BRIEF REPORT Atypical glomerulopathy associated with the cblE inborn error of vitamin B 12 metabolism Erin A. Paul & Marta Guttenberg & Paige Kaplan & David Watkins & David S. Rosenblatt & James R. Treat & Bernard S. Kaplan Received: 25 December 2012 / Revised: 4 February 2013 / Accepted: 14 February 2013 / Published online: 19 March 2013 # IPNA 2013 Abstract Background The cblE disorder is an inherited dis- order of vitamin B 12 metabolism that results in elevated levels of homocysteine and decreased methionine in body fluids. Renal complications have been reported in patients with cblC disease, but not in those with cblE disease. The renal compli- cations of cblC disease include thrombotic microangiopathy (TMA), neonatal hemolytic uremic syndrome, chronic renal failure, tubulointerstitial nephritis and proximal renal tubular acidosis. Previously, we reported a patient with cblC disease who had an atypical glomerulopathy that manifested with proteinuria and progressive renal insufficiency. Case-Diagnosis/Treatment Studies were done on cultured fibroblasts. Renal biopsy tissue was examined by light and electron microscopy. There was decreased incorporation of labeled methyltetrahydrofolate and decreased synthesis of methylcobalamin. Complementation analysis placed the pa- tient into the cblE complementation group. The findings from the histological and ultrastructural studies of renal biopsy were similar, but not identical, to those of idiopathic membranoproliferative glomerulonephritis (MPGN) and overlapped with those of TMA. Conclusions We describe a patient with cblE disease who had an atypical glomerulopathy similar to MPGN. Addition- al findings included migraine headaches, hypothyroidism and livedo reticularis. Keywords Vitamin B 12 . Cobalamin metabolism . cblE disorder . Membranoproliferative glomerulonephritis . Thrombotic microangiopathy Introduction Although inadequate vitamin B 12 [cobalamin (cbl)] intake or absorption accounts for most patients who present with symptoms of cobalamin deficiency [1], a small but signif- icant number have specific mutations in the genes respon- sible for cellular cobalamin uptake and metabolism (inborn errors of cobalamin metabolism) [2]. Cobalamin derivatives act as cofactors for methionine synthase in the conversion of homocysteine to methionine in the cyto- plasm (methylcobalamin), and for methylmalonyl-CoA mutase in the conversion of methylmalonyl-CoA to succinyl-CoA in the mitochondrion (adenosylcobalamin) E. A. Paul Department of Pediatrics, Columbia Medical Center, 630 W 168th St, New York, NY 10032, USA M. Guttenberg Department of Pathology, The Children’ s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, USA P. Kaplan Section of Metabolism and Department of Pediatrics, The Children’ s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, USA D. Watkins : D. S. Rosenblatt Department of Human Genetics, McGill University, 1205 Avenue Docteur Penfield, N5/13, Montreal, Quebec, Canada H3A 1B1 J. R. Treat Section of Dermatology, Department of Pediatrics, The Children’ s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, USA B. S. Kaplan (*) Division of Nephrology and Department of Pediatrics, The Children’ s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, USA e-mail: [email protected]Pediatr Nephrol (2013) 28:1135–1139 DOI 10.1007/s00467-013-2443-6
Transcript
BRIEF REPORT
Atypical glomerulopathy associated with the cblE inbornerror of vitamin B12 metabolism
Erin A. Paul & Marta Guttenberg & Paige Kaplan &
David Watkins & David S. Rosenblatt & James R. Treat &Bernard S. Kaplan
Received: 25 December 2012 /Revised: 4 February 2013 /Accepted: 14 February 2013 /Published online: 19 March 2013# IPNA 2013
Abstract Background The cblE disorder is an inherited dis-order of vitamin B12 metabolism that results in elevated levelsof homocysteine and decreased methionine in body fluids.Renal complications have been reported in patients with cblCdisease, but not in those with cblE disease. The renal compli-cations of cblC disease include thrombotic microangiopathy(TMA), neonatal hemolytic uremic syndrome, chronic renalfailure, tubulointerstitial nephritis and proximal renal tubular
acidosis. Previously, we reported a patient with cblC diseasewho had an atypical glomerulopathy that manifested withproteinuria and progressive renal insufficiency.Case-Diagnosis/Treatment Studies were done on culturedfibroblasts. Renal biopsy tissue was examined by light andelectron microscopy. There was decreased incorporation oflabeled methyltetrahydrofolate and decreased synthesis ofmethylcobalamin. Complementation analysis placed the pa-tient into the cblE complementation group. The findingsfrom the histological and ultrastructural studies of renalbiopsy were similar, but not identical, to those of idiopathicmembranoproliferative glomerulonephritis (MPGN) andoverlapped with those of TMA.Conclusions We describe a patient with cblE disease whohad an atypical glomerulopathy similar to MPGN. Addition-al findings included migraine headaches, hypothyroidismand livedo reticularis.
