Long-term effects of growth hormone (GH) on body fluid distribution in GH deficient adults: a four months double blind placebo controlled trial

OBJECTIVE

Short-term growth hormone (GH) treatment normalises body fluid distribution in adult GH deficient patients, but the impact of long-term treatment on body fluid homeostasis has hitherto not been thoroughly examined in placebo controlled trials. To investigate if the water retaining effect of GH persists for a longer time we examined the impact of 4 months GH treatment on extracellular volume (ECV) and plasma volume (PV) in GH deficient adults.

DESIGN

Twenty-four (18 male, 6 female) adult GH deficient patients aged 25-64 years were included and received either GH (n=11) or placebo (n=13) in a double blind parallel design.

METHODS

Before and at the end of each 4 month period ECV and PV were assessed directly using 82Br- and 125I-albumin respectively, and blood samples were obtained.

RESULTS

During GH treatment ECV increased significantly (before: 20.48+/-0.99 l, 4 months: 23.77+/-1.38 l (P<0.01)), but remained unchanged during placebo administration (before: 16.92+/-1.01 l, 4 months: 17.60+/-1.24 l (P=0.37)). The difference between the groups was significant (P<0.05). GH treatment also increased PV (before: 3.39+/-0.27 l. 4 months: 3.71+/-0.261 (P=0.01)), although an insignificant increase in the placebo treated patients (before: 2.81+/-0.18 l, 4 months: 2.89+/-0.20 l (P=0.37)) resulted in an insignificant treatment effect (P=0.07). Serum insulin-like growth factor-I increased significantly during GH treatment and was not affected by placebo treatment. Plasma renin (mIU/l) increased during GH administration (before: 14.73+/-2.16, 4 months: 26.00+/-6.22 (P=0.03)) and remained unchanged following placebo (before: 20.77+/-5.13, 4 months: 20.69+/-6.67 (P=0.99)) leaving no significant treatment effect (P=0.08).

CONCLUSION

The long-term impact of GH treatment on body fluid distribution in adult GH deficient patients involves expansion of ECV and probably also PV. These data substantiate the role of GH as a regulator of fluid homeostasis in adult GH deficiency.

Reduced lung function in leukaemia patients undergoing bone marrow transplantation

20 patients with leukaemia in remission or early relapse received an allogeneic bone marrow graft. Patients were conditioned according to Seattle protocol with high dose cyclophosphamide and total body irradiation to a total dose of 8 Gray to the lungs delivered by a 6 MV linear accelerator at a dose rate of approximately 0.06 Gray/min. As prophylaxis against the graft versus host reaction, methotrexate and/or cyclosporin A were given. Lung function was studied prior to treatment and every 3 months thereafter. Before treatment a marked decrease was seen in the CO diffusion capacity when compared to the predicted value, while the flow volume relationships were within normal limits. The cause of this is unknown, but may be due to previous infections and the cytostatic treatment given. After bone marrow transplantation, a further irreversible decrease was seen in the CO diffusion capacity and vital capacity indicating an additive effect of the lung irradiation.

Fuel metabolism in growth hormone-deficient adults

Apart from being a stimulator of longitudinal growth, growth hormone (GH) regulates fuel metabolism in children and adults. A halfmark is mobilization of lipids, which involves an inhibition of lipoprotein lipase activity in adipose tissue and activation of the hormone sensitive lipase. Suppression of basal glucose oxidation and resistance to insulin are other important effects. This may cause concern during GH substitution in GH-deficient adults, some of whom may present with insulin resistance due to concomitant abdominal obesity. However, there are data to suggest that the GH-induced reduction in fat mass and increase in lean body mass may offset the insulin antagonistic actions of the hormone. The nitrogen-retaining effects of GH seem to involve a direct stimulation of protein synthesis in addition to secondary effects such as generation of insulin-like growth factor-I (IGF-I), hyperinsulinemia, and promotion of lipolysis. Thus, during periods of substrate affluence, GH acts in concert with insulin and IGF-I to promote protein anabolism. Postabsorptively, GH is primarily lipolytic and thereby indirectly protein-sparing. This effect becomes further accentuated with more prolonged fasting. In that sense, GH is unique by its preservation of protein during both feast and famine. These fuel metabolic effects add merit to the principle of GH substitution in hypopituitary adults.

