RESUMO
BACKGROUND: Mucopolysaccharidoses (MPS) are a group of inborn errors of metabolism that are progressive and usually result in irreversible skeletal, visceral, and/or brain damage, highlighting a need for early diagnosis. METHODS: This pilot study analyzed 2862 dried blood spots (DBS) from newborns and 14 DBS from newborn patients with MPS (MPS I, n = 7; MPS II, n = 2; MPS III, n = 5). Disaccharides were produced from polymer GAGs by digestion with chondroitinase B, heparitinase, and keratanase II. Heparan sulfate (0S, NS), dermatan sulfate (DS) and mono- and di-sulfated KS were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). Median absolute deviation (MAD) was used to determine cutoffs to distinguish patients from controls. Cutoffs were defined as median + 7× MAD from general newborns. RESULTS: The cutoffs were as follows: HS-0S > 90 ng/mL; HS-NS > 23 ng/mL, DS > 88 ng/mL; mono-sulfated KS > 445 ng/mL; di-sulfated KS > 89 ng/mL and ratio di-KS in total KS > 32 %. All MPS I and II samples were above the cutoffs for HS-0S, HS-NS, and DS, and all MPS III samples were above cutoffs for HS-0S and HS-NS. The rate of false positives for MPS I and II was 0.03 % based on a combination of HS-0S, HS-NS, and DS, and for MPS III was 0.9 % based upon a combination of HS-0S and HS-NS. CONCLUSIONS: Combination of levels of two or more different GAGs improves separation of MPS patients from unaffected controls, indicating that GAG measurements are potentially valuable biomarkers for newborn screening for MPS.
Assuntos
Glicosaminoglicanos/metabolismo , Mucopolissacaridoses/diagnóstico , Acetilglucosaminidase/sangue , Acetilglucosaminidase/metabolismo , Condroitinases e Condroitina Liases/sangue , Condroitinases e Condroitina Liases/metabolismo , Cromatografia Líquida/métodos , Dermatan Sulfato/sangue , Dermatan Sulfato/metabolismo , Dissacarídeos/sangue , Dissacarídeos/metabolismo , Glicosaminoglicanos/sangue , Heparitina Sulfato/sangue , Heparitina Sulfato/metabolismo , Humanos , Recém-Nascido , Mucopolissacaridoses/sangue , Mucopolissacaridoses/metabolismo , Triagem Neonatal/métodos , Projetos Piloto , Polissacarídeo-Liases/sangue , Polissacarídeo-Liases/metabolismo , Espectrometria de Massas em Tandem/métodosRESUMO
In a previous paper, we demonstrated that deep hypothermia in dogs provokes a release of a heparin-like factor. In the present study, we investigated some properties of this anticoagulant activity and compared it with exogenous heparin activity. The endogenous anticoagulant inhibited factors IIa and Xa; it was hydrolysed by heparinase and was AT III dependent. However, it differed from heparin in so far as it was adsorbed on cation exchange gel at neutral pH, its inhibition was decreased in the presence of neuraminidase, and it could not be neutralized with Polybrene or protamine. A release of heparan sulphate is suggested but remains to be demonstrated.