Increased osteoprotegerin levels in Cushing's syndrome are associated with an adverse cardiovascular risk profile

Bone Metabolism and RANKL/OPG Ratio in Rheumatoid Arthritis Women Treated with TNF-α Inhibitors

The aim of this study was to evaluate the effect of anti-tumor necrosis factor α (anti-TNF-α) therapy in combination with methotrexate on bone remodeling and osteoclastogenesis in female patients with RA. Serum levels of bone turnover markers (i.e., C- and N-terminal propeptides of type I procollagen (PICP and PINP), C- and N-terminal cross-linking telopeptides of type I collagen (CTX-I and NTX-I), and soluble receptor activator of nuclear factor κB ligand (sRANKL) and osteoprotegerin (OPG)) were determined by immunoassay at baseline and 15 months after initiation of treatment. Bone mineral density was measured by dual-energy x-ray absorptiometry. We found a significant decrease in serum PINP levels, a biomarker of bone formation, and higher levels of CTX-I and sRANKL indicative of increased bone resorption in RA patients prior to TNFαI treatment compared to the controls. Anti-TNF-α therapy was effective in improving bone metabolism in RA patients as reflected in a decrease in CTX-I (at least partially due to the RANKL/OPG reduction) and a concomitant increase in PINP levels. The bone metabolism changes were independent of the type of TNFαI used. PINP and CTX-I were found to be useful markers of bone metabolism, which may prove the effectiveness of TNF-α therapy earlier than the bone density assessment.

Evaluation of bone health in patients with adrenal tumors

PURPOSE OF REVIEW

Adrenal tumors occur in 5% of population with higher prevalence in elderly. Patients with adrenal tumors present with overt hormonal excess in up to 15% of cases, and mild autonomous cortisol secretion in 30-40% of cases. Overt Cushing syndrome, mild autonomous cortisol secretion, pheochromocytoma, and primary aldosteronism have been associated with higher cardiovascular morbidity and mortality. Increasing experimental and clinical evidence also suggests that adrenal hormone excess is detrimental to bone health. This review aims to discuss the effect of cortisol, aldosterone, and catecholamine excess on bone metabolism, secondary osteoporosis, and fragility fractures.

RECENT FINDINGS

Several studies have reported that patients with hormonally active adrenal tumors demonstrate increased prevalence of fragility fractures incongruous to bone density scan findings. The utility of dual absorptiometry X-ray (DXA) in diagnosing secondary osteoporosis is unclear in patients with cortisol, aldosterone, and catecholamine excess. Trabecular bone score and bone turn over markers could serve as potential diagnostic tools in assessment of severity of bone disease in patients with hormonally active adrenal tumors.

SUMMARY

Adrenalectomy is the mainstay of therapy in patients with overt hormone production. Appropriate case detection strategies to identify patients at risk of fragility fractures are needed in patients not treated with adrenalectomy, such as bilateral primary aldosteronism and mild autonomous cortisol secretion.

Portal Vein Thrombosis in the Setting of Newly Diagnosed Cushing's Syndrome

The hallmark manifestations of Cushing’s syndrome (CS) are well known, but hypercoagulability is perhaps least recognized. Patients with CS are at increased risk of both spontaneous and postoperative thromboembolism, with the significant majority of events occurring in the lower extremity and pulmonary venous circulations. We present a case of portal vein thrombosis (PVT) occurring in the setting of newly diagnosed CS due to a left adrenal adenoma. Factor VIII activity was approximately 2.5-fold elevated, a known mechanism by which hypercortisolemia predisposes to venous thrombosis. Acute abdominal pain and fever responded well to unfractionated heparin and parenteral antibiotics, and CS was eventually cured by left adrenalectomy. No thromboembolic events have occurred since surgery. PVT is uncommon and usually occurs as a complication of primary or secondary hepatobiliary malignancies and cirrhosis. To the best of our knowledge, this is just the second reported case of PVT due to CS and the first published in the English language literature.

Extensive Association of Common Disease Variants with Regulatory Sequence

Overlap between non-coding DNA regulatory sequences and common variant associations can help to identify specific cell and tissue types that are relevant for particular diseases. In a systematic manner, we analyzed variants from 94 genome-wide association studies (reporting at least 12 loci at p<5x10^-8) by projecting them onto 466 epigenetic datasets (characterizing DNase I hypersensitive sites; DHSs) derived from various adult and fetal tissue samples and cell lines including many biological replicates. We were able to confirm many expected associations, such as the involvement of specific immune cell types in immune-related diseases and tissue types in diseases that affect specific organs, for example, inflammatory bowel disease and coronary artery disease. Other notable associations include adrenal glands in coronary artery disease, the immune system in Alzheimer’s disease, and the kidney for bone marrow density. The association signals for some GWAS (for example, myopia or age at menarche) did not show a clear pattern with any of the cell or tissue types studied. In general, the identified variants from GWAS tend to be located outside coding regions. Altogether, we have performed an extensive characterization of GWAS signals in relation to cell and tissue-specific DHSs, demonstrating a key role for regulatory mechanisms in common diseases and complex traits.

