Decreased blood pressure response to infused noradrenaline in normotensive as compared to hypertensive patients with primary hypothyroidism

OBJECTIVE AND PATIENTS To further explore the difference in plasma noradrenaline in normotensive and hypertensive hypothyroid patients we have investigated the pressor response to exogenous noradrenaline in 11 normotensive and five hypertensive patients with primary hypothyroidism before and after thyroxine replacement. Seven healthy subjects served as controls. DESIGN The patients were studied under metabolic ward conditions and received a Na⁺ and K⁺ defined diet for 4 days. The controls received the same diet on an ambulatory basis for 3 days and were admitted to the ward in the evening on the third day. In the morning of day 4 a graded noradrenaline infusion was given. When the increase in systolic blood pressure in two consecutive registrations was at least 20 mmHg as compared to basal values the noradrenaline infusion was stopped. The dose required to increase systolic blood pressure by 20 mmHg (I₂₀) was determined. RESULTS During hypothyroidism the I₂₀ was 120 ng/kg BW/min in normotensive patients and 39 in hypertensive patients as compared to 62 in controls. The I₂₀ was higher in normotensives as compared to hypertensives (P = 0.041). The I₂₀ was not different in hypertensives as compared to controls. When the patients had become euthyroid I₂₀ decreased to 51 ng/kg BW/min (P=0.04) in the normotensives, but remained unchanged in the hypertensives. There was no difference in I₂₀ between normotensive and hypertensive patients in the euthyroid state, or when compared to controls. CONCLUSION The pressor response to noradrenaline was decreased in normotensive hypothyroid as compared to hypertensive hypothyroid patients, indicating a decreased peripheral sensitivity to noradrenaline in normotensive hypothyroid patients. Following thyroxine replacement the decreased response became normal.     

Thyroid peroxidase activity in euthyroid and mild hypothyroid patients with Hashimoto's thyroiditis

Thyroid peroxidase (TPO) activity was measured spectrophotometrically according to Hosoya's guaiacol method. The mean TPO activity in ten patients with Hashimoto's thyroiditis was 19.8 +/- 7.6 (mean +/- SE) in an arbitrary unit, which was not significantly different from the normal value in seven normal thyroid tissues (33.7 +/- 5.4). The ten patients were divided into two groups, euthyroid and mild hypothyroid, on the basis of their basal serum TSH. In the euthyroid group, TPO activity (8.17 +/- 1.3) was significantly less than the normal tissue (p less than 0.01). In the hypothyroid group, TPO activity (27.64 +/- 13.8) was almost similar to the normal tissue. A positive correlation was obtained between TPO activity and serum TSH in ten patients with Hashimoto's thyroiditis (r = 0.85, p less than 0.01). It was concluded that TPO activity is significantly decreased in Hashimoto's thyroiditis even when the thyroid function was still within normal range, but the activity might be restored to normal in hypothyroid patients by the stimulation of elevated TSH.     

Cognitive functioning and well-being in euthyroid patients on thyroxine replacement therapy for primary hypothyroidism

OBJECTIVE: Hypothyroidism is associated with neurocognitive impairment. Sparse data suggest that treatment of hypothyroidism, resulting in a return to euthyroidism, may be associated with only partial recovery of overall neurocognitive functioning. The aim of this study was to assess neurocognitive functioning and well-being in euthyroid patients with primary hypothyroidism on adequate thyroxine (T4) treatment. We also investigated whether serum TSH and thyroid antibodies are determinants of neurocognitive functioning and well-being. DESIGN: We assessed neurocognitive functioning and well-being in 141 patients with primary hypothyroidism. METHODS: Neurocognitive test results and scores on questionnaires measuring well-being of 141 patients were compared with the reference values for these tests as published and used in Dutch clinical neuropsychological practice. Assessment of neurocognitive functioning included tests for cognitive or psychomotor speed, attention, working memory as well as learning and memory. Well-being was measured with the Symptom Check List-90 total score and the Rand 36-item Health Survey subscales for 'mental health' and 'vitality'. RESULTS: Patients showed poor performance on various domains of neurocognitive functioning compared with mean standard reference values, especially on a complex attention task and on verbal memory tests. Levels of well-being were significantly lower for patients compared with those of the general population. Neither serum TSH nor thyroid antibodies were determinants of neurocognitive functioning and well-being. CONCLUSION: The results of this study suggest that neurocognitive functioning as well as psychological well-being may not be completely restored in patients with hypothyroidism, despite T4 treatment.     

Increased tumour necrosis factor-alpha plasma levels during moderate-intensity exercise in COPD patients.

