Echocardiographic determination of pulmonary arterial capacitance.

A growing body of evidence has demonstrated that pulmonary arterial capacitance (PAC) is the strongest hemodynamic predictor of clinical outcomes across a wide spectrum of cardiovascular disease, including pulmonary hypertension and heart failure. We hypothesized that a ratio of right ventricular stroke volume (RVOT VTI) to the associated peak arterial systolic pressure (PASP) could function as a reliable non-invasive surrogate for PAC. We performed a prospective study of patients undergoing simultaneous transthoracic echocardiography and right heart catheterization (RHC) for various clinical indications. Measurements of the RVOT VTI/PASP ratio from echocardiographic measurements were compared against PAC calculated from RHC measurements. Correlation coefficients and Bland-Altman analysis compared the RVOT VTI/PASP ratio with PAC. Forty-five subjects were enrolled, 38% were female and mean age was 54 years (SD 13 years). The reason for referral to RHC was most commonly post-heart transplant surveillance (40%), followed by heart failure (22%), and pulmonary hypertension (18%). Pre-capillary pulmonary hypertension was present in 18%, isolated post-capillary pulmonary hypertension was present in 13%, and combined pre-and post-capillary pulmonary hypertension was present in 29%. The RVOT VTI/PASP ratio was obtainable in the majority of patients (78%), and Pearson's correlation demonstrated moderately-strong association between PAC and the RVOT VTI/PASP ratio, r = 0.75 (P < 0.001). Bland-Altman analysis demonstrated good agreement between measurements without suggestion of systematic bias and a mean difference in standardized units of - 0.133. In a diverse population of patients and hemodynamic profiles, we validated that the ratio of RVOT VTI/PASP to be a reliably-obtained non-invasive marker associated with PAC.

Bergeyella cardium: Clinical Characteristics and Draft Genome of an Emerging Pathogen in Native and Prosthetic Valve Endocarditis.

Bergeyella cardium is a new species in the family Flavobacteriaceae that was recently described in 3 cases of native valve infective endocarditis. We report the first case of B. cardium prosthetic valve endocarditis, provide the first draft genome of this species, and review the microbiologic characteristics of this emerging pathogen.

Long-term Clinical Outcomes and Biomarker Analyses of Atezolizumab Therapy for Patients With Metastatic Triple-Negative Breast Cancer: A Phase 1 Study.

Importance: Atezolizumab (anti-programmed cell death ligand 1 [PD-L1]) is well tolerated and clinically active in multiple cancer types. Its safety and clinical activity in metastatic triple-negative breast cancer (mTNBC) has not been reported. Objective: To evaluate the safety, clinical activity, and biomarkers associated with the use of single-agent atezolizumab in patients with mTNBC. Design, Setting, and Participants: Women with mTNBC (defined by investigator assessment) were enrolled between January 2013 and February 2016 in a multicohort open-label, phase 1 study at US and European academic medical centers. Median follow-up was 25.3 months (range, 0.4-45.6 months). Eligible patients regardless of line of therapy had measurable disease by Response Evaluation Criteria in Solid Tumors, version 1.1; Eastern Cooperative Oncology Group performance status of 0 to 1; and a representative tumor sample for assessment of immune cell (IC) PD-L1 expression. Interventions: Atezolizumab was given intravenously every 3 weeks until unacceptable toxic effects or loss of clinical benefit. Main Outcomes and Measures: Primary outcome was safety and tolerability. Activity and exploratory outcomes included objective response rate (ORR), duration of response, progression-free survival (PFS), and overall survival (OS). Outcomes were assessed in all patients and in key patient subgroups. Results: Among 116 evaluable patients (median age, 53 years [range, 29-82 years]), treatment-related adverse events occurred in 73 (63%); 58 (79%) were grade 1 to 2. Most adverse events occurred within the first treatment year. The ORRs were numerically higher in first-line (5 of 21 [24%]) than in second-line or greater patients (6 of 94 [6%]). Median duration of response was 21 months (range, 3 to ≥38 months). Median PFS was 1.4 (95% CI, 1.3-1.6) months by RECIST and 1.9 (95% CI, 1.4-2.5) months by irRC. In first-line patients, median OS was 17.6 months (95% CI, 10.2 months to not estimable). Patients with PD-L1 expression of at least 1% tumor-infiltrating ICs had higher ORRs and longer OS (12% [11 of 91]; 10.1 [95% CI, 7.0-13.8] months, respectively) than those with less than 1% ICs (0 of 21; 6.0 [95% CI, 2.6-12.6] months, respectively). High levels of ICs (>10%) were independently associated with higher ORRs and longer OS. Conclusions and Relevance: Single-agent atezolizumab was well tolerated and provided durable clinical benefit in patients with mTNBC with stable or responding disease and in earlier lines of treatment. Trial Registration: ClinicalTrials.gov identifier: NCT01375842.

