Reduced quantity and function of pneumococcal antibodies are associated with exacerbations of COPD in SPIROMICS.

While hypogammaglobulinemia is associated with COPD exacerbations, it is unknown whether frequent exacerbators have specific defects in antibody production/function. We hypothesized that reduced quantity/function of serum pneumococcal antibodies correlate with exacerbation risk in the SPIROMICS cohort. We measured total pneumococcal IgG in n = 764 previously vaccinated participants with COPD. In a propensity-matched subset of n = 200 with vaccination within five years (n = 50 without exacerbations in the previous year; n = 75 with one, n = 75 with ≥2), we measured pneumococcal IgG for 23 individual serotypes, and pneumococcal antibody function for 4 serotypes. Higher total pneumococcal IgG, serotype-specific IgG (17/23 serotypes), and antibody function (3/4 serotypes) were independently associated with fewer prior exacerbations. Higher pneumococcal IgG (5/23 serotypes) predicted lower exacerbation risk in the following year. Pneumococcal antibodies are inversely associated with exacerbations, supporting the presence of immune defects in frequent exacerbators. With further study, pneumococcal antibodies may be useful biomarkers for immune dysfunction in COPD.

Effects of Ramelteon on the Prevention of Postoperative Delirium in Older Patients Undergoing Orthopedic Surgery: The RECOVER Randomized Controlled Trial.

OBJECTIVES: Postoperative delirium, associated with negative consequences including longer hospital stays and worse cognitive and physical outcomes, is frequently accompanied by sleep-wake disturbance. Our objective was to evaluate the efficacy and short-term safety of ramelteon, a melatonin receptor agonist, for the prevention of postoperative delirium in older patients undergoing orthopedic surgery. DESIGN: A quadruple-masked randomized placebo-controlled trial (Clinical Trials.gov NCT02324153) conducted from March 2017 to June 2019. SETTING: Tertiary academic medical center. PARTICIPANTS: Patients aged 65 years or older, undergoing elective primary or revision hip or knee replacement. INTERVENTION: Ramelteon (8 mg) or placebo MEASUREMENTS: Eighty participants were randomized to an oral gel cap of ramelteon or placebo for 3 consecutive nights starting the night before surgery. Trained research staff conducted delirium assessments for 3 consecutive days starting on postoperative day (POD) 0, after recovery from anesthesia, and on to POD2. A delirium diagnosis was based upon DSM-5 criteria determined by expert panel consensus. RESULTS: Of 80 participants, five withdrew consent (one placebo, four ramelteon) and four were excluded (four ramelteon) after randomization. Delirium incidence during the 2 days following surgery was 7% (5 of 71) with no difference between the ramelteon versus placebo: 9% (3 of 33) and 5% (2 of 38), respectively. The adjusted odds ratio for postoperative delirium as a function of assignment to the ramelteon treatment arm was 1.28 (95% confidence interval: 0.21-7.93; z-value 0.27; p-value = 0.79). Adverse events were similar between the two groups. CONCLUSION: In older patients undergoing elective primary or revision hip or knee replacement, ramelteon was not efficacious in preventing postoperative delirium.

Discovery and Validation of Agonistic Angiotensin Receptor Autoantibodies as Biomarkers of Adverse Outcomes.