Although inadequate vitamin B12 [cobalamin (cbl)] intakeor absorption accounts for most patients who present withsymptoms of cobalamin deficiency [1], a small but signif-icant number have specific mutations in the genes respon-sible for cellular cobalamin uptake and metabolism(inborn errors of cobalamin metabolism) [2]. Cobalaminderivatives act as cofactors for methionine synthase in theconversion of homocysteine to methionine in the cyto-plasm (methylcobalamin), and for methylmalonyl-CoAmutase in the conversion of methylmalonyl-CoA tosuccinyl-CoA in the mitochondrion (adenosylcobalamin)
E. A. PaulDepartment of Pediatrics, Columbia Medical Center,630 W 168th St,New York, NY 10032, USA
M. GuttenbergDepartment of Pathology, The Children’s Hospitalof Philadelphia, 34th Street and Civic Center Boulevard,Philadelphia, PA 19104, USA
P. KaplanSection of Metabolism and Department of Pediatrics,The Children’s Hospital of Philadelphia,34th Street and Civic Center Boulevard,Philadelphia, PA 19104, USA
D. Watkins :D. S. RosenblattDepartment of Human Genetics, McGill University,1205 Avenue Docteur Penfield, N5/13,Montreal, Quebec, Canada H3A 1B1
J. R. TreatSection of Dermatology, Department of Pediatrics,The Children’s Hospital of Philadelphia,34th Street and Civic Center Boulevard,Philadelphia, PA 19104, USA
B. S. Kaplan (*)Division of Nephrology and Department of Pediatrics,The Children’s Hospital of Philadelphia,34th Street and Civic Center Boulevard,Philadelphia, PA 19104, USAe-mail: [email protected]
[1–3]. Mutations in transport proteins and enzymes affect-ing both pathways (cblC, cblD, cblF and cblJ) result inboth hyperhomocysteinemia and methylmalonic acidemia[2–4]. Disorders that have an impact only on the cytosolicpathway (cblD-HC, cblE and cblG) result in elevatedlevels of homocysteine and low or inappropriately low-normal levels of methionine in body fluids without eleva-tion in methylmalonic acid. In the cblE disorder, thisresults in megaloblastic anemia and variable neurologicalmanifestations, including neonatal seizures, cerebral atro-phy, ataxia, developmental delay and mental retardation[2, 3]. The severity of neurologic dysfunction may dependupon the underlying genotype, with less severe hemato-logic abnormalities being associated with later onset [5,6]. The MTRR gene responsible for cblE codes formethionine synthase reductase (MTRR; EC 2.1.1.135).MTRR binds to the activating domain of methioninesynthase, maintaining the cobalamin that is bound to theenzyme in its active reduced form. It may also act as amolecular chaperone, stabilizing newly synthesized methioninesynthase and increasing the rate of binding of cobalaminto the apoenzyme [7].
Tubular proteinuria occurs in Imerslund–Gräsbeck syn-drome, a genetic defect caused by mutations in CUB orAMN and resulting in malabsorption of the intrinsic factor–cobalamin complex by enterocytes and decreasedreabsorption of proteins, including albumin, in the proximaltubule [8]. A few other renal abnormalities have been docu-mented in association with cobalamin deficiency. cblC diseasecan cause an atypical, frequently lethal form of hemolyticuremic syndrome (HUS) in infancy [9, 10] and late-onsetthrombotic microangiopathy (TMA) [11, 12]. High levels ofcirculating methylmalonic acid, which occur in the mut, cblAand cblB disorders, have been linked with chronic renal fail-ure, renal tubular acidosis and tubulointerstitial nephritis withmononuclear inflammatory infiltrate and tubular atrophy [13,14]. There has been one case report of a patient with the cblCdisorder who had focal segmental glomerulosclerosis [15] andanother report of a cblC patient who had an atypicalglomerulopathy resembling membranoproliferative glomeru-lonephritis (MPGN) type III or thrombotic microangiopathy[16]. There have been no reports of cblE disease associatedwith any of these renal manifestations.