Pretreatment with atracurium: the influence on neuromuscular transmission and pulmonary function

The influence of pretreatment with atracurium on neuromuscular transmission was evaluated in 60 healthy volunteers using train-of-four (TOF) nerve stimulation and measurement of respiratory rate (RR), vital capacity (VC), inspiratory force (IF), and peak expiratory flow (PEF). The subjects were randomly allocated to one of four groups: Group I received atracurium 0.02 mg/kg, Group II 0.03 mg/kg, Group III 0.04 mg/kg, and Group IV atracurium 0.05 mg/kg. TOF ratio decreased significantly in all four groups. There was, however, no difference between the groups after injection. PEF decreased significantly in all four groups, VC decreased in Groups I and IV, and RF increased significantly only in Group IV. Three subjects (5%) had shallow, frequent respiration; however, none needed respiratory support. The majority of the volunteers experienced blurring of vision and heavy eyelids: 82% and 67%, respectively. All subjects were able to sustain head lift for 10 s or more after atracurium. Careful observation of respiration is necessary, especially when using the higher doses of atracurium.

Growth hormone and fluid retention

A major side effect of growth hormone (GH) administration is fluid retention. Most data indicate that adult GH-deficient patients are dehydrated, i.e. they have low total body water, low extracellular water and low plasma volume. When GH substitution is initiated in these patients their body fluid compartments are restored to normal. The fluid retaining capacity of GH should therefore be regarded as a desirable physiological normalization of fluid homeostasis rather than an unpleasant side effect.

Growth hormone (GH) therapy in GH-deficient patients, the plasma factor VIII-von Willebrand factor complex, and capillary fragility. A double-blind, placebo-controlled crossover study

It has been suggested that growth hormone (GH) plays a role in the regulation of Factor VIII-von Willebrand factor complex and other parameters associated with haemostasis and vascular integrity. However, limited information is available on these features in GH-deficient patients. We therefore examined, in a double-blind, placebo-controlled crossover design, the effects of 4 months' replacement therapy with biosynthetic human GH in 22 GH-deficient adults on circulating haemostatic parameters and capillary fragility. A non-significant increase in the plasma levels of von Willebrand factor antigen (p = 0.09), Factor VIII antigen (p = 0.6), fibrinogen (p = 0.4) and fibronectin (p = 0.2) was observed at the end of the GH treatment period along with a non-significant decrease in tissue-type plasminogen activator (p = 0.2). Capillary fragility tended to decrease during GH therapy (p = 0.2). All variables remained within the reference range following both the placebo and the GH treatment period. It is concluded that GH-deficient patients display normal levels of the haemostasis parameters recorded, and that 4 months of GH therapy in a conventional replacement dose does not significantly affect these values.

Detection and spatial characterization of minicolumnarity in the human cerebral cortex

BACKGROUND

Spatial characterization of vertical organization of neurons in human cerebral cortex, cortical columnarity or minicolumns, and its possible association with various psychiatric and neurological diseases has been investigated for many years.

NEW METHOD

In this study, we obtained 3D coordinates of disector sampled cells from layer III of Brodmann area 4 of the human cerebral cortex using light microscopy and 140-μm-thick glycolmethacrylate sections. A new analytical tool called cylindrical K-function was applied for spatial point pattern analysis of 3D datasets to see whether there is a spatially organized columnar structure. In order to demonstrate the behaviour of the cylindrical K-function, the result from brain tissues was compared with two models: A homogeneous Poisson process exhibiting complete spatial randomness, and a Poisson line cluster point process. The latter is a point process model in 3D space, which exhibits spatial structure of points similar to minicolumns.

