Palle Pedersen

Iron prophylaxis during pregnancy - How much iron is needed? A randomized dose- response study of 20-80 mg ferrous iron daily in pregnant women

Objective.  To determine the lowest dose of iron preventative of iron deficiency and iron deficiency anemia in pregnancy.

Frequency of the C282Y and H63D mutations of the hemochromatosis gene (HFE) in 2501 ethnic Danes

The aim of the study was to assess the frequency of the C282Y and H63D mutations of the hemochromatosis gene (HFE) in ethnic Danes. The series comprised 2501 subjects (1284 men) of Danish heritage who were drawn at random from the Census Registry in age cohorts of 30, 40, 50, and 60 years. The frequency of the C282Y and H63D mutations was assessed on blood samples by genotyping using a polymerase chain reaction (PCR) technique. The HFE genotype distribution was in Hardy–Weinberg equilibrium (p=0.85). C282Y mutation: 9 subjects (0.36%) were homozygous and 265 subjects (10.6%) were heterozygous. H63D mutation: 40 subjects (1.6%) were homozygous and 584 subjects (23.4%) were heterozygous. C282Y/H63D compound heterozygosity was found in 36 subjects (1.4%). The C282Y allele frequency was 5.7% [95% confidence interval (CI) 5.0–6.3%] and the H63D allele frequency was 13.3% (95% CI 12.3–14.2%). In conclusion, the C282Y frequency is relatively high in the Danes, being close to the frequency in other Scandinavian countries, i.e., Iceland 5.1%, the Faroe Islands 6.6%, and Sweden 5.7%, but significantly lower than in Norway 6.6% (p=0.02). Also, the H63D frequency in Danes is close to and not significantly different from the frequency in Iceland 10.9%, Norway 11.2%, and Sweden 12.4%, but significantly lower than in the Faroe Islands 15.4% (p=0.046).

Frequency of the hemochromatosis HFE mutations C282Y, H63D, and S65C in blood donors in the Faroe Islands

The aim of the study was to assess the frequencies of the hereditary hemochromatosis HFE mutations C282Y, H63D, and S65C in the population in the Faroe Islands. The series comprised 200 randomly selected blood donors of Faroese heritage. The frequency of the C282Y, H63D, and S65C mutations on the HFE gene was assessed by genotyping using the polymerase chain reaction (PCR) technique and calculated from direct allele counting. We found no C282Y homozygous subjects; 28 (14.0%) subjects were C282Y heterozygous and four subjects were C282Y/H63D compound heterozygous (2.0%). The C282Y allele frequency was 8.0% (95% CI 5.3–10.7%). The series contained three (1.5%) H63D homozygous subjects and 60 (30.0%) H63D heterozygous subjects. The H63D allele frequency was 17.5% (95% CI 13.8–21.2%). There were four (2.0%) S65C heterozygous subjects. The S65C allele frequency was 1.0% (95% CI 0.3–2.5%). The frequency of the C282Y mutation is high in Faroese blood donors, being close to and not significantly different from the frequencies reported in other Scandinavian countries: Denmark 5.7%, Norway 6.6%, Iceland 5.1%, and Sweden 6.1%. The frequency of the H63D mutation in Faroese subjects is significantly higher than the frequency in Denmark 12.8% (p=0.007), Iceland 10.9% (p=0.003), and Sweden 12.4% (p=0.015), but not from the frequency in Norway 11.2% (p=0.063). The frequency of the S65C mutation in Faroese subjects is not significantly different from the frequencies in Denmark 1.5% and Sweden 1.6%. Screening of larger groups of the Faroese population for HFE mutations especially C282Y should be considered in order to establish the penetrance.

Subclinical hypothyroidism affects mitochondrial function.

The aim of the present study was to examine mitochondrial function in cells from persons with subclinical hypothyroidism and euthyroid controls. The participating persons were examined clinically and had basal oxygen consumption (VO(2)) determined. The concentrations of thyroid hormones and thyrotropine stimulating hormone were determined, and mitochondrial function in isolated mononuclear blood cells was examined by enzymatic methods [citrate synthase activity (CS)] and by flow cytometry (mitochondrial membrane potential by TMRM fluorescence and mitochondrial mass by MTG fluorescence). The ratio of T(4)/T(3) was lowered in subclinical hypothyroidism patients compared to controls (2.5+/-0.5 vs. 2.9+/-0.4, p=0.005). VO(2) was increased in persons with subclinical hypothyroidism compared to controls (adolescents: 134+/-27 ml O(2)/min*m(2) vs. 119+/-27 ml O(2)/min*m(2), p=0.006, adults: 139+/-14 ml O(2)/min*m(2) vs. 121+/-17 ml O(2)/min*m(2), p=0.001). The mitochondrial function, represented by citrate synthase activity, MTG, and TMRM fluorescence were all increased (CS in subclinical hypothyroidism vs. controls: 0.074+/-0.044 nmol/mg*min vs. 0.056+/-0.021 nmol/mg*min, p=0.005; MTG fluorescence in subclinical hypothyroidism vs. controls: 7,482+/-1,733 a.u. vs. 6,391+/-2,171 a.u., p=0.027; TMRM fluorescence in subclinical hypothyroidism vs. controls: 13,449+/-3,807 a.u. vs. 11,733+/-4,473 a.u, p=0.04). Our results indicate an increased mitochondrial stimulation, eventually caused by increased deiodination of T(4) to intracellular bioactive iodothyronines in adults and adolescents with subclinical hypothyroidism.

