The brain reacting to COVID-19: analysis of the cerebrospinal fluid proteome, RNA and inflammation.

Patients with COVID-19 can have a variety of neurological symptoms, but the active involvement of central nervous system (CNS) in COVID-19 remains unclear. While routine cerebrospinal fluid (CSF) analyses in patients with neurological manifestations of COVID-19 generally show no or only mild inflammation, more detailed data on inflammatory mediators in the CSF of patients with COVID-19 are scarce. We studied the inflammatory response in paired CSF and serum samples of patients with COVID-19 (n = 38). Patients with herpes simplex virus encephalitis (HSVE, n = 10) and patients with non-inflammatory, non-neurodegenerative neurological diseases (n = 28) served as controls. We used proteomics, enzyme-linked immunoassays, and semiquantitative cytokine arrays to characterize inflammatory proteins. Autoantibody screening was performed with cell-based assays and native tissue staining. RNA sequencing of long-non-coding RNA and circular RNA was done to study the transcriptome. Proteomics on single protein level and subsequent pathway analysis showed similar yet strongly attenuated inflammatory changes in the CSF of COVID-19 patients compared to HSVE patients with, e.g., downregulation of the apolipoproteins and extracellular matrix proteins. Protein upregulation of the complement system, the serpin proteins pathways, and other proteins including glycoproteins alpha-2 and alpha-1 acid. Importantly, calculation of interleukin-6, interleukin-16, and CXCL10 CSF/serum indices suggest that these inflammatory mediators reach the CSF from the systemic circulation, rather than being produced within the CNS. Antibody screening revealed no pathological levels of known neuronal autoantibodies. When stratifying COVID-19 patients into those with and without bacterial superinfection as indicated by elevated procalcitonin levels, inflammatory markers were significantly (p < 0.01) higher in those with bacterial superinfection. RNA sequencing in the CSF revealed 101 linear RNAs comprising messenger RNAs, and two circRNAs being significantly differentially expressed in COVID-19 than in non-neuroinflammatory controls and neurodegenerative patients. Our findings may explain the absence of signs of intrathecal inflammation upon routine CSF testing despite the presence of SARS-CoV2 infection-associated neurological symptoms. The relevance of blood-derived mediators of inflammation in the CSF for neurological COVID-19 and post-COVID-19 symptoms deserves further investigation.

Placental expression of sFlt-1 and PlGF in early preeclampsia vs. early IUGR vs. age-matched healthy pregnancies.

OBJECTIVE: To investigate whether differences between early preeclampsia and early fetal growth restriction can be explained by differential placental expression patterns of sFlt-1, Flt-1, and PlGF. METHODS: Placental tissues and maternal blood samples from six cases of preeclampsia, seven IUGR, and six age-matched controls were studied for mRNA and protein levels as well as protein localization and expression intensity. RESULTS: Neither placental PlGF mRNA and protein expression nor placental villous trophoblast expression intensity of PlGF was altered by placental dysfunction. CONCLUSION: High sFlt-1 concentrations may account for diminished maternal serum PlGF levels.

Angiogenic Markers and Cardiovascular Indices in the Prediction of Hypertensive Disorders of Pregnancy.

Angiogenic and antiangiogenic factors have proven to be an accurate predictive means of preeclampsia. Echocardiographic studies have shown that women with preeclampsia exhibit significant cardiovascular strain, especially early-onset preeclampsia. The aim of this study is to determine preeclampsia risk with soluble fms-like tyrosin kinase 1/placental growth factor ratio, serum NT-proBNP (N-terminal pro B-type natriuretic peptide), and biophysical markers of cardiovascular function in a prospective case-control study. We examined a cohort of 110 pregnant women with uneventful pregnancy outcome (controls) and 129 with hypertensive pregnancy disorders, including 77 with preeclampsia and 52 with pregnancy-induced hypertension. Cardiac indices were obtained with a USCOM-1A monitor, and soluble fms-like tyrosin kinase 1, placental growth factor, and NT-proBNP were measured in serum samples on automated platforms. Logistic regression, as well as Cox proportional hazard analysis, was performed. There were significant contributions from all variables tested, except for heart rate, stroke volume index, and cardiac index to the prediction model. When testing accuracy of respective markers in combination (full model) versus individual markers (soluble fms-like tyrosin kinase 1/placental growth factor ratio and total peripheral resistance) was compared. The soluble fms-like tyrosin kinase 1/placental growth factor ratio and total peripheral resistance performed as good as the full model, except for hypertensive pregnancy disorders and pregnancy-induced hypertension, where the full model performed better. The additional assessment of biophysical and biochemical markers of cardiovascular strain in pregnancy increases the detection of the composite group of hypertensive pregnancy disorders, while not significantly improving detection of preeclampsia alone. This offers a more precise insight into the pathogenesis of the disease, as well as offering a window for intervention, possibly decreasing cardiovascular mortality in these women.

