scholarly journals Liver Dysfunction and Steatosis in Familial Hypobetalipoproteinemia

2005 ◽  
Vol 51 (1) ◽  
pp. 266-269 ◽  
Author(s):  
Amanda J Whitfield ◽  
P Hugh R Barrett ◽  
Ken Robertson ◽  
Marek F Havlat ◽  
Frank M van Bockxmeer ◽  
...  

Abstract A 32-year-old man presented with increases in serum alanine aminotransferase activity, iron concentration, and transferrin saturation, suggestive of hepatic dysfunction and iron overload. In addition, he had unusually low plasma concentrations of LDL-cholesterol and apolipoprotein (apo) B. Hepatic ultrasonography was consistent with fatty liver. On liver biopsy, marked steatosis and moderate to marked iron deposition were observed. The patient was found to carry the HFE C282Y and H63D mutations, which are associated with hereditary hemochromatosis, and the α1-antitrypsin PiZ variant. An immunoblot of plasma for apoB showed the presence of a truncated apoB species, indicative of familial hypobetalipoproteinemia. DNA sequence analysis revealed that the patient was heterozygous for the apoB-80.5 (c.11040T>G) mutation. This unique case shows an unusual combination of underlying disorders that could all be contributing to liver dysfunction and fatty liver.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 481-481 ◽  
Author(s):  
Shuling Guo ◽  
Carla Casu ◽  
Sara Gardenghi ◽  
Sheri Booten ◽  
Andy Watt ◽  
...  