BACKGROUND: Agonistic angiotensin II type 1 receptor autoantibodies (AT1RaAbs) have not been associated with functional measures or risk for adverse health outcomes. AT1RaAbs could be used to stratify patient risk and to identify patients who can benefit from angiotensin receptor blocker treatment. METHODS: Demographic and physiological covariates were measured in a discovery set of community-dwelling adults from Baltimore (N=255) and AT1RaAb associations with physical function tests and outcomes assessed. A group from Chicago (N=60) was used for validation of associations and to explore the impact of angiotensin receptor blocker treatment. RESULTS: The Baltimore group had 28 subjects with falls, 32 frail subjects, and 5 deaths. Higher AT1RaAbs correlated significantly with interleukin-6 (Spearman r=0.33, P<0.0001), systolic blood pressure (Spearman r=0.28, P<0.0001), body mass index (Spearman r=0.28, P<0.0001), weaker grip strength (Spearman r=-0.34, P<0.01), and slower walking speed (Spearman r=-0.30, P<0.05). Individuals with high AT1RaAbs were 3.9 (95% confidence interval, 1.38-11.0) times more likely to be at high risk after adjusting for age (P<0.05). Every 1 µg/mL increase in AT1RaAbs increased the odds of falling 30% after adjusting for age, sex, body mass index, and blood pressure. The Chicago group had 46 subjects with falls and 60 deaths. Serum AT1RaAb levels were significantly correlated with grip strength (Spearman r=-0.57, P<0.005), walking speed (Spearman r=-0.47, P<0.005), and falls (Spearman r=0.30, P<0.05). Every 1 µg/mL increase in AT1RaAbs, decreased time to death by 9% after adjusting for age, sex, body mass index, and blood pressure. Chronic treatment with angiotensin receptor blockers was associated with better control of systolic blood pressure and attenuation of decline in both grip strength and time to death. CONCLUSIONS: In older individuals, higher AT1RaAb levels were associated with inflammation, hypertension, and adverse outcomes. Angiotensin receptor blocker treatment may blunt the harm associated with high levels of AT1RaAb.

The short-term and long-term impact of a brief aging research training program for medical students.

Summer training in aging research for medical students is a strategy for improving the pipeline of medical students into research careers in aging and clinical care of older adults. Johns Hopkins University has been offering medical students a summer experience of mentored research, research training, and clinical shadowing since 1994. Long-term outcomes of this program have not been described. The authors surveyed all 191 participants who had been in the program from 1994-2010 (60% female and 27% underrepresented minorities) and received a 65.8% (N = 125) response rate. The authors also conducted Google and other online searches to supplement study findings. Thirty-seven percent of those who have completed training are now in academic medicine, and program participants have authored or coauthored 582 manuscripts. Among survey respondents, 95.1% reported that participation in the Medical Student Training in Aging Research program increased their sensitivity to the needs of older adults. This program may help to build commitment among medical students to choose careers in aging.

Identification and characterization of a functional mitochondrial angiotensin system.

The renin-angiotensin (Ang) system regulates multiple physiological functions through Ang II type 1 and type 2 receptors. Prior studies suggest an intracellular pool of Ang II that may be released in an autocrine manner upon stretch to activate surface membrane Ang receptors. Alternatively, an intracellular renin-Ang system has been proposed, with a primary focus on nuclear Ang receptors. A mitochondrial Ang system has not been previously described. Here we report that functional Ang II type 2 receptors are present on mitochondrial inner membranes and are colocalized with endogenous Ang. We demonstrate that activation of the mitochondrial Ang system is coupled to mitochondrial nitric oxide production and can modulate respiration. In addition, we present evidence of age-related changes in mitochondrial Ang receptor expression, i.e., increased mitochondrial Ang II type 1 receptor and decreased type 2 receptor density that is reversed by chronic treatment with the Ang II type 1 receptor blocker losartan. The presence of a functional Ang system in human mitochondria provides a foundation for understanding the interaction between mitochondria and chronic disease states and reveals potential therapeutic targets for optimizing mitochondrial function and decreasing chronic disease burden with aging.

Plasma neopterin level as a marker of peripheral immune activation in amnestic mild cognitive impairment and Alzheimer's disease.