Influence of Antenatal Glucocorticosteroid Exposure on Osteoprotegerin and Receptor Activator of Nuclear Factor x03BA;B Ligand Levels in Newborn Infants

BACKGROUND/AIMS

The physiologic relevance of osteoprotegerin (OPG) and the receptor activator of nuclear factor x03BA;B ligand (RANKL) in the preterm neonate is unknown. The aim of this study was to examine the effects of prematurity on OPG and RANKL concentrations at birth and to investigate in particular whether antenatal corticosteroid (ACS) exposure affects serum OPG and RANKL levels in premature neonates.

METHODS

Quantitative determination (enzyme immunoassay) of serum OPG and RANKL at 24 postnatal hours was performed in 47 healthy term neonates, 43 preterm newborns not exposed to ACS, and 55 preterm infants exposed to ACS.

RESULTS

OPG in the ACS-exposed preterm group (median 5.13 pmol/l, range 1.62-15.12) was significantly higher compared to preterm neonates not exposed to ACS (median 4.52 pmol/l, range 0.86-8.98, p < 0.05) and to unexposed term neonates (median 4.47 pmol/l, range 2.70-10.72, p < 0.05). Conversely, there was no difference in RANKL levels between the study groups. OPG and RANKL values were also similar between term and preterm neonates not exposed to ACS.

CONCLUSIONS

Preterm neonates exposed to ACS have higher serum levels of OPG, while premature neonates not exposed to ACS have serum OPG and RANKL levels similar to those measured in healthy term neonates.

Impairment of Arterial Compliance in Cushing's Syndrome

Arterial stiffness may be useful for stratifying cardiovascular risk in individuals suffering from a number of pathologies, such as hypertension, diabetes, obesity, dyslipidaemia and coronary artery disease. Cushing's syndrome is underpinned by a complex metabolic syndrome, which is potentially implicated in the onset of blood vessel alterations and the increase in arterial wall stiffness. The aim of this paper was to perform a review about the most important studies conducted in order to evaluate the arterial distensibility profile of subjects affected by Cushing's syndrome. Increased arterial stiffness may persist even after successful cure of this disease. It is therefore of fundamental importance to identify the presence of early vascular alterations in these patients, in order to commence their treatment and thus attempt to prevent the subsequent onset of adverse cardiovascular events.

Osteoprotegerin is not a determinant of metabolic syndrome in sub-Saharan Africans after age adjustment

OBJECTIVES

Osteoprotegerin (OPG), a soluble member of tumor necrosis factor receptor superfamily that inhibits bone resorption, has been suggested as a cardiovascular risk factor in humans. In this study, we aim to investigate the potential relationship between OPG and MetS (MetS) in a sub-Saharan African population.

METHODS

Four hundred and eleven volunteers (152 men, 259 women) aged ≥18 years recruited from the general population in Douala and Edea, Cameroon participated in this study. Anthropometric parameters measured and blood samples were collected for glucose, serum lipids and OPG concentrations measurements. Mean differences of the variables in different groups were compared using Students' t test. We performed logistic regressions to analyze the impact of independent factors on the relation between OPG and MetS outcome. MetS was defined using the Joint Interim Statement 2009.

RESULTS

OPG levels did not vary significantly between both men and women with and without MetS (both P>0.05). However, with high fasting blood glucose (≥5.6 mmol/L) had a significantly higher OPG level than those with lower glucose level (P=0.014). In multiple logistic regression analysis, MetS did not show any significant association with serum OPG levels in men and women after adjusting for age, physical activity, alcohol consumption and menopausal status in women (P=0.720 and P=0.930 respectively).

CONCLUSION

This study failed to demonstrate any relationship between OPG and MetS. Nevertheless, the positive association between blood glucose and OPG levels reveals that OPG might be involved in cardiovascular risk development in this sub-Saharan African population.