RESULTS

The data show in three out of four samples nonrandom patterns in the 3D neuronal positions with the direction of minicolumns perpendicular to the pial surface of the brain - without a priori assuming the existence of minicolumns.

COMPARISON WITH EXISTING METHODS

Studies on columnarity are difficult and have mainly been based on two-dimensional images analysis of thin sections of the cerebral cortex with the a priori assumption that minicolumns existed.

CONCLUSIONS

A clear difference from complete spatial randomness in the data could be detected with the new tool, the cylindrical K-function, although classical functional summary statistics are less useful in this connection.

Investigation of a multi-biomarker disease activity score in rheumatoid arthritis by comparison with magnetic resonance imaging, computed tomography, ultrasonography, and radiography parameters of inflammation and damage

OBJECTIVES

To investigate the multi-biomarker disease activity (MBDA) score by comparison with imaging findings in an investigator-initiated rheumatoid arthritis (RA) trial (HURRAH trial, NCT00696059).

METHOD

Fifty-two patients with established RA initiated adalimumab treatment and had magnetic resonance imaging (MRI), ultrasonography (US), computed tomography (CT), and radiography performed at weeks 0, 26, and 52. Serum samples were analysed using MBDA score assays and associations between clinical measures, MBDA score, and imaging findings were investigated.

RESULTS

The MBDA score correlated significantly with MRI synovitis (rho = 0.65, p < 0.001), MRI bone marrow oedema (rho = 0.36, p = 0.044), and US power Doppler (PD) score at week 26 (rho = 0.35, p = 0.039) but not at week 0 or week 52. In the 15 patients who had achieved a Disease Activity Score based on C-reactive protein (DAS28-CRP) < 2.6 at week 26, MRI and/or US detected subclinical inflammation and 13 (87%) had a moderate/high MBDA score. For the cohort with available data, none of the four patients in MBDA remission (score ≤ 25) at week 26 had progression of imaging damage from baseline to week 52 whereas progression was observed in three out of nine (33%) and seven out of 21 (33%) patients with moderate (30-44) and high (> 44) MBDA scores, respectively.

CONCLUSIONS

In this cohort, the MBDA score correlated poorly with MRI/US inflammation. However, the MBDA score and MRI/US were generally concordant in showing signs of inflammation in most patients in clinical remission during anti-tumour necrosis factor (anti-TNF) therapy. MBDA scores were elevated in all patients with structural damage progression.

Blockade of the renin-angiotensin-aldosterone system prevents growth hormone-induced fluid retention in humans

To test if the renin-angiotensin-aldosterone system (RAAS) is involved in growth hormone (GH)-associated fluid retention, we examined the effect of GH administration in the presence or absence of RAAS blockade at different levels on body fluid homeostasis. Eight subjects were examined in a controlled, randomized double-blinded trial. During four 6-day periods they received subcutaneous GH (6 IU-m-2) or placebo injections and tablets as follows: 1) placebo and placebo, 2) GH and placebo, 3) GH and captopril, and 4) GH and spironolactone. GH increased extracellular volume (liters; placebo 18.87 +/- 0.85; GH + placebo 20.43 +/- 1.01) but this effect was abolished by captopril (GH + captopril 18.82 +/- 0.67) and spironolactone (GH + spironolactone 18.99 +/- 0.85). Correspondingly, the GH-induced reduction in bioimpedance was blocked by captopril and spironolactone. Plasma renin and angiotensin II concentrations increased during all three GH treatment regimens, whereas plasma aldosterone was increased only after GH plus spironolactone. The data demonstrate that GH activates the RAAS and that blockade of the RAAS by two separate mechanisms prevents fluid retention normally encountered after GH exposure. These observations suggest that the RAAS plays a key role in GH-induced regulation of fluid homeostasis.

