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Samarron SL, Miller JW, Cheung AT, Chen PC, Lin X, Zwerdling T, Wun T, Green R. Homocysteine is associated with severity of microvasculopathy in sickle cell disease patients. Br J Haematol 2020; 190:450-457. [PMID: 32307711 DOI: 10.1111/bjh.16618] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 12/31/2022]
Abstract
The pathophysiology of sickle cell disease (SCD) includes vasculopathy as well as anaemia. Elevated plasma homocysteine is a risk factor for vascular disease and may be associated with increased risk of vascular complications in SCD patients. In the present study, microvascular characteristics were assessed in the bulbar conjunctiva of 18 paediatric and 18 adult SCD patients, using the non-invasive technique of computer-assisted intravital microscopy. A vasculopathy severity index (SI) was computed to quantify the degree of microvasculopathy in each patient. Plasma homocysteine and several of its determinants [serum folate and vitamin B12, plasma pyridoxal-5'-phosphate (vitamin B6 status) and creatinine (kidney function)] were measured. Age was strongly correlated with microvasculopathy in the SCD patients, with the SI increasing about 0·1 unit per one-year increase in age (P < 0·001). After adjusting for age, gender, B-vitamin status and creatinine, homocysteine concentration was directly correlated with severity index (P < 0·05). Age and homocysteine concentration were independent predictors of microvasculopathy in SCD patients. It remains to be determined whether lowering homocysteine concentrations using appropriate B-vitamin supplements (folate and vitamins B12 and B6) - particularly if started early in life - could ameliorate microvasculopathy and its associated complications in SCD patients.
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Affiliation(s)
- Sandra L Samarron
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA
| | - Joshua W Miller
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Anthony T Cheung
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA.,Institute for Biomedical Sciences, San Diego, CA, USA
| | - Peter C Chen
- Institute for Biomedical Sciences, San Diego, CA, USA.,Shiley Center for Orthopaedic Research and Education, La Jolla, CA, USA
| | - Xin Lin
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA
| | - Theodore Zwerdling
- Department of Pediatrics (Hematology-Oncology), University of California, Davis, CA, USA
| | - Ted Wun
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA.,Department of Internal Medicine (Hematology-Oncology), University of California, Davis, CA, USA.,UC Davis Clinical and Translational Science Center, Sacramento, CA, USA
| | - Ralph Green
- Department of Medical Pathology and Laboratory Medicine, University of California, Davis, CA, USA.,Department of Internal Medicine (Hematology-Oncology), University of California, Davis, CA, USA
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Al-Saqladi AWM, Harper G, Delpisheh A, Fijnvandraat K, Bin-Gadeem HA, Brabin BJ. Frequency of the MTHFR C677T Polymorphism in Yemeni Children with Sickle Cell Disease. Hemoglobin 2010; 34:67-77. [DOI: 10.3109/09687630903554111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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van der Dijs FPL, Fokkema MR, Dijck-Brouwer DAJ, Niessink B, van der Wal TIC, Schnog JJB, Duits AJ, Muskiet FD, Muskiet FAJ. Optimization of folic acid, vitamin B(12), and vitamin B(6) supplements in pediatric patients with sickle cell disease. Am J Hematol 2002; 69:239-46. [PMID: 11921017 DOI: 10.1002/ajh.10083] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Using homocysteine as a functional marker, we determined optimal folic acid, vitamin B(12), and vitamin B(6) dosages in 21 pediatric sickle cell disease (SCD) patients (11 HbSS, 10 HbSC; 7-16 years). Daily supplements of folic acid (400, 700, or 1,000 microg), vitamin B(12) (1, 3, or 5 U.S. 1989 RDA), and vitamin B(6) (1 or 3 U.S. 1989 RDA) were gradually increased in an 82-week dose-escalation study. Blood was taken at 9 occasions for measurements of erythrocyte (RBC) and serum folate, plasma vitamin B(12), whole-blood vitamin B(6), and plasma homocysteine. Augmentation of folic acid from 700 to 1,000 microg and vitamin B(12) from 3 to 5 RDA did not further decrease homocysteine. Percentages of patients exhibiting significant individual homocysteine decreases amounted to 43% (folic acid from 0 to 400 microg, vitamins B(12) and B(6) from 0 to 1 RDA), 14% (folic acid from 400 to 700 microg), 24% (vitamin B(12) from 1 to 3 RDA), and 18% (vitamin B(6) from 1 to 3 RDA ). The lowest plasma homocysteine at 82 weeks was 5.9 +/- 2.2 micromol/L. Patients with HbSS had higher RBC folate than HbSC. The entire group exhibited an inverse relation between RBC folate and hemoglobin. We conclude that RBC folate is less valuable for folate status assessment in SCD patients. Optimal dosages are as follows: 700 microg folic acid (3.5-7 U.S. 1989 RDA), 3 U.S. 1989 RDA vitamin B(12) (4.2-6.0 microg), and 3 U.S. 1989 RDA vitamin B(6) (4.2-6.0 mg). A practical daily combination is 1 mg folic acid (4.3-8.5 U.S. 1998 RDA when taken with meals), 6 microg vitamin B(12) (2.5-5 U.S. 1998 RDA), and 6 mg vitamin B(6) (4.6-10 U.S. 1998 RDA). This combination may by simple and relatively inexpensive means reduce these patients' inherently high risk of endothelial damage.
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