The re-emerging role of linoleic acid in paediatric asthma

Asthma is the most common chronic disease within the paediatric population. Although it is multifactorial, its onset may be linked to early-life exposures with subsequent impact on immune system development. Microbial and dietary metabolic products have been implicated in the development and exacerbation of paediatric asthma. Linoleic acid is the most common omega-6 polyunsaturated fatty acid in the Western diet. In this review, we summarise the literature regarding the involvement of linoleic acid in the development of and its impact on existing paediatric asthma. First, we summarise the existing knowledge surrounding the relationship between human microbial metabolism and allergic diseases in children. Next, we examine cellular or animal model-based mechanistic studies that investigated the impact of dietary- and microbial-derived linoleic acid metabolites on asthma. Finally, we review the literature investigating the impact of linoleic acid metabolites on the development and exacerbation of childhood asthma. While there is conflicting evidence, there is growing support for a role of linoleic acid in the onset and pathophysiology of asthma. We recommend that additional cellular, animal, and longitudinal studies are performed that target linoleic acid and its metabolites.

Dose-dependent association between inhaled corticosteroid use and risk of obesity and metabolic syndrome in asthma

Background: Inhaled corticosteroids (ICS) are widely prescribed medications. Some studies have reported that ICS may suppress the hypothalamic-pituitary-adrenal axis and induce systemic effects. Objective: To explore the possibility of a dose-dependent association between the long-term use of ICS and the risk of obesity and other markers of metabolic syndrome. Methods: A 5-year retrospective two-arm cohort study explored patients on asthma and not on ICS relative to patients with asthma who were on varying doses of ICS (low, medium, and high) and attributes such as body mass index (BMI) trajectory and prescription of antihypertensive, antidiabetic, and cholesterol-lowering medications. Results: A total of 229 subjects with asthma were in the control cohort, and 215 subjects with asthma were in the ICS cohort. The ICS cohort was subdivided into individuals on low- (n = 88), medium- (n = 107), or high- (n = 20) dose ICS throughout the 5-year study period. For every 1-year increase in time, the BMI in the high-dose ICS group increased at a rate of 0.25 kg/m² when compared with the subjects in the control group after controlling for age and gender. Also, for every 1-year increase in time, the BMI of those on medium-dose ICS increased by 0.06 kg/m² compared with those in the control group after controlling for age and gender. The subjects on ICS also had a statistically increased risk of being prescribed antihypertensive, antidiabetic, and cholesterol-lowering medications. Conclusion: ICS use in the subjects with asthma was associated with a dose-dependent risk of increasing BMI trajectories over time and an increased requirement for antidiabetic and cholesterol-lowering medications. One possible conclusion from this study is that long-term medium- and high-dose ICS have the potential to induce systemic effects.

Mediating Role of Fine Particles Abatement on Pediatric Respiratory Health During COVID-19 Stay-at-Home Order in San Diego County, California

Lower respiratory tract infections disproportionately affect children and are one of the main causes of hospital referral and admission. COVID-19 stay-at-home orders in early 2020 led to substantial reductions in hospital admissions, but the specific contribution of changes in air quality through this natural experiment has not been examined. Capitalizing on the timing of the stay-at-home order, we quantified the specific contribution of fine-scale changes in PM_2.5 concentrations to reduced respiratory emergency department (ED) visits in the pediatric population of San Diego County, California. We analyzed data on pediatric ED visits (n = 72,333) at the ZIP-code level for respiratory complaints obtained from the ED at Rady Children's Hospital in San Diego County (2015-2020) and ZIP-code level PM_2.5 from an ensemble model integrating multiple machine learning algorithms. We examined the decrease in respiratory visits in the pediatric population attributable to the stay-at-home order and quantified the contribution of changes in PM_2.5 exposure using mediation analysis (inverse of odds ratio weighting). Pediatric respiratory ED visits dropped during the stay-at-home order (starting on 19 March 2020). Immediately after this period, PM_2.5 concentrations, relative to the counterfactual values based in the 4-year baseline period, also decreased with important spatial variability across ZIP codes in San Diego County. Overall, we found that decreases in PM_2.5 attributed to the stay-at-home order contributed to explain 4% of the decrease in pediatric respiratory ED visits. We identified important spatial inequalities in the decreased incidence of pediatric respiratory illness and found that brief decline in air pollution levels contributed to a decrease in respiratory ED visits.