Accessory signals in T-T cell interactions between antigen- and alloantigen-specific, human memory T cells generated in vitro

The potential of activated HLA class II-positive T cells as antigen-/alloantigen-presenting cells remains controversial. In our model system we use in vitro-primed, HLA class II-specific T cells of the memory T-cell phenotype, CD4+, CD29+ (4B4+), and CD45RO+ (UCHL-1). We have previously shown that alloactivated, HLA class II-positive T cells (Ta) are unable to stimulate proliferative responses in naive and primed allospecific T cells when 'back-stimulation' is avoided. The explanation of this feature of Ta is unknown, but it is due neither to suppression nor to insufficient HLA class II expression. Accordingly, we investigated the possibility that Ta have a deficient expression of accessory signals critical for the induction of proliferative T-cell responses. We found that (1) non-mitogenic concentrations of phorbol myristate acetate (PMA) in combination with either rIL-4, a CD28-reactive MoAb (Kolt-2), or a calcium ionophore (A23187) enabled Ta to elicit alloantigen-specific memory T-cell responses and to present purified protein derivative (PPD) to PPD-specific T-cell lines. The addition of irradiated, Epstein-Barr virus-transformed B-cell lines (EBV-LCL) (but not their supernatants) had a similar but less pronounced effect; (2) MoAb directed against HLA class II, CD25 (IL-2R), CD2, CD4, CD11a (LFA-1), or CD45RO molecules inhibited these responses; (3) PMA was required within the first hour of culture in order to induce optimal alloantigen-specific T-cell activation, while rIL-4 was fully effective when added after 20-44 h of culture; (4) incubation for 20 h of Ta with rIL-4 plus PMA markedly up-regulated CD54 expression on the Ta, and IL-4 seemed to potentiate the effect of PMA on the CD54 expression. In conclusion, the present data indicate that the inability of Ta to elicit (allo)antigen-specific, proliferative T-cell response is due to a lack of critical accessory signals. Up-regulation of CD54 was not sufficient for Ta to stimulate proliferative responses. Neither cytokines (IL-1, IL-6, and others) nor triggering of CD2 epitopes (T11.2 and T11.3) by soluble MoAb or solid phase support by MoAb against a number of accessory molecules provided the necessary signals. Thus, our data indicate that other, as yet unknown, signalling pathways play a key role in antigen- and alloantigen-specific T-T interactions. These pathways still need to be identified.

An external quality assessment study on the analysis of methylmalonic acid and total homocysteine in plasma

In spite of the increasing interest in the analysis of methylmalonic acid and total homocysteine in plasma, data on interlaboratory variation is lacking. We report the results of an external quality assessment study with the participation of 15 laboratories in the Scandinavian countries performing these analyses on a regular basis. For methylmalonic acid, using serum, heparin fluoride plasma and an aqueous sample, CVs were found in the range of 11-17%. For total homocysteine using EDTA plasma, heparin fluoride plasma and an aqueous sample, CVs were in the range of 6-12%. For both analytes, a significant correlation between the individual recoveries of added analyte and the results for the aqueous sample was found, suggesting that the use of inconsistent calibrations in the participating laboratories are contributing to the interlaboratory variation. An acceptable range for results from the individual laboratory was calculated using data on the biological within-subject and between-subject variations reported in the literature. These ranges were violated by several laboratories when using the consensus mean or median as target values. Even if the results of the present study document a reasonable standard in the measurement of methylmalonic acid and total homocysteine in plasma in the participating laboratories there is room for improvement and a permanent scheme of external quality assessment using relevant samples is essential. From 1997, a regular scheme has been available from our laboratory.

Body temperature elevation, exercise and serum prolactin concentrations

Ten young healthy normal-weight males were studied in four test situations designed to elucidate the relative role of body temperature increase vs that of exercise per se for pituitary hormone release. Tympanic temperature was recorded continuously during the tests. Elevation of body temperature at rest induced by external heating resulted in parallel changes in serum prolactin (Prl), also found when temperature spontaneously returned towards normal. In contrast, temperature elevation of the same magnitude through exercise (450 kpm/min for 40 min) induced no change in Prl secretion. It is concluded that increase in core temperature is a stimulus of Prl secretion and suggested that exercise apparently inhibits the stimulatory effect.

