Johan Verhaeghe

Bone and Mineral Metabolism in BB Rats With Long-Term Diabetes: Decreased Bone Turnover and Osteoporosis

The effect of long-term diabetes mellitus on bone and mineral metabolism was studied in BB rats. Diabetic rats were treated with 1 U of long-acting insulin every other day for 12 wk and compared with nondiabetic littermates. Urinary calcium excretion was increased > 10-fold, but serum total and diffusible calcium remained normal. Serum concentrations of both 1α,25-dihydroxyvitamin D3 and vitamin D–binding protein were significantly decreased in diabetic rats. The intestinal calbindin-D 9K concentration was decreased by nearly 50%, and active duodenal calcium absorption was totally abolished. Trabecular bone volume measured in the tibial metaphysis was decreased by 44%, and the osteoblast and osteoid surfaces were <10% of values observed in control rats, whereas the osteoclast surface was unchanged by diabetes. The daily bone formation (bone mineral apposition rate) measured by labeling twice with calcein was decreased by 86% in diabetic rats. The serum concentration of osteocalcin, a biochemical marker of osteoblast function, was similarly decreased (mean ± SE 23 ± 3 and 62 ± 4 μg/L in diabetic [n = 15] and nondiabetic [n = 15] rats, respectively). Serum osteocalcin was significantly correlated with the serum concentration of insulinlike growth factor I (r = 0.89, P < 0.001). Bone strength measured as the energy needed to fracture the femur was markedly decreased (5.3 ±1.4 and 8.4 ± 1.3 N · m · degree in diabetic and nondiabetic rats, respectively; P < 0.01). These histological, chemical, and biomechanical data clearly indicate that long-standing diabetes in BB rats results in severe low-turnover osteoporosis probably related to decreased osteoblast recruitment and/or function.

C-peptide, insulin-like growth factors I and II, and insulin-like growth factor binding protein-1 in umbilical cord serum: Correlations with birth weight

OBJECTIVE Our purpose was to determine the correlation between birth weight and hormones or growth factors believed to be involved in fetal growth: insulin, insulin-like growth factors I and II, and insulin-like growth factor binding protein-1. STUDY DESIGN Five hundred thirty-eight cord serum samples were analyzed for insulin-like growth factor-I, insulin-like growth factor-II, C-peptide, and insulin-like growth factor binding protein-1 by immunoassay. Samples included all gestational ages in the third trimester and a large range of birth weights. RESULTS Cord serum insulin-like growth factor-I concentrations increased until 39 weeks (+84% from 28 to 29 weeks), followed by a 21% decline at 41 weeks. Insulin-like growth factor-I levels were decreased by 40% in small-for-gestational-age (< 10th percentile) newborns and were increased by 28% in large-for-gestational-age (> 90th percentile) newborns in the absence of diabetes. Insulin-like growth factor-I levels were best correlated with birth weight (R = 0.48, p < 0.001). Cord serum insulin-like growth factor-II concentrations were sixfold to tenfold higher than those of insulin-like growth factor-I and were 8% to 10% (p < 0.001) higher in large-for-gestational-age than in average-weight and small-for-gestational-age newborns. Cord serum C-peptide concentrations were 28% and 34% higher in large-for-gestational-age than in average-for-gestational-age and small-for-gestational-age newborns, respectively. Insulin-like growth factor binding protein-1 levels were increased in preterm average-for-gestational-age and in term small-for-gestational-age newborns compared with term average-for-gestational-age newborns and showed a negative correlation with birth weight (R = -0.43, n = 131, p < 0.001). Insulin-like growth factor binding protein-1 was not correlated with C-peptide concentrations. CONCLUSIONS Insulin-like growth factors I and II and insulin are all related to fetal growth and weight gain, and insulin-like growth factor-I correlates best with birth weight. Insulin is mainly related to fetal overgrowth (macrosomia). Insulin-like growth factor binding protein-1 may be a growth inhibitor in the fetus.

Intestinal calcium transporter genes are upregulated by estrogens and the reproductive cycle through vitamin D receptor-independent mechanisms.

1α,25(OH)2‐vitamin D strongly regulates the expression of the epithelial calcium channel CaT1. CaT1 expression is reduced in ERKOα mice and induced by estrogen treatment, pregnancy, or lactation in VDR WT and KO mice. Estrogens and vitamin D are thus independent potent regulators of the expression of this calcium influx mechanism, which is involved in active intestinal calcium absorption.

