Uridine Diphosphate Hexoses in Leukocytes and Fibroblasts of Classic Galactosemics and Patients with Other Metabolic Diseases

Abstract

To examine uridine diphosphate hexose (UDPhexose) content of cells that have more complete metabolic patterns than erythrocytes, which have been commonly used in the study of galactosemia, the concentrations of uridine diphosphate galactose (UDPgalactose) and uridine diphosphate glucose (UDPglucose) were determined in white blood cells (WBC) and fibroblasts cultured from skin biopsies. Leukocyte UDPgalactose and UDPglucose values were determined in 60 normal individuals, 14 classic galactosemics, and 18 patients with other metabolic diseases on protein-restricted and low-lactose diets. There was no difference in the average concentration of these compounds between any of these groups. There was no relationship between age and WBC UDPhexose content or correlation of WBC and erythrocyte UDPhexose levels in the same blood specimens. WBC from galactosemic individuals differ from their red blood cells because the former do not show the low average UDPgalactose levels and abnormal UDPglucose to UDPgalactose ratio previously reported for erythrocytes from galactose-1-phosphate uridyltransferase-deficient individuals. Fibroblast cell lines from 10 normal and 10 galactosemic individuals, cultured and grown to confluence in glucose medium, also showed no difference in nucleotide sugar concentrations. Thus far, of the cell types easily available, red blood cells appear to be unique in showing an abnormality in nucleotide sugar metabolism. The fact that galactosemic fibroblasts demonstrate no abnormality in the concentration of these compounds suggests that the defective galactosylation that has been observed in galactosemic fibroblasts is not due to (1) reported that UDPgalactose concentration was low in red blood cells, liver biopsies, and cultured fibroblasts of patients with classic galactosemia, much attention has been focused on cellular UDPhexose levels. It has been suggested that a deficiency of UDPgalactose, the obligate donor in galactosylation, could lead to a defect in this important cellular process. The postulate that impaired galactosylation may be the basis for the long-term complications seen in galactosemics,

Pathophysiology of impaired ovarian function in galactosaemia

“…However, with the use of more accurate methods, such as high-performance liquid chromatography (HPLC), only the difference in erythrocyte UDP-galactose was confirmed, although there was a large overlap between cases and controls (Berry et al, 1992;Keevill et al, 1993). In contrast, UDP-galactose content in leukocytes and fibroblasts did not appear to be diminished in galactosaemic patients (Gibson et al, 1994;Keevill et al, 1994). This discrepancy was explained by the inability of red blood cell UDP-galactose epimerase to maintain a normal level of UDP-galactose in these cells (Segal, 1995a).…”

Chinese hamster ovary cells with reduced hexokinase activity maintain normal GDP-mannose levels

“…Fractions containing GDP-mannose (8-10 ml), which eluted at pH 7.5 were pooled, dried on a rotary evaporator, and resuspended in 1 ml water. The solution was centrifuged through an 0.2µ filter (Amicon, Micropure) and a 0.5 ml sample was injected onto a Dionex Carbopac PA1 column [Gibson et al, 1994] on a Waters 660E HPLC. GDP-mannose was eluted with a linear gradient in which the concentration of KH 2 PO 4 , pH 4.5 was increased from 0.25 to 0.35 M over a period of 60 min at a flow rate of 1 ml/min.…”

Pathophysiology and targets for treatment in hereditary galactosemia: A systematic review of animal and cellular models

“…UDP‐hexoses levels measured in patient erythrocytes, lymphocytes, and normal or transformed fibroblasts show sometimes contradictory results (Table ) . Drawing any conclusion from the observed findings is therefore very difficult.…”

“…50 UDP-hexoses levels measured in patient erythrocytes, lymphocytes, and normal or transformed fibroblasts show sometimes contradictory results (Table 1). [51][52][53][54][55] Drawing any conclusion from the observed findings is therefore very difficult. Various techniques (high-performance liquid chromatography [HPLC], indirect enzyme-based techniques) have been applied to measure UDP-hexoses levels, some of which are now recognised as susceptible to interference.…”