Patterns of allergenic food introduction in Los Angeles inner-city children

Background

Early introduction of allergenic foods is recommended to reduce the risk of developing food allergies, but it is unclear whether recommendations are being followed.

Objective

We examine patterns of allergenic food introduction in inner-city children enrolled in an academic pediatric practice in the greater Los Angeles area

Methods

This was a prospective study with patients ages 12 to 24 months recruited from the pediatrics continuity clinic at an inner-city tertiary medical center in the greater Los Angeles area. Caregivers were asked via anonymous surveys about their child’s history of atopic diseases and at what age they first introduced egg, soy, wheat, peanut, tree nuts, fish, shrimp, and shellfish into their child’s diet.

Results

Two hundred caregivers responded to the survey. The average age of introduction of egg was 9.2 months, soy 10 months, wheat 9.3 months, peanut 10.5 months, tree nuts 10.9 months, fish 10.9 months, shrimp 11.3 months, and shellfish 11.5 months. Between ages 4–11 months, 65.3% of children were introduced egg, 19.1% soy, 55.8% wheat, 28.6% peanut, 17.1% tree nuts, 28.1% fish, 13.6% shrimp, and 7.0% shellfish. By age 24 months, 92% of children were introduced egg, 37.7% soy, 85.4% wheat, 67.3% peanut, 47.7% tree nuts, 67.8% fish, 48.2% shrimp, and 30.2% shellfish. Of the 14 children with eczema or egg allergy, 26.1% were introduced peanut by age 4-6 months and 50% by age 4–11 months.

Conclusion

Despite recommendations, inner-city caregivers may not be introducing allergenic foods in a timely manner to their children.

A Perspective on Pediatric Respiratory Outcomes During California Wildfires Due to Smoke and PM2.5 Exposure

As wildfires increase in prevalence and intensity across California and globally, it is anticipated that more children will be exposed to wildfire smoke, and thus face associated adverse health outcomes. Here, we provide a concise summary of the respiratory effects of California's wildfires on pediatric healthcare utilization, examine global examples of wildfire smoke exposure within the pediatric population and associated physiological effects, and assess the efficacy of metrics used to measure and communicate air quality during wildfires within the United States and elsewhere.

Fine Particles in Wildfire Smoke and Pediatric Respiratory Health in California

BACKGROUND AND OBJECTIVES

Exposure to airborne fine particles with diameters ≤2.5 μm (PM_2.5) pollution is a well-established cause of respiratory diseases in children; whether wildfire-specific PM_2.5 causes more damage, however, remains uncertain. We examine the associations between wildfire-specific PM_2.5 and pediatric respiratory health during the period 2011-2017 in San Diego County, California, and compare these results with other sources of PM_2.5.

METHODS

Visits to emergency and urgent care facilities of Rady's Children Hospital network in San Diego County, California, by individuals (aged ≤19 years) with ≥1 of the following respiratory conditions: difficulty breathing, respiratory distress, wheezing, asthma, or cough were regressed on daily, community-level exposure to wildfire-specific PM_2.5 and PM_2.5 from ambient sources (eg, traffic emissions).

RESULTS

A 10-unit increase in PM_2.5 (from nonsmoke sources) was estimated to increase the number of admissions by 3.7% (95% confidence interval: 1.2% to 6.1%). In contrast, the effect of PM_2.5 attributable to wildfire was estimated to be a 30.0% (95% confidence interval: 26.6% to 33.4%) increase in visits.