Post-training downregulation of muscle tumour necrosis factor (TNF)-alpha messenger ribonucleic acid (mRNA) expression and decrease in cellular TNF-alpha levels have been reported in the elderly. It is hypothesised that chronic obstructive pulmonary disease (COPD) patients may not show these adaptations due to their reduced ability to increase muscle antioxidant capacity with training. Eleven COPD patients (forced expiratory volume in one second 40 +/- 4.4% of the predicted value) and six age-matched controls were studied. Pre- and post-training levels of TNF-alpha, soluble TNF receptors (sTNFRs: sTNFR55 and sTNFR75) and interleukin (IL)-6 in plasma at rest and during exercise and vastus lateralis TNF-alpha mRNA were examined. Moderate-intensity constant-work-rate exercise (11 min at 40% of pretraining peak work-rate) increased pretraining plasma TNF-alpha levels in COPD patients (from 17 +/- 3.2 to 23 +/- 2.7 pg x mL(-1); p<0.005) but not in controls (from 19 +/- 4.6 to 19 +/- 3.2 pg x mL(-1)). No changes were observed in sTNFRs or IL-6 levels. After 8 weeks' endurance training, moderate-intensity exercise increased plasma TNF-alpha levels similarly to pretraining (from 16 +/- 3 to 21 +/- 4 pg x mL(-1); p<0.01). Pretraining muscle TNF-alpha mRNA expression was significantly higher in COPD patients than in controls (29.3 +/- 13.9 versus 5.0 +/- 1.5 TNF-alpha/18S ribonucleic acid, respectively), but no changes were observed after exercise or training. It is concluded that moderate-intensity exercise abnormally increases plasma tumour necrosis factor-alpha levels in chronic obstructive pulmonary disease patients without exercise-induced upregulation of the tumour necrosis factor-alpha gene in skeletal muscle.     

Increased plasma levels of endothelin in diabetic patients with hypertension.

In order to gain insight into the potential role of endothelin, a 21 amino acid peptide produced by endothelial cells, in the development of complications of diabetes mellitus, basal plasma endothelin levels were measured in 152 patients with diabetes mellitus (83 patients with type 1 diabetes mellitus, 69 patients with type 2 diabetes mellitus) and compared to those in 50 healthy controls. Blood was drawn at 8:00 AM under resting conditions and endothelin was measured after prior extraction by a sensitive radioimmunoassay specific for both endothelin 1 and 2. Endothelin levels were increased in patients with diabetes mellitus in comparison to controls. In type 1 diabetes mellitus a positive correlation between endothelin levels and age was found. We found that 60% of patients with type 1 diabetes mellitus and elevated endothelin levels higher than 2.5 pg/mL (highest value in a control person) had had diabetes for more than 20 years (P less than .05 v patients with normal endothelin levels). In type 2 diabetes mellitus the relation between elevated endothelin levels and diabetes duration was reversed. Glycosylated hemoglobin (HbA1) concentrations above 10% of total hemoglobin were measured in 62% of the patients. Arterial hypertension was present in 60% of the patients with type 1 diabetes mellitus and increased endothelin levels greater than 2.5 pg/mL (both P less than .05 v patients with normal endothelin levels).(ABSTRACT TRUNCATED AT 250 WORDS)     

Thyroid hormone indices during illness in six hypothyroid subjects rendered euthyroid with levothyroxine therapy.

PURPOSE: We wanted to evaluate changes in the natural course of serum thyroxine (T4), tri-iodothyronine (T3), reverse tri-iodothyronine (rT3), and thyroid stimulating hormone (TSH) concentrations during hospitalization for an acute illness, in subjects rendered euthyroid with Levothyroxine (LT4) replacement therapy. METHODS: Six male subjects ranging in age 30 - 65 years with a history of primary hypothyroidism were included. They were euthyroid prior to hospitalization. LT4 continued to be administered orally in the same pre-admission daily dose. Serum, T4, T3, rT3, and TSH concentrations were determined on day of admission to the intensive care unit (ICU) for an acute illness. These were repeated during the first week on alternate days and again during a follow-up visit 1 week after discharge. Student's t-test, analysis of variance, and linear regression were used to analyze the data. RESULTS: Serum T4, T3 declined to a nadir and serum rT3 rose to its peak by day 3 of hospitalization before returning to pre admission euthyroid levels. Serum TSH declined initially but rose to supernormal levels on day 7 before normalization. Significant correlations were noted between TSH on one hand and T3/T4 (r = 0.76, p < 0.001) and rT3/T4 (r= - 0.64, p < 0.001) ratios. CONCLUSIONS: Alterations ensuing during a short stay in the hospital due to an acute illness in subjects with primary hypothyroidism rendered euthyroid with appropriate replacement therapy with Levothyroxine (LT4) are almost identical to those in normal subjects. These changes are probably secondary to altered thyroid hormone metabolism. The altered levels of thyroid hormones and TSH noted in these subjects are transient and therefore providers should refrain from initiating frequent changes in daily LT4 replacement dose during the acute illness in these subjects.     

