Does treatment with bisphosphonates protect against fractures in real life? The HUNT study, Norway.

Bisphosphonates reduce fractures in randomized controlled trials (RCT); however, there is less information from real life. In our population including 14,990 women and 13,239 men, use of bisphosphonates reduced risk of fractures in hip and forearm in women. The magnitude of the effect was comparable to results from RCT. INTRODUCTION: The objective was to examine if treatment with bisphosphonates (BPs) was associated with reduced risk of fractures in the hip and forearm in women and men in the general population. METHODS: In a cohort study based on data from the third wave of the population-based HUNT Study (HUNT3), the fracture registry in Nord-Trøndelag, and the Norwegian Prescription Database, 14,990 women and 13,239 men 50-85 years were followed from the date of participating in HUNT3 (2006-2008) until the date of first fracture in the hip or forearm, death, or end of study (31 December 2012). Hazard ratios with 95% confidence intervals for hip and forearm fracture according to use of BPs were estimated using Cox proportional hazards models with time-dependent exposure. Adjustment for individual FRAX® fracture risk assessment scores was included. RESULTS: BPs, predominantly alendronate, were used by 9.4% of the women and 1.5% of the men. During a median of 5.2 years of follow-up, 265 women and 133 men had a hip fracture, and 662 women and 127 men had a forearm fracture. Compared with non-users of BPs, the hazard ratios with 95% confidence interval for a fracture among users of BPs adjusted for age and FRAX® were 0.67 (0.52-0.86) for women and 1.13 (0.50-2.57) for men. Among users of glucocorticoids, the corresponding figures were 0.35 (0.19-0.66) and 1.16 (0.33-4.09), respectively. CONCLUSIONS: Use of BPs was associated with reduced risk of fractures in hip and forearm in women, and the magnitude of effect is comparable to results from RCTs.

Proton pump inhibitors and fracture risk. The HUNT study, Norway.

Proton pump inhibitors (PPIs) have been linked to increased risk of fracture; the data have, however, been diverging. We did not find any increased risk of fractures among users of PPIs in a Norwegian population of 15,017 women and 13,241 men aged 50-85 years with detailed information about lifestyle and comorbidity. INTRODUCTION: Proton pump inhibitors (PPIs) are widely prescribed and have been linked to increased risk of fracture. METHODS: We used data from the Nord-Trøndelag Health Study (HUNT3), The Fracture registry in Nord-Trøndelag, and the Norwegian Prescription Database, including 15,017 women and 13,241 men aged 50-85 years. The study population was followed from the date of participating in HUNT3 (2006-2008) until the date of first fracture (forearm or hip), death, or end of study (31 December 2012). The Cox proportional hazards model with time-dependent exposure to PPIs was applied, and each individual was considered as unexposed until the first prescriptions was filled. To be included, the prescription of PPIs should minimum be equivalent to 90 defined daily doses (DDD) in the period. Individuals were defined as exposed until 6 months after end of drug supply. RESULTS: The proportion of women and men using PPIs was 17.9% and 15.5%, respectively. During a median of 5.2 years follow-up, 266 women and 134 men had a first hip fracture and 662 women and 127 men, a first forearm fracture. The combined rate/1000 patient-years for forearm and hip fractures in women was 49.2 for users of PPIs compared with 64.1 among non-users; for men 18.6 and 19.8, respectively. The hazard ratios with 95% confidence interval for the first forearm or hip fracture among users of PPIs in the age-adjusted analysis were 0.82 (0.67-1.01) for women and 1.05 (0.72-1.52) for men. Adjusting for age, use of anti-osteoporotic drugs, and FRAX, the HR declined to 0.80 (0.65-0.98) in women and 1.00 (0.69-1.45) in men. CONCLUSIONS: Use of PPIs was not associated with an increased risk of fractures.

Vitamin D and stress urinary incontinence in pregnancy: a cross-sectional study.