CONCLUSIONS

Wildfire-specific PM_2.5 was found to be ∼10 times more harmful on children's respiratory health than PM_2.5 from other sources, particularly for children aged 0 to 5 years. Even relatively modest wildfires and associated PM_2.5 resolved on our record produced major health impacts, particularly for younger children, in comparison with ambient PM_2.5.

Screening Social Determinants of Health in a Multidisciplinary Severe Asthma Clinical Program

Supplemental Digital Content is available in the text.

Asthma is the most common cause of chronic disease in children and has high healthcare utilization costs. Minority children living in poverty have a higher asthma burden. These health disparities are associated with the social determinants of health (SDH). A severe asthma clinic was implemented at Rady Children’s Hospital in San Diego to determine whether a multidisciplinary approach, including an asthma home visit addressing SDH, would lead to decreased healthcare utilization in terms of emergency department (ED) visits and hospitalizations.

Estimating Cost-Effectiveness of Confirmatory Oral Food Challenges in the Diagnosis of Children With Food Allergy

Introduction. Food allergies affect 8% of the pediatric population in the United States with an estimated annual cost of US$25 billion. The low specificity of some of the main food allergy tests used in diagnosis may generate false positives incurring unnecessary costs. We examined the cost-effectiveness of oral food challenges (OFC) as confirmatory tests in the diagnosis of food allergy. Methods. We constructed a decision tree with a Markov model comparing the long-term (15 years) cost and effectiveness—in the form of quality-adjusted life years (QALY)—of confirmatory OFCs compared with immediate allergenic food elimination (FE) after a skin prick test or blood immunoglobulin E (IgE) level in children with suspected food allergy. For costs, we included the costs of OFCs and the reported annual costs of having a food allergy, including direct medical costs and costs borne by families. Results. The cost of OFC strategy was $8671 compared with $18 012 for the FE strategy for the length of the model. Also, the OFC strategy had a total QALY of 21.942 compared with 21.740 for the FE strategy. In the OFC strategy, the total cost was $9341 less than FE and the increase in QALY after OFCs led to a 0.202 higher effectiveness in the OFC strategy. Conclusion. In conclusion, our study shows that the confirmatory OFC strategy dominated the FE strategy and that a confirmatory OFC for children, within a year of diagnosis, is a cost-effective strategy that decreases costs and appears to improve quality of life.

Effect of inhaled corticosteroid use on weight (BMI) in pediatric patients with moderate-severe asthma

OBJECTIVES

Assess the relationship between inhaled corticosteroid use (ICS) and weight (BMI) in pediatric patients with moderate-severe asthma. Assess if the number of emergency department (ED) visits correlates with overall BMI trajectory. Assess the trend of prescribing biologic therapy in pediatric patients with moderate-severe asthma and determine its relationship with weight (BMI).

METHODS

A retrospective chart review was performed on 93 pediatric patients with moderate-severe asthma to determine the relationship between ICS use and weight (BMI), biologic therapy and BMI, and number of ED visits and BMI trajectory. A mixed effects model was employed with the correlation between repeated measures accounted for through the random effects.

RESULTS

There is a statistically significant increase of 0.369 kg/m² in BMI trajectory per year in subjects on high-dose steroids compared to an increase of 0.195 kg/m² in the low dose group (p < 0.05). The BMI of subjects initiated on biologic therapy (omalizumab or mepolizumab) had a statistically significant decrease in BMI trajectory of 0.818 kg/m² per year (p < 0.05). Subjects with ≥5 ED visits due to asthma exacerbations had a significantly higher BMI trajectory (p < 0.05).

CONCLUSIONS

The potency of ICS use in pediatric patients with moderate-severe asthma affects BMI trajectory; the higher the dose, the greater the projected BMI increase per year. Initiation of biologic therapy decreased BMI trajectory over time. Lastly, those with frequent ED visits had a higher BMI trend. Future prospective studies are warranted that further evaluate the potential metabolic impacts of ICS and assess the effects of biologic therapy on BMI.