The effect of somatostatin on TSH levels in patients with primary hypothyroidism.

Somatostatin, a growth hormone inhibiting factor (GHIF), was infused into 8 patients with primary hypothyroidism at a dosage of 1000 mug for 105 min. GHIF caused a suppression of TSH levels from 42.6 to 76.9% of preinfusion levels with a mean nadir of 65.0 +/- 4.0%;(mean +/- SEM).     

Comparative effectiveness of dextrothyroxine and levothyroxine in correcting hypothyroidism and lowering blood lipid levels in hypothyroid patients.

Data reported here establish that treatment regimens of 4 mg dextrothyroxine and 0.15 mg levothyroxine in hypothyroid subjects produce similar degrees of lowering of serum TSH, cholesterol, triglycerides, and phospholipid levels and equal stimulation of metabolic rate. The Murphy-Pattee total T4 determination applied to blood samples drawn 24 h after the last dose of dextrothyroxine can be used to assess adequacy of treatment. Correction of hypothyroidism requires high serum levels of dextrothyroxine than of levothyroxine. Serum T3 levels increase in patients treated with dextrothyroxine. In the treatment of hypothyroidism, the cholesterol-lowering and metabolic rate-stimulating effects of dextrothyroxine do not appear to be dissociated. Further studies are needed to determine whether such an effect can be demonstrated in euthyroid hypercholesterolemic subjects with doses established herein as equivalent in terms of the stimulating effect on metabolic rate.     

Increase in plasma growth hormone levels following thyrotropin-releasing hormone injection in children with primary hypothyroidism.

Thyrotropin-releasing hormone (TRH) induced a significant increase in plasma growth hormone (GH) levels in 4 of 8 children with primary hypothyroidism, while a slight decrease was observed in 8 control children. Base-line plasma prolactin (PRL) levels and peak responses to TRH were higher in hypothyroid children than in controls. These data may indicate the existence of dysfunction of central nervous system mechanisms of control of GH and PRL secretion in subjects with primary hypothyroidism.     

Antiatherogenic properties of high-density lipoproteins from arterial plasma are attenuated as compared to their counterparts of venous origin

Background and aimsHigh-density lipoprotein (HDL) particles play atheroprotective roles by their ability to efflux cholesterol from foam cells and to protect low-density lipoproteins (LDLs) from oxidative damage in the arterial intima. We hypothesized that antioxidative properties of HDLs can be attenuated in the oxygen-rich prooxidative arterial environment, contributing to the development of atherosclerosis. To evaluate this hypothesis, we compared antioxidative activity of HDLs from arterial and venous plasmas.Methods and resultsArterial and venous blood samples were simultaneously obtained from 16 patients (age 68 ± 10 years; 75% males) presenting with ischemic or valvular heart disease. Major HDL subfractions and total HDLs were isolated by density gradient ultracentrifugation and their chemical composition and the capacity to protect LDLs from in vitro oxidation were evaluated. HDL-cholesterol, triglycerides and apolipoprotein (apo) B-100 levels were slightly but significantly reduced by −4 to −8% (p < 0.01) in the arterial vs. venous samples. Total mass of HDL subpopulations was similar and HDL subpopulations did not reveal marked compositional differences between the arterial and venous circulation. Potent antioxidative activity of the small, dense HDL3c subpopulation was significantly reduced in the particles of arterial origin vs. their counterparts from venous plasma (increase of +21% in the propagation rate of LDL oxidation, p < 0.05). Interestingly, antioxidative properties of venous HDLs were enhanced in statin-treated patients relative to untreated subjects.ConclusionAntioxidative properties of small, dense HDLs from arterial plasma are attenuated as compared to the particles of venous origin, consistent with the development of atherosclerosis in the arterial wall.     

Fractures in patients with primary idiopathic hypothyroidism.