OBJECTIVE: Alterations of the immune system play important roles in Alzheimer's disease (AD). The primary purpose of this study was to compare the plasma levels of neopterin, a marker of cellular immune activity, in amnestic mild cognitive impairment (aMCI), early (mild to moderate) AD, and cognitively normal controls. In addition, the correlation of plasma neopterin with interferon-gamma (IFN-γ) and interleukin-6 (IL-6) was also examined. METHODS: Plasma samples from patients with mild-to-moderate AD (N = 34), aMCI (N = 27), and cognitively normal controls (N = 30) were obtained from the Johns Hopkins Alzheimer's Disease Research Center. Plasma neopterin, IFN-γ, and IL-6 levels were measured using commercially available ELISAs. Multiple linear regression was performed to study differences in the baseline neopterin levels between normal, aMCI, and AD patients. Pearson correlation coefficients were estimated for neopterin and IFN-γ and IL-6 levels. All analyses were conducted using SAS (SAS Institute, Inc., Cary, NC) and GraphPad Prism version 5.00 for Window (GraphPad Software, San Diego, CA, USA). RESULTS: AD subjects had significantly higher neopterin values compared with aMCI (ß = 0.202, p = 0.004) and normal (ß = 0.263, p = 0.0004) subjects. There was no statistically significant difference between normal and aMCI subjects. Significant associations between neopterin and IFN-γ (r = 0.41, p < 0.0001) and IL-6 (r = 0.35, p = 0.0006) levels were found. CONCLUSIONS: Our study demonstrates that peripheral immune response may be stronger in later stages of AD pathophysiology, when dementia has developed.

Detection and Quantification of Calcitonin Gene-Related Peptide (CGRP) in Human Plasma Using a Modified Enzyme-Linked Immunosorbent Assay.

Calcitonin gene-related peptide (CGRP) is a vasoactive neuropeptide that plays a putative role in the pathophysiology of migraine headaches and may be a candidate for biomarker status. CGRP is released from neuronal fibers upon activation and induces sterile neurogenic inflammation and arterial vasodilation in the vasculature that receives trigeminal efferent innervation. The presence of CGRP in the peripheral vasculature has spurred investigations to detect and quantify this neuropeptide in human plasma using proteomic assays, such as the enzyme-linked immunosorbent assay (ELISA). However, its half-life of 6.9 min and the variability in technical details of assay protocols, which are often not fully described, have yielded inconsistent CGRP ELISA data in the literature. Here, a modified ELISA protocol for the purification and quantification of CGRP in human plasma is presented. The procedural steps involve sample collection and preparation, extraction using a polar sorbent as a means of purification, additional steps to block non-specific binding, and quantification via ELISA. Further, the protocol has been validated with spike and recovery and linearity of dilution experiments. This validated protocol can theoretically be used to quantify CGRP concentrations in the plasma of individuals not only with migraine, but also with other diseases in which CGRP may play a role.

The role of proprotein convertase subtillisin/kexin type 9 in placental salvage and lipid metabolism in women with preeclampsia.

INTRODUCTION: Preeclampsia is associated with decreased maternal low-density lipoprotein cholesterol (LDL-c), which is essential for fetal growth. The underlying mechanisms for decreased LDL-c in preeclampsia remain unknown. Proprotein convertase subtillisin/kexin type 9 (PCSK9) regulates serum LDL-c via LDL receptor (LDL-R) degradation. We describe the possible role of PCSK9 in lipid metabolism in all compartments of the parturient (maternal blood, placental tissue, and fetal blood) in pregnancies with and without preeclampsia. METHODS: This is an observational study examining PCSK9 levels in maternal sera, umbilical cord blood, and PCSK9 protein content in placental tissue in three different locations (maternal placental interface, fetal placental interface, and umbilical cord) in women with and without preeclampsia at >23 weeks gestation. RESULTS: 68 parturients with preeclampsia and 55 without preeclampsia were enrolled. Maternal serum LDL-c (116.6 ± 48.9 mg/dL vs 146.1 ± 47.1 mg/dL, p = 0.0045) and PCSK9 (83 [61.8127.6] ng/mL vs 105.3 [83.5142.9] ng/mL, p = 0.011) were also reduced in the preeclamptics versus controls. There were no differences in PCSK9 protein content between preeclamptics and controls at comparative placental interfaces. However, PCSK9 protein content increased between the preeclampsia maternal placental interface (1.87 ± 0.62) and the preeclampsia umbilical cord (2.67 ± 1.08, p = 0.0243). DISCUSSION: PCSK9 levels are lower in maternal sera in preeclampsia when compared to controls. Placental PCSK9 protein content in preeclampsia increases from the maternal interface to the umbilical cord; however, this is not seen in controls. This suggests a potential compensatory mechanism for PCSK9 which allows for higher circulating fetal LDL-c levels in preeclampsia.

