Mary Ann O’Riordan

Heightened inflammation is linked to carotid intima-media thickness and endothelial activation in HIV-infected children☆☆☆

OBJECTIVES HIV+ patients are at increased risk of cardiovascular disease (CVD). Inflammation plays a role in adults, but has not yet been assessed in HIV+ children. We compared proinflammatory cytokines and adhesion molecules in HIV+ children versus healthy controls, and assessed their relationship to carotid intima-media thickness (IMT). METHODS Evaluations were performed on 27 HIV+ children and 30 HIV-healthy controls (2-21 years) who were prospectively enrolled in our pediatric cohort. Measurements included internal carotid artery (ICA) and common carotid artery (CCA) IMT, fasting lipids, insulin, proinflammatory markers (TNF-alpha, soluble TNF receptors (sTNFR-I, -II), IL-6, high sensitivity C-reactive protein (hsCRP), myeloperoxidase (MPO)), and adhesion molecules (soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1 (sVCAM-1), von Willebrand factor). RESULTS Among HIV+, mean age was 11 years, 33% males, 70% black. 96% acquired HIV vertically; median CD4 count (CD4%) was 1058 (35%) cells/ml; 96% were on antiretroviral therapy (ART); 70% had HIV-1 RNA <50copies/ml. Groups were similar in age, race, sex, BMI, proinflammatory cytokines, adhesion markers, and carotid IMT except for hsCRP which was higher in HIV+ (P<0.001). In multiple regression analyses, hCRP, age, and female sex were positively associated with IMT. ART duration and sTNFR-II were positively associated with sVCAM-1. CONCLUSIONS This study shows increased hsCRP in HIV+ children compared to healthy controls. As seen in adults, hCRP was associated with carotid IMT, which support a role for inflammation in CVD risk of HIV+ children.

Intrinsic hyperreactivity of mucosal T cells to interleukin-2 in pediatric Crohn’s disease☆☆☆★★★

OBJECTIVES To cells play a crucial role in many chronic inflammatory diseases. Mucosal T cells are particularly important in the pathogenesis of Crohns disease (CD). We investigated the response of T cells in CD and other intestinal inflammatory conditions to interleukin-2 (IL-2), a cytokine essential for T-cell activation, growth, and function. STUDY DESIGN T-cell reactivity was assessed by measuring growth induced by IL-2 in mucosal endoscopic biopsy specimens obtained from children with CD, ulcerative colitis, indeterminate colitis, and chronic nonspecific colitis and from children without gastrointestinal inflammation. RESULTS CD mucosal T cells grew remarkably and significantly more than T cells from normal, ulcerative colitis, and chronic nonspecific colitis mucosa. T cells from indeterminate colitis mucosa grew similarly to those of CD mucosa. The enhanced growth response in CD was independent of disease location, presence or absence of intestinal inflammation, treatment, disease duration, or clinical activity. CONCLUSION Mucosal T cells from children with CD exhibit an intrinsic hyperreactivity to IL-2. This may represent a primary pathogenic abnormality in this condition.

The Relationship between Vitamin D Status and HIV-Related Complications in HIV-infected Children and Young Adults

Background: In HIV-infected adults, we and others have shown that vitamin D deficiency is independently associated with increased carotid intima-media thickness (cIMT), a surrogate marker for cardiovascular disease (CVD). This study explored for the first time the relationship between vitamin D and CVD risk in HIV-infected youth. Methods: This is a cross-sectional assessment of cIMT, inflammation, metabolic markers and vitamin D status in HIV-infected youth and healthy controls. We measured serum 25-hydroxyvitamin D (25(OH)D), fasting lipids, insulin, glucose, inflammatory markers and cIMT. Results: Thirty HIV-infected subjects and 31 controls were included. Among HIV-infected subjects, median age was 11 years (37% males; 73% black; similar to controls). HIV-infected subjects’ mean (standard deviation) serum 25(OH)D was 24 (35) ng/mL; 70% had 25(OH)D <20 ng/mL (deficient), 23% between 20–30 ng/mL (insufficient) and 7% >30 ng/mL (sufficient); proportions were similar to controls (P = 0.17). After adjusting for season, sex and race, there was no difference in serum 25(OH)D between groups (P = 0.11). Serum 25(OH)D was not significantly correlated with cIMT, inflammatory markers or lipids. Serum 25(OH)D was negatively correlated with body mass index, insulin resistance, HIV duration, and cumulative use of antiretroviral therapy, non- and nucleoside reverse transcriptase inhibitors. Conclusions: Most HIV-infected youth have vitamin D deficiency or insufficiency. Despite no direct association between serum 25(OH)D and cIMT, there were notable associations with some CVD risk factors, particularly inverse correlation with insulin resistance. Studies are needed to determine whether CVD risk, including insulin resistance, could be improved with vitamin D supplementation.