Persistent Comorbidities in Cushing’s Syndrome after Endocrine Cure

It was assumed that resolution of hypercortisolism in Cushing syndrome (CS) was followed by normalization of morbidity; however, in the last decade evidence is accumulating that patients with cured CS still have increased morbidity and mortality after the biochemical control of hypercortisolism. Patients with CS have an increased cardiovascular and metabolic risk and persistent accumulation of central fat, with an unfavorable adipokine profile, not only during the active phase of the disease but also long after biochemical remission. Clinical management should be particularly careful in identifying global cardiovascular risk, as a primary goal during the followup of these patients, aimed at improving global vascular morbidity. Moreover bone mass is reduced not only due to the endogenous hypercortisolism but also due to duration and dose of exogenous glucocorticoid (GC) replacement therapy after surgery. Thus, therapy in operated patients with inhibition of the hypothalamic-pituitary-adrenal axis should be reduced to the lowest dose and duration possible. Specific treatments should be considered in patients with decreased bone mass, aimed at reducing the increased fracture incidence. Finally, cognitive and health related quality of life impairments, described in active disease, are still abnormal after endocrine cure. Thus, residual morbidity persists in cured CS, suggesting irreversibility of GC-induced phenomena, typical of chronic hypercortisolism.

Serum extracellular secreted antagonists of the canonical Wnt/β-catenin signaling pathway in patients with Cushing's syndrome

Patients with endogenous hypercortisolism have higher sclerostin, but do not differ in Dickkopf 1 (Dkk1) or secreted frizzled-related protein 1 (SFRP1) levels as compared to healthy control.

INTRODUCTION

Endogenous Cushing's syndrome (CS), usually affecting young and otherwise healthy patients, is a good model to validate the effects of supraphysiological levels of glucocorticoids in humans. This study evaluates circulating levels of extracellular antagonists of the Wnt/β-catenin signaling pathway (sclerostin, Dkk1, SFRP1) in patients with CS versus healthy individuals.

METHODS

Forty patients with clinically and biochemically evident CS and 40 sex-, age-, and body mass index-matched healthy subjects provided fasting serum samples for sclerostin, SFRP1 and Dkk1, along with bone turnover markers.

RESULTS

Patients with CS had higher sclerostin levels (34.5 (30.3-37.1) pmol/L) versus healthy individuals (29.9 (24.3-36.8) pmol/L) (p = 0.032). Differences in sclerostin were due to the lack of lower sclerostin values rather than an increase in protein levels above the upper limits of the healthy control. The odds of sclerostin levels being higher than 30 pmol/L were greater in patients with CS as compared with the odds in healthy subjects (odds ratio = 3.81 95 % confidence interval 1.45-10.02) (p = 0.01). It coexisted with suppressed bone formation and unchanged bone resorption markers. Dkk1, SFRP1 did not differ from the control group.

CONCLUSIONS

Of all the tested proteins (sclerostin, Dkk1, SFRP1), only sclerostin showed a significant difference when contrasting CS with healthy subjects. Hypercortisolism might prevent the down-regulation of sclerostin. Targeting sclerostin seems to be a promising therapeutic approach to treating osteoporosis in patients with CS.

Is there an association between non-functioning adrenal adenoma and endothelial dysfunction?

BACKGROUND AND AIM

Subtle changes in hypothalamic- pituitary-adrenal (HPA) axis of subjects with nonfunctioning adrenal adenoma may be associated with endothelial alterations. We sought to investigate endothelial function, visceral adiposity and osteoprotegerin (OPG) and interleukin- 18 (IL-18) levels in subjects with non-functioning adrenal adenomas.

SUBJECTS AND METHODS

The adenoma group included 40 subjects without clinical and subclinical findings of hypercortisolism or other adrenal gland disorders. Twenty-two body mass index-matched controls were also enroled. The patients and control subjects underwent hormonal evaluation and assessment of anthropometric and metabolic parameters. Endothelial function was assessed with flowmediated dilatation (FMD) of the brachial artery and intima media thickness (IMT) of common carotid arteries. Visceral adipose tissue area was measured by computed tomography. Plasma OPG and serum IL-18 levels were also measured.

RESULTS

When compared with healthy controls, the adenoma group had elevated systolic blood pressure, post-dexamethasone suppression test cortisol and reduced DHEAS. Visceral adipose tissue area and IMT of common carotid arteries were comparable. In the adenoma group, FMD of the brachial artery was significantly impaired and IL-18 level was significantly elevated. Visceral adipose tissue area was independently related with FMD. Homeostasis model assessment (HOMA) was the independent factor associated with visceral adipose tissue area. Cortisol, DHEAS and visceral adipose tissue area were independently associated with HOMA.

CONCLUSIONS

We achieved evidence that could be attributable to endothelial alterations in subjects with non-functioning adrenal adenomas. Impaired FMD appeared to be a consequence of subtle changes in HPA axis in terms of elevated cortisol and reduced DHEAS as these conditions were known to disturb endothelial-dependent vasodilatation.