AIM: To study fracture risk and risk factors for fractures in patients with primary idiopathic hypothyroidism (ICD 10: E03.9). DESIGN: Historical follow-up. MATERIAL AND METHODS: A self-administered questionnaire was issued to 628 patients with primary idiopathic levothyroxine-substituted hypothyroidism. A total of 412 (65.6%) responded and of these, 408 could be analyzed. The 408 respondents were age- (+/- 5 years) and gender-matched with 408 normal controls randomly selected from the background population who responded to the same questionnaire. RESULTS: Overall fracture risk was increased in patients compared to controls (relative risk: RR = 1.6, 95% CI: 1.0-2.5). However, the increase was temporary and limited to the period within the first 2 years after the diagnosis of hypothyroidism (RR = 3.1, 95% CI: 1.4-7.0). Before the diagnosis and more than 2 years after the diagnosis, the fracture risk in patients did not deviate from that of the controls. The increase in fracture risk was only significant in the age group above 50 years (RR = 1.8, 95% CI: 1-3.2), and was limited to the forearms (RR = 3.0, 95% CI: 1.4-6.3 for the entire patient population). CONCLUSIONS: There was a temporary increase in fracture risk within the first 2 years after diagnosis of primary idiopathic hypothyroidism. The fracture risk was mainly increased in the age group above 50 years, and the increased risk was limited to the forearms.     

Increased plasma total nitric oxide among patients with severe chronic venous disease.

BACKGROUND: Skin damage in chronic venous disease (CVD) may be partially attributable to free radical injury including that of nitric oxide (NO). The aim of this study was to measure total plasma NO in patients with CVD compared to control subjects. METHODS: Forty-four patients with CVD and 13 control subjects with no arterial or venous disease were included in this study. The patients underwent duplex ultrasonography to confirm the extent of the venous disease and were assigned to the appropriate CEAP clinical stage. Exhaustive exclusion criteria were applied to prevent the influence of dietary intake and other diseases in total NO production. Patients were studied after resting supine for 10 min in room temperature. Blood samples were taken from the long saphenous or a dorsal foot vein. Plasma was separated and frozen at -80 degrees C within 1 hour of venesection. Total NO was assayed with a colorimetric test using the Griess reaction (R&D systems, UK). RESULTS: The median total NO levels among patients with the C5 was 55 micromol/L (interquartile range 51 to 64); with C4 was 53 micromol/L (interquartile range 44 to 58); C2 and C3 was 44 micromol/L (interquartile range 36 to 50) and with control subjects it was 43 micromol/L (interquartile range 41 to 50). Those with healed ulcers (C5) showed statistically raised NO levels compared to controls (median difference 12 micromol/L [95% confidence interval: 5-22]). Combining the data in the C4 and C5 patients results in a set of data significantly different from control subjects (median difference 9 [95% C.I. 2-15]). CONCLUSIONS: Raised total NO is strongly associated with the more severe stages (lipodermatosclerosis and healed ulceration), in patients with venous disease.     

Increased soluble E-selectin levels in type 2 diabetic patients with peripheral arterial disease.

AIM: Abnormal endothelial function is well known in patients with type 2 diabetes mellitus and thought to induce macroangiopathy. Increased levels of adhesion molecules have been found in type 2 diabetic patients and it has been suggested that they play an important role in the initiation of atherosclerosis. The aim of the present study was to clarify the relationship between objectively proven peripheral arterial disease (pAVD) and serum levels of soluble adhesion molecules in patients with type 2 diabetes mellitus. METHODS: Levels of soluble E-selectin, ICAM-1 and VCAM-1 were evaluated in 18 type 2 diabetic patients with pAVD assessed by Doppler ultrasound, in 19 type 2 diabetic patients and 22 non-diabetic subjects without pAVD. RESULTS: Soluble E-selectin levels were significantly increased in pAVD-diabetic patients compared to diabetics and non-diabetics without pAVD (78.7+/-29 vs 49.7+/-20.4 and 36+/-17 ng/ml respectively, p<0.001), while sICAM-1 and sVCAM-1 levels were comparable between the groups. No significant correlation was found between pAVD and adhesion molecule levels. Peripheral AVD was correlated with smoking (p=0.024), duration of diabetes (p=0.048) and microalbuminuria (p=0.041). Regression analysis revealed that only smoking (R=0.536, p=0.012) and glycosylated hemoglobin (R=0.435, p=0.036) were independent factors related to pAVD. Soluble ICAM-1 levels were significantly higher (p=0.041) in diabetic smokers with pAVD and sVCAM-1 (p=0.011) in patients with longer duration of diabetes. CONCLUSION: Type 2 diabetic patients with pAVD showed increased serum sE-selectin levels. No significant relationship was found between the presence or extent of pAVD and measured adhesion molecules. Our results suggest that sE-selectin reflects endothelial activation and is possibly involved in the atherogenesis process with the contribution of other factors that characterize the metabolic syndrome of diabetes.     