Abstract Abstract 481 Hepcidin, the master regulator of iron homeostasis, is a peptide that is mainly expressed and secreted by the liver. Low levels of hepcidin are associated with increased iron absorption. In conditions in which hepcidin is chronically repressed, such as hereditary hemochromatosis and b-thalassemia, patients suffer from iron overload and very severe pathophysiological sequelae associated with this condition. Hepcidin expression is regulated predominantly at the transcriptional level by multiple factors. TMPRSS6, a transmembrane serine protease mutated in iron-refractory, iron-deficient anemia, is a major suppressor of hepcidin expression. It has been demonstrated that hepcidin expression is significantly elevated in Tmprss6−/− mice and reduction of Tmprss6 expression in hereditary hemochromatosis (Hfe−/−) mice ameliorates the iron overload phenotype (Finberg et al. Nature Genetics, 2008; Du et al. Science 2008; Folgueras et al. Blood 2008; Finberg et al., Blood, 2011). It has also been demonstrated that hepcidin up-regulation using either a hepcidin transgene or Tmprss6−/− significantly improves iron overload and anemia in a mouse model of β-thalassemia intermedia (th3/+ mice) (Gardenghi et al. JCI, 120:4466, 2010; Nai et al. Blood, 119: 5021, 2012). In this report, we have examined whether reduction of Tmprss6 expression using antisense technology is an effective approach for the treatment of hereditary hemochromatosis and β-thalassemia. Second generation antisense oligonucleotides (ASOs) targeting mouse Tmprss6 were identified. When normal male C57BL/6 mice were treated with 25, 50 and 100mg/kg/week ASO for four weeks, we achieved up to >90% reduction of liver Tmprss6 mRNA levels and up to 5-fold induction of hepcidin mRNA levels in a dose-dependent manner. Dose-dependent reductions of serum iron and transferrin saturation were also observed. ASOs were well tolerated in these animals. In Hfe−/− mice (both males and females), ASOs were administrated at 100 mg/kg for six weeks. This treatment normalized transferrin saturation (from 92% in control animals to 26% in treatment group) and significantly reduced serum iron (from >300ug/dl in control group to <150ug/dl in treatment group), as well as liver iron accumulation. Histopathological evaluation and Prussian's Perl Blue staining indicated that iron was sequestered by macrophages, which led to an increase in spleen iron concentration. The mouse model of thalassemia intermedia that we utilized mimics a condition defined as non-transfusion dependent thalassemia (NTDT) in humans. These patients exhibit increased iron absorption and iron overload due to ineffective erythropoiesis and suppression of hepcidin; iron overload is the most frequent cause of morbidity and mortality. Th3/+ animals exhibit ineffective erythropoiesis, characterized by increased proliferation and decreased differentiation of the erythroid progenitors, apoptosis of erythroblasts due to the presence of toxic hemichromes, reticulocytosis and shorter lifespan of red cells in circulation, leading to splenomegaly, extramedullary hematopoiesis and anemia (∼ 8 g/dL; Libani et al, Blood 112(3):875–85, 2008). Five month old th3/+ mice (both males and females) were treated with Tmprss6 ASO for six weeks. In th3/+ mice, ∼85% Tmprss6 reduction led to dramatic reductions of serum transferrin saturation (from 55–63% in control group down to 20–26% in treatment group). Liver iron concentration (LIC) was also greatly reduced (40–50%). Moreover, anemia endpoints were significantly improved with ASO treatment, including increases in red blood cells (∼30–40%), hemoglobin (∼2 g/dl), and hematocrit (∼20%); reduction of splenomegaly (∼50%); decrease of serum erythropoietin levels (∼50%); improved erythroid maturation as indicated by a strong reduction in reticulocyte number (50–70%) and in a normalized proportion between the pool of erythroblasts and enucleated erythroid cells. Hemichrome analysis showed a significant decrease in the formation of toxic alpha-globin/heme aggregates associated with the red cell membrane. This was consistent with a remarkable improvement of the red cell distribution width (RDW) as well as morphology of the erythrocytes. In conclusion, these data demonstrate that targeting TMPRSS6 using antisense technology is a promising novel therapy for the treatment of hereditary hemochromatosis and β-thalassemia. Disclosures: Guo: Isis Pharmaceuticals: Employment. Booten:Isis Pharmaceuticals: Employment. Watt:Isis Pharmaceuticals: Employment. Freier:Isis Pharmaceuticals: Employment. Rivella:Novartis Pharmaceuticals: Consultancy; Biomarin: Consultancy; Merganser Biotech: Consultancy, Equity Ownership, Research Funding; Isis Pharma: Consultancy, Research Funding. Monia:Isis Pharmaceuticals: Employment.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 943-943
Author(s):  
Kris V Kowdley ◽  
Nishit B Modi ◽  
Frank Valone ◽  
Victor M. Priego ◽  
Christopher Ferris ◽  
...  

Abstract Introduction: Patients with hereditary hemochromatosis (HH) require continued phlebotomies to limit end-organ damage. Approximately 25% of patients in maintenance felt receiving phlebotomies was "inconvenient" or "very inconvenient" (Brisott et al, 2011). Patient compliance with phlebotomies generally declines with time (Hicken et al, 2003), and therapeutic phlebotomies may not be medically suitable for some HH patients. Rusfertide, a peptide mimetic of hepcidin, is an effective regulator of iron distribution and utilization that has demonstrated control of iron in an animal model of HH. Methods: We conducted an open-label, dose-finding efficacy study that investigated subcutaneous rusfertide in HH patients on a stable phlebotomy regimen of 0.25 to 1 phlebotomy per month for at least 6 months. Patients with clinical laboratory abnormalities and those receiving iron chelation therapy or erythrocytapheresis were excluded. Subjects received individually titrated rusfertide doses once or twice a week to maintain transferrin saturation (TSAT) below 45% and were followed for 6 months. Study measures included TSAT, serum iron, transferrin and ferritin, liver iron concentration (LIC) measured by MRI, and adverse events (AEs). Results: Sixteen subjects (10 male/6 female) were enrolled. Mean age and weight were 62.5 years and 88.1 kg, respectively. LIC values were maintained at pre-study levels, with minimal use of phlebotomies during the duration of the study (Figure 1A). Average pre-study phlebotomy rate was 0.27 phlebotomies/month compared to 0.03 phlebotomies/month during the study (p&lt;0.0001; Figure 1B). There was a dose- and concentration-dependent decrease in serum iron and TSAT (Figure 2A and 2B). Transferrin levels were relatively constant over the course of the study. There were no notable changes in hematological parameters such as hematocrit, erythrocytes, leucocytes, or platelets. Rusfertide was generally well tolerated. Adverse events reported in 2 or more subjects included diarrhea, fatigue, injection site reactions (erythema, induration, pain, pruritis), dizziness, and headache. Conclusions: Rusfertide demonstrated a pharmacodynamic effect in reducing TSAT and serum iron, with corresponding significant reduction in the number of phlebotomies, and with LIC maintained at pre-study levels with minimal use of phlebotomies. These data indicate rusfertide was well tolerated in patients with HH and controls LIC, supporting development of rusfertide as a potential treatment for HH. Figure 1 Figure 1. Disclosures Kowdley: PTG: Consultancy, Research Funding. Modi: Protagonist Therapeutics: Current Employment. Valone: Protagonist Therapeutics: Current Employment, Current equity holder in publicly-traded company. Gupta: Protagonist Therapeutics: Current Employment.