Association of osteoprotegerin and rankl levels with insulin resistance in pubertal obese children

Osteoprotegerin (OPG)/“receptor activator of nuclear factor kappa B-ligand” (RANKL) system has an important role in the remodeling of bone through regulation of osteoclastogenesis. We aimed to detect OPG and RANKL levels, particularly in obese children in the pubertal period and to investigate whether these parameters correlate with insulin resistance in childhood. Our study included 66 obese children ranging in age from 9.1 to 16 years, and 22 non-obese children ranging in age from 10.5 to 16 years. Blood glucose, insulin, total cholesterol, HDL cholesterol, and LDL cholesterol levels were measured for all cases; HOMA-IR, Quicki index and atherogenic index were calculated. Serum OPG and RANKL levels were also measured. OPG and RANKL levels did not show any difference between obese and non-obese children (P>.05). No difference in these 2 parameters were observed among the children with and without insulin resistance (P>.05). No correlation could be established between the OPG, the HOMA-IR, Quick and atherogenic indices. Obesity and insulin resistance are believed to show their effect in the later period of life to become able to change some of the parameters.

Persistent increase of osteoprotegerin levels after cortisol normalization in patients with Cushing's syndrome

OBJECTIVE

Osteoprotegerin (OPG) has been identified as a decoy receptor that inhibits osteoclast differentiation and, more recently, as a paracrine regulator of vascular calcification. OPG is suppressed by glucocorticoids (GC); however, results from experimental and clinical studies are not univocal. The aim of this study was to evaluate OPG and bone metabolism in patients with Cushing's syndrome (CS) before and after cure.

DESIGN AND METHODS

Twenty-six patients with CS (all women, mean age: 39.1+/-11.9 years) and 24 age- and gonadal status-matched healthy women were studied for bone mineral density, bone metabolism, OPG, and receptor activator of nuclear factor-kB ligand at baseline. Twelve patients were also studied 6-18 months after surgery, with persistent normalization of cortisol levels.

RESULTS

OPG was significantly higher and osteocalcin (OC) was significantly lower in CS patients than in controls (OPG: 4.17+/-1.23 vs 2.95+/-0.79 pmol/l, P=0.00001; OC: 15.0+/-6.1 vs 18.8+/-6.8 ng/ml, P=0.04 in CS and controls respectively). After cure, we found no difference in OPG levels, despite a significant increase in OC levels (from 16.4+/-11 to 37.2+/-15 ng/ml, P=0.03).

CONCLUSION

Patients with CS showed increased OPG serum levels that remained unchanged after recovery, despite a restoration of bone formation. We speculate that high levels of OPG could reflect the persistent damage of the GCs on cardiovascular system.

Variations along the 24-hour cycle of circulating osteoprotegerin and soluble RANKL: a rhythmometric analysis

The variability of serum osteoprotegerin (OPG) and soluble RANKL (sRANKL) along the 24-h cycle was assessed in 20 healthy women. No rhythmic variations of serum OPG, sRANKL or sRANKL/OPG ratio were detected as a group phenomenon. Timing of sampling is unlikely to influence the results of measurements of circulating OPG and sRANKL.

INTRODUCTION

Physiological bone turnover shows diurnal variations. The aim of the study was to assess variability of OPG and sRANKL serum levels along the 24-h cycle.

METHODS

Blood was collected from 20 healthy women (median age 31 years, range 25-65 years) at 4-h intervals between 08:00 and 24:00 and at 2-h intervals between 24:00 and 08:00. Serum albumin, cortisol, osteocalcin (OC), C-terminal telopeptide of type I collagen (CTX), OPG and total sRANKL were measured. Temporal variations were assessed by the COSINOR model.

RESULTS

Circadian rhythms of cortisol and albumin documented a normal synchronization within the circadian structure. Serum OC and CTX showed rhythmic variations, peaking at night-time. Rhythmic variations of serum OPG, sRANKL and sRANKL/OPG ratio were not detected as a group phenomenon. On an individual basis, rhythmic changes were detected in ten patients for OPG and eight patients for sRANKL, with very small amplitudes and heterogeneous acrophases.

CONCLUSIONS

The absence of consistent rhythmic variations of circulating OPG and sRANKL levels may reflect the absence of rhythmic variations of their expression in the bone microenvironment. Were this the case, the nocturnal rise of bone resorption should be accounted for by different, not RANKL/OPG-mediated factors. Since circulating OPG and sRANKL may derive from sources other than bone, rhythmicity could be masked by non-rhythmic or non-synchronized rhythmic expression in these sources. Timing of sampling is unlikely to influence the results of measurements of circulating OPG and sRANKL.