Assessment of fetal cardiac function before and after therapy for twin-to-twin transfusion syndrome

OBJECTIVE We sought to assess fetal cardiac function in monochorionic twins before and after therapy for twin-to-twin transfusion syndrome (TTTS) and compare it with control subjects. STUDY DESIGN We conducted prospective longitudinal assessment of fetal cardiac function in cases undergoing curative fetal therapy for TTTS (n = 39) until 4 weeks postoperatively and in uncomplicated monochorionic twins (n = 23). Fetal cardiac function was assessed by the left and right ventricular myocardial performance index, atrioventricular valve flow pattern, ductus venosus a-wave, and umbilical vein pulsations. RESULTS Nomograms for the myocardial performance index were constructed. Fetal cardiac function was grossly abnormal in recipient twins of TTTS when compared with control subjects (P < .001 for all indices) but normalized by 4 weeks postoperatively. The donor developed abnormal ductus venosus flow and tricuspid regurgitation postoperatively that regressed within 4 weeks. CONCLUSION The cardiac dysfunction in the recipient twin of TTTS normalizes within 1 month after laser. The donor develops a transient impairment of cardiac function postoperatively.

Debilitating musculoskeletal pain and stiffness with letrozole and exemestane: associated tenosynovial changes on magnetic resonance imaging

ObjectiveArthralgia, skeletal and muscle pain have been reported in postmenopausal women under treatment with third generation aromatase inhibitors (AIs). However, the pathogenesis and anatomic correlate of musculoskeletal pains have not been thoroughly evaluated. Moreover, the impact of AI-induced musculoskeletal symptoms on normal daily functioning needs to be further explored.Patients and methodsWe examined 12 consecutive non-metastatic breast cancer patients who reported severe musculoskeletal pain under a third generation AI; 11 were on letrozole and 1 on exemestane. Clinical rheumatological examination and serum biochemistry were performed. Radiological evaluation of the hand/wrist joints were performed using ultrasound (US) and/or magnetic resonance imaging (MRI).ResultsThe most common reported symptom was severe early morning stiffness and hand/wrist pain causing impaired ability to completely close/stretch the hand/fingers and to perform daily activities and work-related skills. Six patients had to discontinue treatment due to severe symptoms. Trigger finger and carpal tunnel syndrome were the most frequently reported clinical signs. US showed fluid in the tendon sheath surrounding the digital flexor tendons. On MRI, an enhancement and thickening of the tendon sheath was a constant finding in all 12 patients.ConclusionsMusculoskeletal pains in breast cancer patients under third generation AIs can be severe, debilitating, and can limit compliance. Characteristic tenosynovial, and in some patients joint changes on US and MRI were observed in this series and have not been reported before.

Exercise in the fasted state facilitates fibre type-specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans

The effects were compared of exercise in the fasted state and exercise with a high rate of carbohydrate intake on intramyocellular triglyceride (IMTG) and glycogen content of human muscle. Using a randomized crossover study design, nine young healthy volunteers participated in two experimental sessions with an interval of 3 weeks. In each session subjects performed 2 h of constant‐load bicycle exercise (∼75%), followed by 4 h of controlled recovery. On one occasion they exercised after an overnight fast (F), and on the other (CHO) they received carbohydrates before (∼150 g) and during (1 g (kg bw)−1 h−1) exercise. In both conditions, subjects ingested 5 g carbohydrates per kg body weight during recovery. Fibre type‐specific relative IMTG content was determined by Oil red O staining in needle biopsies from m. vastus lateralis before, immediately after and 4 h after exercise. During F but not during CHO, the exercise bout decreased IMTG content in type I fibres from 18 ± 2% to 6 ± 2% (P= 0.007) area lipid staining. Conversely, during recovery, IMTG in type I fibres decreased from 15 ± 2% to 10 ± 2% in CHO, but did not change in F. Neither exercise nor recovery changed IMTG in type IIa fibres in any experimental condition. Exercise‐induced net glycogen breakdown was similar in F and CHO. However, compared with CHO (11.0 ± 7.8 mmol kg−1 h−1), mean rate of postexercise muscle glycogen resynthesis was 3‐fold greater in F (32.9 ± 2.7 mmol kg−1 h−1, P= 0.01). Furthermore, oral glucose loading during recovery increased plasma insulin markedly more in F (+46.80 μU ml−1) than in CHO (+14.63 μU ml−1, P= 0.02). We conclude that IMTG breakdown during prolonged submaximal exercise in the fasted state takes place predominantly in type I fibres and that this breakdown is prevented in the CHO‐fed state. Furthermore, facilitated glucose‐induced insulin secretion may contribute to enhanced muscle glycogen resynthesis following exercise in the fasted state.

