Cell-state dependent regulation of PPAR γ signaling by ZBTB9 in adipocytes

Adipocytes play a critical role in metabolic homeostasis. Peroxisome proliferator-activated receptor- γ (PPAR γ ) is a nuclear hormone receptor that is a master regulator of adipocyte differentiation and function. ZBTB9 was predicted to interact with PPAR γ based on large-scale protein interaction experiments. In addition, GWAS studies in the type 2 diabetes (T2D) Knowledge Portal revealed associations between Z btb9 and both BMI and T2D risk. Here we show that ZBTB9 positively regulates PPAR γ activity in mature adipocytes. Surprisingly Z btb9 knockdown (KD) also increased adipogenesis in 3T3-L1 cells and human preadipocytes. E2F activity was increased and E2F downstream target genes were upregulated in Zbtb9 -KD preadipocytes. Accordingly, RB phosphorylation, which regulates E2F activity, was enhanced in Zbtb9 -KD preadipocytes. Critically, an E2F1 inhibitor blocked the effects of Zbtb9 deficiency on adipogenic gene expression and lipid accumulation. Collectively, these results demonstrate that Zbtb9 inhibits adipogenesis as a negative regulator of Pparg expression via altered RB-E2F1 signaling. Our findings reveal complex cell-state dependent roles of ZBTB9 in adipocytes, identifying a new molecule that regulates adipogenesis and adipocyte biology as both a positive and negative regulator of PPAR γ signaling depending on the cellular context, and thus may be important in the pathogenesis and treatment of obesity and T2D.

Low-Dose Anti-HIV Drug Efavirenz Mitigates Retinal Vascular Lesions in a Mouse Model of Alzheimer's Disease

A small dose of the anti-HIV drug efavirenz (EFV) was previously discovered to activate CYP46A1, a cholesterol-eliminating enzyme in the brain, and mitigate some of the manifestation of Alzheimer's disease in 5XFAD mice. Herein, we investigated the retina of these animals, which were found to have genetically determined retinal vascular lesions associated with deposits within the retinal pigment epithelium and subretinal space. We established that EFV treatment activated CYP46A1 in the retina, enhanced retinal cholesterol turnover, and diminished the lesion frequency >5-fold. In addition, the treatment mitigated fluorescein leakage from the aberrant blood vessels, deposit size, activation of retinal macrophages/microglia, and focal accumulations of amyloid β plaques, unesterified cholesterol, and Oil Red O-positive lipids. Studies of retinal transcriptomics and proteomics identified biological processes enriched with differentially expressed genes and proteins. We discuss the mechanisms of the beneficial EFV effects on the retinal phenotype of 5XFAD mice. As EFV is an FDA-approved drug, and we already tested the safety of small-dose EFV in patients with Alzheimer's disease, our data support further clinical investigation of this drug in subjects with retinal vascular lesions or neovascular age-related macular degeneration.

PI(3,4)P2-mediated cytokinetic abscission prevents early senescence and cataract formation

[Figure: see text].

eIF2A-knockout mice reveal decreased life span and metabolic syndrome

Eukaryotic initiation factor 2A (eIF2A) is a 65 kDa protein that functions in minor initiation pathways, which affect the translation of only a subset of messenger ribonucleic acid (mRNAs), such as internal ribosome entry site (IRES)-containing mRNAs and/or mRNAs harboring upstream near cognate/non-AUG start codons. These non-canonical initiation events are important for regulation of protein synthesis during cellular development and/or the integrated stress response. Selective eIF2A knockdown in cellular systems significantly inhibits translation of such mRNAs, which rely on alternative initiation mechanisms for their translation. However, there exists a gap in our understanding of how eIF2A functions in mammalian systems in vivo (on the organismal level) and ex vivo (in cells). Here, using an eIF2A-knockout (KO) mouse model, we present evidence implicating eIF2A in the biology of aging, metabolic syndrome and central tolerance. We discovered that eIF2A-KO mice have reduced life span and that eIF2A plays an important role in maintenance of lipid homeostasis, the control of glucose tolerance, insulin resistance and also reduces the abundance of B lymphocytes and dendritic cells in the thymic medulla of mice. We also show the eIF2A KO affects male and female mice differently, suggesting that eIF2A may affect sex-specific pathways. Interestingly, our experiments involving pharmacological induction of endoplasmic reticulum (ER) stress with tunicamycin did not reveal any substantial difference between the response to ER stress in eIF2A-KO and wild-type mice. The identification of eIF2A function in the development of metabolic syndrome bears promise for the further identification of specific eIF2A targets responsible for these changes.