Increased placental sFlt-1 but unchanged PlGF expression in late-onset preeclampsia.

OBJECTIVE: To investigate whether differences between late-onset preeclampsia (PE) and intrauterine growth restriction (IUGR) can be explained by differential placental expression patters of sFlt-1, Flt-1, and placental growth factor (PlGF). METHODS: Placental tissues and maternal blood samples from seven patients with PE, five IUGR, and seven age-matched controls were studied for mRNA and protein levels as well as protein localization and expression intensity. RESULTS: Placental PlGF mRNA and protein expression were not altered by placental dysfunction while placental villous trophoblast expression intensity of PlGF was increased. CONCLUSION: High sFlt-1 concentrations may account for diminished maternal serum PlGF levels.

Modeling risk for severe adverse outcomes using angiogenic factor measurements in women with suspected preterm preeclampsia.

INTRODUCTION: Preeclampsia (PE) is a pregnancy-specific syndrome associated with adverse maternal and fetal outcomes. Patient-specific risks based on angiogenic factors might better categorize those who might have a severe adverse outcome. METHODS: Women evaluated for suspected PE at a tertiary hospital (2009-2012) had pregnancy outcomes categorized as 'referent' or 'severe', based solely on maternal/fetal findings. Outcomes that may have been influenced by a PE diagnosis were considered 'unclassified'. Soluble fms-like tyrosine kinase (sFlt1) and placental growth factor (PlGF) were subjected to bivariate discriminant modeling, allowing patient-specific risks to be assigned for severe outcomes. RESULTS: Three hundred twenty-eight singleton pregnancies presented at ≤34.0 weeks' gestation. sFlt1 and PlGF levels were adjusted for gestational age. Risks above 5 : 1 (10-fold over background) occurred in 77% of severe (95% CI 66 to 87%) and 0.7% of referent (95% CI <0.1 to 3.8%) outcomes. Positive likelihood ratios for the modeling and validation datasets were 19 (95% CI 6.2-58) and 15 (95% CI 5.8-40) fold, respectively. CONCLUSIONS: This validated model assigns patient-specific risks of any severe outcome among women attending PE triage. In practice, women with high risks would receive close surveillance with the added potential for reducing unnecessary preterm deliveries among remaining women. © 2015 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd.

Effects of 60-day bed rest with and without exercise on cellular and humoral immunological parameters.

Exercise at regular intervals is assumed to have a positive effect on immune functions. Conversely, after spaceflight and under simulated weightlessness (e.g., bed rest), immune functions can be suppressed. We aimed to assess the effects of simulated weightlessness (Second Berlin BedRest Study; BBR2-2) on immunological parameters and to investigate the effect of exercise (resistive exercise with and without vibration) on these changes. Twenty-four physically and mentally healthy male volunteers (20-45 years) performed resistive vibration exercise (n=7), resistance exercise without vibration (n=8) or no exercise (n=9) within 60 days of bed rest. Blood samples were taken 2 days before bed rest, on days 19 and 60 of bed rest. Composition of immune cells was analyzed by flow cytometry. Cytokines and neuroendocrine parameters were analyzed by Luminex technology and ELISA/RIA in plasma. General changes over time were identified by paired t-test, and exercise-dependent effects by pairwise repeated measurements (analysis of variance (ANOVA)). With all subjects pooled, the number of granulocytes, natural killer T cells, hematopoietic stem cells and CD45RA and CD25 co-expressing T cells increased and the number of monocytes decreased significantly during the study; the concentration of eotaxin decreased significantly. Different impacts of exercise were seen for lymphocytes, B cells, especially the IgD(+) subpopulation of B cells and the concentrations of IP-10, RANTES and DHEA-S. We conclude that prolonged bed rest significantly impacts immune cell populations and cytokine concentrations. Exercise was able to specifically influence different immunological parameters. In summary, our data fit the hypothesis of immunoprotection by exercise and may point toward even superior effects by resistive vibration exercise.

