Healthy ranges of serum alanine aminotransferase levels in Tranian blood donors

AIM:The healthy ranges for serum alanine aminotransferase (ALT) levels are less well studied. The aim of this study was to define the upper limit of normal (ULN) for serum ALT levels, and to assess factors associated with serum ALT activity in apparently healthy blood donors.METHODS: A total of 1 939 blood donors were included.ALT measurements were performed for all cases using the same laboratory method. Healthy ranges for ALT levels were computed from the population at the lowest risk for liver disease. Univariate and multivariate analyses were performed to evaluate associations between clinical factors and ALT levels.RESULTS: Serum ALT activity was independently associated with body mass index (BMI) and male gender, but not associated with age. Association of ALT with BMI was more prominent in males than in females. Upper limit of normal for non-overweight women (BMI of less than 25) was 34 U/L,and for non-overweight men was 40 U/L.CONCLUSION: Serum ALT is strongly associated with sex and BMI. The normal range of ALT should be defined for male and female separately.     

Prevalence and etiology of persistently elevated alanine aminotransferase levels in healthy Iranian blood donors

BACKGROUND AND AIM: Causes of elevated serum alanine aminotransferase (ALT) levels vary depending on the population under study. The aim of this study was to determine the prevalence and causes of elevated ALT levels among apparently healthy Iranian blood donors in Tehran. METHODS: A total of 1959 (1465 male) randomly selected blood donors were enrolled in the study. Body mass index (BMI), viral markers and ALT levels were measured. If ALT was elevated (> 40 U/L), it was rechecked twice within 6 months. Blood donors with > or =2 times elevated ALT levels (persistently elevated ALT) were invited for further evaluation. RESULTS: A total of 100 donors (5.1%) had elevated ALT levels at the first measurement. Fifty-two persons (2.65%) were found to have persistently elevated serum ALT. Among subjects with persistently elevated serum ALT, non-alcoholic steatohepatitis (NASH) was diagnosed in 46 (88.4%), chronic hepatitis C virus (HCV) infection in four (7.7%), alcoholic liver disease in one (1.92%), and drug-induced liver disease in one (1.92%). The prevalence of NASH and HCV infection in the studied population was 2.35% and 0.4%, respectively. The mean BMI of NASH subjects was 30.58 kg/m(2), compared with 27.28 kg/m(2) of those without NASH (P < 0.001). CONCLUSION: Non-alcoholic steatohepatitis is the most common cause of persistently elevated serum ALT in the asymptomatic Iranian blood donors in Tehran.     

Influence of body mass index, sex and age on serum alanine aminotransferase (ALT) level in healthy blood donors.

BACKGROUND AND AIM: Serum alanine aminotransferase (ALT) level is the most common screening test as part of a routine evaluation of liver damage. In order to determine the factors influencing this liver function test in normal subjects, the relationship between ALT level and gender, age and body mass index (BMI) was studied in a large population of healthy blood donors. METHODS: This population included 9,420 volunteer blood donors (4,488 men and 4,932 women aged from 18 to 70 years) selected on the basis of negative answers to a detailed medical questionnaire including past medical history, drug and alcohol consumption, on the absence of clinical signs of liver disease, on the negativity of serological testing for hepatitis B and C virus and HIV. RESULTS: In the overall population, the mean serum ALT value was 21.8 I.U./L and the mean BMI was 24.4 kg/m2. There was a positive significant correlation between serum ALT level and BMI (Pearson r = 0.54; p < 0.001) and between ALT and age (Pearson r = 0.25; p < 0.001). A major sex-difference in ALT value was observed, the mean ALT value being higher in men than in women (26.8 +/- 13.6 vs. 17.2 +/- 8.1 I.U./L, p < 0.0001). In both sexes, ALT level was significantly correlated with BMI (Pearson r = 0.45 in men and r = 0.37 in women; p < 0.001). In women a consistent rise in BMI and ALT value with increasing age was observed whereas in men BMI and ALT level only increased with age up to the fifth decade. IN CONCLUSION: There was a significant positive correlation between ALT and BMI regardless the gender in a population of healthy volunteer blood donors. Moreover, at the same age and the same BMI, ALT was significantly lower in women than in men suggesting that the normal range for ALT value should be adjusted for gender. So gender and BMI have to be considered in the interpretation of ALT values.     