Increased plasma and joint tissue adrenomedullin concentrations in patients with rheumatoid arthritis compared to those with osteoarthritis

OBJECTIVE: To elucidate the pathophysiological role of adrenomedullin (AM) in rheumatoid arthritis (RA), plasma AM concentration was measured in patients with RA and in healthy contols. The concentration of AM in joint fluid, synovial tissue, and articular cartilage of patients with RA and osteoarthritis (OA) were measured and compared. METHODS: Twenty-six patients with RA (aged 62 +/- 4 yrs, all female), 10 healthy controls (aged 57 +/- 5 yrs, all female), and 10 patients with OA (aged 68 +/- 8 yrs, all female) were studied. We measured plasma levels of total and mature AM by immunoradiometric assay and levels of AM in joint tissue by radioimmunoassay. RESULTS: Plasma levels of AM in patients with RA (18.35 +/- 6.9 fmol/ml) were found to exceed those in healthy controls (11.64 +/- 2.8 fmol/ml). Moreover, plasma AM showed a significant positive correlation with plasma C-reactive protein (CRP). The correlation coefficient of total AM was 0.685, and that of mature AM was 0.624. Similarly, AM levels in synovium and joint fluid in patients with RA were significantly higher than in OA. In contrast, AM levels in articular cartilage were found to be low, with no significant difference in levels between patients with RA and OA. CONCLUSION: The relation between plasma AM levels and plasma CRP in patients with RA suggests that plasma AM levels increase with the activity of RA. Moreover, AM levels in synovium and joint fluid of patients with RA were significantly higher than those of patients with OA. Thus, AM probably plays a part in the regulation of the inflammatory process of RA.     

Increased plasma levels of thioredoxin in patients with glucose intolerance

OBJECTIVE: The aim of the present study was to determine the effects of glucose intolerance on oxidative stress in patients with coronary artery disease (CAD). METHODS: The patients were divided into 3 groups, diabetes mellitus (DM), IGT or normal glucose tolerance (NGT) according to the criteria of the American Diabetes Association. PATIENTS: The present study consisted of 178 consecutive patients who underwent diagnostic coronary arteriography and a 75-g glucose tolerance test. RESULTS: The level of plasma thioredoxin, a marker of oxidative stress was measured in every patient during the fasting state. The levels of plasma thioredoxin were significantly higher in the DM and IGT groups than the NGT group. Furthermore, we found that there was a positive association between thioredoxin levels and glycosylated hemoglobin (sigma=0.225, p=0.018). In multivariate logistic regression analysis, glucose intolerance (DM or IGT) was only independently associated with the high levels of thioredoxin. The levels of plasma thioredoxin were significantly higher in the CAD group compared to the non-CAD group. In multivariate logistic regression analysis, high levels of thioredoxin, male, age and hypertension were independently associated with the presence of CAD. CONCLUSION: Glucose intolerance was associated with the high levels of thioredoxin. High levels of thioredoxin were related to the presence of CAD. The measurement of thioredoxin as the marker of oxidative stress may be useful for monitoring the development of the cardiovascular diseases.     

Coronary spasm with ventricular fibrillation during thyrotoxicosis: response to attaining euthyroid state.

Although myocardial ischemia may occur in thyrotoxic patients with normal coronary arteries, the mechanism remains unclear. This report describes a woman with hyperthyroidism who had ventricular fibrillation during an apisode of myocardial ischemia. The event was documented with continuous ambulatory electrocardiography. Subsequent angiography revealed normal coronary anatomy with spasm of the right coronary artery that disappeared after ingestion of one sublingual nitroglycerin tablet. The angina, electrocardiographic evidence of myocardial ischemia, ventricular arrhythmias and the patient's need for nitroglycerin were eliminated after she became euthyroid. These findings suggest that coronary spasm may be associated with myocardial ischemia and arrhythmias in a hyperthyroid patient.     

Increased fasting plasma ghrelin levels in patients with bulimia nervosa

OBJECTIVE: Fasting plasma ghrelin levels play an important role in the pathophysiology of the eating disorder anorexia nervosa. Bulimia nervosa (BN) also has been associated with abnormal neuroendocrine regulation. Thus, we examined the relationship between body mass index (BMI) and plasma ghrelin concentrations in patients with BN for the first time. METHODS: The subjects included 15 female BN patients and 11 female healthy volunteers (controls). Fasting blood samples were collected from all subjects. RESULTS: The plasma ghrelin concentrations in all subjects demonstrated a significantly negative correlation with BMI. Mean plasma ghrelin level in BN patients was significantly higher than that in the controls, though mean BMIs between the groups were not significantly different. CONCLUSION: These findings suggest that not only BMI but also abnormal eating behaviors with habitual binge eating and purging may have some influence on circulating ghrelin level in BN.