In this report we describe a patient with cblE diseasewho presented in childhood with an acute glomerulone-phritis of unknown etiology and who progressed overmany years to chronic renal insufficiency. The renalhistopathological findings resembled those of atypicalMPGN with TMA that we previously described in apatient with cblC disorder [16]. We speculate that cblCor cblE can result in several different phenotypes thatinclude HUS, TMA and an atypical MPGN in additionto a spectrum of neurological manifestations.
Case report
Our 22-year-old female patient is the only child born tounrelated parents of Slavic and Irish ethnicity. At the age of5 years she complained of headaches and periorbital and pedaledema. She was found to have hypertension, hypercholester-olemia and on urinalysis had 3+ blood, 3+ protein and redblood cell casts. Her blood pressure ranged from 121/76 to134/70 mmHg, protein excretion ranged from 1.58 to 2.49 g/24 h, serum creatinine concentration was 0.5 mg/dL, serumcholesterol was 273 mg/dL, serum albumin was 3.4 g/dL,serum C3 complement level was 91 (range 83–180) mg/dL,sedimentation rate was 77 mm/h, anti-nuclear antibody(ANA) titer was <1:40, anti-DNA double strand (anti-dsDNA) titer was <1:10 and the Anti-streptolysin O titer(ASOT) was negative. Tests for hepatitis C and hepatitis Bwere negative. Hemoglobin (11.6 g/dL) and hematocrit(33 %) were in the low range of normal and mean corpuscularvolume was 99 fL (normal 80–99 fL). Renal biopsy findings1 month after presentation demonstrated features similar toMPGN (see section Renal biopsy findings).
The patient had never been treated with corticosteroids orimmunosuppressive agents. Treatment consisted of 2.5 mgenalapril daily, which was increased to 2.5 mg twice daily after6 months of continued proteinuria that ranged from 885 to2.6 g/24 h. At age 8 years, during testing for scoliosis (15° leftlong thoracolumbar curve), she was found to have asymptom-atic spina bifida occulta at the fifth lumbar vertebra; the neu-rological examination was normal. At age 11 years she had aperiod of remission with 24-h urine protein as low as 145 mg,serum creatinine concentration of 0.8 mg/dL, normal serumcholesterol and albumin concentrations and normal sedimen-tation rate. Concentrations of C3 remained normal, and C4levels were slightly low at 10–12 mg/dL (normal 15.7–47).Over the next 4 years she developed migraine headaches, buthad no neurological or cognitive deficits.
Twelve years after the initial presentation, at 17 years, shebegan to have increased proteinuria (3+ protein on urinalysis),and her serum creatinine concentration increased to 1.0 mg/dL.She also had progressive livedo reticularis on the digits, hands,feet, legs and arms without ulceration (Fig. 1). Although therewere no clinical features of hypothyroidism, the free thyroxine(T4) level was 0.5 (normal range 0.9–1.4) ng/dL, total thyroxinewas 1.1 (normal range 1.4–3.8) mcg/dL, thyroid stimulatinghormone (TSH) was >150 (normal range 0.5–3.8) uLU/mLand anti-thyroid antibodies were not detected. She was treatedwith thyroxine replacement therapy, which she took intermit-tently. Evaluation of recurrent headaches included repeat testsfor ANA, anti-dsDNA antibody as well as anti-neutrophil cyto-plasmic antibody, and anti-cardiolipin antibody; all titers werenormal. C3, C4 and total hemolytic complement (59 μ/mL;normal range 31–66 u/ml) were normal. A brain magneticresonance imaging (MRI) scan was unremarkable, and the
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results of the neurological examination remained normal. Thefollowing year the serumcreatinine had increased to 1.54mg/dL.A macrocytic anemia was noted (hemoglobin 10.6 g/dL, meancorpuscular volume 115.7 fL/cell). Serum vitamin B12 wasnormal prior to treatment with cyanocobalamin (561 pg/mL;normal range 200–1,100 pg/mL), as was serum folate (>20ng/mL; normal >3 ng/mL). After treatment with intramuscularcyanocobalamin at a dose of 100 mcg monthly for 2 monthsimprovement was observed for hemoglobin (13 g/dL) but mac-rocytosis persisted. Subsequent studies showed plasma totalhomocysteine levels of >50 (normal <10.4) μmol/L, methio-nine levels of 17 (normal 16–34) μmol/L and methylmalonicacid levels of 213 nmol/L (within normal limits).