Seamless Designs: Current Practice and Considerations for Early-Phase Drug Development in Oncology.

Traditionally, drug development has evaluated dose, safety, activity, and comparative benefit in a sequence of phases using trial designs and endpoints specifically devised for each phase. Innovations in drug development seek to consolidate the phases and rapidly expand accrual with "seamless" trial designs. Although consolidation and rapid accrual may yield efficiencies, widespread use of seamless first-in-human (FiH) trials without careful consideration of objectives, statistical analysis plans, or trial oversight raises concerns. A working group formed by the National Cancer Institute convened to consider and discuss opportunities and challenges for such trials as well as encourage responsible use of these designs. We reviewed all abstracts presented at American Society of Clinical Oncology annual meetings from 2010 to 2017 for FiH trials enrolling at least 100 patients. We identified 1786 early-phase trials enrolling 57 559 adult patients. Fifty-one of the trials (2.9%) investigated 50 investigational new drugs, were seamless, and accounted for 14.6% of the total patients. The seamless trials included a median of 3 (range = 1-13) expansion cohorts. The overall risk of clinically significant treatment-related adverse events (grade 3-4) was 49.1% (range = 0.0-100%), and seven studies reported at least one toxic death. Rapid expansion of FiH trials may lead to earlier drug approval and corresponding widespread patient access to active therapeutics. Nevertheless, seamless designs must adhere to established ethical, scientific, and statistical standards. Protocols should include prospectively planned analyses of efficacy in disease- or biomarker-defined cohorts of sufficient rigor to support accelerated approval.

Clinical activity and safety of atezolizumab in patients with recurrent glioblastoma.

PURPOSE: Glioblastoma is the most common primary malignant brain tumor. No standard treatment exists for recurrent disease. Glioblastoma is associated with an immunosuppressive tumor microenvironment. Immune checkpoint inhibitors, including atezolizumab (anti-programmed death-ligand 1), have demonstrated clinical activity in various cancers. Here, we present the safety and efficacy of atezolizumab in patients with glioblastoma from the phase 1a PCD4989g clinical trial (NCT01375842). METHODS: Eligible patients had confirmed recurrent glioblastoma and measurable disease per RANO criteria. Atezolizumab (1200 mg) was administered intravenously every 3 weeks until progression or unacceptable toxicity. Patients were monitored for safety; response was evaluated at least every 6 weeks. Baseline biomarkers were evaluated. RESULTS: All 16 patients enrolled had received prior chemotherapy, and 50% prior bevacizumab. Ten patients (63%) experienced a treatment-related event. No treatment-related grade 4-5 events were reported. All deaths occurred due to progression or during follow-up. One patient experienced a partial response (5.3 months); 3 experienced disease stabilization. The median overall survival was 4.2 months (range 1.2 to 18.8+ months). Association between peripheral CD4+ T cells and efficacy was observed. Two patients with IDH1-mutant tumors and 1 with a POLE-mutant tumor experienced ≥ 16 months survival. CONCLUSIONS: Atezolizumab was safe and well tolerated in this group of patients with recurrent glioblastoma. Our preliminary findings suggest that biomarkers, including peripheral CD4+ T cells and hypermutated tumor status, may help guide selection of patients with recurrent glioblastoma who might receive most benefit from atezolizumab therapy, supporting further atezolizumab combination studies in glioblastoma.

