Bronchoscopic lung volume reduction using tissue engineering principles

Bronchoscopic lung volume reduction (BLVR), a minimally invasive procedure based on tissue engineering principles, was performed in six sheep with papain-induced experimental emphysema (EMPH). Physiologic measurements, at baseline, after generation of EMPH, and at 3 and 9 weeks after BLVR, included lung volumes, diffusing capacity (DL(CO)), pressure-volume relationships for the lung and chest wall, pleural pressures generated during active respiratory muscle contraction, lung resistance and dynamic elastance. The animal model displayed hyperinflation (change in total lung capacity +8%; change in residual volume +66%), reduced DL(CO) (-21%), and elevated airway resistance (+76%) that resembled advanced human EMPH. BLVR was well tolerated without complications, and it reduced lung volumes (change in total lung capacity -16%; change in residual volume -55%) in a pattern that resulted in significant improvements in vital capacity (10%). At autopsy, well-organized, peripheral scars associated with tissue contraction were observed at 33 of the 36 (91%) treated sites. There was no evidence of infection, abscess, or granuloma formation, or allergic reaction. Scar tissue, generated by BLVR, replaced hyperinflated lung, reduced overall lung volume, and improved respiratory function safely and consistently. The BLVR technology employed in this study addresses the limitations identified in our prior attempt at BLVR therapy and appears safe and effective enough to justify a trial in humans.     

A Qualitative Analysis of Job Burnout in Eating Disorder Treatment Providers

Although job burnout is common in mental health care settings, almost no research has examined burnout in eating disorder treatment providers. Using qualitative methodology, this study examined a) perceived contributors of burnout, b) efforts to manage burnout, and c) recommendations for avoiding burnout in a sample of professional eating disorder treatment providers. Recruited via professional organizations, 298 participants completed an online questionnaire designed by the authors. Qualitative responses were coded and grouped into themes. Results indicated that almost all participants worried about their patients' health, which frequently resulted in negative affect (e.g., anxiety, sadness). The most frequently cited contributors to burnout were common characteristics of eating pathology (e.g., chronicity, relapse, symptom severity); patient characteristics (e.g., personality conflict); work-related factors (e.g., time demands); and, financial issues (e.g., inadequate compensation). To avoid burnout, over 90% of participants engaged in self-care behaviors (e.g., exercise, social support). Early-career practitioners were encouraged to utilize supervision, create a work/life balance, engage in self-care, and limit caseloads. These results suggest that supervision and training of eating disorder treatment providers should include burnout management.     

From the Cover: FGF2 is a target and a trigger of epigenetic mechanisms associated with differences in emotionality: Partnership with H3K9me3

Posttranslational modifications of histone tails in chromatin template can result from environmental experiences such as stress and substance abuse. However, the role of epigenetic modifications as potential predisposing factors in affective behavior is less well established. To address this question, we used our selectively bred lines of high responder (bHR) and low responder (bLR) rats that show profound and stable differences in affective responses, with bLRs being prone to anxiety- and depression-like behavior and bHRs prone to addictive behavior. We first asked whether these phenotypes are associated with basal differences in epigenetic profiles. Our results reveal broad between-group differences in basal levels of trimethylated histone protein H3 at lysine 9 (H3K9me3) in hippocampus (HC), amygdala, and nucleus accumbens. Moreover, levels of association of H3K9me3 at Glucocorticoid Receptor (GR) and Fibroblast growth Factor 2 (FGF2) promoters differ reciprocally between bHRs and bLRs in these regions, consistent with these genes’ opposing levels of expression and roles in modulating anxiety behavior. Importantly, this basal epigenetic pattern is modifiable by FGF2, a factor that modulates anxiety behavior. Thus, early-life FGF2, which decreases anxiety, altered the levels of H3K9me3 and its binding at FGF2 and GR promoters of bLRs rendering them more similar to bHRs. Conversely, knockdown of HC FGF2 altered both anxiety behavior and levels of H3K9me3 in bHRs, rendering them more bLR-like. These findings implicate FGF2 as a modifier of epigenetic mechanisms associated with emotional responsiveness, and point to H3K9me3 as a key player in the regulation of affective vulnerability.Chromatin remodeling is a mediator of lasting neural changes in response to experience, such as exposure to stress and drugs of abuse (1–7). Indeed, the interaction of certain modified histones with specific gene promoters has been shown to be an important mechanism of experience-dependent neuroplasticity (8–13). Although numerous studies have examined the impact of the environment on neural epigenetic profiles, relatively few studies have focused on preexisting differences in epigenetic profiles as potential predisposing factors in emotional reactivity. Such studies require the availability of an animal model where difference in “temperament” or propensity for specific affective responses can be reliably predicted and altered. Our laboratory has generated such an animal model that captures vulnerability for “internalizing disorders” vs. “externalizing disorders.” Selectively bred high responder (bHR) rats exhibit greater responsiveness to novelty and to drug seeking behavior (externalizing behaviors), whereas selectively bred low responders (bLR) exhibit greater anxiety and depression-like responses (internalizing behaviors) (14, 15). These genetically bred phenotypes amplify behavioral traits observed in outbred animals (16–20).Several genes have been implicated in modifying these phenotypes, both in the bred and outbred lines (14). In particular, a key gene in stress regulation, the glucocorticoid receptor (GR) showed higher levels of mRNA expression in the hippocampus (HC) of outbred LRs relative to outbred HRs, and has been implicated in increased anxiety behavior in these animals. Thus, administration of a GR antagonist into the HC reduced anxiety behavior in outbred LR rats. Importantly, bLRs also exhibit significantly higher levels of hippocampal GR mRNA compared with bHRs, whereas the mineralocorticoid receptor (MR) showed no differences between the lines (17). Moreover, our mouse genetic studies have demonstrated that GR is an early-life modifier of emotional reactivity, with its overexpression before weaning enhancing anxiety throughout life (21). This then suggests that GR a critical molecular organizer of stable differences in affective reactivity.A countervailing modifier of anxiety behavior is the Fibroblast Growth Factor-2 (FGF2). This molecular organizer plays a critical role in brain development and hippocampal neurogenesis (22, 23). Moreover, FGF2 has been proposed as an endogenous anxiolytic and antidepressant that is depleted in the brain of depressed humans (24, 25). Its direct chronic administration was anxiolytic and antidepressant in rodents (25) and the silencing of endogenous hippocampal FGF2 using short-hairpin RNA increased anxiety-like behavior in outbred rats (26, 27). Our bLRs, which exhibit higher anxiety and depression behaviors, have lower basal levels of FGF2 mRNA in HC and nucleus accumbens (NAcc) (28, 29), and an environmental manipulation during adulthood that decreases anxiety behavior induces FGF2 expression selectively in these bLRs (30). Moreover, early-life FGF2 administration selectively decreases anxiety in bLRs throughout life (28).In the present study, we evaluated the basal levels of various modified histone proteins (H3 and H4) in the HC, amygdala, and NAcc in the bHR and bLR rats. We then focused on a repressive trimethylated histone protein H3 at lysine 9 (H3K9me3) which is one of the most widely studied repressed modified histones (31), and which showed reliable bHR vs. bLR differences. Using chromatin immunoprecipiation (ChIP) assays, we asked whether some of the basal variations in GR and FGF2 expression between the bred lines might be the result of differences in the association of this histone at their promoter. Finally, we asked whether manipulating FGF2 either via early-life administration or via virally mediated knockdown can modify the epigenetic patterns observed in the bred lines.     