Engineered nasal cartilage for the repair of osteoarthritic knee cartilage defects

[Figure: see text].

Adipocyte-specific deletion of zinc finger protein 407 results in lipodystrophy and insulin resistance in mice

PPARγ deficiency in humans and model organisms impairs the transcriptional control of adipogenesis and mature adipocyte function resulting in lipodystrophy and insulin resistance. Zinc finger protein 407 (ZFP407) positively regulates PPARγ target gene expression and insulin-stimulated glucose uptake in cultured adipocytes. The in vivo physiological role of ZFP407 in mature adipocytes, however, remains to be elucidated. Here we generated adipocyte-specific ZFP407 knockout (AZKO) mice and discovered a partial lipodystrophic phenotype with reduced fat mass, hypertrophic adipocytes in inguinal and brown adipose tissue, and reduced adipogenic gene expression. The lipodystrophy was further exacerbated in AZKO mice fed a high-fat diet. Glucose and insulin tolerance tests revealed decreased insulin sensitivity in AZKO mice compared to control littermates. Cell-based assays demonstrated that ZFP407 is also required for adipogenesis, which may also contribute to the lipodystrophic phenotype. These results demonstrate an essential in vivo role of ZFP407 in brown and white adipose tissue formation and organismal insulin sensitivity.

PACT-mediated PKR activation acts as a hyperosmotic stress intensity sensor weakening osmoadaptation and enhancing inflammation

The inability of cells to adapt to increased environmental tonicity can lead to inflammatory gene expression and pathogenesis. The Rel family of transcription factors TonEBP and NF-κB p65 play critical roles in the switch from osmoadaptive homeostasis to inflammation, respectively. Here we identified PACT-mediated PKR kinase activation as a marker of the termination of adaptation and initiation of inflammation in Mus musculus embryonic fibroblasts. We found that high stress-induced PACT-PKR activation inhibits the interaction between NF-κB c-Rel and TonEBP essential for the increased expression of TonEBP-dependent osmoprotective genes. This resulted in enhanced formation of TonEBP/NF-κB p65 complexes and enhanced proinflammatory gene expression. These data demonstrate a novel role of c-Rel in the adaptive response to hyperosmotic stress, which is inhibited via a PACT/PKR-dependent dimer redistribution of the Rel family transcription factors. Our results suggest that inhibiting PACT-PKR signaling may prove a novel target for alleviating stress-induced inflammatory diseases.

Mitochondrial Dysfunction in Primary Ovarian Insufficiency

Primary ovarian insufficiency (POI) is defined by the loss or dysfunction of ovarian follicles associated with amenorrhea before the age of 40. Symptoms include hot flashes, sleep disturbances, and depression, as well as reduced fertility and increased long-term risk of cardiovascular disease. POI occurs in ∼1% to 2% of women, although the etiology of most cases remains unexplained. Approximately 10% to 20% of POI cases are due to mutations in a single gene or a chromosomal abnormality, which has provided considerable molecular insight into the biological underpinnings of POI. Many of the genes for which mutations have been associated with POI, either isolated or syndromic cases, function within mitochondria, including MRPS22, POLG, TWNK, LARS2, HARS2, AARS2, CLPP, and LRPPRC. Collectively, these genes play roles in mitochondrial DNA replication, gene expression, and protein synthesis and degradation. Although mutations in these genes clearly implicate mitochondrial dysfunction in rare cases of POI, data are scant as to whether these genes in particular, and mitochondrial dysfunction in general, contribute to most POI cases that lack a known etiology. Further studies are needed to better elucidate the contribution of mitochondria to POI and determine whether there is a common molecular defect in mitochondrial function that distinguishes mitochondria-related genes that when mutated cause POI vs those that do not. Nonetheless, the clear implication of mitochondrial dysfunction in POI suggests that manipulation of mitochondrial function represents an important therapeutic target for the treatment or prevention of POI.