Subjective Clinical Lipoatrophy Assessment Correlates with DEXA-Measured Limb Fat

Abstract Objectives: Although physician- and patient-rated diagnoses of lipoatrophy are currently used as a basis for inclusion into clinical trials, few studies have compared physician- or patient-rated lipoatrophy severity with objective measures. We aim to assess the validity of physician- and patient-rated diagnoses of lipoatrophy by evaluating the correlation between clinical assessments of lipoatrophy and objective fat indices. Methods: This cross-sectional study evaluated the association between clinical lipoatrophy scores and DEXA-measured limb fat (n = 154) and subcutaneous fat mitochondrial DNA (mtDNA) levels (n = 80) in HIV+ individuals. Results: There was a signifi cant negative correlation between DEXA-measured limb fat and lipoatrophy scores generated by either the patients (r = –0.27, p = .008) or the physician (r = –0.48, p < .0001). Also, a signifi cant positive correlation was found between the patient-generated lipoatrophy score and the physician score (r = 0.68, p < .0001). However, there was no correlation between fat mtDNA levels and DEXA-measured limb fat (r = –0.09, p = .42) or between physician- or patient-generated lipoatrophy scores (r = –0.09, p = .43, and r = 0.04, p = .71, respectively). Conclusion: These results suggest that physician- and patient-rated lipoatrophy scores may be useful surrogates for more expensive measures of lipoatrophy, which could be reserved for research studies.

Meropenem use and colonization by antibiotic-resistant Gram-negative bacilli in a pediatric intensive care unit.

Objective: The carbapenems are broad-spectrum &bgr;-lactam antibiotics with activity against most organisms encountered in the pediatric intensive care unit (PICU). In anticipation of their increased use in critically ill children, we measured the effect of sustained meropenem use on the pattern of Gram-negative bacillus colonization in patients admitted to a tertiary care PICU. Design: Prospective preintervention/postintervention comparison. Setting: Medical/surgical PICU. Patients: Consecutive PICU admissions over 2.5 yrs. Interventions: After a 6-mo baseline period, all children with serious infections admitted to the PICU during the subsequent 2 yrs were administered meropenem. The incidence of colonization by Gram-negative bacilli resistant to one of a battery of broad-spectrum parenteral agents, and by organisms resistant specifically to meropenem, during the baseline period was compared with the period of preferred meropenem use. Results: During the period of preferred meropenem use, the amount of meropenem used increased >seven-fold, whereas the use of other advanced generation &bgr;-lactams was reduced by nearly 80%. The mean prevalence of colonization by antibiotic-resistant bacilli in general was not statistically altered during the period of meropenem preference (7.3 organisms/100 patient-days, vs. 9.4 organisms/100 patient-days at baseline, p < 0.09). The prevalence of colonization by Gram-negative organisms resistant specifically to meropenem was 0.61 organisms/100 patient-days during the baseline period vs. 1.04 organisms/100 patient-days during the period of meropenem preference (p < 0.30). The incidence of nosocomial infections did not change, and the prevalence of nosocomial infections caused by meropenem-resistant organisms was always <1% of all admissions during the period of meropenem preference. Conclusion: There was no statistically detectable effect on the prevalence of colonization by Gram-negative organisms resistant to one or more classes of broad-spectrum parenteral antibiotics, or to colonization by organisms resistant specifically to meropenem, when meropenem was the preferred antibiotic in a PICU.

