Transferrin Isoform Distribution: Gender and Alcohol Consumption

Abstract

Transferrin (Tf) has different isoforms based on the degree of sialylation of its two N-linked oligosaccharide chains. The least sialylated isoforms of Tf; with 0 (asialo Tf), 1 (monosialo Tf), and 2 (disialo Tf) sialic acids are referred to as carbohydrate-deficient transferrin (CDT). CDT has been reported to be a specific and sensitive marker for the detection and monitoring of alcohol abuse. However, the possible differences between the three CDT isoforms in males and females relative to alcohol consumption has not been known. The present study included 82 males (M) and 43 females (F) with well documented drinking habits. The Tf isoforms were separated by FPLC and measured by RIA in the collected fractions, as well as by a commercially available method (CDTect RIA). The results were expressed as relative values and absolute values. Female low consumers compared to male low consumers had higher levels of asialo Tf (p < 0.01) and monosialo Tf (p < 0.01), but not of disialo Tf or sum of asialo, monosialo, and disialo Tf. Male high consumers and chronic consumers compared to male low consumers had 53% and 219% higher levels of asialo Tf, 4% and 28% higher monosialo Tf, 57% and 148% higher disialo Tf, and 48% and 134% higher sum of CDT isoforms, respectively. The corresponding increases in females were for asialo Tf 68% and 249%, for monosialo Tf 36% and 58%, for disialo Tf 54% and 225%, and for sum of CDT isoforms 52% and 192%, respectively. For both genders, total Tf, trisialo Tf, and the levels of more sialylated transferrin isoforms were constant when comparing the consumption groups. Results expressed as relative values and absolute values were in good agreement. In conclusion, the present study indicates that alcohol consumption strongly increases the levels of asialo Tf and disialo Tf and slightly increases the level of monosialo Tf. However, women had higher asialo Tf and monosialo Tf levels than men. Alcohol consumption does not increase trisialo or more sialyated Tf subfractions. Expressing the CDT results as absolute or relative values made no obvious difference in diagnostic efficiency.

Improved HPLC Method for Carbohydrate-deficient Transferrin in Serum

“…However, because asialotransferrin was not detected in all samples with an increased disialotransferrin in the present study, this analytical strategy might suffer from a lower diagnostic sensitivity. This is further supported by the observation that significant increases in asialotransferrin were observed only in "chronic" but not in "high" alcohol consumers, whereas disialotransferrin was significantly increased in both these groups (29 ).…”

Serum Carbohydrate Deficient Transferrin as A Sensitive Marker in Diagnosing Alcohol Abuse: A Case – Control Study

“…The study population comprised fully of males which may be attributed to the cultural background of the local population. However, this is not a limitation of the study since no gender variation has been found in the level of %CDT among alcoholics [18] and hence the conclusion of the present study may be extended to the female alcoholics also.…”

Asialotransferrin—An Alternative to Carbohydrate-deficient Transferrin?

“…The fourth argument is that asialotransferrin represents the transferrin isoform with the most distinct increase after chronic alcohol abuse. Serum asialotransferrin increases by 219 -250%, monosialotransferrin by only 28 -58%, and disialotransferrin by 148 -225% (12 ).…”

“…(c) Following from (a) and (b), the analysis of asialotransferrin should be more robust against pH variations compared with CDT analysis, where slight pH differences can cause coelution or cofocusing of CDT and non-CDT isoforms (3)(4)(5). (d) Monosialotransferrin (isoelectric point ϳ5.8), which is anodically next to asialotransferrin, is usually absent (13 ) or is present in only very small amounts [Ͻ0.9% of total transferrin (12 )]. Under conditions of complete transferrin-Fe 3ϩ saturation, there is no transferrin isoform cathodically next to asialotransferrin.…”