Placental lesions of vascular insufficiency are associated with anti-angiogenic state in women with preeclampsia.

OBJECTIVE: To evaluate if placental histopathological changes of vascular insufficiency correlate with circulating angiogenic factors in patients with preeclampsia. MATERIALS AND METHODS: Subjects were selected from a previous prospective cohort study of preeclampsia based on the availability of plasma anti-angiogenic factor (sFlt1) and pro-angiogenic factor (PlGF) measurements and placental histology specimens. Preeclamptic patients were divided into two groups based on plasma levels of these factors described as a ratio: anti-angiogenic preeclampsia with sFlt1/PlGF ratio ≥85 and normal angiogenic preeclampsia with sFlt1/PlGF < 85. The placental lesions of vascular insufficiency that were studied specifically included atherosis, infarcts, syncytial knots, acute and chronic abruption, hematoma, and fetal thrombosis. The data are shown as median (quartile 1 and quartile 3) or n (%) when appropriate. RESULTS: The anti-angiogenic preeclampsia group (N = 48) presented at an earlier gestational age (weeks) than the normal angiogenic group (N = 28); {32 (28, 34) versus 35 (32, 36), p = 0.002}, had higher systolic blood pressure (mmHg) {154 (147, 168) versus 147 (132, 158), p = 0.02}, delivered early (weeks) {(32 (29, 34) versus 36 (34, 37), p < 0.001} and had lower birth weight (grams) {(1550 (1055, 2060) versus 2655 (2285, 3343), p < 0.001}. Several pathologic lesions were found significantly more often in the anti-angiogenic preeclampsia group; atherosis {27.7% versus 3.6%, p < 0.05}, infarcts {58.3% versus 3.6%, p = 0.002}, and syncytial knots {81.3% versus 39.3%, p < 0.001}. CONCLUSION: Preeclamptic patients with imbalance in circulating angiogenic factors have disproportionally higher rates of placental vascular lesions historically associated with severe disease.

Clinical characterization and outcomes of preeclampsia with normal angiogenic profile.

OBJECTIVE: To compare the clinical characteristics and outcomes of preeclamptic women presenting with a normal plasma angiogenic profile with those subjects who are characterized by an abnormal angiogenic profile. METHODS: This was a secondary analysis of a prospective cohort study in women presenting to obstetrical triage at <37 weeks of gestation and diagnosed with preeclampsia within 2 weeks of enrollment and in whom angiogenic factors (sFlt1 and PlGF) measurements were available. Patients were divided into two groups based on their circulating levels of these factors described as a ratio; the sFlt1/PlGF ratio, non-angiogenic preeclampsia (sFlt1/PlGF ratio <85) and angiogenic preeclampsia (sFlt1/PlGF ratio ≥85). The data are presented by sFlt1/PlGF category using median and quartile 1-quartile 3 for continuous variables and by frequency and sample sizes for categorical variables. RESULTS: In our cohort, the patients with non-angiogenic preeclampsia (N = 46) were more obese [BMI: 35.2 (31.6, 38.7) versus 31.1 (28.0, 39.0), p = 0.04], more likely to have preexisting diabetes (21.7% versus 2.0%, p = 0.002) and presented at a later gestational age [35 (32, 37) versus 32 (29, 34) weeks, p < 0.0001] as compared with women with angiogenic preeclampsia (N = 51). Women with non-angiogenic preeclampsia had no serious adverse outcomes (elevated liver function tests/low platelets: 0% versus 23.5%, abruption: 0% versus 9.8%, pulmonary edema: 0% versus 3.9%, eclampsia: 0% versus 2.0 %, small for gestational age: 0% versus 17.7% and fetal/neonatal death: 0% versus 5.9%) as compared with women with angiogenic preeclampsia. The rate of preterm delivery <34 weeks was 8.7% in non-angiogenic preeclampsia compared with 64.7% in angiogenic preeclampsia (p < 0.0001). Interestingly, delivery between 34 and 37 weeks and resource utilization (hospital admission days) were similar in the two groups. CONCLUSION: In contrast to the angiogenic form, the non-angiogenic form of preeclampsia is characterized by little to no risk of preeclampsia-related adverse outcomes, other than iatrogenic prematurity. Incorporation of angiogenic biomarkers in the evaluation of preeclampsia may allow accurate and early identification of severe disease.