Time-related increase of biochemical markers of bone turnover in androgen-deficient male rats

Bone loss during androgen deficiency has been associated with accelerated bone turnover and imbalance between bone formation and resorption but the relative increase of both phenomena is not well described. Serum osteocalcin as marker of bone formation and urinary excretion of pyridinoline (PYD) and deoxypyridinoline (DPD) as markers of bone resorption were measured in both orchidectomized (ORCH, n = 8) and sham-operated (SHAM, n = 8) aged (12-month-old) male rats from 2 days before until 66 days after surgery. PYD and DPD were significantly higher in the ORCH group compared to the SHAM group starting from 21 days after surgery until the end of the experiment. Serum osteocalcin was only significantly increased in the ORCH group at 30 and 40 days. The maximal increase of serum osteocalcin was also smaller than the increase in PYD and DPD (30% versus 74% and 112%, respectively). The two markers of bone resorption were correlated with osteocalcin (r = 0.63 for PYD and r = 0.71 for DPD). Based on these results, we conclude that (1) bone resorption, as measured by PYD and DPD, increased during androgen deficiency; (2) moreover, the increase of bone resorption, as measured by DPD and PYD, was followed by a more moderate increase in bone formation as measured by serum osteocalcin, supporting the hypothesis that androgen deficiency causes accelerated bone turnover and imbalance between bone resorption and bone formation.

Validation of the fetal myocardial performance index in the second and third trimesters of gestation

To test the validity of the myocardial performance index (MPI) and its components against the more conventional methods of fetal cardiac function assessment: the ejection fraction (EF) for systolic function and the E/A index (ratio of transmitral flow during early (E) ventricular filling to flow during atrial (A) contraction) for diastolic function, both in a normal population and in a population at risk for cardiac failure because of volume overload (recipient fetuses in cases of twin–twin transfusion syndrome (TTTS)).

C-peptide, insulin-like growth factors I and II, and insulin-like growth factor binding protein-1 in cord serum of twins" Genetic versus environmental regulation

OBJECTIVE Our purpose was to examine the regulation of fetal serum concentrations of insulin (C-peptide), insulin-like growth factor-I, insulin-like growth factor-II, and insulin-like growth factor binding protein-1, which are growth-regulating factors in the fetus, in monozygotic and dizygotic twin pairs. STUDY DESIGN Cord serum samples were collected from 110 twin pairs and compared with 178 nonsibling singleton pairs with the same gestational age. Five twin pairs were excluded from the statistical analyses because of severe intrauterine growth restriction and placental abnormalities in one. Zygosity was assigned by histologic examination of the placenta and by a questionnaire sent to the mother when the twins were > or = 6 months old. Analyses included the calculation of correlation coefficients, between-pair variation, and univariate genetic analysis. RESULTS Cord serum C-peptide concentrations were highly correlated in monozygotic (r = 0.94) and dizygotic twins (r = 0.79) but not in singleton pairs (r = -0.05); the between-pair variation was also smaller in twins than in singletons. Genetic analysis demonstrated a large contribution of the common environment to the variance in C-peptide concentrations (80%) and a smaller genetic contribution (12%). Insulin-like growth factor-I concentrations were better correlated in monozygotic (r = 0.82) than in dizygotic twins (r = 0.42), with a smaller between-pair variation in the former group (22% +/- 4% vs 51% +/- 5%). Univariate genetic analysis indicated that insulin-like growth factor-I levels were regulated predominantly by genetic mechanisms (93% in boys and 77% in girls). The regulation of insulin-like growth factor-II was more complex, with a gender-specific genetic contribution (50% for both sexes combined, 63% for girls but only 5% for boys). Insulin-like growth factor binding protein-1 was regulated by genetic mechanisms (41%) and the common environment (32%) but also by the specific or unique environment of each fetus (27%). In all five twins with intrauterine growth restriction of one member insulin-like growth factor binding protein-1 concentrations were markedly higher in the growth-restricted fetus. CONCLUSIONS Insulin secretion in twin fetuses is determined primarily by their common, probably maternal, environment, whereas insulin-like growth factor-I production is predominantly genetically regulated. Insulin-like growth factor-II and insulin-like growth factor binding protein-1 are regulated by both genetic and environmental factors. Of these growth-regulating factors, insulin-like growth factor binding protein-1 appears to be the best marker of intrauterine growth restriction in the individual case.

Left ventricular cardiac function in fetuses with congenital diaphragmatic hernia and the effect of fetal endoscopic tracheal occlusion

The pre‐existing compression of the left ventricle in congenital diaphragmatic hernia (CDH) could be aggravated by the amplified lung growth after fetoscopic endoluminal tracheal occlusion (FETO). Our aim was to document left ventricular (LV) size and function in fetuses with isolated left‐sided CDH and to document the effect of FETO on the fetal heart.