Growth Differentiation Factor-15 Predicts Mortality and Heart Failure Exacerbation But Not Ventricular Arrhythmias in Patients With Cardiomyopathy.

Background Heart failure (HF) has been increasing in prevalence, and a need exists for biomarkers with improved predictive and prognostic ability. GDF-15 (growth differentiation factor-15) is a novel biomarker associated with HF mortality, but no serial studies of GDF-15 have been conducted. This study aimed to investigate the association between GDF-15 levels over time and the occurrence of ventricular arrhythmias, HF hospitalizations, and all-cause mortality. Methods and Results We used a retrospective case-control design to analyze 148 patients with ischemic and nonischemic cardiomyopathies and primary prevention implantable cardioverter-defibrillator (ICD) from the PROSe-ICD (Prospective Observational Study of the ICD in Sudden Cardiac Death Prevention) cohort. Patients had blood drawn every 6 months and after each appropriate ICD therapy and were followed for a median follow-up of 4.6 years, between 2005 to 2019. We compared serum GDF-15 levels within ±90 days of an event among those with a ventricular tachycardia/fibrillation event requiring ICD therapies and those hospitalized for decompensated HF. A comparator/control group comprised patients with GDF-15 levels available during 2-year follow-up periods without events. Median follow-up was 4.6 years in the 148 patients studied (mean age 58±12, 27% women). The HF cohort had greater median GDF-15 values within 90 days (1797 pg/mL) and 30 days (2039 pg/mL) compared with the control group (1062 pg/mL, both P<0.0001). No difference was found between the ventricular tachycardia/fibrillation subgroup within 90 days (1173 pg/mL, P=0.60) or 30 days (1173 pg/mL, P=0.78) and the control group. GDF-15 was also significantly predictive of mortality (hazard ratio, 3.17 [95% CI, 2.33-4.30]). Conclusions GDF-15 levels are associated with HF hospitalization and mortality but not ventricular arrhythmic events.

Bone effects of rosiglitazone in HIV-infected patients with lipoatrophy.

OBJECTIVES: Thiazoledinediones increase limb fat in HIV+ patients with lipoatrophy. However, their use in the general population has been associated with bone loss and fracture. We sought to determine the effects of rosiglitazone on bone metabolism in HIV-infected patients. METHODS: HIV+ patients with lipoatrophy were randomized to rosiglitazone versus placebo for 48 weeks in a double-blind, placebo-controlled trial. Limb fat, bone mineral density (BMD), bone formation markers (procollagen type 1 amino-terminal propeptide [P1NP], osteocalcin [OC]) and bone resorption markers (C-terminal telopeptide of type I collagen [CTX]) were measured, along with receptor activator for nuclear factor kappa ß ligand (RANKL), osteoprotegerin (OPG), and inflammatory cytokines. RESULTS: Seventy-one subjects were randomized to rosiglitazone or placebo: 17% female and 51% white. Total BMD did not change significantly in either group. In the rosiglitazone group, P1NP showed statistically significant decreases at 24 and 48 weeks; however, changes compared to placebo were only significant at 24 weeks. OC decreased significantly in the rosiglitazone group at 24 weeks, but there were no between-group differences. CTX, RANKL, or OPG did not change for either group. Multivariable regression within the rosiglitazone arm showed P1NP changes were inversely associated with limb fat changes, protease inhibitors, and tenofovir use. CONCLUSION: Rosiglitazone use was associated with decreased bone formation, but it did not alter bone resorption or total BMD. The increase in limb fat that accompanies rosiglitazone use appears to be associated with decreased osteoblast activity. Further studies are needed to determine the effect of thiazoledinediones on bone health in HIV-infected persons.

IL-6-independent association of elevated serum neopterin levels with prevalent frailty in community-dwelling older adults.