Germline USP8 Mutation Associated With Pediatric Cushing Disease and Other Clinical Features: A New Syndrome

BACKGROUND

Somatic mutations in the ubiquitin-specific peptidase 8 (USP8) gene are common in corticotropinomas of children with Cushing disease (CD). We report a unique patient with a germline USP8 mutation who presented with CD and a constellation of other findings that constitute an intriguing genetic syndrome.

CASE DESCRIPTION

We describe a 16-year-old female with CD, developmental delay, dysmorphic features, ichthyosiform hyperkeratosis, chronic lung disease, chronic kidney disease, hyperglycemia, dilated cardiomyopathy with congestive heart failure, and previous history of hyperinsulinism and partial GH deficiency. She was diagnosed with CD at 14 years old and underwent transsphenoidal surgery. Despite initial improvement, she developed recurrent CD.

METHODS

DNA was extracted from peripheral blood and tumor DNA; whole-exome and Sanger confirmatory sequencing were performed. Immunohistochemistry was performed on the resected adenoma.

RESULTS

A de novo germline heterozygous USP8 mutation (c.2155T>C, p.S719P) in the critical 14-3-3 binding motif hot spot locus of the gene was identified in both the peripheral blood and tumor DNA. Histopathologic evaluation of the resected tumor confirmed an ACTH-secreting adenoma.

CONCLUSION

Somatic USP8 mutations are common in adenomas causing CD, but to date, no germline defects have been reported. We describe a patient with a de novo germline USP8 mutation with recurrent CD and multiple other medical problems. This unique patient informs us of the multitude of signaling events that may be controlled by USP8.

Mutations in PIK3C2A cause syndromic short stature, skeletal abnormalities, and cataracts associated with ciliary dysfunction

PIK3C2A is a class II member of the phosphoinositide 3-kinase (PI3K) family that catalyzes the phosphorylation of phosphatidylinositol (PI) into PI(3)P and the phosphorylation of PI(4)P into PI(3,4)P2. At the cellular level, PIK3C2A is critical for the formation of cilia and for receptor mediated endocytosis, among other biological functions. We identified homozygous loss-of-function mutations in PIK3C2A in children from three independent consanguineous families with short stature, coarse facial features, cataracts with secondary glaucoma, multiple skeletal abnormalities, neurological manifestations, among other findings. Cellular studies of patient-derived fibroblasts found that they lacked PIK3C2A protein, had impaired cilia formation and function, and demonstrated reduced proliferative capacity. Collectively, the genetic and molecular data implicate mutations in PIK3C2A in a new Mendelian disorder of PI metabolism, thereby shedding light on the critical role of a class II PI3K in growth, vision, skeletal formation and neurological development. In particular, the considerable phenotypic overlap, yet distinct features, between this syndrome and Lowe’s syndrome, which is caused by mutations in the PI-5-phosphatase OCRL, highlight the key role of PI metabolizing enzymes in specific developmental processes and demonstrate the unique non-redundant functions of each enzyme. This discovery expands what is known about disorders of PI metabolism and helps unravel the role of PIK3C2A and class II PI3Ks in health and disease.