Ferrous bisglycinate 25 mg iron is as effective as ferrous sulfate 50 mg iron in the prophylaxis of iron deficiency and anemia during pregnancy in a randomized trial.

Abstract Objective: To compare the effects of oral ferrous bisglycinate 25 mg iron/day vs. ferrous sulfate 50 mg iron/day in the prevention of iron deficiency (ID) and iron deficiency anemia (IDA) in pregnant women. Design: Randomized, double-blind, intention-to-treat study. Setting: Antenatal care clinic. Sample: 80 healthy ethnic Danish pregnant women. Methods: Women were allocated to ferrous bisglycinate 25 mg elemental iron (Aminojern®) (n=40) or ferrous sulfate 50 mg elemental iron (n=40) from 15 to 19 weeks of gestation to delivery. Hematological status (hemoglobin, red blood cell indices) and iron status (plasma iron, plasma transferrin, plasma transferrin saturation, plasma ferritin) were measured at 15–19 weeks (baseline), 27–28 weeks and 36–37 weeks of gestation. Main outcome measures: Occurrence of ID (ferritin <15 μg/L) and IDA (ferritin <12 μg/L and hemoglobin <110 g/L). Results: At inclusion, there were no significant differences between the bisglycinate and sulfate group concerning hematological status and iron status. The frequencies of ID and IDA were low and not significantly different in the two iron groups. The frequency of gastrointestinal complaints was lower in the bisglycinate than in the sulfate group (P=0.001). Newborns weight was slightly higher in the bisglycinate vs. the sulfate group (3601±517 g vs. 3395±426 g, P=0.09). Conclusions: In the prevention of ID and IDA, ferrous bisglycinate was not inferior to ferrous sulfate. Ferrous bisglycinate in a low dose of 25 mg iron/day appears to be adequate to prevent IDA in more than 95% of Danish women during pregnancy and postpartum.

Frequencies of the Hereditary Hemochromatosis Allele in Different Populations, Comparison of Previous Phenotypic Methods and Novel Genotypic Methods

AimThe frequencies of the hereditary hemochromatosis allele were compared for different populations assessed by previous phenotypic methods and the present genotypic methods.MethodsFrom a literature survey, the calculated hemochromatosis allele frequencies from 16 studies using phenotypic biochemical markers (threshold levels for transferrin saturation [range, 46%–70%] and serum ferritin [range, 164–700 µg/L]) were compared with allele frequencies of the Cys282Tyr mutation of the hemochromatosis gene reported in 19 genotypic studies.ResultsCalculated phenotypic allele frequencies are high in Scandinavia: Iceland, 6.1% to 7.4%; Norway, 5.8%; central Sweden, 6.3% to 6.9%; Denmark, 6.1%. Frequencies are similarly high in Wales, Canada, Utah, South Africa, and Australia (range, 5.2%–9.8%). Frequencies are low in Finland (1.9%) and northern Italy (4.5%). Genotypic allele frequencies of the Cys282Tyr mutation are likewise high in Scandinavia. Frequencies are high in the United Kingdom and northern France and low in Finland, central Germany, northern Italy, and Greece. The phenotypic-genotypic ratios of the hemochromatosis homozygosity frequencies for the same geographic area were calculated. A ratio of 1.0 indicates that the 2 methods give similar results. In 3 studies, the ratio was above 1.0, the highest ratio of 1.67 being reported from Italy. In most studies the ratio was slightly below 1.0 (0.71–0.97). The lowest ratio was found in Finland (0.33).ConclusionIn most studies there was good agreement between the hemochromatosis allele frequencies determined by phenotypic and genotypic methods. A high ratio (northern Italy) may indicate that phenotypic selection criteria were too loose and/or that causes of iron overload other than the Cys282Tyr mutation are frequent in the region. A low ratio (in Finland) may indicate phenotypic selection criteria that were too stringent and/or a low penetration rate of the mutation.

Frequency of the HFE C282Y and H63D mutations in Danish patients with clinical haemochromatosis initially diagnosed by phenotypic methods.