Normal serum alanine aminotransferase activity in uncomplicated obesity

AIM: To evaluate serum alanine aminotransferase (ALT) activity in a well-characterized group of uncomplicated obese subjects and its correlation with insulin resistance, plasma adiponectin, and leptin concentrations. METHODS: One hundred and five uncomplicated obese subjects (87 women, 18 men, age 34.3±9.6 years, BMI 39.9±8.3 kg/m2)were studied. Serum ALT activity was evaluated. Insulin sensitivity was assessed by euglycemic hyperinsulinemic clamp (M index) and fasting insulin. Plasma leptin and adiponectin levels were also measured. RESULTS: Serum ALT concentration in the whole group of uncomplicated obese subjects was 17.73±6.33 U/L with none of the subjects presenting ALT levels greater than 43 U/L and only 9 (11%) women and 3 (19%) men showed ALT levels >19 and >30 U/L for women and men, respectively. No significant difference was detected in serum ALT levels between severe obese subjects (BMI >40 kg/m2) and those with BMI <40 kg/m2 (18.63±6.25 vs 17.26±6.02 U/L). ALT was significantly correlated with fasting insulin (r=0.485, P= 0.02) and triglycerides (r= 0.358, P=0.03). CONCLUSION: Serum ALT activity is practically normal in uncomplicated obese subjects, independently of their obesity degree. These findings suggest the role of obesityrelated comorbidities and not of BMI as main risk factors for elevated ALT levels in obese subjects.     

Prevalence of TT virus infection in blood donors with elevated ALT in the absence of known hepatitis markers

OBJECTIVE: Recently a novel DNA virus (TT virus) has been identified in Japan and shown to be associated with elevated aminotransferase levels after blood transfusion. The exact role of TTV in the pathogenesis of liver disease is yet to be established. Our aim was to determine the prevalence and role of TTV in the pathogenesis of elevated transaminases in healthy blood donors in the absence of markers for viral hepatitis A-C. METHODS: Stored sera were collected from 99 healthy blood donors with elevated alanine amino transferase (ALT) values that were discovered at the time of blood donation. A total of 146 samples were obtained from healthy donors with normal ALT values who were used as controls. None of the patients or controls had a history of blood transfusion or had clinical signs of acute or chronic hepatitis. Serological markers for hepatitis A, hepatitis B, and hepatitis C viruses were negative. TTV DNA was amplified and detected using polymerase chain reaction followed by gel electrophoresis. RESULTS: Five of 99 (5%) samples obtained from donors with elevated ALT had TTV DNA detected by PCR, as compared to one of 146 (0.7%) of those with normal ALT (p = 0.006). Among those with elevated ALT, mean ALT values in patients with TTV (296 +/- 305 U/L) were higher than in patients without TTV (95 +/- 37 U/L), but the difference was not statistically significant (p = 0.08). The two samples with highest ALT values (both >450 U/L) were among the five samples with detectable TTV DNA in serum. CONCLUSIONS: Although TTV is not likely to explain the majority of elevated ALT cases in otherwise healthy blood donors, TTV infection may potentially be associated with some cases. Based on these findings, we propose that the role of TTV in the pathogenesis of acute and chronic liver diseases merits further investigation.     

Relationship between serum leptin and fatty liver in Japanese male adolescent university students