Human immunodeficiency virus type 1 Vpr protein does not modulate surface expression of the CD4 receptor

The CD4 receptor is required for the entry of human immunodeficiency virus (HIV) into target cells. It has long been known that Nef, Env, and Vpu participate in the removal of the viral receptor from the cell surface. Recently, it has been proposed that the HIV type 1 (HIV-1) Vpr protein may also play a role in the downmodulation of CD4 from the surfaces of infected cells (L. Conti, B. Varano, M. C. Gauzzi, P. Matarrese, M. Federico, W. Malorani, F. Belardelli, and S. Gessani, J. Virol. 74:10207-10211, 2000). To investigate the possible role of Vpr in the downregulation of the viral receptor Vpr alleles from HIV-1 and simian immunodeficiency virus were transiently expressed in transformed T cells and in 293T fibroblasts, and their ability to modulate surface CD4 was evaluated. All Vpr alleles efficiently arrested cells in the G(2) stage of the cell cycle. However, none of the tested Vpr proteins altered the expression of CD4 on the cell surface. In comparison, HIV-1 Nef efficiently downmodulated surface CD4 in all the experimental settings. Transformed T cells and primary lymphocytes were challenged with wild-type, Nef-defective, and Vpr-defective viruses. A significant reduction in the HIV-induced downmodulation of surface CD4 was observed in viruses lacking Nef. However, Vpr-deletion-containing viruses showed no defect in their ability to remove CD4 from the surfaces of infected cells. Our results indicate that Vpr does not play a role in the HIV-induced downmodulation of the CD4 receptor.

Pretreatment nomogram for predicting freedom from recurrence after permanent prostate brachytherapy in prostate cancer

OBJECTIVES

To develop a prognostic nomogram to predict the freedom from recurrence for patients treated with permanent prostate brachytherapy for localized prostate cancer.

METHODS

We performed a retrospective analysis of 920 patients treated with permanent prostate brachytherapy between 1992 and 2000. The clinical parameters included clinical stage, biopsy Gleason sum, pretreatment prostate-specific antigen (PSA) value, and administration of external beam radiation. Patients who received neoadjuvant androgen deprivation therapy were excluded. Failure was defined as any post-treatment administration of androgen deprivation, clinical relapse, or biochemical failure, defined as three PSA rises. Patients with fewer than three PSA rises were censored at the time of the first PSA rise. Data from two outside institutions served as validation.

RESULTS

A nomogram that predicts the probability of remaining free from biochemical recurrence for 5 years after brachytherapy without adjuvant hormonal therapy was developed using Cox proportional hazards regression analysis. External validation revealed a concordance index of 0.61 to 0.64, and calibration of the nomogram suggested confidence limits of +5% to -30%.

CONCLUSIONS

The pretreatment nomogram we developed may be useful to physicians and patients in estimating the probability of successful treatment 5 years after brachytherapy for clinically localized prostate cancer.

Local detection of prostate cancer by positron emission tomography with 2-fluorodeoxyglucose: comparison of filtered back projection and iterative reconstruction with segmented attenuation correction

BACKGROUND

To compare filtered back projection (FBP) and iterative reconstruction with segmented attenuation correction (IRSAC) in the local imaging of prostate cancer by positron emission tomography with 2-fluorodeoxyglucose (FDG-PET).

METHODS

We retrospectively identified 13 patients with primary (n=7) or recurrent (n=6) prostate cancer who had increased uptake in the prostate on FDG-PET performed without urinary catheterization, contemporaneous biopsy confirming the presence of active tumor in the prostate, and correlative cross-sectional imaging by MRI (n=8) or CT (n=5). FDG-PET images were reconstructed by FBP and IRSAC. Two independent nuclear medicine physicians separately rated FBP and IRSAC images for visualization of prostatic activity on a 4-point scale. Results were compared using biopsy and cross-sectional imaging findings as the standard of reference.

RESULTS

IRSAC images were significantly better that FBP in terms of visualization of prostatic activity in 12 of 13 patients, and were equivalent in 1 patient (p<0.001, Wilcoxon signed ranks test). In particular, 2 foci of tumor activity in 2 different patients seen on IRSAC images were not visible on FBP images. In 11 patients who had a gross tumor mass evident on cross-sectional imaging, there was good agreement between PET and cross-sectional anatomic imaging with respect to tumor localization.