2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Amanda J Hooper ◽  
Ken Robertson ◽  
Liesl V Heeks ◽  
Danie Champain ◽  
P Hugh R Barrett ◽  
...  

Familial hypobetalipoproteinemia (FHBL) is a codominant disorder of lipoprotein metabolism characterized by decreased plasma concentrations of LDL-cholesterol and apolipoprotein (apo) B. We examined the effect of heterozygous APOB L343V FHBL on fasting and postprandial lipoprotein metabolism. VLDL, IDL-, and LDL-apoB kinetics were determined in the fasting state using stable isotope methods and compartmental modeling. VLDL-apoB concentrations in FHBL subjects (n=2) were reduced by more than 75% compared to healthy, normolipidemic control subjects ( P <0.01). VLDL-apoB fractional catabolic rate (FCR) was more than 5-fold higher in the FHBL subjects ( P =0.07). ApoB production rates and IDL- and LDL-apoB FCRs were not different between FHBL subjects and controls. To assess postprandial lipoprotein metabolism, a standardized oral fat load was given after a 12 h fast to heterozygous APOB L343V FHBL subjects (n=3) and normolipidemic controls. The postprandial incremental area under the curve (0-10 h) in FHBL subjects was decreased for large TRL-triglyceride (-77%; P <0.0001), small TRL-cholesterol (-83%; P <0.001), small TRL-triglyceride (-88%; P <0.0.001) and plasma apoB (-63%; P <0.0001) compared with controls. Compartmental modeling analysis showed that apoB-48 production was decreased (-91%; P <0.05) compared with controls. We conclude that when compared to controls, APOB L343V FHBL heterozygotes show decreased TRL production with normal postprandial TRL particle clearance. In contrast, VLDL-apoB production was normal, while the FCR was higher in heterozygotes compared with lean control subjects. These mechanisms account for the marked hypolipidemic state observed in these FHBL subjects.


2006 ◽  
Vol 52 (7) ◽  
pp. 1339-1345 ◽  
Author(s):  
Michael W Clarke ◽  
Amanda J Hooper ◽  
Henrietta A Headlam ◽  
Jason HY Wu ◽  
Kevin D Croft ◽  
...  