OBJECTIVE: To assess the association between levels of vitamin D and urinary incontinence (UI) in pregnancy. DESIGN: A cross-sectional study. Secondary analysis of a randomised controlled trial. SETTING: Two university hospitals in Norway. POPULATION: A total of 851 healthy, pregnant women >18 years in gestational weeks 18-22 with a singleton live fetus. METHODS: Data on UI were collected from a questionnaire at inclusion and serum analysis of 25-hydroxy vitamin D (25(OH)D) was performed. Univariable and multivariable logistic regression analyses were applied to study associations between exposure and outcomes. MAIN OUTCOME MEASURES: Prevalence of self-reported UI, stress (SUI) and urge (UUI) or mixed UI. RESULTS: In total, 230/851 (27%) of the participants were vitamin D insufficient (25(OH)D <50 nmol/l) and 42% reported to have any UI. Women with 25(OH)D <50 nmol/l were more likely to report any UI (P = 0.03) and SUI (P < 0.01) compared with women with 25(OH)D ≥50 nmol/l. In a univariable logistic regression analysis, serum levels of 25(OH)D <50 nmol/l was associated with increased risk of any UI (odds ratio [OR] 1.5 with 95% CI 1.0-2.1), SUI only (OR 1.7, 95% CI 1.2-2.4), but not mixed UI or UUI only (OR 0.8, 95% CI 0.5-1.5). In a multivariable logistic regression model, serum levels of 25(OH)D <50 nmol/l were associated with a higher risk of experiencing SUI only (OR 1.5, 95% CI 1.1-2.2). CONCLUSIONS: Serum 25(OH)D <50 nmol/l was associated with increased risk of any UI, and SUI in particular. TWEETABLE ABSTRACT: Low levels of vitamin D are associated with increased risk of urinary incontinence in pregnancy.

Anti-osteoporosis drug use: too little, too much, or just right? The HUNT study, Norway.

Use of anti-osteoporotic drugs (AODs) was examined in a Norwegian population 50-85 years. Among them with Fracture Risk Assessment Tool (FRAX) score for major osteoporotic fracture ≥ 20, 25% of the women and 17% of the men received AODs. The strongest predictors for AODs were high age in women and use of glucocorticoids among men. INTRODUCTION: To examine the use of anti-osteoporotic drugs (AODs) and to identify predictors for prescriptions. METHODS: Data were obtained from the Nord-Trøndelag Health Study (HUNT3) performed in 2006-2008 and the Norwegian Prescription Database, including 15,075 women and 13,386 men aged 50-85 years. Bone mineral density (BMD) in the femoral neck was measured in a subgroup of 4538 women and 2322 men. High fracture risk was defined as a FRAX score for major osteoporotic fracture (MOF) ≥ 20%; in the subgroup with BMD, high risk was in addition defined as FRAXMOF ≥ 20% or T-score ≤ - 2.5. Hazard ratios (HRs) for predictors of incident use of AODs within 2 years after HUNT3 were estimated by Cox' proportional hazards model. RESULTS: Among individuals with FRAX MOF ≥ 20%, 25% of the women and 17% of the men were treated with AODs. Among those with FRAX MOF < 20%, 3% and 1% were treated, respectively. In the subgroup with BMD measurement, 24% of the women and 16% of the men at high risk of fractures were treated, compared to 3 and 1% in women and men not fulfilling the criteria. In women, high age was the strongest predictor for treatment (HR 3.84: 95% confidence interval 2.81-5.24), followed by use of glucocorticoids (GCs) (2.68:1.84-3.89). In men, predictors were use of GCs (5.28: 2.70-10.35) followed by multimorbidity (3.16:1.31-7.63). In the subgroup with BMD, T-score ≤ - 2.5 was the strongest predictor (women 3.98:2.67-5.89; men 13.31:6.17-28.74). CONCLUSIONS: This study suggests an undertreatment of AODs in individuals at high risk of fracture.

Validation of FRAX and the impact of self-reported falls among elderly in a general population: the HUNT study, Norway.