Dose-dependent effects of recombinant human growth hormone on biochemical markers of bone and collagen metabolism in adult growth hormone deficiency

Administration of growth hormone (GH) to patients with growth hormone deficiency (GHD) has beneficial effects, but so far has been employed only empirically. We have, therefore, investigated the dose-dependent effect of GH on target tissue by studying biochemical markers of bone and collagen turnover in GHD. Then patients with GHD (nine males and one female aged 21-43 years, mean age 28 years) participated in the study. Growth hormone deficiency was defined as a peak serum GH response of less than 15 mU/l in two provocation tests. After a 4-week run-in period, the study population received increasing doses of GH at 4-week intervals (1, 2 and 4 U/m2). Blood samples were collected in the fasting state at 7.00 h on the last day of each period and assayed for serum levels of osteocalcin (S-BGP), bone alkaline phosphatase (B-ALP), C-terminal propeptide of type I collagen (S-PICP), carboxy-terminal pyridinoline cross-linked telopeptide of type I collagen (S-ICTP) and N-terminal propeptide of type III collagen (S-PIIINP). Following replacement therapy, serum insulin-like growth factor I and insulin-like growth factor binding protein 3 increased sequentially with time (p < 0.001 and p < 0.001, MANOVA) and the values were elevated significantly over baseline levels after treatment with 1 U/m2. Serum BGP values were below normal at the start of the study and increased gradually following GH treatment to levels in the low-normal range. Baseline values for serum bone alkaline phosphatase (B-ALP), PICP and PIIINP were within the normal range. The collagen parameters increased with GH replacement (p < 0.001, MANOVA) to levels above normal, whereas B-ALP stayed within normal limits. Serum ICTP values were elevated above the normal range at baseline, indicating increased bone resorption in GHD. A linear increase in values was observed with GH treatment (p < 0.001, MANOVA). Serum ICTP did not correlate significantly with the bone formative parameters but was correlated positively to PIIINP. The sensitivity of S-ICTP as a bone resorptive marker is thus questioned. In conclusion, a dose-dependent increase in markers of growth hormone metabolism and in biochemical markers of both bone and non-bone collagen synthesis was seen following incremental doses of GH in GHD.

Microbiological assessments of compost toilets: in situ measurements and laboratory studies on the survival of fecal microbial indicators using sentinel chambers

Compost toilet systems were assessed for their ability to reduce microbial indicators and pathogens. Bacterial pathogens were not detected in any samples indicating a low survival rate in composting feces and/or an initial low occurrence. Indicator bacteria showed large variations with no clear trend of lower bacterial numbers after longer storage. In controlled composting experiments, thermophilic conditions were only reached when amendments were made (grass and a sugar solution). Even then it was impossible to ensure a homogenous temperature in the composting fecal material and therefore difficult to achieve a uniform reduction and killing of indicator organisms. Presumptive thermotolerant coliforms, Salmonella typhimurium Phage 28 B and eggs of Ascaridia galli, proved useful as indicators. However, regrowth was detected for enterococci and total numbers of bacteria grown at 36 degrees C. These indicator parameters may therefore overestimate the level of other (pathogenic) bacteria present in the material and can not be recommended for use as reliable indicator organisms in composting toilet systems. The addition of indicator bacteria to fecal material contained in semi-permeable capsules proved to be a useful technique to ensure that microorganisms were contained in a small test volume.