Renal tubular protein absorption in the rat

Radioiodinated protein solutions, 20 nl in volume, were injected into surface proximal and distal convoluted tubules of the rat kidney. The unabsorbed fraction was collected in ureteral urine, and the percentage recovered was expressed as a function of the injection site. Recovery increased progressively from more distal sites of injection indicating absorption along the proximal tubule of human serum albumin, insulin, and ribonuclease. Fractional absorption of albumin along the proximal tubule varied from 0 to 20% of the injected load, and was similar when the injectate concentration was 20, 40, or 100 mg/100 ml. Fractional absorption along the proximal tubule of insulin and ribonuclease, smaller proteins, was 30 to 50% of the injected load, and was similar with insulin concentrations of 0.09 mg/100 ml and 40 mg/100 ml and ribonuclease concentration of 40 mg/100 ml. In addition to this constant fractional absorption of each protein in the proximal tubule, smaller amounts were absorbed when injections were made in distal convoluted tubules.     

The relationship of parental overprotection, perceived child vulnerability, and parenting stress to uncertainty in youth with chronic illness

OBJECTIVE: To examine the relationship of parent-reported overprotection (OP), perceived child vulnerability (PCV), and parenting stress (PS) to youth-reported illness uncertainty, and to explore potential developmental differences. METHOD: Eighty-two children and 82 adolescents (n = 164) diagnosed with Type 1 diabetes mellitus (DM1) or asthma, completed a measure of illness uncertainty, while their parents completed measures of OP, PCV, and PS. RESULTS: After controlling for demographic and illness parameters, both PCV and PS significantly predicted youth illness uncertainty in the combined sample. Within the child group, only PS significantly predicted illness uncertainty, whereas only PCV significantly predicted uncertainty for adolescents. CONCLUSION: Specific parenting variables are associated with youth-reported illness uncertainty; however, their relationship varies according to developmental level. Although OP has been identified as a predictor of child psychological outcomes in other studies, it does not appear to be associated with illness uncertainty in youth with DM1 or asthma.     

Dynamic lung mechanics in late-stage emphysema before and after lung volume reduction surgery

This study evaluated the effects of lung volume reduction surgery (LVRS) on the heterogeneity of lung function in awake, late-stage emphysema patients with measurements taken before and after full recovery from LVRS. We assessed standard clinical measures of lung function and functional heterogeneity in six awake, late-stage emphysema patients before and 6 months after LVRS. Functional heterogeneity was quantified by measuring dynamic inspiratory resistance (R(L)(insp)) and elastance (E(L)(insp)) over a frequency range that included normal breathing ( approximately 0.33-8 Hz). Since LVRS involves targeted resection of emphysematous regions of the lung, we hypothesized that emphysema patients would be functionally more homogeneous post-LVRS. We also compared our measures of functional heterogeneity with indices of anatomic heterogeneity and severity using high-resolution computed tomography (HRCT). After LVRS, 6 min walk distance increased by 22% (940+/-91 versus 1158+/-299, p=0.031) and recoil pressure at TLC increased (9.0+/-2.0 versus 14+/-5, p=0.031), but changes in R(L)(insp) and E(L)(insp) varied greatly between subjects. A measure of anatomic severity quantified using HRCT positively correlated with airway resistance (r(s)=0.89, p=0.048). These results suggest that subjects with more severe disease as assessed by HRCT criteria had reduced overall effective airway caliber consequent to active airway constriction, reduced parenchymal tethering, and/or loss of parallel lung units. Furthermore, LVRS may not necessarily improve lung function via a substantial reduction in mechanical heterogeneity.