Fracture Risk Assessment Tool (FRAX) without bone mineral density (BMD) for hip fracture prediction was validated in a Norwegian population 50-90 years. Fracture risk increased with higher FRAX score, and the observed number of hip fractures agreed well with the predicted number, except for the youngest and oldest men. Self-reported fall was an independent risk factor for fracture in women. INTRODUCTION: The primary aim was to validate FRAX without BMD for hip fracture prediction in a Norwegian population of men and women 50-90 years. Secondary, to study whether information of falls could improve prediction of fractures in the subgroup aged 70-90 years. METHODS: Data were obtained from the third survey of the Nord-Trøndelag Health Study (HUNT3), the fracture registry in Nord-Trøndelag, and the Norwegian Prescription Database (NorPD), including 15,432 women and 13,585 men. FRAX hip without BMD was calculated, and hip fractures were registered for a median follow-up of 5.2 years. The number of estimated and observed fractures was assessed, ROC curves with area under the curve (AUC), and Cox regression analyses. For the group aged 70-90 years, self-reported falls the last year before HUNT3 were included in the Cox regression model. RESULTS: The risk of fracture increased with higher FRAX score. When FRAX groups were categorized in a 10-year percentage risk for hip fracture as follows, <4, 4-7.9, 8-11.9, and ≥12%, the hazard ratio (HR) for hip fracture between the lowest and the highest group was 17.80 (95% CI: 12.86-24.65) among women and 23.40 (13.93-39.30) in men. Observed number of hip fractures agreed quite well with the predicted number, except for the youngest and oldest men. AUC was 0.81 (0.78-0.83) for women and 0.79 (0.76-0.83) for men. Self-reported fall was an independent risk factor for fracture in women (HR 1.64, 1.20-2.24), and among men, this was not significant (1.09, 0.65-1.83). CONCLUSIONS: FRAX without BMD predicted hip fracture reasonably well. In the age group 70-90 years, falls seemed to imply an additional risk among women.

Impaired skeletal health and neuromuscular function among amphetamine users in clinical treatment.

SUMMARY: This study examined musculoskeletal health in amphetamine users, compared with healthy age-matched controls. We show that amphetamine users have reduced bone mass at several skeletal sites and attenuated maximal muscle strength and force development capacity in the lower extremities. INTRODUCTION: Amphetamine use may cause poor bone quality and elevated risk of osteoporosis. The purpose of this study was to investigate whether amphetamine users exhibit reduced regional and whole body bone mineral density (BMD), altered bone metabolism, and how muscle function may relate to the patient groups' skeletal health. METHODS: We assessed hip, lumbar spine and whole body BMD, and trabecular bone score (TBS) by dual x-ray absorptiometry (DXA), and bone metabolism markers in serum and maximal strength and force development capacity in 36 amphetamine users (25 men, 30 ± 7 years; 11 women 35 ± 10 years) and in 37 healthy controls (23 men, 31 ± 9 years; 14 women, 35 ± 7 years). RESULTS: Whole body BMD was lower in amphetamine users (8% in males and 7% females, p < 0.01), as were BMD at the total hip and sub-regions of the hip (9-11% in men and 10-11 % in women, p < 0.05). Male users had 4% lower TBS (p < 0.05) and higher serum level of type 1 collagen amino-terminal propeptide (p < 0.01). This coincided with reduced lower extremity maximal strength of 30% (males, p < 0.001) and 25% (females, p < 0.05) and 27% slower muscular force development in males compared to controls (p < 0.01). CONCLUSIONS: These findings demonstrate that amphetamine users suffer from a generalized reduction in bone mass, which was associated with attenuated maximal muscle strength and force development capacity in the lower extremities.

Bone mineral density and vitamin D status in ambulatory and non-ambulatory children with cerebral palsy.

UNLABELLED: This study assessed distal femur and lumbar spine bone mineral density (BMD) Z-scores in children with cerebral palsy. BMD z-score was lower in non-ambulatory than in ambulatory children. Somewhat surprisingly, among ambulatory children, those with better walking abilities had higher BMD z-score than those with more impaired walking ability. INTRODUCTION: Children with cerebral palsy (CP) have increased risk for low bone mineral density (BMD). The aim was to explore the difference in BMD at the distal femur and lumbar spine between ambulatory and non-ambulatory children with CP and the relationship between vitamin D status and BMD. METHODS: Fifty-one children (age range 8-18 years; 20 girls) with CP participated. Their BMD Z-scores were measured in the lumbar spine and the distal femur using dual X-ray absorptiometry, and 25-hydroxy-vitamin D (25-OHD) concentrations were measured in serum. Children with GMFCS level I-III were defined as 'walkers' while children with level IV-V were defined as 'non-walkers. RESULTS: Non-walkers had lower mean BMD Z-scores (range -1.7 to -5.4) than walkers at all sites (range -0.8 to -1.5). Among walkers, BMD Z-scores at the distal femur were lower in those with GMFCS level II than with level I (p values < 0.004). A similar difference was found between the affected and unaffected limb in children with hemiplegia. Mean 25-OHD concentration was 45 nmol/L (SD = 18); lower in walkers (mean = 41 nmol/L; SD = 18) than in non-walkers (mean = 53 nmol/L; SD = 19; p = 0.041). There were no correlations between 25-OHD and BMD z-scores. CONCLUSIONS: The main predictor of low BMD Z-scores in the distal femur was the inability to walk, but the results suggest that the degree of the neuromotor impairment may also be a significant predictor. Vitamin D status did not correlate with BMD z-scores.