Safety and clinical activity of atezolizumab monotherapy in metastatic non-small-cell lung cancer: final results from a phase I study.

INTRODUCTION: Atezolizumab, an anti-programmed death-ligand 1 (PD-L1) antibody, inhibits PD-L1:PD-1 and PD-L1:B7.1 interactions, restoring anticancer immunity. Here, we report final analyses from the non-small-cell lung cancer (NSCLC) cohort of the first atezolizumab phase I study. METHODS: Patients with NSCLC received atezolizumab 1-20 mg/kg or 1200 mg intravenously every 3 weeks. Baseline PD-L1 expression on tumour cells (TCs) and tumour-infiltrating immune cells (ICs) was assessed (VENTANA SP142 immunohistochemistry assay). Exploratory subgroup analyses investigated responses by baseline PD-L1 expression and oncogenic mutational status. RESULTS: Eighty-nine patients, 98% of whom had received previous systemic therapy, were evaluable for safety and antitumour activity. Atezolizumab was well tolerated, with grade III/IV treatment-related adverse events (TRAEs) observed in 10 patients (11%). All-grade TRAEs occurring in >10% of patients were fatigue, nausea and decreased appetite; grade III/IV TRAEs occurring in >2% of patients were fatigue, dyspnoea, hyponatremia and hypoxia. One patient died from treatment-unrelated pneumonia. Objective response rate (ORR) was 50% (95% confidence interval [CI], 28%-72%), 33% (20%-48%), 29% (18%-41%) and 11% (1%-35%) for the TC3 or IC3, TC2/3 or IC2/3, TC1/2/3 or IC1/2/3 and TC0 and IC0 subgroups, respectively. All-patient ORR was 23% (95% CI, 14%-33%). Median duration of response was 16.4 months (range, 7.2-53.4+). One-, 2-, and 3-year survival rates were 63% (95% CI, 53%-73%), 37% (26%-47%) and 28% (18%-38%), respectively. CONCLUSIONS: Single-agent atezolizumab was well tolerated with long-term clinical benefits, including durable responses and survival, in pretreated NSCLC. Improved responses and survival rates were seen with increasing baseline PD-L1 expression. CLINICALTRIALS. GOV IDENTIFIER: NCT01375842.

Validity of self-reported adult secondhand smoke exposure.

OBJECTIVES: Exposure of adults to secondhand smoke (SHS) has immediate adverse effects on the cardiovascular system and causes coronary heart disease. The current study evaluated brief self-report screening measures for accurately identifying adult cardiology patients with clinically significant levels of SHS exposure in need of intervention. DESIGN AND SETTING: A cross-sectional study conducted in a university-affiliated cardiology clinic and cardiology inpatient service. PATIENTS: Participants were 118 non-smoking patients (59% male, mean age=63.6 years, SD=16.8) seeking cardiology services. MAIN OUTCOME MEASURES: Serum cotinine levels and self-reported SHS exposure in the past 24 h and 7 days on 13 adult secondhand exposure to smoke (ASHES) items. RESULTS: A single item assessment of SHS exposure in one's own home in the past 7 days was significantly correlated with serum cotinine levels (r=0.41, p<0.001) with sensitivity ≥75%, specificity >85% and correct classification rates >85% at cotinine cut-off points of >0.215 and >0.80 ng/mL. The item outperformed multi-item scales, an assessment of home smoking rules, and SHS exposure assessed in other residential areas, automobiles and public settings. The sample was less accurate at self-reporting lower levels of SHS exposure (cotinine 0.05-0.215 ng/mL). CONCLUSIONS: The single item ASHES-7d Home screener is brief, assesses recent SHS exposure over a week's time, and yielded the optimal balance of sensitivity and specificity. The current findings support use of the ASHES-7d Home screener to detect SHS exposure and can be easily incorporated into assessment of other major vital signs in cardiology.