Studies on cultured fibroblasts
The incorporation of [14C]-propionate, a measure ofmethylmalonyl-CoA mutase function, was within the reference
range. Incorporation of [14C]- methyltetrahydrofolate, a mea-sure of methionine synthase function, was low and slightlyresponsive to the presence of OHCb1 in the culture medium.The uptake of [57Co]-cyanocobalamin was not decreased, andthere was adequate synthesis of adenosylocobalamin. The syn-thesis of methylcobalamin was decreased. Complementationanalysis placed the patient into the cblE complementationgroup. Mutation analysis of MTRR was not performed.
Renal biopsy findings
Light microscopy (Fig. 2) showed enlarged, hypercellularlobulated glomeruli. Periodic Acid Schiff staining showedthickened capillary loops. Silver staining confirmed the pres-ence of thickened loops and the appearance of a split orduplicated basement membrane. No glomerular necrosis orinflammation was noted. Proximal and distal tubule morphol-ogy appeared to be normal. Electron microscopy (Fig. 3)
Fig. 1 Livedo reticularis on thedigits and hands
a bFig. 2 Glomerulus structure bylight microscopy. a Glomerulushas a lobular appearance withan increased number ofmesangial cells. Hematoxylinand eosin stain, ×40. b Silverstaining demonstratesthickening and duplication(arrow) of the glomerularbasement membrane. Jones’silver stain, ×40
Pediatr Nephrol (2013) 28:1135–1139 1137
demonstrated widening of the subendothelial space by electronlucent material. No epimembranous deposits, basementmembrane spikes or fibrillary deposits were noted. No tissuewas available for immunofluorescence microscopy.
Treatment and course
At the age of 22 years she is a college student. Her neurologicfunction is normal. The patient has not always been adherentto hydroxocobalamine treatment. Eight months after re-startinghydroxocobalamine therapy, the macrocytic anemia had re-solved (hemoglobin 14.2 g/dL, mean corpuscular volume99.0 fL). She has not had fragmented erythrocytes, thrombo-cytopenia or thrombi. The serum total homocysteine hasremained elevated, and the plasma methionine has been inthe low-normal range, presumably because of non-compliancewith therapy. Laboratory testing revealed a hemoglobin con-centration of 15.2 g/dL and elevated mean corpuscular volumeat 101.5 fL, and macrocytic cells were seen on the peripheralblood smear. She continues to havemigraine headaches, livedoreticularis and intermittent biochemical features, but there is noclinical evidence of hypothyroidism. She has stage 3 chronickidney disease with a serum concentration of 1.4mg/dL and anestimated glomerular filtration rate according to the MDRD(Modification of Diet in Renal Disease) formula of53 mL/min/1.73 m2. Serum C3 concentrations are persistentlywithin normal range, while the C4 concentrations are mildlydecreased at 10–12 (normal range 16–47) mg/dL.
Discussion
A 22-year-old woman with hyperhomocysteinemia, and meg-aloblastic anemia and low plasma methionine, but withoutevidence of developmental delay, MRI abnormalities or neu-rological deficits except for migraine headaches, was
diagnosed with cblE disorder by complementation analysis.The patient’s relatively mild phenotype is similar to thatreported for two patients with less severe neurological pre-sentations [2]. The spina bifida occulta of our patient mayrepresent a neurological manifestation of disease, or it may bethe result of a maternal deficiency of folate. Macrocytosis wasnot apparent until she was 13 years old, and the anemiabecame persistent by the age of 16 years. At no time did shehave schistocytes or thrombocytopenia. The temporal separa-tion between her renal illness, which initially presented as amild nephritic–nephrotic syndrome and her subsequent hema-tologic manifestations may represent variable onset of a broadphenotypic constellation.