BACKGROUND: neopterin is a monocyte/macrophage-derived immune activation marker and its levels increase with age. Frailty is an important clinical syndrome of old age. Previous studies have shown significant association between elevated interleukin-6 (IL-6) levels and frailty. The objective of this study was to evaluate IL-6-independent association of serum neopterin levels with prevalent frailty. METHODS: this is a cross-sectional study in community-dwelling older adults recruited from residential and retirement communities in Baltimore, MD, USA. Frailty was determined using validated screening criteria. Serum neopterin and IL-6 levels were measured using standard enzyme-linked immunosorbent assay. Pearson correlation and multivariate linear regression analysis was performed to assess the relationship between log(neopterin) and log(IL-6). Odds ratios (ORs) for frailty were calculated using log(neopterin) and log(IL-6) as continuous measures and across tertiles of neopterin and IL-6 levels, adjusting for age, race, sex, education and body mass index. RESULTS: one hundred and thirty-three individuals with a mean age of 84 years (range 72-97) completed the study. Neopterin levels were significantly higher in frail older adults than those in non-frail controls [median: 8.94 versus 8.35 nM, respectively, P < 0.001 t-test on log(neopterin)]. Log(neopterin) was significantly associated with prevalent frailty, adjusting for log(IL-6). Participants in the top tertile of neopterin had OR of 3.80 [95% confidence interval (CI) = 1.36-10.6, P < 0.01] for frailty. As expected, participants in the top tertile of IL-6 had OR of 3.29 (95% CI = 1.21-7.86, P < 0.05) for frailty. Log(neopterin) correlated with log(IL-6) (correlation coefficient = 0.19, P < 0.05). Moreover, OR for participants in the top neopterin tertile remained significant after adjusting for IL-6 (OR = 3.97, 95% CI = 1.15-13.72, P < 0.05). CONCLUSION: elevated neopterin levels had IL-6-independent association with prevalent frailty, suggesting potential monocyte/macrophage-mediated immune activation in the frail elderly.

Leveraging naturally occurring variation in financial stress to examine associations with inflammatory burden among older adults.

BACKGROUND: Financial strain is associated with earlier disability and mortality, but causal links are underexplored, partly because it is unethical to randomise people to financial stress. This study leverages naturally occurring random variation in days since monthly Social Security payment arrival among older adults to test associations with inflammatory biomarkers. METHODS: Biomarker data, including tumour necrosis factor (TNF)-α, interleukin (IL)-6 and C reactive protein (CRP), was collected from 2155 non-working healthy adults aged 70-79 years, participating in the Health, Aging and Body Composition Study. Days since payment arrival was independent of all demographic, socioeconomic or health characteristics measured in this study. Restricted cubic spline models estimated associations separately for each week of the month, stratified by financial strain status (interaction term p value for TNF-α model <0.05). RESULTS: Among financially strained older adults, more days since payment arrival was associated with higher TNF-α levels during the first week of the month (coefficient=0.102). Associations with IL-6 and CRP differed depending on the degree of financial strain (interaction term p values <0.05). Those with low, but not high, strain had lower levels of IL-6 (coefficient=-0.152) and CRP (coefficient=-0.179) during the first week. CONCLUSIONS: Days since monthly payments were associated with inflammatory cytokines among older adults who have difficulty making ends meet financially and associations depended on financial strain severity, suggesting that results are attributable to monthly variation in financial stress. Future research should examine whether more frequent Social Security disbursement would modify financial strain and inflammatory biomarkers.

Prevalence of Angiotensin II Type 1 Receptor Antibodies in Persons With Hypertension and Relation to Blood Pressure and Medication.