Portrait of a leader in immunotherapeutics.

It's the question that every grade school kid has to answer at some point or another--"What do you want to be when you grow up?" My mom still has the second grade paper on which I first wrote down that I wanted to be a "physician scientist." I'm quite certain that I probably didn't know exactly what a physician scientist was at the time. I certainly didn't know any physician scientists personally, nor was I exposed to academic environments in the tiny Minnesota town in which I grew up. All I'm certain of, was at that time, I liked reading about science. Unfortunately, I soon came to know the medical profession all too personally.

Myocardial stress and hypertrophy: a complex interface between biophysics and cardiac remodeling.

Pressure and volume overload results in concentric and eccentric hypertrophy of cardiac ventricular chambers with, respectively, parallel and series replication of sarcomeres. These divergent patterns of hypertrophy were related 40 years ago to disparate wall stresses in both conditions, with systolic wall stress eliciting parallel replication of sarcomeres and diastolic wall stress, series replication. These observations are relevant to clinical practice, as they relate to the excessive hypertrophy and contractile dysfunction regularly observed in patients with aortic stenosis. Stress-sensing mechanisms in cardiomyocytes and activation of cardiomyocyte death by elevated wall stress continue to intrigue cardiovascular scientists.

Sca-1+ cardiosphere-derived cells are enriched for Isl1-expressing cardiac precursors and improve cardiac function after myocardial injury.

BACKGROUND: Endogenous cardiac progenitor cells are a promising option for cell-therapy for myocardial infarction (MI). However, obtaining adequate numbers of cardiac progenitors after MI remains a challenge. Cardiospheres (CSs) have been proposed to have cardiac regenerative properties; however, their cellular composition and how they may be influenced by the tissue milieu remains unclear. METHODOLOGY/PRINCIPAL FINDING: Using "middle aged" mice as CSs donors, we found that acute MI induced a dramatic increase in the number of CSs in a mouse model of MI, and this increase was attenuated back to baseline over time. We also observed that CSs from post-MI hearts engrafted in ischemic myocardium induced angiogenesis and restored cardiac function. To determine the role of Sca-1(+)CD45(-) cells within CSs, we cloned these from single cell isolates. Expression of Islet-1 (Isl1) in Sca-1(+)CD45(-) cells from CSs was 3-fold higher than in whole CSs. Cloned Sca-1(+)CD45(-) cells had the ability to differentiate into cardiomyocytes, endothelial cells and smooth muscle cells in vitro. We also observed that cloned cells engrafted in ischemic myocardium induced angiogenesis, differentiated into endothelial and smooth muscle cells and improved cardiac function in post-MI hearts. CONCLUSIONS/SIGNIFICANCE: These studies demonstrate that cloned Sca-1(+)CD45(-) cells derived from CSs from infarcted "middle aged" hearts are enriched for second heart field (i.e., Isl-1(+)) precursors that give rise to both myocardial and vascular tissues, and may be an appropriate source of progenitor cells for autologous cell-therapy post-MI.

Newborn screening for severe combined immunodeficiency; the Wisconsin experience (2008-2011).

Severe combined immunodeficiency is a life-threatening primary immune deficiency characterized by low numbers of naïve T cells. Early diagnosis and treatment of this disease decreases mortality. In 2008, Wisconsin began newborn screening of infants for severe combined immunodeficiency and other forms of T-cell lymphopenia by the T-cell receptor excision circle assay. In total, 207,696 infants were screened. Seventy-two infants had an abnormal assay. T-cell numbers were normal in 38 infants, abnormal in 33 infants, and not performed in one infant, giving a positive predictive value for T-cell lymphopenia of any cause of 45.83% and a specificity of 99.98%. Five infants with severe combined immunodeficiency/severe T-cell lymphopenia requiring hematopoietic stem cell transplantation or other therapy were detected. In summary, the T-cell receptor excision circle assay is a sensitive and specific test to identify infants with severe combined immunodeficiency and severe T-cell lymphopenia that leads to life-saving therapies such as hematopoietic stem cell transplantation prior to the acquisition of severe infections.