Maternal vitamin D status in pregnancy and molar incisor hypomineralisation and hypomineralised second primary molars in the offspring at 7-9 years of age: a longitudinal study.

PURPOSE: The study aimed to investigate associations between maternal vitamin D status during pregnancy and molar incisor hypomineralisation (MIH) and hypomineralised second primary molars (HSPM) among children. METHODS: The study had a longitudinal design using prospectively collected data from 176 mother and child pairs. Mothers were initially recruited in a randomised controlled trial to assess a pregnancy exercise programme. Along with the 7-year follow-up, we invited the children to a dental examination. The exposure variable was maternal serum 25-hydroxyvitamin D in gestational weeks 18-22 and 32-36, categorised as insufficient (< 50 nmol/l) and sufficient (≥ 50 nmol/l). Negative binomial hurdle models were used to analyse potential associations between the exposure variables and MIH or HSPM. The models were adjusted for potential confounders. RESULTS: Among the children (7-9 years old), 32% and 22% had at least one tooth with MIH or HSPM, respectively. A significant association was found between insufficient maternal vitamin D measured in gestational weeks 18-22 and the number of affected teeth among those with MIH at 7-9 years (adjusted RR = 1.82, 95% CI 1.13-2.93). CONCLUSION: Considering any limitations of the present study, it has been shown that insufficient maternal serum vitamin D at mid-pregnancy was associated with a higher number of affected teeth among the offspring with MIH at 7-9 years of age. Further prospective studies are needed to investigate whether this finding is replicable and to clarify the role of maternal vitamin D status during pregnancy and MIH, as well as HSPM, in children.

Adipocytes express a functional system for serotonin synthesis, reuptake and receptor activation.

AIMS: Serotonergic pathways in the central nervous system (CNS) are activated in the regulation of food intake and body weight. We hypothesized that adipocytes, like other cells of mesenchymal origin, possess serotonin receptors and thus could be regulated by peripherally circulating serotonin. METHODS: In vivo studies: four Sprague-Dawley rats were given daily serotonin (5HT) injections subcutaneously (s.c., 25 mg/kg) for 5 days; four controls received saline. In a long-term study, 12 rats were given serotonin s.c. for 4 months, 10 controls received saline. Body weight was registered throughout the studies, and visceral adipose tissue and plasma were collected and analysed. Adipocytes were isolated from normal rat visceral abdominal adipose tissue and analysed for the expression of serotonin receptors, the serotonin transporter (5HTT/SERT), activation of serotonin synthesis (tryptophan hydroxylase 1, Tph1) and secretion and serotonin-induced leptin regulation by RT-PCR and protein analyses. RESULTS: Hyperserotoninergic rats had significantly lower body weight (-7.4 and -6.8%) and plasma leptin levels (-44 and -38%) than controls, after both short- and long-term serotonin treatment, respectively, whereas plasma ghrelin levels were unaffected. Compared to controls, serotonin induced a 40-fold upregulation of 5HTT mRNA in visceral adipose tissue after 5 days of treatment. In vitro experiments showed that adipocytes express serotonin receptors, Tph1 and 5HTT, synthesize and secrete serotonin and that serotonin regulates leptin in mature adipocytes. CONCLUSIONS: These findings show that serotonin may regulate adipocyte function in a direct manner via the blood circulation and/or paracrine and autocrine mechanisms, and not only indirectly via the CNS as previously assumed.

Skeletal effects of plyometric exercise and metformin in ovariectomized rats.