Increased Immune Activation and Exhaustion in HIV-infected Youth

Background: Immune activation and exhaustion drive several comorbidities and disease progression in HIV-infected adults; however, they are not well studied in HIV-infected youth. Thus, this study sought to examine levels of immune activation and exhaustion in this population, investigate associated HIV- and non-HIV-related variables and compare results with a matched healthy control group. Methods: HIV-infected youth 8–25 years of age on stable antiretroviral therapy with an HIV-1 RNA level <1000 copies/mL were enrolled, along with matched healthy controls. We measured T-cell and monocyte immune activation and exhaustion markers in cryopreserved peripheral blood mononuclear cell and plasma samples. Results: A total of 136 subjects (80 HIV+: 66% male; 91% black) were enrolled. Markers of CD4+ and CD8+ T-cell activation were higher in the HIV-infected group versus controls [mean % CD4+CD38+HLA-DR+ and CD8+CD38+HLA-DR+ = 2.2 versus 1.5 (P=0.002) and 4.9 versus 2.2 (P<0.0001), respectively], as were exhausted CD4+ and CD8+ T-cells [mean % CD4+CD38+HLA-DR+PD-1+ and CD8+CD38+HLA-DR+PD-1+ = 1.0 versus 0.5 (P<0.0001) and 1.6 versus 0.7 (P<0.0001), respectively]. There were no differences in proportions of inflammatory or patrolling monocytes between groups (P>0.05); however, soluble CD14 was higher in HIV-infected compared with controls (1.6 versus 1.4 µg/mL; P=0.01). Current CD4 count, low-density lipoprotein cholesterol and age were the variables most associated with CD4+ and CD8+ T-cell activation. Conclusions: CD4+ and CD8+ T-cell immune activation and exhaustion are higher in HIV-infected youth compared with matched controls, while monocyte subpopulations are not altered despite a high soluble CD14 level. The clinical significance of the increased immune activation and exhaustion should be further explored.

Low Frequency of Endemic Patient-to-Patient Transmission of Antibiotic-Resistant Gram-Negative Bacilli in a Pediatric Intensive Care Unit

We sought to determine the frequency of horizontal transmission of antibiotic-resistant gram-negative bacilli (ARGNB) in a pediatric intensive care unit during a nonoutbreak period. Among 5,300 admissions over 39 consecutive months, 13 ARGNB clusters involving 35 children were identified by pulsed-filed gel electrophoresis analysis, which suggests that person-to-person transmission was uncommon.

Effects of cholecalciferol supplementation on serum and urinary vitamin D metabolites and binding protein in HIV-infected youth

Vitamin D insufficiency is widespread in HIV-infected patients. HIV and/or antiretroviral therapy (ART), particularly efavirenz (EFV), may interfere with vitamin D metabolism. However, few data from randomized, controlled trials exist. Here, we investigate changes in vitamin D metabolites and binding protein (VDBP) after 6 months of supplementation in a randomized, active-control, double-blind trial investigating 2 different monthly cholecalciferol (vitamin D3) doses [60,000 (medium) or 120,000 (high) IU/month] vs. a control arm of 18,000 IU/month in 8-25year old HIV-infected youth on ART with HIV-1 RNA <1000 copies/mL and baseline 25-hydroxycholecalciferol (25(OH)D3) ≤30ng/mL. A matched healthy uninfected group was enrolled in a similar parallel study for comparison. Changes after 6 months were analyzed as intent-to-treat within/between groups [control group (low dose) vs. combined supplementation doses (medium+high)]. At 6 months, 55% vs. 82% of subjects in control and supplementation groups, respectively, reached 25(OH)D3 ≥30ng/mL (P=0.01) with no difference between medium and high doses (both 82% ≥30ng/mL). There were few differences for those on EFV vs. no-EFV, except serum VDBP decreased in EFV-treated subjects (both within- and between-groups P≤0.01). There were no significant differences between the HIV-infected vs. healthy uninfected groups. The major finding of the present study is that cholecalciferol supplementation (60,000 or 120,000 IU/month) effectively raises serum 25(OH)D3 in the majority of HIV-infected subjects, regardless of EFV use. Notably, response to supplementation was similar to that of uninfected subjects.