Granzyme B regulates antiviral CD8+ T cell responses.

CTLs and NK cells use the perforin/granzyme cytotoxic pathway to kill virally infected cells and tumors. Human regulatory T cells also express functional granzymes and perforin and can induce autologous target cell death in vitro. Perforin-deficient mice die of excessive immune responses after viral challenges, implicating a potential role for this pathway in immune regulation. To further investigate the role of granzyme B in immune regulation in response to viral infections, we characterized the immune response in wild-type, granzyme B-deficient, and perforin-deficient mice infected with Sendai virus. Interestingly, granzyme B-deficient mice, and to a lesser extent perforin-deficient mice, exhibited a significant increase in the number of Ag-specific CD8(+) T cells in the lungs and draining lymph nodes of virally infected animals. This increase was not the result of failure in viral clearance because viral titers in granzyme B-deficient mice were similar to wild-type mice and significantly less than perforin-deficient mice. Regulatory T cells from WT mice expressed high levels of granzyme B in response to infection, and depletion of regulatory T cells from these mice resulted in an increase in the number of Ag-specific CD8(+) T cells, similar to that observed in granzyme B-deficient mice. Furthermore, granzyme B-deficient regulatory T cells displayed defective suppression of CD8(+) T cell proliferation in vitro. Taken together, these results suggest a role for granzyme B in the regulatory T cell compartment in immune regulation to viral infections.

Cardiology Rx for Change: improving clinical attention to tobacco use and secondhand smoke exposure in cardiology.

BACKGROUND: Heart disease is the leading cause of tobacco-related death in smokers and of deaths due to secondhand smoke (SHS) exposure in nonsmokers. This study centers on the development and evaluation of an evidence-based model curriculum for improving clinical attention to tobacco use and SHS exposure in cardiology. HYPOTHESIS: We hypothesized that the curriculum would be associated with improvements in clinician tobacco-related knowledge, attitudes, confidence, and counseling behaviors from pre-to post-training and at the 3-month follow-up. METHODS: The 1-hour Cardiology Rx for Change curriculum was evaluated with 22 cardiology fellows and 77 medical residents with consistent training effects observed between the 2 groups. RESULTS: Trainees' tobacco treatment knowledge increased significantly from pre- to post-training (t[81] = 6.51, P<0.001), and perceived barriers to providing cessation treatment decreased significantly (t[81] = -3.97, P<0.001). The changes, however, were not sustained at the 3-month follow-up, suggesting the need for booster training efforts. From pretraining to 3-month follow-up, the training was associated with significant sustained gains in clinician confidence for treating tobacco dependence (t[61] = 3.69, P = 0.001) and with improvements in clinicians assessing patients' readiness to quit smoking (from 61% to 79%, t[59] = 3.69,P<0.001) and providing assistance with quitting (from 47% to 59%, t[59] = 2.12, P = 0.038). Asking patients about tobacco use, advising cessation, and arranging follow-up also increased over time, but not significantly. All participants (100%) recommended the curriculum for dissemination to other training programs. CONCLUSIONS: Available online via http://rxforchange.ucsf.edu, Cardiology Rx for Change offers a packaged training tool for improving treatment of tobacco use and SHS exposure in cardiology care.

Efficacy, safety, and pharmacokinetics of a 10% liquid immune globulin preparation (GAMMAGARD LIQUID, 10%) administered subcutaneously in subjects with primary immunodeficiency disease.