BACKGROUND: We aimed to determine the prevalence of antibodies against angiotensin II type 1 receptor (AT1RAb) in hypertensive adults and elucidate the relation of antihypertensive medication type to blood pressure (BP) among persons with and without AT1RAb. METHODS: Sera from participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study with hypertension were tested for AT1RAb using a commercial Enzyme-linked immunosorbent assay (ELISA) (One Lambda; positive ≥17 units/ml). BP measurements, uncontrolled BP (systolic BP ≥140 and/or diastolic BP ≥90 mm Hg), and effect of BP medication type were compared for AT1RAb positive (+) vs. negative (-) participants using descriptive statistics and multivariable regression. RESULTS: One hundred and thirty-two (13.1%) participants were AT1RAb+. Compared with AT1RAb-, AT1RAb+ persons were more likely to be white (47% vs. 36.7%; P = 0.03) but had similar comorbid disease burden. In models adjusting for age, sex, and race, AT1RAb+ persons had higher diastolic BP (ß = 2.61 mm Hg; SE = 1.03; P = 0.01) compared with AT1RAb- participants. Rates of uncontrolled BP were similar between the groups. AT1RAb+ persons on an angiotensin receptor blocker (ARB; n = 21) had a mean of 10.5 mm Hg higher systolic BP (SE = 4.56; P = 0.02) compared with AT1RAb+ persons using other BP medications. The odds of uncontrolled BP among AT1RAb+ participants on an ARB was 2.05 times that of those on other medications. AT1RAb- persons prescribed an angiotensin-converting enzyme inhibitor (ACEi) had 1.8 mm Hg lower diastolic BP (SE = 0.81; P = 0.03) than AT1RAb- persons not prescribed an ACEi. CONCLUSIONS: AT1RAb was prevalent among hypertensive adults and was associated with higher BP among persons on an ARB.

Upregulated ex vivo expression of stress-responsive inflammatory pathway genes by LPS-challenged CD14(+) monocytes in frail older adults.

Frailty has been increasingly recognized as an important clinical syndrome in old age. The frailty syndrome is characterized by chronic inflammation, decreased functional and physiologic reserve, and increased vulnerability to stressors, leading to disability and mortality. However, molecular mechanisms that contribute to inflammation activation and regulation in frail older adults have not been investigated. To begin to address this, we conducted a pathway-specific gene array analysis of 367 inflammatory pathway genes by lipopolysaccharide (LPS)-challenged CD14(+) monocytes from 32 community-dwelling frail and age-, race-, and sex-paired nonfrail older adults (mean age 83 years, range 72-94). The results showed that ex vivo LPS-challenge induced average 2.0-fold or higher upregulated expression of 116 genes in frail participants and 85 genes in paired nonfrail controls. In addition, frail participants had 2-fold or higher upregulation in LPS-induced expression of 7 stress-responsive genes than nonfrail controls with validation by quantitative real time RT-PCR. These findings suggest upregulated expression of specific stress-responsive genes in monocyte-mediated inflammatory pathway in the syndrome of frailty with potential mechanistic and interventional implications.

Upregulated monocytic expression of CXC chemokine ligand 10 (CXCL-10) and its relationship with serum interleukin-6 levels in the syndrome of frailty.

Frailty is an important geriatric syndrome that predicts disability and mortality. Substantial evidence suggests inflammation marked by elevated IL-6 levels as a key pathophysiologic factor that contributes to frailty. CXCL-10, a potent pro-inflammatory chemokine, has increased levels with age and is implicated in several inflammatory conditions. To better understand molecular mechanisms of inflammation activation in frailty, we evaluated monocytic expression of CXCL-10 and other inflammatory pathway genes by pathway-specific gene array analysis and quantitative RT-PCR. Frailty status was determined by the validated criteria. Sixteen pairs of community-dwelling frail and age-, race-, and sex-matched non-frail participants (mean age 83 years, range 72-94) completed the study. Here we report that frail participants had higher CXCL-10 expression levels than matched non-frail controls (1.05+/-0.88 versus 0.53+/-0.39, p=0.04). CXCL-10 expression correlated with IL-6 levels only in frail participants (Spearman correlation coefficient r=0.52, p=0.03). Furthermore, frailty-associated CXCL-10 upregulation was highly correlated with IL-6 elevation, both measured by frail-over-non-frail ratios (r=0.93, p<0.0001). These findings suggest upregulated monocytic expression of CXCL-10 as an important molecular mechanism that contributes to inflammation activation in frail older adults. Therapeutic implications include potential development of CXCL-10-based interventional strategies for the prevention and treatment of frailty in older adults.