CONCLUSIONS

In selected patients, cancer can be imaged within the prostate using FDG-PET, and IRSAC is superior to FBP in image reconstruction for local tumor visualization.

The definition of biochemical failure in patients treated with definitive radiotherapy

PURPOSE

The American Society for Therapeutic Radiology and Oncology (ASTRO) published a definition for biochemical failure following treatment of prostate cancer. Others have noted difficulties with interpreting this definition and recommended modifications to accommodate special recurrence patterns. We have compared various modifications to the original ASTRO definition on our series of 1213 patients treated with transperineal permanent prostate brachytherapy.

METHODS AND MATERIALS

The ASTRO modifications we considered adjusted for (1) early censoring of nonrecurrent patients with rising prostate-specific antigen levels (PSA), (2) cumulative rather than consecutive rises (without a decrease) as evidence of recurrence, (3) both of the above, and (4) waiting 2 years before data analysis. The Kaplan-Meier method was used to compute the effects on recurrence rate for patients treated with and without neoadjuvant hormones.

RESULTS

With the original ASTRO definition, freedom from recurrence in our series of men who did not receive neoadjuvant hormones was 83% at 4 years. All of the modifications considered had statistically insignificant effects on freedom from recurrence rates, varying from 80% to 83% at 4 years. Patients treated with neoadjuvant hormones also showed very little sensitivity to the recurrence definition employed.

CONCLUSION

Early censoring of equivocal patients and counting cumulative rather than consecutive rises in PSA (without a decrease) had little empiric effect on the ASTRO recurrence rates. However, we favor the addition of both these modifications to the ASTRO definition on conceptual grounds for evaluating patients following any modality (radiation or surgery), whereby a trend over multiple PSA values is used to judge failure.

Towards multidimensional radiotherapy (MD-CRT): biological imaging and biological conformality

PURPOSE

The goals of this study were to survey and summarize the advances in imaging that have potential applications in radiation oncology, and to explore the concept of integrating physical and biological conformality in multidimensional conformal radiotherapy (MD-CRT).

METHODS AND MATERIALS

The advances in three-dimensional conformal radiotherapy (3D-CRT) have greatly improved the physical conformality of treatment planning and delivery. The development of intensity-modulated radiotherapy (IMRT) has provided the "dose painting" or "dose sculpting" ability to further customize the delivered dose distribution. The improved capabilities of nuclear magnetic resonance imaging and spectroscopy, and of positron emission tomography, are beginning to provide physiological and functional information about the tumor and its surroundings. In addition, molecular imaging promises to reveal tumor biology at the genotype and phenotype level. These developments converge to provide significant opportunities for enhancing the success of radiotherapy.

RESULTS

The ability of IMRT to deliver nonuniform dose patterns by design brings to fore the question of how to "dose paint" and "dose sculpt", leading to the suggestion that "biological" images may be of assistance. In contrast to the conventional radiological images that primarily provide anatomical information, biological images reveal metabolic, functional, physiological, genotypic, and phenotypic data. Important for radiotherapy, the new and noninvasive imaging methods may yield three-dimensional radiobiological information. Studies are urgently needed to identify genotypes and phenotypes that affect radiosensitivity, and to devise methods to image them noninvasively. Incremental to the concept of gross, clinical, and planning target volumes (GTV, CTV, and PTV), we propose the concept of "biological target volume" (BTV) and hypothesize that BTV can be derived from biological images and that their use may incrementally improve target delineation and dose delivery. We emphasize, however, that much basic research and clinical studies are needed before this potential can be realized.

CONCLUSIONS

Whereas IMRT may have initiated the beginning of the end relative to physical conformality in radiotherapy, biological imaging may launch the beginning of a new era of biological conformality. In combination, these approaches constitute MD-CRT that may further improve the efficacy of cancer radiotherapy in the new millennium.