Abstract: Aim: To assess the frequency of the C282Y and H63D mutations on the HFE gene in Danish patients with clinical hereditary haemochromatosis initially diagnosed by phenotypic methods.

Thyroid hormone effect on human mitochondria measured by flow cytometry

Abstract Background: Mitochondrial function may be impaired in a number of diseases including metabolic syndrome, cardiovascular disease and endocrine disorders. Therefore it is important to be able to measure mitochondrial function in human cells. Purpose: The aim of the present study was to evaluate a method to measure mitochondrial function in human derived cells, which also would reflect regulation by thyroid hormones. Methods: The MDA-MB-231 cell line (a human breast cancer cell line) was incubated with bioactive iodothyronines (T4, 3′-3, 5-T3, 3, 5-T2) 50nmol/l for 3 h. Mitochondrial membrane potentials (MMP) were measured by a flow cytometer after staining with Tetramethylrhodamine methyl ester (TMRM). Also, the effect of TRIAC (a stimulator of thyroid hormone nuclear receptors) and L-Carnitine (an inhibitor of thyroid hormone passage into the nucleus) was examined. Findings: It was possible to measure mitochondrial membrane potential (MMP) in human derived cells and to examine thyroid hormone effects using flow cytometry. Bioactive iodothyronines increased mitochondrial membrane potential. TRIAC had no effect and L-Carnitine only inhibited T4 stimulation of membrane potential. Conclusion: Flow cytometry may be a valuable method for examining and testing mitochondrial function in human cells. Our findings demonstrate increase of mitochondrial membrane potential and an extra nuclear short time effect of 3, 5-T2 on mitochondrial activity.

Impaired Fertility Associated with Subclinical Hypothyroidism and Thyroid Autoimmunity: The Danish General Suburban Population Study

Introduction. The aim of this study was to estimate the significance of TSH, thyroid peroxidase antibody (TPOAb), and mild (subclinical) hypothyroidism in women from The Danish General Suburban Population Study (GESUS) on the number of children born, the number of pregnancies, and the number of spontaneous abortions. Methods. Retrospective cross sectional study of 11254 women participating in GESUS. Data included biochemical measurements and a self-administrated questionnaire. Results. 6.7% had mild (subclinical) hypothyroidism and 9.4% prevalent hypothyroidism. In women with mild hypothyroidism TPOAb was significantly elevated and age at first child was older compared to controls. TSH and TPOAb were negatively linearly associated with the number of children born and the number of pregnancies in the full cohort in age-adjusted and multiadjusted models. TSH or TPOAb was not associated with spontaneous abortions. Mild (subclinical) hypothyroidism was associated with a risk of not having children and a risk of not getting pregnant in age-adjusted and multiadjusted models. Prevalent hypothyroidism was not associated with the number of children born, the number of pregnancies, or spontaneous abortions. Conclusion. Impaired fertility is associated with TSH, TPOAb, and mild (subclinical) hypothyroidism in a Danish population of women.

Basal and T₃-induced ROS production in lymphocyte mitochondria is increased in type 2 diabetic patients

Mitochondrial function, including production of reactive oxygen species (ROS), is important in the pathogenesis of diabetes and its complications. Thyroid hormones are major regulator of these processes. Hence, the aim of this study was to examine the thyroid hormone regulation of ROS production in human lymphocytes in patients with diabetes mellitus type 2 (T2DM). Lymphocytes from 10 controls and 10 persons with T2DM were examined. Mitochondrial membrane potential (MMP) was examined by flow cytometry after staining with MitoTracker Green (MTG). Similarly ROS was measured following staining with carboxy-H₂DCFDA. MMP was increased in T2DM patients and T₃ stimulation increased MMP in controls [1398 a.u. (979-4094) vs. 2156 a.u. (1611-15189), p=0.04, median and quartiles] as well as in T2DM patients [9167 a.u. (7387-11746) vs. 20274 a.u. (17183-27839 p=0.004, median and quartiles]. Basal ROS concentration was increased in lymphocytes from T2DM and T₃ significantly stimulated ROS concentration in controls [3691 a.u. (2584-6396) vs. 5650 a.u. (3001-7802) p=0.013, median and quartiles] and in T2DM patients [19271 a.u. (6288-25282) vs. 23178 a.u. (10004-28857) p=0.013, median and quartiles]. The ratio of ROS production related to MMP was significantly higher in T2DM, unstimulated as well as T₃-stimulated in T2DM. Unstimulated and T₃ stimulated ROS production and MMP were higher in lymphocytes from diabetic patients. An altered balance between ROS production and MMP, favoring ROS production in T2DM patients, was found suggesting that an increased mitochondrial sensitivity for T₃ may be a significant factor responsible for increased ROS activity in diabetic patients.