Abstract Background: Vitamin E supplementation has been recommended for persons with familial hypobetalipoproteinemia (FHBL), a rare disorder of lipoprotein metabolism that leads to low serum α-tocopherol and decreased LDL-cholesterol and apolipoprotein (apo) B. We examined the effect of truncated apoB variants on vitamin E metabolism and oxidative stress in persons with FHBL. Methods: We studied 9 individuals with heterozygous FHBL [mean (SE) age, 40 (5) years; body mass index (BMI), 27 (10) kg/m2] and 7 normolipidemic controls [age, 41 (5) years; BMI, 25 (2) kg/m2]. We also studied 3 children—2 with homozygous FHBL (apoB-30.9) and 1 with abetalipoproteinemia—who were receiving α-tocopherol supplementation. We used HPLC with electrochemical detection to measure α- and γ-tocopherol in serum, erythrocytes, and platelets, and gas chromatography–mass spectrometry to measure F2-isoprostanes and tocopherol metabolites in urine as markers of oxidative stress and tocopherol intake, respectively. Results: Compared with controls, persons with FHBL had significantly lower fasting plasma concentrations of total cholesterol [2.4 (0.2) vs 4.7 (0.2) mmol/L], triglycerides [0.5 (0.1) vs 0.9 (0.1) mmol/L], LDL-cholesterol [0.7 (0.1) vs 2.8 (0.3) mmol/L], apoB [0.23 (0.02) vs 0.84 (0.08) g/L], α-tocopherol [13.6 (1.0) vs 28.7 (1.4) μmol/L], and γ-tocopherol [1.0 (0.1) vs 1.8 (0.3) μmol/L] (all P &lt;0.03). Erythrocyte α-tocopherol was decreased [5.0 (0.2) vs 6.0 (0.3) μmol/L; P &lt;0.005], but we observed no differences in lipid-adjusted serum tocopherols, erythrocyte γ-tocopherol, platelet α- or γ-tocopherol, urinary F2-isoprostanes, or tocopherol metabolites. Conclusion: Taken together, our findings do not support the recommendation that persons with heterozygous FHBL receive vitamin E supplementation.


2010 ◽  
Vol 298 (4) ◽  
pp. G525-G529 ◽  
Author(s):  
João Vilares Neves ◽  
Ingrid Anna Sofia Olsson ◽  
Graça Porto ◽  
Pedro Nuno Rodrigues

Hereditary hemochromatosis (HH), a widespread hereditary iron metabolism disorder, is characterized by an excessive absorption of dietary iron, resulting in increased body iron stores. Some studies indicate a sex difference in disease expression, with women showing a slower disease progression and a less severe clinical profile. This is usually attributed to iron loss during menstruation and pregnancy. However, this link has not been clearly demonstrated. The Hfe−/− mouse model recapitulates key aspects of HH, including an iron overload phenotype similar to that observed in human patients. In this study, we use it to test the impact of multiple pregnancies in the iron stores. One-year-old nulliparous and pluriparous (averaging 29 weaned pups per female) C57BL/6 (B6) and Hfe−/− mice were euthanized, and blood and tissues were collected. Several serological and erythroid parameters were evaluated, as well as tissue nonheme iron content and serum ferritin. Hepcidin 1, hepcidin 2, and bone morphogenetic protein 6 (BMP6) expressions in the liver were determined by real-time PCR. No significant differences were observed for many serological and erythroid parameters although differences occurred in transferrin saturation and mean corpuscular volume in Hfe−/− mice and total iron-binding capacity in B6 mice. Hepatic iron concentration was similar for nulliparous and pluriparous mice of both genotypes, but total iron per organ (liver, spleen, heart, and pancreas) was higher overall in pluriparous females than nulliparous. Hepcidin 1 and 2 and BMP6 expressions were significantly decreased in pluriparous females, when compared with nulliparous, in both genotypes. In conclusion, multiple pregnancies do not reduce body iron stores in Hfe−/− mice.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 47-48
Author(s):  
Roopa Taranath ◽  
Gregory Bourne ◽  
Jie Zhang ◽  
Brian Frederick ◽  
Tran T Tran ◽  
...  