A multi-center, prospective, open-label study was conducted in primary immunodeficiency disease patients to determine the tolerability and pharmacokinetics of a 10% liquid IgG preparation administered subcutaneously. Forty-nine subjects (3-77 years old) were enrolled. Pharmacokinetic equivalence of subcutaneous treatment was achieved at a median dose of 137% of the intravenous dose, with a mean trough IgG level of 1,202 mg/dL at the end of the assessment period. The overall infection rate during subcutaneous treatment was 4.1 per subject-year. Three acute serious bacterial infections were reported, resulting in a rate of 0.067 per subject-year. A low overall rate of temporally associated adverse events (8%), and a very low rate of infusion site adverse events (2.8%), was seen at volumes up to 30 mL/site and rates ≤ 30 mL/h/site. Thus, subcutaneous replacement therapy with a 10% IgG preparation proved effective, safe and well-tolerated in our study population of subjects with primary immunodeficiency disease.

Advanced Donor Age Impairs Bone Marrow Cell Therapeutic Efficacy for Cardiac Disease.

Therapeutic results of clinical autologous bone marrow cell (BMC) therapy trials for cardiac disease have been modest compared to results of BMC implantation into rodent hearts post-myocardial infarction (MI). In clinical trials, autologous BMCs are typically harvested from older patients who have recently suffered an MI. In contrast, experimental studies in rodent models typically utilize donor BMCs isolated from young, healthy, inbred mice that are not the recipients. Using unfractionated BMCs from donor mice at ages of young, middle-aged, and old, we discovered that recipient left ventricular function post-MI was significantly improved by young donor BMC implantation but was only preserved by middle-aged donor BMCs. Notably, old donor BMCs did not slow the decline in recipient post-MI cardiac function, suggesting BMC impairment by advanced donor age. Furthermore, we also show here that BMCs that are therapeutically impaired by donor age can be further impaired by concurrent donor MI. In conclusion, our findings suggest that therapeutic impairment of BMCs by advanced age is one of the important factors that can limit the success of clinical autologous BMC-based therapy.

Timing of bone marrow cell therapy is more important than repeated injections after myocardial infarction.

BACKGROUND: Bone marrow cell treatment has been proposed as a therapy for myocardial infarction, but the optimal timing and number of injections remain unknown. METHODS: Myocardial infarction was induced in mice followed by ultrasound-guided injection of mouse bone marrow cells at different time points post myocardial infarction (Days 3, 7, and 14) as monotherapy and at Days 3+7 as "double" therapy and at Days 3+7+14 as "triple" therapy. Controls received saline injections at Day 3 and Days 3+7+14. Left ventricular ejection fraction was evaluated post myocardial infarction prior to any therapy and at Day 28. Hearts were analyzed at Day 28 for infarct size and survival of donor cells. RESULTS: Left ventricular ejection fraction decreased from 55.3±0.9% to 37.6±0.6% (P<.001) 2 days post myocardial infarction in all groups. Injection of bone marrow cells at Day 3 post myocardial infarction resulted in smaller infarct size (17.8±3.6% vs. 36.6±7.1%; P=.05) and improved LV function (left ventricular ejection fraction 40.3±2.0% vs. 31.1±8.3%; P<.05) compared to control. However, delayed therapy at Day 7 or 14 did not. Multiple injections of bone marrow cells, either double therapy or triple therapy, did not result in reduction in infarct size, but led to improvements in left ventricular ejection fraction at Day 28 compared to control (39.9±3.6% and 38.8±5.5% vs. 34.8±5.3%; all P<.05). The number of donor cells surviving at Day 28 did not correlate with improvement in left ventricular ejection fraction. CONCLUSIONS: Injection of bone marrow cells at Day 3 reduced infarct size and improved left ventricular function. Multiple injections of bone marrow cells had no additive effect. Delaying cell therapy post myocardial infarction resulted in no functional benefit at all. These results will help inform future clinical trials.

Cytokine combination therapy with erythropoietin and granulocyte colony stimulating factor in a porcine model of acute myocardial infarction.