Antiangiogenic factors and maternal hemodynamics during intensive hemodialysis in pregnancy.

We report on a 21-year-old pregnant patient with IgA nephropathy who was initiated on intensive hemodialysis (8 hours of hemodialysis 3 times a week) at a gestational age of 26 weeks on the basis of worsening kidney function resulting in rapidly progressive fatigue and difficulties in metabolic control. Throughout the pregnancy, and while on intensive hemodialysis, 24-hour ambulatory blood pressure control was within the target, and results of weekly 24-hour measurement of central hemodynamics and pulse wave velocity, and of serial levels of circulating (anti-)angiogenic factors were comparable to normal pregnancies. Estimated fetal growth evolved along the 50th percentile, and no polyhydramnios was detected. After induction for a sudden, unexplained increase in blood pressure, she delivered a healthy boy of 2480 g at a gestational age of 36 weeks. This case adds to the expanding literature that supports the use of intensive hemodialysis in pregnant patients with end-stage renal disease and illustrates, for the first time, the potential use of serial (anti-) angiogenic factors and 24-hour measurements of blood pressure and hemodynamic indices in order to facilitate monitoring of these complicated patients.

Circulating angiogenic factors and risk of adverse maternal and perinatal outcomes in twin pregnancies with suspected preeclampsia.

To evaluate whether angiogenic factor levels correlate with preeclampsia-related adverse maternal and perinatal outcomes in women with twin pregnancy, we studied 79 women with suspected preeclampsia in the 3rd trimester. Antiangiogenic soluble fms-like tyrosine kinase-1 (sFlt-1) and proangiogenic placental growth factor (PlGF) were measured at presentation on an automated platform. An adverse outcome was defined as hemolysis, elevated liver enzymes, and low platelets syndrome; disseminated intravascular coagulation; abruption; pulmonary edema; cerebral hemorrhage; maternal, fetal, and neonatal death; eclampsia; acute renal failure; small for gestational age; and indicated delivery. All outcomes were ascertained 2 weeks after initial evaluation. Comparing the 52 women (65.8%) who experienced an adverse outcome with the 27 women (34.2%) without an adverse outcome, the median sFlt-1 was elevated (11461.5 pg/mL [8794.0-14847.5] versus 7495.0 pg/mL [3498.0-10482.0; P=0.0004]), PlGF was reduced (162.5 pg/mL [98.0-226.5] versus 224.0 pg/mL [156.0-449.0]; P=0.005), and sFlt-1/PlGF ratio was elevated (74.2 [43.5-110.5] versus 36.2 [7.1-71.3]; P=0.0005). Among those presenting <34 weeks (n=40), the difference in sFlt-1/PlGF ratio was more striking (97.7 [76.6-178.1] versus 31.7 [6.5-48.7]; P=0.001). Addition of sFlt-1/PlGF to the highest systolic blood pressure and proteinuria improved prediction of adverse outcomes. We conclude that in women with twin pregnancy and suspected preeclampsia, the sFlt-1/PlGF ratio at the time of initial evaluation is associated with subsequent adverse maternal and perinatal outcomes. These findings are similar to those in singleton pregnancies and may implicate common pathogenic pathways.

Angiogenic factors and the risk of adverse outcomes in women with suspected preeclampsia.