Antibodies against Angiotensin II Type 1 and Endothelin A Receptors: Relevance and pathogenicity.

Antibodies against two G-protein coupled receptors (GPCRs), angiotensin II type 1 receptor (AT1R) and endothelin A receptor (ETAR) are among a growing number of autoantibodies that are found to be associated with allograft dysfunction. AT1R antibodies (AT1Rabs) and ETAR antibodies (ETARabs) have been shown to activate their target receptors and affect signaling pathways. Multiple single center reports have shown an association between presence of these antibodies and acute or chronic rejection and graft loss in kidney, heart, liver, lung and composite tissue transplantations. However, the characteristics of patients that are most likely to develop adverse outcomes, the phenotypes associated with graft damage solely due to these antibodies, and the antibody titer required to cause dysfunction are areas that remain controversial. This review compiles existing knowledge on the effect of antibodies against GPCRs in other diseases in order to bridge the gap in knowledge within transplantation biology. Future areas for research are highlighted and include the need for functional assays and treatment protocols for transplant patients who present with AT1Rabs and ETARabs. Understanding how antibodies that activate GPCRs influence transplantation outcome will have direct clinical implications for preemptive evaluation of transplant candidates as well as the post-transplant care of organ recipients.

Angiotensin receptor autoantibodies as exposures that modify disease progression: Cross sectional, longitudinal and in vitro studies of prostate cancer.

Circulating angiotensin type I receptor (AT1R) agonistic autoantibodies (AT1RaAbs) that bind and chronically activate the receptor have been associated with a number of diseases suggesting that while the autoantibodies are not necessarily causative they may promote disease progression. The prostate has a local renin angiotensin system. The current study examines associations between AT1RaAbs and prostate cancer (PCA), disease-free survival (DFS), overall survival (OS) and AT1RaAb effects on PCA cell phenotype. In a cross-sectional set of serum obtained from 151 men diagnosed with PCA, nonmalignant prostate disease or no disease, higher serum AT1RaAb levels were associated with PCA and non-organ confined PCA. The odds ratio for PCA was 6.3 (95% confidence interval 2.2 to 18) for a positive 1:1600 titer and 18 (95% confidence interval 6.9 to 45) at AT1RaAb levels > 1.04 µg/ml, (p < 0.0001). In a longitudinal set of pre-diagnosis samples from 109 men, DFS hazard ratios of 2.2 (95% confidence interval 1.4 to 3.5) and 1.6 (95% confidence interval 1.0 to 2.5) for most proximal to diagnosis and most distal to diagnosis samples, respectively, were found for high versus low AT1RaAb groups. Hazard ratios for OS in most proximal and distal samples were 2.4 (95% confidence interval 1.6 to 3.6) and 1.8 (95% confidence interval 1.1 to 2.8), respectively. Accelerated failure modeling of survival indicated that a 1 µg/ml increase in AT1RaAb levels was associated with a reduction of DFS and OS by 20% at the most proximal time point and by 15% at the most distal time points. Adjusting for age, did not affect the association with DFS in proximal samples but changed distal time point DFS and OS to a 10% decrease for every 1 µg/ml increase in AT1RaAb. Additional adjustments for body mass index, systolic blood pressure and prostate-specific antigen did not appreciably alter these associations. AT1RaAb treatment of PC3, DU145, and LNCaP cells significantly increased the maximal growth rate approximately 2-fold and invasiveness approximately 3-fold. Conclusions: These observations provide evidence supporting AT1RaAbs as exposures that may modify prostate cancer progression and indicate they may be predictive markers for risk stratification.

Structural requirements for bone sialoprotein binding and modulation of matrix metalloproteinase-2.

Bone sialoprotein (BSP) has been shown to induce limited gelatinase activity in latent matrix metalloproteinase-2 (MMP-2) without removal of the propeptide and to restore enzymatic activity to MMP-2 previously inhibited by tissue inhibitor of matrix metalloproteinase-2 (TIMP2). The current study identifies structural domains in human BSP and MMP-2 that contribute to these interactions. The 26 amino acid domain encoded by exon 4 of BSP is shown by a series of binding and activity assays to be involved in the displacement of MMP-2's propeptide from the active site and thereby inducing the protease activity. Binding assays in conjunction with enzyme activity assays demonstrate that both amino- and carboxy-terminal domains of BSP contribute to restoration of activity to TIMP2-inhibited MMP-2, while the MMP-2 hemopexin domain is not required for reactivation.