PURPOSE: Erythropoietin (EPO) and granulocyte colony stimulating factor (GCSF) have generated interest as novel therapies after myocardial infarction (MI), but the effect of combination therapy has not been studied in the large animal model. We investigated the impact of prolonged combination therapy with EPO and GCSF on cardiac function, infarct size, and vascular density after MI in a porcine model. METHODS: MI was induced in pigs by a 90 min balloon occlusion of the left anterior descending coronary artery. 16 animals were treated with EPO+GCSF, or saline (control group). Cardiac function was assessed by echocardiography and pressure-volume measurements at baseline, 1 and 6 weeks post-MI. Histopathology was performed 6 weeks post-MI. RESULTS: At week 6, EPO+GCSF therapy stabilized left ventricular ejection fraction, (41 ± 1% vs. 33 ± 1%, p < 0.01) and improved diastolic function compared to the control group. Histopathology revealed increased areas of viable myocardium and vascular density in the EPO+GCSF therapy, compared to the control. Despite these encouraging results, in a historical analysis comparing combination therapy with monotherapy with EPO or GCSF, there were no significant additive benefits in the LVEF and volumes overtime using the combination therapy. CONCLUSION: Our findings indicate that EPO+GCSF combination therapy promotes stabilization of cardiac function after acute MI. However, combination therapy does not seem to be superior to monotherapy with either EPO or GCSF.

Impact of trough IgG on pneumonia incidence in primary immunodeficiency: A meta-analysis of clinical studies.

Primary immunodeficiency disease (PIDD) associated with hypogammaglobulinemia is typically treated with immunoglobulin replacement therapy. When administered as intravenous immunoglobulin (IVIG), an IgG trough occurs prior to the next replacement dose. While frequently measured, IgG trough levels required to minimize infection risk are not established. To address this question, all available studies evaluating trough IgG and pneumonia incidence in PIDD patients with hypogammaglobulinemia receiving IVIG were quantitatively combined by meta-analysis. Seventeen studies with 676 total patients and 2,127 patient-years of follow-up were included. Pneumonia incidence declined by 27% with each 100mg/dL increment in trough IgG (incidence rate ratio, 0.726; 95% confidence interval, 0.658-0.801). Pneumonia incidence with maintenance of 500 mg/dL IgG trough levels (0.113 cases per patient-year) was 5-fold that with 1000 mg/dL (0.023 cases per patient-year). This meta-analysis provides evidence that pneumonia risk can be progressively reduced by higher trough IgG levels up to at least 1000 mg/dL.

Nitric oxide synthase expression and functional response to nitric oxide are both important modulators of circulating angiogenic cell response to angiogenic stimuli.

OBJECTIVE: Circulating angiogenic cells (CACs), also termed endothelial progenitor cells, play an integral role in vascular repair and are functionally impaired in coronary artery disease (CAD). The role of nitric oxide (NO) in CAC function is poorly understood. We hypothesized that CAC migration toward angiogenic signals is modulated by both NO synthase (NOS) expression and functional response to NO. METHODS AND RESULTS: Similar to endothelial cells, CAC chemotaxis to vascular endothelial growth factor (VEGF) was blocked by inhibition of NOS, phosphatidylinositol 3-kinase, or guanylyl cyclase or by treatment with an NO scavenger. Addition of an NO donor (S-nitroso-N-acetylpenicillamine) and the NOS substrate l-arginine increased random cell migration (chemokinesis) and enhanced VEGF-dependent chemotaxis. Healthy CACs expressed endothelial NOS, but endothelial NOS was not detected in CAD patient CACs. Both chemokinesis and chemotaxis to VEGF of patient CACs were decreased compared with healthy CACs but were restored to healthy values by S-nitroso-N-acetylpenicillamine. In parallel, CAD patients exhibited lower flow-mediated vasodilation and plasma NO source nitrite than young, healthy subjects, indicating endothelial dysfunction with reduced NO bioavailability. CONCLUSIONS: NOS activity is required for CAC chemotaxis. In CAD patients, impairment of NOS expression and NO bioavailability, rather than response to NO, may contribute to dysfunction of CACs and limit their regenerative capacity.