The assessment of serum soluble transferrin receptor in alcoholics

Abstract

The consumption of large amounts of alcohol disturbs body iron metabolism and leads to increase of body iron stores and may cause various hematologic changes. Both, iron overload and iron depletion could have effect on the metabolic, transit and storage pools. These pools and its indicators were evaluated previously in abusers, but there is no information concerning the serum soluble transferrin receptor (sTfR) as a new marker of transit compartment. Therefore, the aim of this study was to assess the sTfR and compare it to the other indicators of transit pool in alcoholics. sTfR was measured immunoturbidimetrically. The markers of alcohol abuse, metabolic, transport and storage pools and the other hematologic assays were determined by routine laboratory methods. The tested group consisted of 148 alcoholics. The abusers were not affected by anemia. Every second patient had increased iron storage pool. Serum iron level only tended to increase. The mean serum sTfR did not show any significant difference and the mean transferrin-ferritin index (sTfR/log ferritin ratio) was significantly decreased compared with the controls. None of the transit pool markers presented significant differences between subgroups classified according to liver enzyme activities. We suggest that the iron excess in alcoholics did not limit the cellular iron uptake by transferrin receptor-mediated endocytosis which was confirmed by the unchanged level of serum soluble transferrin receptor. Additionally, the serum sTfR in alcohol abusers is independent of the weekly alcohol intake, age of the patients, duration of dependence, time of abstinence, time of last drinking and the liver function tests.

Iron and iron-related proteins in alcohol consumers: cellular and clinical aspects

“…May remain similar to corresponding controls (Unknown function; elevated in the serum in iron deficiency anemia) [20] • Reference range: 2.2-5.0 mg/L; In controls: 2.65 (1.9-3.7) mg/L (n = 30; social drinkers consumed less than 30 g/day (210 g/week)) [20] • In non-dependents on alcohol (social drinkers): 2.9 mg/L (n = 115; alcohol non-dependents with a negative AUDIT score of ≤ 6/8 and negative diagnosis of alcohol dependence, as defined by ICD-10 and DSM-IV) [ • Reference range: 11.17-17.0 g/dL; [70] • Range in controls: 1.4 ± 0.1 g/dL (n = 20; alcohol consumption less than 20 g/day in women and 40 g/day in men) [25] • In non-dependents on alcohol (social drinkers): 14.2 g/dL (n = 115; alcohol non-dependents with a negative AUDIT score of ≤ 6/8 and negative diagnosis of alcohol dependence, as defined by ICD-10 and DSM-IV) [68] • 12-18 g/dL in 82.5% of patients; 13.35 g/dL (2.16) (total number of patients = 103); consumption of at least 16 g/day or 2 units (drinks)/day) [47] • 1.4 ± 0.2 g/dL (n = 25; ALD active drinkers without cirrhosis, average daily alcohol intake of 154 g) [25] • 14.6 g/dL (n = 101; alcohol dependent patients with a positive AUDIT score of > 6/8 and positive diagnosis for alcohol dependence, as defined by ICD-10 and DSM-IV) [68] May be lower than corresponding controls or at lower end of reference range…”

“…Some ALD patients have shown serum iron levels similar to controls [20][21][22]. Moreover, a study showed similar levels of serum iron in patients with ALD cirrhosis, alcoholic hepatitis, and healthy volunteers that did not demonstrate any acute or chronic health conditions and consumed alcohol within the recommended guidelines [21].…”

“…• Range in controls: 115.7 ± 81.8 µg/L (n = 20; alcohol consumption less than 20 g/day in women and 40 g/day in men) [25] • Under alcohol abstinence: 388 ± 237 µg/L (n = 13, after abstaining for 1.5 to 6 weeks) [77] • Reference range: 30-400 µg/L [46] • Range in controls: 258.74 ± 37.39 µg/L (n = 32; nonalcoholics) [53] • In controls: 83 (21.6-207.5) µg/L (n = 30; social drinkers consumed less than 30 g/day (210 g/week)) [20] • [22] • Transferrin saturation index: 29.45 ± 17.35%; n = 32; nonalcoholics [53] • Healthy controls: Approximate range: 20-45%; n = 60 [23] • 32.22 ± 4.88% (n = 24; ALD patients) [22] • Transferrin saturation index: 31.90 ± 24.98% (n = 238; heavy alcohol consumers drinking 199 ± 115 g/day during the last 31 ± 12 years) [53] • Approximate range: 20-45% (n = 13; alcoholic fatty liver patients with an intake of 40 g/ day) [23] May be higher than corresponding controls or reference range…”

“…• Range in controls: 27.8 ± 12.8% (n = 20; alcohol consumption less than 20 g/day in women and 40 g/day in men) [25] • 30.0 ± 10.4% in non-drinkers (men) (n = 267; drank 2-3 times/ year or less, or did not drink at all) [80] • In controls: 27.32% (9.11-50.22) (n = 30; social drinkers consumed less than 30 g/day (210 g/week)) [20] •Hemochromatosis patients that consumed < 60 g/day alcohol: [32]. Here, there was no significant difference between the two groups, but the range of values in both groups appeared to be higher than the reference ranges in controls/non-drinkers stated in other studies…”

“…• In controls: 1.95% (1.25-3.31) (n = 30; social drinkers consumed less than 30 g/day (210 g/week)) [20] • In non-dependents on alcohol (social drinkers): 2.2% (n = 115; alcohol non-dependents with a negative AUDIT score of ≤ 6/8 and negative diagnosis of alcohol dependence, as defined by ICD-10 and DSM-IV) [68] • Average disialotransferrin to total transferrin fraction: 1.2% (0.20) [87] • In non-drinkers: 1.71 ± 0.04%; n = 29 [88] • 6.27% (1.26-17.66) (n = 148; alcohol-dependent patients, mean alcohol consumption of 1344 g/week) [20] • 3.9% (n = 101; alcohol dependent patients with a positive AUDIT score of > 6/8 and positive diagnosis for alcohol dependence, as defined by ICD-10 and DSM-IV) [68] • Upper limit of reference interval for disialotransferrin to total transferrin fraction (in nondrinkers and light and heavy drinkers combined): 1.70% [87] • Heavy drinkers: 2.44 ± 0.14% (n = 29; consuming ≥ 420 g alcohol/week) [88] Soluble transferrin receptor (sTfR)…”