Hepcidin peptidomimetics that are orally stable and systemically active will mark a paradigm change in management of blood disorders that exhibit aberrant iron homeostasis (e.g. hereditary hemochromatosis) and in conditions that can be influenced by modulating stressed iron homeostasis (e.g. polycythemia vera). Hepcidin modulates the iron exporter membrane protein ferroportin and is the master regulator of iron homeostasis in the body. Orally bioavailable "Minihepcidins" have been previously shown to be efficacious in lowering serum iron in mice when dosed peroral (PO) (Preza GC et. al., Journal of Clinical Investigation 2011). Here we describe hepcidin mimetic peptides that are metabolically stable in the gastrointestinal tract, systemically absorbed when delivered orally, and pharmacodynamically active in reducing serum iron parameters in pre-clinical models. Further, we also demonstrate improvement in disease parameters in a mouse model for hereditary hemochromatosis. The oral peptides, PN20076 and PN20089, have EC50 of 16.5 nM and 1.39 nM respectively in cell based ferroportin internalization assay (Table 1). In comparison EC50 was 67.8 nM for Hepcidin and 6.12 nM for PTG-300. (PTG-300 is an injectable hepcidin mimetic currently in Phase 2 clinical studies for polycythemia vera and hereditary hemochromatosis.) Oral stability of the peptides was evaluated in a panel of assays, including in vitro matrices simulating the gastric and intestinal conditions, and ex vivo matrices of serum/plasma from different species. Table 1 shows data for peptides PN20018, PN20076 and PN20089. PN20076 demonstrated extended stability in gastric and intestinal conditions, and degradation half-life of &gt;24 hr in mouse plasma and 14.8 hr in rat serum. Based on their stability and potency data from the above battery of screening assays, the peptides were selected for in vivo evaluation in healthy mice to characterize their pharmacodynamic (PD) and pharmacokinetic (PK) properties. PN20076 and PN20089 showed equivalent PD response of reduction in serum iron concentration in wild type mice. After two successive PO doses of PN20076 or PN20089 approximately 24 hr apart, serum iron concentration was reduced from ~30 µM to ~10 µM (group averages), i.e. ~66% reduction, at 4.5 hr post-second dose for both peptides (Fig. 1). At 4.5 hr post-dose, the serum concentration of PN20076 was ~262 nM. PN20076 was further evaluated for its effect in lowering iron overload in a mouse model for hemochromatosis (HFE2-/- with homozygous deletion of hemojuvelin, a positive regulator of hepcidin expression). This mouse model is marked by hyper-absorption of dietary iron, higher transferrin saturation and deposition of excessive iron in liver, all manifestations of aberrant iron homeostasis caused by the genetic disruptions of the hepcidin-iron pathway. Liver iron accumulation was significantly prevented in groups treated with PN20076 once daily (QD) by PO administration for over two weeks, as compared to vehicle treated controls (Fig. 2). The reduction in non-heme iron concentration in liver homogenates (measured using a colorimetric iron assay) was statistically significant in the female group treated with PN20076. We have described orally stable and systemically active hepcidin mimetic peptides and demonstrated oral activity in preventing liver iron overload in hemochromatosis mice. The effective reduction of iron absorption from the diet and the steady state lowering of transferrin-saturation can potentially prevent tissue iron toxicity in hereditary hemochromatosis. Similarly, the sustained reduction of systemic iron levels with an oral hepcidin mimetic to control stressed iron homeostasis should reduce excessive erythrocytosis, a hallmark of polycythemia vera and other congenital and acquired erythropoietic disorders. Disclosures Bourne: Protagonist Therapeutics: Current Employment, Other: shareholder. Zhang:Protagonist Therapeutics: Current Employment, Other: shareholder. Frederick:Protagonist Therapeutics: Current Employment, Other: shareholder. Tran:Protagonist Therapeutics: Current Employment, Other: shareholder. Vengalam:Protagonist Therapeutics: Current Employment, Current equity holder in private company. McMahon:Protagonist Therapeutics: Current Employment, Other: shareholder. Huie:Protagonist Therapeutics: Current Employment, Other: shareholder. Ledet:Protagonist Therapeutics: Current Employment, Other: shareholder. Zhao:Protagonist Therapeutics: Current Employment, Other: shareholder. Tovera:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Lee:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Yang:Protagonist Therapeutics: Current Employment, Other: shareholder. Dion:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Yuan:Protagonist Therapeutics: Current Employment, Other: shareholder. Zemede:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Nguyen:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Masjedizadeh:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Cheng:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Mattheakis:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Liu:Protagonist Therapeutics: Current Employment, Current equity holder in private company. Smythe:Protagonist Therapeutics: Current Employment, Other: shareholder.


Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 482
Author(s):  
Valentina Natalucci ◽  
Edy Virgili ◽  
Federica Calcagnoli ◽  
Giacomo Valli ◽  
Deborah Agostini ◽  
...  

Cancer is often accompanied by worsening of the patient’s iron profile, and the resulting anemia could be a factor that negatively impacts antineoplastic treatment efficacy and patient survival. The first line of therapy is usually based on oral or intravenous iron supplementation; however, many patients remain anemic and do not respond. The key might lie in the pathogenesis of the anemia itself. Cancer-related anemia (CRA) is characterized by a decreased circulating serum iron concentration and transferrin saturation despite ample iron stores, pointing to a more complex problem related to iron homeostatic regulation and additional factors such as chronic inflammatory status. This review explores our current understanding of iron homeostasis in cancer, shedding light on the modulatory role of hepcidin in intestinal iron absorption, iron recycling, mobilization from liver deposits, and inducible regulators by infections and inflammation. The underlying relationship between CRA and systemic low-grade inflammation will be discussed, and an integrated multitarget approach based on nutrition and exercise to improve iron utilization by reducing low-grade inflammation, modulating the immune response, and supporting antioxidant mechanisms will also be proposed. Indeed, a Mediterranean-based diet, nutritional supplements and exercise are suggested as potential individualized strategies and as a complementary approach to conventional CRA therapy.


Gut ◽  
2019 ◽  
Vol 69 (3) ◽  
pp. 487-501 ◽  
Author(s):  
Cécile Vors ◽  
Laurie Joumard-Cubizolles ◽  
Manon Lecomte ◽  
Emmanuel Combe ◽  
Lemlih Ouchchane ◽  
...  

ObjectiveTo investigate whether milk polar lipids (PL) impact human intestinal lipid absorption, metabolism, microbiota and associated markers of cardiometabolic health.DesignA double-blind, randomised controlled 4-week study involving 58 postmenopausal women was used to assess the chronic effects of milk PL consumption (0, 3 or 5 g-PL/day) on lipid metabolism and gut microbiota. The acute effects of milk PL on intestinal absorption and metabolism of cholesterol were assessed in a randomised controlled crossover study using tracers in ileostomy patients.ResultsOver 4 weeks, milk PL significantly reduced fasting and postprandial plasma concentrations of cholesterol and surrogate lipid markers of cardiovascular disease risk, including total/high-density lipoprotein-cholesterol and apolipoprotein (Apo)B/ApoA1 ratios. The highest PL dose preferentially induced a decreased number of intestine-derived chylomicron particles. Also, milk PL increased faecal loss of coprostanol, a gut-derived metabolite of cholesterol, but major bacterial populations and faecal short-chain fatty acids were not affected by milk PL, regardless of the dose. Acute ingestion of milk PL by ileostomy patients shows that milk PL decreased cholesterol absorption and increased cholesterol-ileal efflux, which can be explained by the observed co-excretion with milk sphingomyelin in the gut.ConclusionThe present data demonstrate for the first time in humans that milk PL can improve the cardiometabolic health by decreasing several lipid cardiovascular markers, notably through a reduced intestinal cholesterol absorption involving specific interactions in the gut, without disturbing the major bacterial phyla of gut microbiota.Trial registration numberNCT02099032 and NCT02146339; Results.


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