Estrogen deficiency causes bone loss and skeletal muscle dysfunction, and attenuates the musculoskeletal effects of exercise. The anti-diabetic drug metformin has been suggested to promote beneficial skeletal effects. To explore whether metformin can improve musculoskeletal training response during estrogen deficiency, we investigated the skeletal effects of plyometric exercise and metformin, in an ovarectomized (OVX) rat model of osteoporosis. Female Sprague Dawley rats, 12 weeks of age, rats were allocated to a sham-operated group (Sham), and four OVX groups; metformin (OVX-Met), exercise (OVX-Ex), combined metformin and exercise (OVX-MetEx) and a control group (OVX-Ctr), n = 12/group. Dual X-ray absorptiometry, micro computed tomography, fracture toughness testing, histomorphometry and plasma analyses were performed to explore skeletal effects. All intervention groups exhibited a higher gain in femoral bone mineral density (BMD) than OVX-Ctr (p < .01). The combined intervention also resulted in a higher gain in femoral and spine BMD compared to OVX-Met (p < .01). Both exercise groups displayed improved microarchitecture, including both cortical and trabecular parameters (p < .05). This was most evident in the OVX-MetEx group where several indices were at sham level or superior to OVX-Ctr (p < .05). The OVX-MetEx group also exhibited an enhanced toughening effect compared to the other OVX groups (p < .05). The beneficial skeletal effects seemed to be mediated by inhibition of bone resorption and stimulation of bone formation. The training response (i.e. jumping height) was also greater in the metformin treated rats compared to OVX-Ex (p < .01), indicating a performance-enhancing effect of metformin. Both exercise groups displayed higher lean mass than OVX-Ctr (p < .05). In conclusion, the combination of plyometric exercise and metformin improved trabecular microarchitecture and bone material properties relative to OVX controls. However, no additive effect of the combined intervention was observed compared to exercise alone.

Leptin is expressed in and secreted from primary cultures of human osteoblasts and promotes bone mineralization.

The adipose hormone leptin and its receptor are important for regulation of food intake and energy metabolism. Leptin also is involved in the growth of different tissues. In this study, we show the expression of leptin in primary cultures of normal human osteoblasts (hOBs) as evidenced by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunocytochemistry. Release of leptin into the medium also was found. Leptin was not detected in commercially available hOBs (NHOst) or in three different human monoclonal osteosarcoma cell lines. Leptin expression was observed in OBs in the mineralization and/or the osteocyte transition period but not during the matrix maturation period. Furthermore, hOBs and osteosarcoma cell lines expressed the long signal-transducing form of the leptin receptor (OB-Rb) as shown by RT-PCR. We observed no significant changes in leptin or OB-Rb genes in hOBs after incubation with recombinant leptin, indicating no autoregulation of the leptin expression. Incubation of both hOBs entering the mineralization phase and osteosarcoma cell lines with recombinant leptin markedly increased the number of mineralized nodules as shown by alizarin S staining. These findings indicate that leptin may be of importance for osteoblastic cell growth and bone mineralization.

The effect of teriparatide [human parathyroid hormone (1-34)] therapy on bone density in men with osteoporosis.

Teriparatide [rhPTH(1-34)] increases bone mineral density and reduces the risk of vertebral fracture in women. We randomized 437 men with spine or hip bone mineral density more than 2 SD below the young adult male mean to daily injections of placebo, teriparatide 20 microg, or teriparatide 40 microg. All subjects also received supplemental calcium and vitamin D. The study was stopped after a median duration of 11 months because of a finding of osteosarcomas in rats in routine toxicology studies. Biochemical markers of bone formation increased early in the course of therapy and were followed by increases in indices of osteoclastic activity. Spine bone mineral density was greater than in placebo subjects after 3 months of teriparatide therapy, and by the end of therapy it was increased by 5.9% (20 microg) and 9.0% (40 microg) above baseline (p < 0.001 vs. placebo for both comparisons). Femoral neck bone mineral density increased 1.5% (20 microg; p = 0.029) and 2.9% (40 microg; p < 0.001), and whole body bone mineral content increased 0.6% (20 microg; p = 0.021) and 0.9% (40 microg;p = 0.005) above baseline in the teriparatide subjects. There was no change in radial bone mineral density in the teriparatide groups. Bone mineral density responses to teriparatide were similar regardless of gonadal status, age, baseline bone mineral density, body mass index, smoking, or alcohol intake. Subjects experienced expected changes in mineral metabolism. Adverse events were similar in the placebo and 20-microg groups, but more frequent in the 40-microg group. This study shows that teriparatide treatment results in an increase in bone mineral density and is a potentially useful therapy for osteoporosis in men.

Chromogranin A and pancreastatin-like immunoreactivity in normal pregnancies.