OBJECTIVE: The aim of this study was to elucidate the relationship between serum leptin levels and fatty liver in male adolescents. METHODS: We investigated the relationship between the concentration of circulating leptin and fatty liver by measuring the serum concentration of leptin in 284 male students who received the matriculation health examination in Okayama University in 1996 (n = 197; age, 18-20 yr) or 1997 (n = 87; age, 18-20 yr). RESULTS: Serum leptin levels correlated positively with body mass index (BMI), percent body fat (%FAT), thickness of skin fold (TSF), and serum concentration of ALT in 197 subjects. Examination of serum leptin in 67 subjects with BMI > or = 24.2 but < 28.6 kg/m2 showed a progressively higher levels in subjects with high serum ALT. Serum leptin levels in subjects with abnormally high serum ALT (> or = 37 IU/L) were significantly higher (p < 0.05) than in subjects with normal serum ALT, independent of BMI, %FAT, and TSF. Serum leptin levels were also significantly higher in subjects with fatty liver (detected by abdominal ultrasonography), independent of BMI and %FAT, compared with subjects without fatty liver. Stepwise multiple regression analysis showed that serum leptin level was an independent risk factor for fatty liver. In addition, serum leptin levels correlated with serum ALT (r = 0.518; p < 0.0005) and cholinesterase (r = 0.511; p < 0.0005) levels in 48 subjects with fatty liver. CONCLUSIONS: Our results demonstrated that serum leptin concentrations are high in male adolescents with simple obesity and are associated with high serum ALT or fatty liver, independent of BMI and %FAT, suggesting that the concentration of circulating leptin correlates with fatty liver caused by accumulation of visceral fat.     

Large-scale population analysis reveals an extremely low threshold for "non-healthy" alanine aminotransferase that predicts diabetes mellitus

Background and Aims: Serum alanine aminotransferase (ALT) is commonly used to detect liver damage. Recent studies indicate that ALT levels at the upper range of normal limits are predictors of adverse outcomes, especially diabetes mellitus (DM) and the metabolic syndrome. The aim of our study was to define the ALT threshold for both men and women that may predict the onset of DM. Methods: We analyzed a large Health Maintenance Organization cohort of 157 308 healthy subjects with no evidence of liver disease and with baseline ALT levels ≤ 120 U/L, and identified those who developed DM within 6 years. Results: Overall, an elevated baseline serum ALT value was significantly associated with the development of DM, with an odds ratio of 3.3 when comparing the higher and the lower quartiles of the whole study population. A subgroup analysis revealed that baseline ALT values higher than 10 U/L among women and 22 U/L among men were already significantly associated with an increased risk for DM for any increment in ALT level. Notably, ALT values higher than ～55 U/L were associated with increased risk for DM that was relatively constant for any increment in ALT. Higher baseline ALT levels were stronger predictors for DM as compared with age, triglycerides and cholesterol levels. Conclusion: Our study implies that ALT values higher than 10 U/L and 22 U/L for women and men, respectively, may predict DM. We suggest redefining ALT values as either ‘normal’ or ‘healthy’, with the later reflecting much lower values, above which an individual is at increased risk for DM.     

Reappraisal of biochemical hepatitis C activity in hemodialysis patients

We reappraised biochemical hepatitis C activity in hemodialysis patients in comparison with normal controls. A total of 111 hemodialysis patients and 66 healthy volunteer blood donors with hepatitis C virus (HCV) infection were consecutively enrolled. Serum alanine aminotransferase (ALT) levels were normal (< or =45 U/L) in 103 (93%) hemodialysis patients and 34 (52%) donors (p < 0.001). HCV viremic levels were lower in the hemodialysis group (p = 0.044), with no difference in the HCV genotype prevalence. During two-year follow-up, 60 (67%) of 90 hemodialysis patients and 13 (26%) of 50 donors showed persistently normal ALT levels (p < 0.001). For hemodialysis patients, however, the upper normal limit of ALT activity was reset at 25 U/L corresponding to the mean + 2 x SD for the normalized ALT distribution in 400 control patients. The adjusted ALT levels were initially normal in 73 (66%) hemodialysis patients and persistently normal in 19 (21%). Thus, ALT levels were the same for the two groups. GB virus C (GBV-C)/hepatitis G virus (HGV) coinfection found only in the hemodialysis group (10/111) had no influence on the disease. A relationship was noted between low disease activity and female gender in both groups. These findings indicate that biochemical hepatitis C activity in hemodialysis patients is similar to that in normal controls and should be monitored based on adjusted ALT levels.     

