglobin were more remarkable, and 84.2% had a positive urine hemoglobin. On day 5, groups A and B had NAG indices of 18.8 +/- 3.3 and 133.6 +/- 33.8 U/L/creatinine respectively (P < 0.01). These findings led us to conclude that trauma caused hemolysis and that the administration of 4,000 U haptoglobin did not improve either the severity of hemolysis or the deteriorated renal tubular function caused by massive transfusion.

[Haptoglobin administration for hemolysis with autotransfusion of blood ultrafiltered after cardiopulmonary bypass].

Ultrafiltration is well known as a useful method of hemoconcentration of the blood after cardiopulmonary bypass, but free hemoglobin increase is a problem in autotransfusion. The purpose of this study was to investigate the effect of haptoglobin administration for hemolysis with autotransfused blood ultrafiltered after cardiopulmonary bypass. By means of haptoglobin administration, autotransfusion of blood ultrafiltered with Hemocon (CD Medical Inc.) composed cellulose acetate membrane was performed in patients over a long period (max 313 min) of cardiopulmonary bypass, and with high serum free hemoglobin levels (max 128 mg/dl) at the end of the cardiopulmonary bypass. Comparing the prophylactic administration with the therapeutic administration of haptoglobin, both methods effectively prevented the increment of serum free hemoglobin level, but prophylactic administration (priming administration) was safer and more useful considering free hemoglobin level in ultrafiltered blood and changes of serum free haptoglobin, free hemoglobin and creatinine clearance during and after the operation.

Regulation of renal function in thermal injury.

Hypovolemia, low cardiac output, and systemic vasoconstriction are major etiologic factors in acute renal failure occurring in the early postburn period, and elevated levels of stress-related hormones (catecholamines, angiotensin, aldosterone, and vasopressin) are implicated in the mechanism. By counteracting the effects of the hormones, atrial natriuretic polypeptide (ANP) regulates the renal response to burns. ANP was elevated after burns, protecting the kidneys by increasing renal blood flow and urine output. In pulmonary acid injury, increased ANP levels were associated with natriuresis which was reduced by administration of anti-ANP serum. Exogenous ANP given to dogs under constant norepinephrine infusion resulted in improvement of hemodynamic and renal parameters. To prevent tubular damage due to hemoglobinuria, a haptoglobin preparation is administered to patients with extensive third-degree burns. With sufficient fluid replacement, these new treatments will reduce the incidence of acute renal failure in the early postburn period.

[Administration of haptoglobin in ABO incompatible bone marrow transplantation].

Haptoglobin was administered i.v. in 2 cases of ABO incompatible bone marrow transplantation for the prevention of hemoglobinuria due to acute hemolysis. The first case was a 25-year-old woman with severe aplastic anemia. The transplantation was both major and minor mismatch, where the donor was type A and the recipient was type B. The second case was a 31-year-old man with chronic phase of chronic myelogenous leukemia. The transplantation was major mismatch, where the donor was type B and the recipient was type O. After the administrations of haptoglobin 8,000 units we transfused bone marrow infusates from which incompatible erythrocytes were removed. Though prominent hemoglobinemia was observed in both cases, the serum haptoglobin values were not saturated and hemoglobinuria was not detectable. Haptoglobin appears to be useful for the prevention of acute renal failure associated with acute hemolysis in ABO incompatible bone marrow transplantation. Intravenous haptoglobin supplement therapy makes transplantation safer and may contribute to improve the recovery rate of total nucleated bone marrow cells after the erythrocyte depletion without worrying much about their contamination.