Light microscopy examination of the renal biopsy showeda lobulated glomerulus and mesangial hypercellularity withbasement membrane thickening. The ultrastructural studiesshowed widening of the subendothelial space with loose andfluffy material and no subendothelial deposits or thrombi.Such a pattern is often seen with the resolution of a TMA.While the subendothelial involvement, split and thickenedbasement membrane and decreased serum C4 are most con-sistent with type I MPGN, persistently normal C3 is unusualfor any of the MPGN subtypes [17, 18]. Furthermore, thispatient’s serum complement and biopsy findings cannot be re-classified as an MPGN under the rubric of the C3glomerulopathies [19]. There is one previously reported caseof intrinsic cobalamin deficiency associated with an atypicalglomerulopathy [16]. That case showed features similar totype III MPGN, while our patient’s biopsy has features resem-bling type I MPGN. Nevertheless, although not exactly thesame, there are similarities with the atypical MPGN previous-ly reported in our cblC cases to justify linking the MPGN tocblE disease. Methylmalonic aciduria has been evoked as themechanism of renal injury in mut, cblA and cblB patients [20,21], but cannot explain renal findings in cblE deficiencywhere there is homocystinuria without methylmalonicaciduria. We speculate that there may be a direct detrimentaleffect of homocysteine on the kidneys or an effect of low orlow-normal methionine for glomerular preservation and func-tion. Homocysteine may damage renal endothelium directlythrough the accumulation of oxygen radicals [22] or theinduction of metalloproteinases [23]. The procoagulant milieuinduced by homocysteine may result in intravascular coagu-lation that could lead to cortical necrosis and leave a histo-pathological impression of TMA [24]. cblC disease can causean atypical, frequently lethal form of HUS in infancy [9] andlate-onset TMA [14]. Homocysteine-induced toxicity mayrender the endothelial barrier more fragile and might facilitateother pathophysiological processes that are then expressed atthe endothelial cells, such as circulating immune complexes orcomplement abnormalities. This may help to explain the va-riety of phenotypes associated with cbl abnormalities. Forexample, late-onset TMA caused by cblC disease was
Fig. 3 Ultrastructural appearance of a glomerular loop showing fluffy,sub-endothelial deposits (arrow)
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associated with a factor H mutation in one patient [12], andatypical HUS occurred in another patient with a CD46 muta-tion and hyperhomocysteinemia [25].
Conclusions
We describe a patient with cblE disease who presented inchildhood with an acute glomerulonephritis that progressedover many years to chronic renal insufficiency. The renalhistopathological findings resembled the atypical MPGNwith TMA that we described in a patient with cblC defi-ciency. We speculate that cblC or cblE disease can result inseveral different phenotypes that include HUS, MPGN andTMA in addition to a spectrum of neurological manifesta-tions. In addition, our patient also had biochemical evidenceof hypothyroidism and non-progressive livedo reticularis,which have no known association with cblE.