Serum γ-glutamyltransferase, alanine aminotransferase, and aspartate aminotransferase activity in Iranian healthy blood donor men

AIM: To determine serum γ-glutamyltransferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activity, and to assess their correlation with demographic and clinical findings in healthy blood donors.METHODS: This cross-sectional study was performed in 934 male blood donors, aged 18 to 68 years, who consecutively attended Tehran blood transfusion service in 2006. All participants were seronegative for HBV or HCV infections, non alcohol users, and all underwent a standard interview and anthropometric tests. Clinical and biochemical parameters including AST, ALT, and GGT activities were determined. Patients taking drugs known to cause hepatic fat deposition were excluded. For AST, ALT, and GGT variables, we used 33.33 and 66.66 percentiles, so that each of them was divided into three tertiles.RESULTS: Mean AST, ALT, and GGT activities were 25.26 ± 12.58 U/L (normal range 5-35 U/L), 33.13 ± 22.98 (normal range 5-35 U/L), and 25.11 ± 18.32 (normal range 6-37 U/L), respectively. By univariate analyses, there were significant associations between increasing AST, ALT, or GGT tertiles and age, body weight, body mass index, and waist and hip circumferences (P < 0.05). By multiple linear regression analyses, ALT was found to be positively correlated with dyslipidemia (B = 6.988, P = 0.038), whereas ALT and AST were negatively correlated with age. AST, ALT, and GGT levels had positive correlation with family history of liver disease (B = 15.763, P < 0.001), (B = 32.345, P < 0.001), (B =24.415, P < 0.001), respectively.CONCLUSION: Although we did not determine the cutoffs of the upper normal limits for AST, ALT, and GGT levels, we would suggest screening asymptomatic patients with dyslipidemia and also subjects with a family history of liver disease.     

Serum γ-glutamyltransferase, alanine aminotransferase, and aspartate aminotransferase activity in Iranian healthy blood donor men

AIM： To determine serum γ-glutamyltransferase （GGT）, alanine aminotransferase （ALT）, and aspartate aminotransferase （AST） activity, and to assess their correlation with demographic and clinical findings in healthy blood donors.
METHODS： This cross-sectional study was performed in 934 male blood donors, aged 18 to 68 years, who consecutively attended Tehran blood transfusion service in 2006. All participants were seronegative for HBV or HCV infections, non alcohol users, and all underwent a standard interview and anthropometric tests. Clinical and biochemical parameters including AST, ALT, and GGT activities were determined. Patients taking drugs known to cause hepatic fat deposition were excluded. For AST, ALT, and GGT variables, we used 33.33 and 66.66 percentiles, so that each of them was divided into three tertiles.
RESULTS： Mean AST, ALT, and GGT activities were 25.26 ± 12.58 U/L （normal range 5-35 U/L）, 33.13 ± 22.98 （normal range 5-35 U/L）, and 25.11±18.32 （normal range 6-37 U/L）, respectively. By univariate analyses, there were significant associations between increasing AST, ALT, or GGT tertiles and age, body weight, body mass index, and waist and hip circumferences （P 〈 0.05）. By multiple linear regression analyses, ALT was found to be positively correlated with dyslipidemia （B = 6.988, P = 0.038）, whereas ALT and AST were negatively correlated with age. AST, ALT, and GGT levels had positive correlation with family history of liver disease （B = 15.763, P 〈 0.001）, （B = 32.345, P 〈 0.001）, （B =24.415, P 〈 0.001）, respectively.
CONCLUSION： Although we did not determine the cutoffs of the upper normal limits for AST, ALT, and GGT levels, we would suggest screening asymptomatic patients with dyslipidemia and also subjects with a family history of liver disease.     

Healthy range for serum ALT and the clinical significance of "unhealthy" normal ALT levels in the Korean population

Background and Aims: It remains unclear whether the currently‐used normal range for serum alanine aminotransferase (ALT) levels really reflects a healthy liver. The present study was conducted to evaluate the healthy range of serum ALT in the Korean adult population and to determine the clinical significance of unhealthy levels. Methods: We reviewed the medical records, including questionnaires and the results of laboratory and radiological tests conducted at the Health Promotion Center at Korea University Anam Hospital between March 2005 and February 2007. The records, written in questionnaire form, included baseline data, such as physical status, social behaviors, medication history, and past and present disease histories. Results: The mean age of the 7403 enrolled patients was 48 years, and 49.9% of these patients were male. A healthy cohort was selected after excluding patients who showed any abnormalities of the factors that were significantly associated with the serum ALT level upon multivariate regression analysis. The upper limit of the healthy range of the serum ALT level (i.e. 95th percentile) in the healthy population was 31 IU/L for males and 23 IU/L for females. The prevalence of metabolic syndrome and insulin resistance (IR) were significantly higher in patients with an ‘unhealthy’ normal ALT level than in those with a healthy ALT level. Conclusion: In our study, the upper limit of the healthy range of the serum ALT level was 31 IU/L for males and 23 IU/L for females. An unhealthy normal ALT level was associated with a higher prevalence of metabolic syndrome and IR.     