Placenta is a neuroendocrine organ, and we therefore wanted to study the occurrence of the general neuroendocrine marker chromogranin A (CgA) and its split product pancreastatin. CgA and pancreastatin-like immunoreactivity (PST-LI) were determined by ELISA and RIA methods, respectively, in homogenates from term placentas, sera from pregnant women, nonpregnant women, umbilical cords, and in amniotic fluids. In placental homogenates, the mean level of CgA was 7.1 +/- 8.6 pmol/g wet wt (mean +/- SD), whereas PST-LI was not detectable. CgA immunoreactivity was demonstrated by immunofluorescence studies of isolated trophoblasts and decidual cells from term placentas. In trophoblasts, CgA was colocalized with human chorionic gonadotropin (hCG) and human placental lactogen. By Northern blotting, a distinct band corresponding to CgA messenger RNA (mRNA) was demonstrated in the placental cell line, whereas, in placental homogenates, a mRNA band of a slightly larger size was found. Median CgA level in maternal sera at term tended to be higher (median: 469 pmol/L, range 61-980 pmol/L, P < 0.1) than at 6-11 weeks (286 pmol/L, 61-653 pmol/L) or in sera from nonpregnant women (306 pmol/L, 204-469 pmol/L). In umbilical cord sera, median CgA level was significantly higher (898 pmol/L, 102-2245 pmol/L, P < 0.05) than in term sera. Median serum level of PST-LI was significantly higher at term (38 pmol/L, 0-131 pmol/L) than at 6-11 weeks (9 pmol/L (0-85 pmol/L, P < 0.05), than in nonpregnant women (6 pmol/L, 0-52 pmol/L, P < 0.05), and in umbilical cord sera (12 pmol/L, 0-76 pmol/L, P < 0.05). In amniotic fluid, median CgA value was significantly higher at term (1163 pmol/L, 714-1673 pmol/L) than at 14-17 weeks (551 pmol/L, 82-980 pmol/L, P < 0.01), whereas median level of PST-LI was significantly higher at 14-17 weeks (32 pmol/L, 6-97 pmol/L) than at term (0 pmol/L, 0-15 pmol/L, P < 0.01). To our knowledge, this is the first report describing the presence of CgA and PST-LI in placenta and amniotic fluid and the occurrence CgA mRNA in placental tissue and in a placental cell line. The presence of CgA in placenta may indicate a physiological role in pregnancy.

Review article: the use of gastric acid-inhibitory drugs--physiological and pathophysiological considerations.

All vertebrates secrete gastric acid. Acid denatures the proteins in the food and thus makes them more accessible to proteolytic enzymes, and it kills swallowed micro-organisms. Gastric acid plays an important pathogenetic role in peptic ulcer disease and reflux oesophagitis. In these diseases, drugs that inhibit secretion of gastric acid will heal the lesions and suppress the symptoms. However, both reflux oesophagitis and peptic ulcer tend to recur when the acid-inhibitory treatment is stopped. Therefore, these patients often require long-term treatment with acid-inhibitors. In this overview the potential risks of long-term profound inhibition of acid secretion, raising the pH above 4 for a considerable time, resulting in reduced killing of micro-organisms and secondary hypergastrinaemia, are discussed. Gastrin regulates both the function (production and release of histamine) and growth of the enterochromaffin-like (ECL) cell. Hitherto, the role that this cell plays in gastric carcinogenesis appears to have been underestimated.

The effect of tripotassium dicitrato bismuthate on the rat stomach.

BACKGROUND: Bismuth has been used as symptomatic treatment of dyspepsia for many years. It promotes healing of peptic ulcers and reduces their recurrence. The beneficial effect of bismuth on duodenal ulcer disease is thought to be due to an effect on Helicobacter pylori, although it has a rather weak bactericidal effect on H. pylori in vitro. Eradication of H. pylori in duodenal ulcer patients by a combination of bismuth, tetracycline and metronidazole has been reported to increase the density of somatostatin-producing D cells in the antrum. A reduced D cell density in the antral mucosa of duodenal ulcer patients could explain their exaggerated gastrin release. AIMS/METHODS: To test the possibility that bismuth could affect the neuroendocrine cells independently of the presence of H. pylori or not, we gave rats a diluted tripotassium dicitrato bismuthate solution by gastric gavage for 14 days. RESULTS: Tripotassium dicitrato bismuthate treatment did not affect maximal pentagastrin-stimulated acid secretion or histamine release in isolated rat stomachs or the density of argyrophil cells in the oxyntic and antral mucosa. However, it significantly reduced the duodenal concentration of gastrin and calcitonin gene-related peptide, and the density of G cells in the antrum and duodenum. CONCLUSION: The effect of tripotassium dicitrato bismuthate on the G cell may be of significance for its beneficial effect on duodenal ulcer disease.