Bone sialoprotein binding to matrix metalloproteinase-2 alters enzyme inhibition kinetics.

Bone sialoprotein (BSP) is a secreted glycophosphoprotein normally restricted in expression to skeletal tissue that is also induced by multiple neoplasms in vivo. Previous work has shown that BSP can bind to matrix metalloproteinase-2 (MMP-2). Because of MMP-2 activity in promoting tumor progression, potential therapeutic inhibitors were developed, but clinical trials have been disappointing. The effect of BSP on MMP-2 modulation by inhibitors was determined with purified components and in cell culture. Enzyme inhibition kinetics were studied using a low-molecular weight freely diffusable substrate and purified MMP-2, BSP, and natural (tissue inhibitor of matrix metalloproteinase-2) and synthetic (ilomastat and oleoyl- N-hydroxylamide) inhibitors. We determined parameters of enzyme kinetics by varying substrate concentrations at different fixed inhibitor concentrations added to MMP-2 alone, MMP-2 and BSP, or preformed MMP-2-BSP complexes and solving a general linear mixed inhibition rate equation with a global curve fitting program. Two in vitro angiogenesis model systems employing human umbilical vein endothelial cells (HUVECs) were used to follow BSP modulation of MMP-2 inhibition and tubule formation. The presence of BSP increased the competitive K I values between 15- and 47-fold for natural and synthetic inhibitors. The extent of tubule formation by HUVECs cocultured with dermal fibroblasts was reduced in the presence of inhibitors, while the addition of BSP restored vessel formation. A second HUVEC culture system demonstrated that tubule formation by cells expressing BSP could be inhibited by an activity blocking antibody against MMP-2. BSP modulation of MMP-2 activity and inhibition may define its biological role in promoting tumor progression.

Impact on bone of an estrogen receptor-alpha gene loss of function mutation.

CONTEXT: The kindred described is the only known instance of a germ line loss of function mutation of estrogen receptor (ER)-alpha. OBJECTIVE: Our objective was to assess the impact of a loss of function mutation in the ER-alpha gene on histomorphometry, bone volumetric density, bone geometry and skeletal growth, and ER-alpha heterozygosity on spine density and adult height in an extended pedigree. DESIGN AND PARTICIPANTS: A longitudinal follow-up of the propositus with homozygous loss of function mutation of ER-alpha and single contact evaluation of the kindred were performed. MAIN OUTCOME MEASURES: Iliac crest bone biopsy and peripheral quantitative computed tomography of propositus with serial measures of areal spine bone mineral density (aBMD) by dual-energy x-ray absorptiometry and bone age were performed. Members of pedigree were evaluated for ER-alpha mutation carrier status and spine aBMD. RESULTS: Bone biopsy revealed marked osteopenia (cortex: 641 microm), low trabecular volume (10.6%), decreased thickness (76.2 microm), normal trabecular number, and low activation frequency (0.099/yr). Radial periosteal circumference was similar, endosteal circumference larger, and trabecular and cortical volumetric bone mineral density markedly lower (158 and 1092 mg/cm(3), respectively) than controls. Spine aBMD at age 28.5 yr (0.745 g/cm(2)) decreased to 0.684 g/cm(2) (Z score -3.85) in 3.5 yr. Bone age advanced from 15-17.5 yr. Kindred analysis revealed that gene carriers had spine aBMD Z scores less than zero (P = 0.003), but carriers and nonmutant members were similar (-0.84 +/- 0.26 vs. -0.64 +/- 0.16). CONCLUSION: Homozygous ER-alpha disruption markedly affects bone growth, mineral content, and structure but not periosteal circumference. ER-alpha heterozygosity appears to not impair spine aBMD.