Alanine aminotransferase levels among volunteer blood donors: geographic variation and risk factors

The incidence of elevated levels of alanine aminotransferase (ALT) in the serum of volunteer blood donors from different geographic areas of the United States was evaluated. Five regional blood collection centers participated by collecting samples randomly from volunteer blood donors. Serum samples were centrally tested for elevated ALT levels, and a sociodemographic questionnaire was sent to donors with elevated ALT levels and to a randomly selected group with normal levels. Significant regional variation was found in the incidence of elevated ALT levels. Age, sex, and the use of alcohol were all significantly associated with elevated ALT levels. These preliminary data are important in the consideration of a program to screen blood donors for elevated ALT levels in serum.     

Can “Healthy” Normal Alanine Aminotransferase Levels Identify the Metabolically Obese Phenotype? Findings from The Korea National Health and Nutrition Examination Survey 2008–2010

Background

There is no established parameter with which to screen metabolically obese phenotypes.

Aim

The aim of the study was to revise the upper limit of normal (ULN) of serum alanine aminotransferase (ALT) and to investigate the predictive value of updated ALT levels for metabolic obese phenotype stratified according to body mass index (BMI).

Methods

We analyzed a nationally representative data from the Fourth Korea National Health and Nutrition Examination Survey. This cross-sectional study included 2,416 healthy people aged 33.9 ± 0.3 years. The ULN of healthy ALT level was set at the 95th percentile of the healthy population. A metabolic obese phenotype was defined as having insulin resistance or metabolic syndrome. A logistic regression analysis was performed to assess the odds ratio for a metabolic obese phenotype according to the healthy ALT level.

Results

The revised ULN of serum ALT level in healthy participants were 30 IU/L and 22 IU/L for males and females, respectively. Serum ALT level was higher in individuals with metabolic obesity compared with those without metabolic obesity in both genders, stratified according to BMI. After adjusting for age, BMI, smoking, alcohol drinking, and regular physical activity, unhealthy normal ALT levels (males 30–40 IU/L, females 22–40 IU/L) were significantly associated with metabolic obesity, especially in both obese and non-obese women.

Conclusions

A newly revised threshold for ALT is proposed as a simple clinical metabolic parameter that can identify a metabolic obese phenotype. We suggest that people with unhealthy normal ALT levels may need further investigation for the presence of metabolic obesity.     

Upper limit of normal serum alanine and aspartate aminotransferase levels in Korea

Background and Aim: The widely accepted range of upper limits of normal (ULN) alanine aminotransferase (ALT) levels (ULN < 40 U/L) was recently challenged by several reports. Both ALT and aspartate aminotransferase (AST) are commonly used as surrogate markers of liver disease, but almost all studies of aminotransferase activity were conducted on ALT. We investigated not only ULN of ALT but also AST activity and to identify factors modulating them in healthy Korean. Methods: A cross‐sectional study of 411 240 registered blood donors in all nationwide blood banks belonging to the Korean Red Cross were conducted. ULN of ALT and AST was evaluated adjusting their age according to the national population census database. “Decision tree model” was used to identify the affecting factors of ALT and AST and optimal cut‐off points of affecting factors. Results: “ULN of ALT” was 34 U/L in men and 24 U/L in women and “ULN of AST” was 32 U/L in men and 26 U/L in women in the blood donor database. Decision tree analysis showed that ALT levels were mostly influenced by body mass index level and its critical two cut‐off points were 23.5 kg/m² and 25.8 kg/m², respectively. The most affecting factor of AST was gender. Conclusion: Upper limits of normal of ALT and AST in Koreans were lower than conventional accepted values (< 40 U/L) but higher than recently suggested values (male < 30 U/L and female < 19 U/L). Body mass index was the most determining factor for ALT and gender was the most influencing factor for AST activity.     