BACKGROUND: An imbalance in circulating angiogenic factors plays a central role in the pathogenesis of preeclampsia. METHODS AND RESULTS: We prospectively studied 616 women who were evaluated for suspected preeclampsia. We measured plasma levels of antiangiogenic soluble fms-like tyrosine kinase 1 (sFlt1) and proangiogenic placental growth factor (PlGF) at presentation and examined for an association between the sFlt1/PlGF ratio and subsequent adverse maternal and perinatal outcomes within 2 weeks. The median sFlt1/PlGF ratio at presentation was elevated in participants who experienced any adverse outcome compared with those who did not (47.0 [25th-75th percentile, 15.5-112.2] versus 10.8 [25th-75th percentile, 4.1-28.6]; P<0.0001). Among those presenting at <34 weeks (n=167), the results were more striking (226.6 [25th-75th percentile, 50.4-547.3] versus 4.5 [25th-75th percentile, 2.0-13.5]; P<0.0001), and the risk was markedly elevated when the highest sFlt1/PlGF ratio tertile was compared with the lowest (odds ratio, 47.8; 95% confidence interval, 14.6-156.6). Among participants presenting at <34 weeks, the addition of sFlt1/PlGF ratio to hypertension and proteinuria significantly improved the prediction for subsequent adverse outcomes (area under the curve, 0.93 for hypertension, proteinuria, and sFlt1/PlGF versus 0.84 for hypertension and proteinuria alone; P=0.001). Delivery occurred within 2 weeks of presentation in 86.0% of women with an sFlt1/PlGF ratio ≥85 compared with 15.8% of women with an sFlt1/PlGF ratio <85 (hazard ratio, 15.2; 95% confidence interval, 8.0-28.7). CONCLUSIONS: In women with suspected preeclampsia presenting at <34 weeks, circulating sFlt1/PlGF ratio predicts adverse outcomes occurring within 2 weeks. The accuracy of this test is substantially better than that of current approaches and may be useful in risk stratification and management. Additional studies are warranted to validate these findings.

Low vagal tone is associated with impaired post stress recovery of cardiovascular, endocrine, and immune markers.

Reduced heart rate variability (HRV) and delayed blood pressure recovery are associated with increased cardiovascular risk. Besides this evident link, the vagus is thought to play an inhibitory role in the regulation of other allostatic systems, including inflammation and the hypothalamic-pituitary-adrenal (HPA) axis. However, human evidence is scarce. To further explore these associations and with special regard to the postulated mediating role of the vagus, we hypothesised that subjects with low vagal tone as indexed by reduced resting HRV would show impaired post-stress recovery of cardiovascular, endocrine and immune system markers involved in cardiovascular pathology. 44 healthy men underwent a standardised mental stress test. Besides continuous measurement of systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), and HRV serum cortisol, tumour necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) were measured before, after, 20, and 60 min after stress. Low versus high HRV groups was defined by median split on resting HRV (RMSSD). The task elicited significant time effects for SBP, DBP, HR, HRV, cortisol, and TNF-alpha. Subjects with low baseline HRV showed almost no modulation of HRV coupled with overall reduced HRV levels, and impaired recovery of DBP, cortisol, and TNF-alpha. Confirming our hypothesis, low vagal tone was associated with impaired recovery of cardiovascular, endocrine, and immune markers in healthy males. The data support an inhibitory role of the vagus in the regulation of allostatic systems as described in the neurovisceral integration model. We posit reduced resting HRV as a risk marker for future cardiovascular and other stress-related disease.

Clonidine improves hyperarousal in borderline personality disorder with or without comorbid posttraumatic stress disorder: a randomized, double-blind, placebo-controlled trial.