Rapid, high-yield isolation of human chromogranin A from chromaffin granules of pheochromocytomas.

Chromogranin A (CgA) is a useful probe of human neuroendocrine neoplasia and exocytotic sympathoadrenal activity, but the application of CgA immunoassays has not been widespread because of limited availability of purified human CgA. Here we describe a rapid, high yield isolation of human CgA. After obtaining and lysing pheochromocytoma chromaffin granules, the soluble core proteins (chromogranins) were depleted of dopamine-beta-hydroxylase by passage over a concanavalin A-Sepharose affinity column, then lyophilized, resuspended in volatile buffer, and gel filtered on Sephacryl S-300. SDS-PAGE-analyzed column fractions contained homogeneous human CgA, which was verified structurally (N-terminal amino acid sequence) and immunologically (radioimmunoassay and immunoblot). The overall 22.6 mg yield of purified CgA represented 5.7% of the starting vesicle core protein. This preparation will be useful in evaluating the sympathoadrenal system and endocrine neoplasia in man.

Immunoassays for measurement of chromogranin A and pancreastatin-like immunoreactivity in humans: correspondence in patients with neuroendocrine neoplasia.

Chromogranin A (CgA) is a useful marker of neuroendocrine tumors in humans. Here we describe and compare two immunoassay methods for determination of CgA, a radioimmunoassay (RIA) and an enzyme linked immunoassay (ELISA). The detection limit of the ELISA was lower than that of the RIA method (2 ng/ml versus 10 ng/ml, respectively), though the CgA RIA method covered a wider range than the CgA ELISA (10-920 ng/ml versus 2-500 ng/ml, respectively). There was no cross-reactivity with synthetic human and porcine pancreastatin (PST) in the two assays. There was a significant positive correlation between levels of CgA in sera from patients with carcinoid disease, measured by the two methods (r = 0.9, p < 0.0001), and the values were in the same range. Similarly, serum CgA levels in normal controls were also in the same range when assayed by the two methods. A commercially available porcine PST RIA method was evaluated, especially with respect to the influence of Sep-Pak extraction of serum on the levels of pancreastatin-like immunoreactivity (PST-LI). Ten sera from carcinoid patients were treated with Sep-Pak extraction, and levels of PST-LI were determined in non-extracted and extracted sera. There was a significant positive correlation between the concentrations of PST-LI measured in extracted and non-extracted carcinoid sera (r = 0.9, p < 0.002), and the levels were in the same range. There was also a significant positive correlation between levels of CgA and PST-LI in 49 carcinoid sera (r = 0.8, p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Neuroendocrine differentiation in colorectal carcinomas.

OBJECTIVE: To evaluate neuroendocrine differentiation in tumours from patients with colorectal carcinomas by immunostaining with antibodies against human chromogranin A (CgA) and neuron-specific enolase (NSE), and to correlate these finding with serum levels of CgA and pancreastatin-like immunoreactivity (PST-LI). We also investigated the degree of neuroendocrine differentiation found in colorectal carcinomas of different embryonic origins (hindgut and midgut). PATIENTS AND METHODS: The presence of CgA and NSE in tumours from 91 patients with colorectal carcinoma was investigated using immunohistochemistry; levels of CgA and PST-LI in sera from 55 of these patients were determined using radioimmunoassays. RESULTS: Immunostaining for CgA and NSE was found in 15 and 36% of tumours, respectively. One or both markers of neuroendocrine differentiation were demonstrated in 40% of the colorectal carcinomas. In patients who died during the study, 23 and 51% expressed CgA and NSE in their tumours, respectively, while the corresponding values in survivors were 11 and 27% (P = 0.14 and P = 0.025, respectively). The median survival time tended to be lower in patients with neuroendocrine differentiation of their tumours than in those without such differentiation (P = 0.1). The expression of NSE was significantly higher in colorectal carcinomas derived from the midgut than in those of hindgut origin. Elevated serum levels of CgA and PST-LI were found in 38 and 43% of the patients, respectively; 62% had elevated levels of one or both markers. Of the patients with elevated serum levels of CgA or PST-LI, 44% had positive immunohistochemistry for either NSE or CgA compared with 29% of those with normal serum levels of CgA and PST-LI (P = 0.27). Serum levels of CgA were increased in a significantly higher percentage of patients with colorectal carcinomas of midgut than of hindgut origin (63 and 28%, respectively, P = 0.03). Of patients with hindgut-derived carcinomas who died during the study, 64% had raised serum values of CgA compared with 19% of those who survived (P = 0.023). The corresponding figures for PST-LI elevation were 75 and 44%, respectively (P = 0.096). In the midgut group, no difference was demonstrated for these parameters between survivors and non-survivors. CONCLUSION: Neuroendocrine differentiation was demonstrated in 40% of the colorectal carcinomas investigated and was more frequent in midgut-derived carcinomas than in those of hindgut origin. We have shown for the first time that serum levels of CgA and PST-LI are elevated in patients with colorectal carcinomas. In accordance with previous studies, our data support the value of neuroendocrine differentiation as an indicator of poor prognosis; they also suggest a role for serum CgA and PST-LI as prognostic markers.