Determination of the upper cut-off values of serum alanine aminotransferase and aspartate aminotransferase in Chinese

AIM:To determine the upper cut-off values of serumalanine aminotransferase(ALT)and aspartate aminotransferase(AST)in a Northern Chinese population.METHODS:A total of 3769 subjects in Jilin Province Northeast China were stratified to determine the potential factors affecting serum ALT and AST levels.The upper cut-off values of serum ALT and AST in these subjects were determined using receiver operating characteristic analysis and their sensitivity and specificity were evaluated.RESULTS:Stratification analysis revealed that serum ALT and AST levels were associated with gender,alcohol consumption,serum cholesterol and triglyceride levels,and body mass index.The upper cut-off values of serum ALT and AST were 22.15 U/L and 25.35 U/L for healthy men and 22.40 U/L and 24.25 U/L for healthy women,respectively.The new cut-off values had a higher sensitivity,but a slightly lower specificity than the current standards.CONCLUSION:Our results indicate that the new upper cut-off values of serum ALT and AST are markedly lower than current standards and may be valuable for the evaluation of liver function.     

Prevalence of antibodies to hepatitis C (anti HCV) in blood donors in Rio de Janeiro, Brazil. Its relation to ALT and anti HBC]

We have studied 933 volunteer blood donors from May to July, 1990. After a interview and screening tests for syphilis, Chagas disease, malaria and HIV, they underwent an enzyme immunoassay for HBsAg, anti HBc and anti HCV antibodies. Alanine aminotransferase (ALT) serum levels were determined by auto analyser. Most blood donors were male with mean age of 33 years (19-65). Anti HCV prevalence was 3.1% (29 from 933 blood donors). Among anti HCV+, blood donors, 44.8% (13/29) had ALT 40 UI/L, 31% (9/29) were anti HBc+ and 17.2% (5/29) had both surrogate markers simultaneously. From 109 donors with ALT 40 UI/L, 13 (11.9%) were anti HCV+, while among 153 anti HBc+ donors, the anti HCV was 5.8%. Conclusions: 1) we found a higher anti HCV prevalence among our blood donors than previous published reports from other countries; 2) our data show that surrogate assays do not adequately identify anti HCV blood donors, 41.4% of them would not have been excluded by anti HBc and ALT tests alone; 3) there were a correlation between anti HCV positivity with a sample to cutoff optical density ratio equal or greater than 4 and elevated ALT serum levels.     

Alanine aminotransferase cut-off values for blood donor screening using the new International Federation of Clinical Chemistry reference method at 37 degrees C

BACKGROUND AND OBJECTIVES: Serum alanine aminotransferase (ALT) determination is recommended, or even required by law, in the screening of blood donors in many countries, and donors with an increased catalytic activity of ALT are excluded from blood donation. In most countries, the ALT cut-off value for blood donor screening for men and women is twice the upper limit of the normal range. The introduction, in 2002, of the new International Federation of Clinical Chemistry (IFCC) reference method, performed at 37 degrees C, required new ALT reference values to be established for healthy individuals and a new cut-off point to be determined for blood donor screening. MATERIALS AND METHODS: We compared ALT values of donor blood units using the previous German standard method, which measures ALT values at 25 degrees C, and the new IFCC reference procedure, where ALT levels are measured at 37 degrees C. RESULTS: We found a linear correlation between the ALT values obtained by the method at 25 degrees C and the new IFCC reference method (37 degrees C) (r = 0.983), and a gender- and age-independent ratio of 0.523. Using this ratio we calculated the new ALT cut-off for blood donations and now propose a new upper limit of 132 U/l (2.20 microkat/l) for men and 86 U/l (1.43 microkat/l) for women. Only 220 of 151 678 blood donations collected over a period of 5 years showed an ALT value higher than the cut-off. None were hepatitis C virus (HCV) positive in serological or nucleic acid amplification technology (NAT) assays. Only 0.006% of all blood donations were positive for antibody to HCV and thus excluded. CONCLUSIONS: With the implementation of the new IFCC reference method for ALT determination at 37 degrees C, we propose a new ALT cut-off for blood donor screening, which, for men, is about three times the upper limit of the normal range and for women about 2.5 times. Our results show that a lower cut-off would probably not yield a higher safety of blood products in terms of detecting viral infections, but would result in a loss of approximately 0.75% of suitable blood donors.     