Pharmacokinetics, Tolerability and Efficacy of Bolus-Dose vs Continuous-Infusion Granisetron in the Prevention of Vomiting in Patients Undergoing Haematopoietic Stem-Cell Transplantation

AbstractObjective: We compared bolus-infusion with continuous-infusion administration of granisetron antiemetic therapy in patients undergoing haematopoietic stem-cell transplantation. Methods: We evaluated in a double-blind fashion the efficacy and pharmacokinetics of intravenous bolus-dose granisetron (10 µg/kg bodyweight/day) versus continuous-infusion granisetron (10 µg/kg bodyweight infused over 24 hours) in patients undergoing haematopoietic stem-cell transplantation. Antiemetic therapy was begun within 30 minutes of starting chemotherapy and was continued for 2 days after cytotoxic treatment was completed. All patients also received intravenous dexamethasone 10mg every 12 hours during cytotoxic therapy. Haloperidol 2mg intravenously was permitted as rescue therapy in patients who experienced two or more episodes of vomiting within a 24-hour period. Results: Forty-three patients (median age 42 years, range 19 to 65 years) were studied: 24 received bolus-dose and 19 continuous-infusion granisetron. Complete success (no vomiting) was observed in nine patients in the bolus-dose group compared with seven in the continuous-infusion group. Success with rescue antiemetic treatment (haloperidol) was observed in 10 patients in the bolus-dose group compared with three patients in the continuous-infusion group. Failures were noted in five bolus-dose and nine continuous-infusion-treated patients. Granisetron pharmacokinetics were determined in five patients receiving the drug by continuous-infusion and in seven patients after bolus-dose administration. Pharmacokinetic parameter values ranged widely but were similar between the two groups. No relationship between granisetron success or failure and granisetron plasma concentration or pharmacokinetic characteristics was observed. Conclusion: Continuous-infusion granisetron does not appear to possess any antiemetic superiority to bolus-dose administration in the transplant setting.

Mycobactericidal activity of bedaquiline plus rifabutin or rifampin in ex vivo whole blood cultures of healthy volunteers: A randomized controlled trial

Background Bedaquiline, an antimycobacterial agent approved for drug-resistant tuberculosis, is metabolized by CYP3A4, an hepatic enzyme strongly induced by rifampin, an essential part of drug-sensitive tuberculosis treatment. We examined the pharmacokinetic interactions of bedaquiline plus either rifampin or rifabutin in 33 healthy volunteers. This sub-study of that trial examined the mycobactericidal activity of these drugs against intracellular Mycobacterium tuberculosis using ex vivo whole blood culture. Methods Subjects were randomly assigned to receive two single 400 mg doses of bedaquiline, alone, and, after a 4 week washout period, in combination with steady-state daily dosing of either rifabutin 300 mg or rifampin 600 mg. Blood samples were collected prior to dosing and at multiple time points subsequently, to measure plasma drug concentrations and bactericidal activity in ex vivo M tuberculosis-infected whole blood cultures (WBA). Results Single oral doses of bedaquiline produced readily detectable WBA ex vivo, reaching a maximal effect of -0.28 log/day, with negative values indicating bacterial killing. Plasma concentrations of 355 ng/ml were sufficient for intracellular mycobacteriostasis. Combined dosing with rifampin or rifabutin produced maximal effects of -0.91 and -0.79 log/d, respectively. However, the activity of the rifabutin combination was sustained throughout the dosing interval, thereby producing a greater cumulative or total effect. At low drug concentrations, rifabutin plus bedaquiline yielded greater mycobactericidal activity than the sum of their separate effects. Neither drug metabolites nor cellular drug accumulation could account for this observation. Conclusions The combination of rifabutin plus bedaquiline produces sustained intracellular mycobactericidal activity that is greater than the sum of their individual effects. Further studies of the treatment-shortening potential of this combination are warranted.