Effects of the peroxisome proliferator-activated receptor (PPAR)-δ agonist GW501516 on bone and muscle in ovariectomized rats.

Estrogen deficiency promotes bone loss and skeletal muscle dysfunction. Peroxisome proliferator-activated receptors (PPARs) have 3 subtypes (α, δ, and γ). PPARγ agonists induce bone loss, whereas PPARα agonists increase bone mass. Although PPARδ agonists are known to influence skeletal muscle metabolism, the skeletal effects are unsettled. This study investigated the musculoskeletal effects of the PPARδ agonist GW501516 in ovariectomized (OVX) rats. Female Sprague Dawley rats, 12 weeks of age, were allocated to a sham-operated group and 3 OVX groups; high-dose GW501516 (OVX-GW5), low-dose GW501516 (OVX-GW1), and a control group (OVX-CTR), respectively (n = 12 per group). Animals received GW501516 or vehicle (methylcellulose) daily for 4 months by gavage. Bone mineral density (BMD) was assessed by dual x-ray absorptiometry at the femur, spine, and whole body. Bone microarchitecture at the proximal tibia was assessed by microcomputed tomography, and dynamic histomorphometry was performed. Quadriceps muscle morphology and the relative expression of mitochondrial proteins were analyzed. Bone metabolism markers and metabolic markers were measured in plasma. After 4 months, the OVX-GW5 group displayed lower femoral BMD than OVX-CTR. Trabecular separation was higher in the GW-treated groups, compared with OVX-CTR. The OVX-GW5 group also exhibited lower cortical area fraction and a higher structure model index than OVX-CTR. These effects coincided with impaired bone formation in both GW groups. The OVX-GW5 group displayed elevated triglyceride levels and reduced adiponectin levels, whereas no effects on muscle morphology or mitochondrial gene expression appeared. In summary, the PPARδ agonist GW501516 negatively affected bone properties in OVX rats, whereas no effects were detected in skeletal muscle.

Serum gastrin and gastric enterochromaffin-like cells during estrous cycle, pregnancy and lactation, and in response to estrogen-like agents in rats.

Histamine-containing enterochromaffin-like (ECL) cells are numerous in the gastric mucosa. They operate under the control of gastrin. ECL-cell tumors (gastric carcinoids) may arise as a consequence of sustained hypergastrinemia. For reasons unknown, such tumors have a female preponderance both in laboratory animals and humans. The present study consisted of four experiments exploring the possibility that gender-related factors might affect rat ECL cells. 1) A gender difference in terms of serum gastrin concentration and oxyntic mucosal histidine decarboxylase (HDC) activity appeared in Sprague-Dawley but not Wistar rats. Ultrastructural appearance of the ECL cells did not differ between genders. 2) During the different phases of the estrous cycle, the serum gastrin concentration, HDC activity and histamine concentration did not change. 3) During pregnancy, the serum gastrin concentration was suppressed, while it was increased during lactation. The HDC activity and the histamine concentration of the oxyntic mucosa were correlated with the levels of circulating gastrin. 4) Twelve-month treatment with estrogen-like agents, dieldrin and/or toxaphene (alone or in combination) was without any effect on the ECL cells neither in male nor in female rats. In conclusion, the ECL cells are under the control of gastrin, but probably not hormones that involve in the estrous cycle and pregnancy and lactation in rats. Possible gender-related factors behind the female preponderance of ECL-cell tumors remain unknown.