The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition borderline personality disorder (BPD) seems to constitute a very heterogeneous category. Therefore, pharmacological therapy is symptom-oriented or targets comorbid conditions. A high comorbidity exists between BPD and posttraumatic stress disorder (PTSD). In a double-blind, randomized, placebo-controlled crossover study, we sought to determine whether the antinoradrenergic agent clonidine was effective in reducing hyperarousal and measures of BPD-specific and general psychopathology in a sample of 18 patients with BPD, with or without comorbid PTSD, and with a prominent hyperarousal syndrome. Hyperarousal as measured by the Clinician Administered PTSD scale improved significantly compared with placebo (P = 0.003) irrespective of PTSD comorbidity. Improvements in general and BPD-typical psychopathology were mainly seen in the PTSD-positive subgroup, whereas the subjective sleep latency (P = 0.005) and the restorative qualities of the sleep (P = 0.014) improved in the whole sample. Improvements, despite the small sample size of this pilot study, lead us to conclude that clonidine might be a useful adjunct to pharmacotherapy in patients with BPD who have marked hyperarousal and/or sleep problems and, in particular, in patients with BPD who have a PTSD comorbidity.

Growth hormone response during oral glucose tolerance test: the impact of assay method on the estimation of reference values in patients with acromegaly and in healthy controls, and the role of gender, age, and body mass index.

CONTEXT: Besides the measurement of IGF-I, GH suppression during an oral glucose tolerance test is recommended to assess the biochemical status in acromegaly. However, the development of highly sensitive and specific GH assays necessitates a critical reevaluation of criteria for diagnosis and follow-up of disease activity. OBJECTIVE: Our objective was to evaluate the between-method discrepancies in GH determinations by different immunoassays considering further confounders like age, gender, and body mass index (BMI). DESIGN, SUBJECTS, AND METHODS: We measured GH during a 75-g oral glucose tolerance test in 46 acromegaly patients (18 controlled, 28 uncontrolled; 19 men; 31-63 yr; BMI 26.4 +/- 0.4 kg/m(2)) and 213 healthy subjects (66 men; 20-76 yr; BMI 30 +/- 0.5 kg/m(2)), using three different commercially available assays [Immulite (Diagnostic Products Corp., Los Angeles, CA), Nichols (Nichols Institute Diagnostika GmbH, Bad Vilbel, Germany), and Diagnostic Systems Laboratories (Sinsheim, Germany)] that were calibrated against the recently recommended GH standards. RESULTS: Results from all assays strongly correlated (r = 0.8-0.996; P < 0.0001). However, the results obtained with the Immulite assay were, on average, 2.3-fold higher than those obtained with Nichols and 6-fold higher than those obtained with Diagnostic Systems Laboratories. Using cutoff limits of 1 microg/liter (Immulite) and 0.5 microg/liter (Nichols) identified 95% of patients with active disease and 78-80% of patients in remission. Basal and nadir GH levels were significantly higher in females than in males (Immulite 2.2 +/- 0.28 microg/liter vs. 0.73 +/- 0.15 microg/liter and 0.16 +/- 0.01 microg/liter vs. 0.08 +/- 0.01 microg/liter; P < 0.001, respectively). In multiple regression analysis, age, BMI, and gender were predictors for basal and nadir GH levels. CONCLUSION: Postglucose GH-nadir values are assay, gender, age, and BMI specific, indicating the need of individual cutoff limits for each assay.

Nicotine and biochanin A, but not cigarette smoke, induce anti-inflammatory effects on keratinocytes and endothelial cells in patients with Behçet's disease.

During periods of smoking, patients with Behçet's disease have less oral aphthae than in abstinence. To elucidate this observation, human keratinocytes and dermal microvascular endothelial cells (HMEC-1) were incubated with serum of 20 patients with Behçet's disease and 20 healthy controls for 4 hours. Maximum non-toxic concentrations were determined and the cells were further treated with 6 microM nicotine, 3.3% cigarette smoke extract (CES), 100 microM biochanin A, and 6.25/12.5 microM pyrrolidine dithiocarbamate alone and in combinations for 24 hours. Serum IL-8 levels of patients were significantly lower than those of controls. However, after 4 hours incubation with patients' sera, IL-8 release by both cell types was markedly increased when compared with the corresponding serum levels. The levels of IL-6 and vascular endothelial growth factor (VEGF) release were after 4 hours similar with the corresponding levels in serum. IL-1 was not detected. Nicotine significantly decreased IL-8 and -6 release by HMEC-1 maintained in both patients' and controls' sera, but only IL-6 release by keratinocytes maintained in patients' sera. VEGF release by both cells was markedly increased after nicotine treatment in either serum. CES significantly decreased IL-8 release and increased production of VEGF in keratinocytes maintained in patients' serum. The phytoestrogen biochanin A alone and in combination with nicotine further decreased the secretion of IL-8, -6, and VEGF in all experimental settings. Our data support a specific anti-inflammatory effect of nicotine on keratinocytes and endothelial cells maintained in the serum of patients with Behçet's disease. Moreover, biochanin A is likely to exhibit similar and even more profound results than nicotine.