Serum leptin levels are associated with the presence of syndesmophytes in male patients with ankylosing spondylitis

The aim of this study is to clarify the association between serum leptin levels and the presence of syndesmophytes in male patients with ankylosing spondylitis (AS). Seventy-two male patients with AS and 20 age-matched healthy male controls were included. Patients were stratified by the presence of syndesmophytes. Serum leptin levels were measured and adjusted for body mass index (BMI). In addition, bone-specific alkaline phosphatase (BALP), osteocalcin, and telopeptide of type I collagen were determined. Patients with syndesmophytes were associated with older age (p < 0.001), longer disease duration (p = 0.003), and higher BMI (p = 0.038). Serum leptin levels and leptin per BMI (leptin/BMI) ratio were not different between AS patients and healthy controls. However, serum leptin/BMI ratio was significantly higher in patients with syndesmophytes compared to those without (p = 0.010). In multivariate analysis, higher serum leptin/BMI ratio remained significantly associated with the presence of syndesmophytes (p = 0.029). Moreover, serum leptin/BMI ratio was positively correlated with serum BALP (γ = 0.279, p = 0.039). However, there was no significant association between serum leptin/BMI ratio and bone mineral density. Serum leptin levels are elevated in male AS patients with syndesmophytes and were found to be correlated with bone formation marker, suggesting a potential role of leptin in new bone formation in AS.     

Testosterone modulates serum leptin concentrations in a male patient with hypothalamic hypogonadism

Serial measurements of body mass index (BMI), serum concentrations of testosterone (T), estradiol (E) and leptin (L) were performed before and after gonadotropin (Gn) therapy in an 18-year-old male subject (BMI 25.4 kg/m2) with idiopathic hypothalamic hypogonadism (IHH). We also measured the BMI and serum concentrations of L in 99 age-matched healthy subjects. Serum L correlated significantly with BMI in control subjects (r=0.84, p<0.0001). Baseline serum concentrations of L in our case were markedly high and both T and E were very low, but Gn therapy resulted in a gradual decrease in L and improvement in T and E, finally reaching the control levels of BMI-matched subjects. Our results demonstrate that T is a powerful negative modulator of serum L independent of BMI in conditions associated with low T levels, such as IHH.     

TT virus infection in hemodialysis patients

OBJECTIVE: Recently, TT virus (TTV), associated with posttransfusion hepatitis, was discovered. Prevalence of TTV infection in maintenance hemodialysis (HD) units and its pathogenicity to liver was investigated. METHODS: A total of 115 patients on HD were assessed for presence of serum TTV. DNA was purified from sera, and nested polymerase chain reaction was done for the detection of TTV DNA. RESULTS: TTV was detected in 59 patients on HD (51.3%), as compared with healthy blood donors (15 of 91 [16.5%], p < 0.0001). Serum HCV RNA and HBs antigen were positive in 16 and three patients, respectively. The prevalence rate of TTV was already 58.3% in the patients on HD for only 1 yr, and did not change according to the duration of HD until 15 yr on HD. TTV was positive in 51.2% (43 of 84) of the patients with history of blood transfusion, and in 51.6% (16 of 31) of those without it. In HCV-negative patients, alanine aminotransferase (ALT) levels of TTV-positive patients were similar to those of TTV-negative patients. Contrarily, in HCV-positive patients, ALT levels were more frequently > or =15 IU/L in TTV-positive patients (14 of 18) than in TTV-negative patients (five of 15) (p < 0.05). CONCLUSIONS: TTV infection is remarkably prevalent in patients on HD and in healthy blood donors. It is suggested that TTV generally does not cause liver disease by itself, but there remains the possibility that TTV may aggravate liver disease caused by HCV.