Marked effects of sustained low growth hormone (GH) levels on day-to-day fuel metabolism: studies in GH-deficient patients and healthy untreated subjects

The metabolic effects of circadian GH levels in the very low physiological range are unknown. Therefore, we studied 1) GH-deficient patients on receiving GH replacement therapy in whom the last GH injection was replaced with a constant iv infusion starting at 24 h of either GH (35 micrograms/h) or saline (SAL), and 2) an untreated healthy control group. Glucose turnover, indirect calorimetry, and forearm exchange of metabolites were investigated the following day in the basal state (8-11 h) and during a euglycemic (11-13 H) and a hypoglycemic (13-14 h) glucose clamp. During infusion, steady state GH levels increased by 1.9 micrograms/L. Basal and insulin-stimulated energy expenditures (EE) were lower in the patients during SAL than during GH infusion, and the basal respiratory exchange ratio was also lower during GH treatment. Protein EE was elevated during SAL compared to GH infusion (P < 0.05). During the clamp, forearm glucose uptake decreased in the GH study compared to that in the SAL study ((P < 0.05). The patients in the SAL study were more sensitive to insulin during the clamp in terms of suppression of endogenous glucose production (EGP; P < 0.05) and infusion rate of glucose necessary to maintain euglycemia (M value; P < 0.01). Lipid oxidation, in particular in the basal state, was decreased during SAL compared to GH infusion (P < 0.01). The SAL-treated compared with the control group was characterized by decreased basal and insulin-stimulated EE (P < 0.01), increased protein EE (P < 0.01), and hypersensitivity to insulin in terms of suppression of EGP (P < 0.05) and M value (P < 0.01). During the hypoglycemic clamp, the patients in the SAL study were hypersensitive to the hypoglycemic actions of insulin in terms of increased M-value and suppression of EGP, and lipolysis was impaired, as judged by the inhibition of net forearm uptake of FFA. In conclusion, very low GH levels exert powerful actions on day-to-day metabolism, resulting in protein and glucose sparing at the expense of lipids.

The effect of low-dose supplementation with n-3 polyunsaturated fatty acids on some risk markers of coronary heart disease

Epidemiological data have suggested that a low dose of dietary n-3 polyunsaturated fatty acids from seafood may protect against coronary heart disease. We studied the effect of supplementation with a low dose of very long-chain n-3 fatty acids (0.65 g day-1) on plasma lipids, haemostasis, and neutrophil aggregation. Twenty-four healthy subjects were randomized to supplementation with very long-chain n-3 fatty acids or a control oil for 8 weeks. Laboratory analyses were done twice before and twice at the end of the supplementation period. The supplement with n-3 polyunsaturated fatty acid did not significantly affect plasma lipids or plasma levels of fibrinogen, factor VII, plasminogen activator inhibitor, whole blood aggregation or aggregability of neutrophil leukocytes. Therefore, the potential beneficial effect of very long-chain n-3 fatty acids in coronary heart disease is likely to be mediated through other mechanisms.

Pharmacological aspects of growth hormone replacement therapy: route, frequency and timing of administration

Two or three weekly, daytime intramuscular injections of GH has been the traditional treatment of GH deficiency since the first studies. A recent reevaluation of the feasibility of subcutaneous GH injections revealed no side-effects, but a very strong preference by the patients for the subcutaneous route, and also an increase in growth rate in studies where the patients received daily injections given in the evening. That could indicate that the route, frequency and timing of GH administration may be of clinical importance. Subcutaneous injections result in a slower absorption, a smaller peak value, and a prolonged serum disappearance phase compared to intramuscular injections. This extends the periods of elevated serum GH levels in the patient, which might be advantageous. On the other hand, a reduced bioavailability of GH by the subcutaneous route has also been reported. The frequency of subcutaneous injections correlates positively with growth rate in animal studies. This is commonly ascribed to a closer resemblance to the endogenous pulsatile pattern. However, frequent subcutaneous injections do not induce a pulsatile pattern, but a pattern which is intermediary between continuous and true pulsatile administration. In a short-term patient study, we observed that pulsatile and continuous intravenous administration of GH generated identical increases in serum insulin-like growth factor I, which suggests that both pulsatory and constant, small elevations in serum GH are important for its actions. Concerning the time of administration, evening GH injections yield a more physiological pattern, and it has been shown that evening GH administration induces increased nitrogen retention and is more successful in normalizing circadian patterns of pertinent hormones and metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)