Prospective identification of postmenopausal osteoporotic women at high vertebral fracture risk by radiography, bone densitometry, quantitative ultrasound, and laboratory findings: results from the PIOS study.

Women with established osteoporosis are at high risk to sustain additional vertebral fractures. Treatment may affect the predictive power of bone densitometry and biochemical techniques. There are few prospective studies comparing fracture prediction by dual-energy X-ray absorptiometry (DXA) and other techniques in treated women with established osteoporosis. The objective of this study was to prospectively assess the predictive power of various DXA and quantitative ultrasound (QUS) techniques for identification of women at high risk to develop new fractures over 1-2 yr. Moreover, we wanted to investigate whether previous or ongoing therapy precluded the use of common clinical laboratory blood tests and bone turnover markers for prediction of fracture risk. We measured prevalent fracture status; bone mineral density (BMD) of the whole body, spine, and hip by DXA; QUS of the calcaneus and the patella; hormones and various markers of bone resorption and formation; and took standard blood tests in 124 women (age 64.9 yr +/- 7.9) with manifest and variously treated postmenopausal osteoporosis. Subsequently, new spine fractures were assessed after 1 yr and, in a subset of 87 women, after 2 yr. Prevalent fractures turned out to be the strongest predictor of subsequent vertebral fractures with an age-adjusted odds ratio (OR) of 3.9 per prevalent fracture over 2 yr. Furthermore, our results underline the predictive power of spinal BMD (sOR = 2.1; standardized OR per 1 standard deviation population variance decrease), whole body BMD (sOR: 2.4), and QUS stiffness index of the calcaneus (sOR: 2.8) for vertebral fracture prediction. QUS of the patella did not predict vertebral fractures. Blood sedimentation rate was predictive in the first year (sOR: 1.9). The predictive power of bone turnover markers, however, appeared to be too low to be detectable in a group of this sample size and it may have been reduced because most women were already receiving treatment. In conclusion, radiographic measures, but not the tested laboratory bone turnover markers, enabled us to identify women (from a population of osteoporotic women who have been treated for some time with a variety of medications) who are at highest risk for developing new vertebral fractures within 1-2 yr.

Validation of a new automated renin assay.

BACKGROUND: Measurement of plasma renin is important for the treatment of patients with congenital adrenal hyperplasia (CAH) and in the evaluation of patients with suspected hyperaldosteronism. Immunologic assays for plasma renin offer easier implementation and standardization than enzyme-kinetic assays for plasma renin activity, but their sensitivity and specificity have been questioned. We studied a renin immunochemiluminescence assay on an automated platform. METHODS: Renin was measured by an enzymatic assay, by IRMA, and by the new Nichols Advantage Specialty System immunochemiluminometric assay (ICMA), in plasmas from unselected individuals from our outpatient departments and in samples from patients with selected diagnoses. RESULTS: The detection limit in the ICMA was 0.1 mU/L. The recovery was >90%, and the imprecision (CV) was generally <9%. Mean (SD) concentrations measured by ICMA were 32 (21)% lower than those measured by IRMA. Renin concentrations as measured by ICMA were identical in serum and EDTA-, heparin-, and citrate-anticoagulated plasmas. Prolonged incubation of whole blood at room temperature before centrifugation did not affect renin concentrations. The central 95% interval for 80 healthy adults was 6-85.5 mU/L. Plasma renin as assessed by ICMA in patients with primary hyperaldosteronism was <0.2 mU/L. CONCLUSIONS: The performance characteristics of the new renin ICMA allow its use for patients with CAH and for the diagnosis of mineralocorticoid hypertension. In view of the variability of renin concentrations, use for other forms of hypertension or physiologic research calls for the development of uniform sampling protocols.