References
1. Carmel R, Green R, Rosenblatt DS, Watkins D (2003) Update oncobalamin, folate, and homocysteine. Hematol Am Soc HematolEduc Program 62–81
2. Watkins D, Rosenblatt DS (2012) Update and new concepts invitamin responsive disorders of folate transport and metabolism. JInherit Metab Dis 35:665–670
3. Watkins D, Rosenblatt DS (2011) Inherited disorders of folate andcobalamin transport and metabolism. In: Valle D, Beaudet AL,Vogelstein B, Kinzler KW, Antonarakis SE, Ballabio A (eds) Theonline metabolic and molecular bases of inherited disease. McGraw-Hill, New York. Chapter 155, pp 1–6. doi:10.1036/ommbid.187
4. Coelho D, Kim JC, Miousse IR, Fung S, Du Moulin M, Buers I,Suormala T, Burda P, Frapolli M, Stucki M, Nürnberg P, Thiele H,Robenek H, Höhne W, Longo N, Pasquali M, Mengel E, WatkinsD, Shoubridge EA, Majewski J, Rosenblatt DS, Fowler B, RutschF, Baumgartner M (2012) Mutations in ABCD4 cause a new inbornerror of vitamin B12 metabolism. Nature Genet 44:1152–1155
5. Vilaseca MA, Vilarinho L, Zavadakova P, Vela E, Cleto E, PinedaM, Coimbra E, Suormala T, Fowler B, Kozich V (2003) CblE typeof homocystinuria: mild clinical phenotype in two probands ho-mozygous for a novel mutation in the MTRR gene. J Inherit MetabDis 26:361–369
6. Steen C, Rosenblatt DS, Scheying H, Braeuer HC, Kohlschutter A(1997) Cobalamin E (cblE) disease: a severe neurological disorderwith megaloblastic anaemia, homocystinuria and low serum me-thionine. J Inherit Metab Dis 20:705–706
7. Yamada K, Gravel RA, Toraya T, Matthews RG (2006) Humanmethionine synthase reductase is a molecular chaperone for humanmethionine synthase. Proc Natl Acad Sci USA 103:9476–9481
8. Wahlstedt-Fröberg V, Pettersson T, Aminoff M, Dugué B,Gräsbeck R (2003) Proteinuria in cubilin-deficient patients withselective vitamin B12 malabsorption. Pediatr Nephrol 18:417–421
9. Russo P, Doyon J, Sonsino E, Ogier H, Saudubray JM (1992) Acongenital anomaly of vitamin B12 metabolism: a study of threecases. Hum Pathol 23:504–512
10. Sharma AP, Greenberg CR, Prasad AN, Prasad C (2007)Hemolytic uremic syndrome (HUS) secondary to cobalamin C(cblC) disorder. Pediatr Nephrol 22:2097–2103
11. Van Hove JL, Van Damme-Lombaerts R, Grünewald S, Peters H,Van Damme B, Fryns JP, Arnout J, Wevers R, Baumgartner ER,Fowler B (2002) Cobalamin disorder Cbl-C presenting with late-onset thrombotic microangiopathy. Am J Med Genet 111:195–201
12. Guigonis V, Frémeaux-Bacchi V, Giraudier S, Favier R, BorderieD, Massy Z, Mougenot B, Rosenblatt DS, Deschênes G (2005)Late-onset thrombocytic microangiopathy caused by cblC disease:association with a factor H mutation. Am J Kidney Dis 45:588–595
13. Hörster F, Baumgartner MR, Viardot C, Suormala T, Burgard P,Fowler B, Hoffmann GF, Garbade SF, Kölker S, Baumgartner ER(2007) Long-term outcome in methylmalonic acidurias isinfluenced by the underlying defect (mut0, mut-, cblA, cblB).Pediatr Res 62:225–230
14. Cosson MA, Benoist JF, Touati G, Déchaux M, Royer N, GrandinL, Jais JP, Boddaert N, Barbier V, Desguerre I, Campeau PM,Rabier D, Valayannopoulos V, Niaudet P, de Lonlay P (2009)Long-term outcome in methylmalonic aciduria: a series of 30French patients. Mol Genet Metab 97:172–178
15. Brandstetter Y, Weinhouse E, Splaingard ML, Tang TT (1990) Corpulmonale as a complication of methylmalonic acidemia andhomocystinuria (Cb1-C type). Am J Med Genet 36:167–171
16. Brunelli SM, Meyers KE, Guttenberg M, Kaplan P, Kaplan BS(2002) Cobalamin C deficiency complicated by an atypicalglomerulopathy. Pediatr Nephrol 17:800–803
17. Meyers KE, Strife CF, Witzleben C, Kaplan BS (1996) Discordantrenal histopathologic findings and complement profiles inmembranoproliferative glomerulonephritis type III. Am J KidneyDis 28(6):804–810
22. McCully KS (2009) Chemical pathology of homocysteine. IV.Excitotoxicity, oxidative stress, endothelial dysfunction, and in-flammation. Ann Clin Lab Sci 39:219–232
23. Ke XD, Foucault-Bertaud A, Genovesio C, Dignat-George F,Lamy E, Charpiot P (2010) Homocysteine modulates the proteo-lytic potential of human arterial smooth muscle cells through areactive oxygen species dependant mechanism. Mol Cell Biochem335:203–210
24. Dionisio N, Jardin I, Salido GM, Rosado JA (2010) Homocysteine.Intracellular signaling and thrombotic disorders. Curr Med Chem17:3109–3119