Identifying the genetic basis of rare disorders can provide insight into gene function, susceptibility to disease, guide the development of new therapeutics, improve opportunities for genetic counseling, and help clinicians evaluate and potentially treat complicated clinical presentations. However, it is estimated that the genetic basis of approximately one-half of all rare genetic disorders remains unknown. We describe one such rare disorder based on genetic and clinical evaluations of individuals from 3 unrelated consanguineous families with a similar constellation of features including short stature, coarse facial features, cataracts with secondary glaucoma, multiple skeletal abnormalities, neurological manifestations including stroke, among other findings. We discovered that these features were due to deficiency of the PIK3C2A enzyme. PIK3C2A is a class II member of the phosphoinositide 3-kinase (PI3K) family that catalyzes the phosphorylation of the lipids phosphatidylinositol (PI) into PI(3)P and the phosphorylation of PI(4)P into PI(3,4)P2 that are essential for a variety of cellular processes including cilia formation and vesicle trafficking. This syndrome is the first monogenic disorder caused by mutations in a class II PI3K family member and thus sheds new light on their role in human development.

Mutations in the mitochondrial ribosomal protein MRPS22 lead to primary ovarian insufficiency

Primary ovarian insufficiency (POI) is characterized by amenorrhea and loss or dysfunction of ovarian follicles prior to the age of 40. POI has been associated with autosomal recessive mutations in genes involving hormonal signaling and folliculogenesis, however, the genetic etiology of POI most often remains unknown. Here we report MRPS22 homozygous missense variants c.404G>A (p.R135Q) and c.605G>A (p.R202H) identified in four females from two independent consanguineous families as a novel genetic cause of POI in adolescents. Both missense mutations identified in MRPS22 are rare, occurred in highly evolutionarily conserved residues, and are predicted to be deleterious to protein function. In contrast to prior reports of mutations in MRPS22 associated with severe mitochondrial disease, the POI phenotype is far less severe. Consistent with this genotype-phenotype correlation, mitochondrial defects in oxidative phosphorylation or rRNA levels were not detected in fibroblasts derived from the POI patients, suggesting a non-bioenergetic or tissue-specific mitochondrial defect. Furthermore, we demonstrate in a Drosophila model that mRpS22 deficiency specifically in somatic cells of the ovary had no effect on fertility, whereas flies with mRpS22 deficiency specifically in germ cells were infertile and agametic, demonstrating a cell autonomous requirement for mRpS22 in germ cell development. These findings collectively identify that MRPS22, a component of the small mitochondrial ribosome subunit, is critical for ovarian development and may therefore provide insight into the pathophysiology and treatment of ovarian dysfunction.

Widespread epistasis regulates glucose homeostasis and gene expression

The relative contributions of additive versus non-additive interactions in the regulation of complex traits remains controversial. This may be in part because large-scale epistasis has traditionally been difficult to detect in complex, multi-cellular organisms. We hypothesized that it would be easier to detect interactions using mouse chromosome substitution strains that simultaneously incorporate allelic variation in many genes on a controlled genetic background. Analyzing metabolic traits and gene expression levels in the offspring of a series of crosses between mouse chromosome substitution strains demonstrated that inter-chromosomal epistasis was a dominant feature of these complex traits. Epistasis typically accounted for a larger proportion of the heritable effects than those due solely to additive effects. These epistatic interactions typically resulted in trait values returning to the levels of the parental CSS host strain. Due to the large epistatic effects, analyses that did not account for interactions consistently underestimated the true effect sizes due to allelic variation or failed to detect the loci controlling trait variation. These studies demonstrate that epistatic interactions are a common feature of complex traits and thus identifying these interactions is key to understanding their genetic regulation.

Most complex traits and diseases are regulated by the combined influence of multiple genetic variants. However, it remains controversial whether these genetic variants independently influence complex traits, and therefore the impact of each variant could be simply added together (additivity), or whether the variants work together to influence trait variation, in which case the combined impact of multiple variants would differ from the summed impact of each individual variant (epistasis). In this study in mice, we discovered that the genetic regulation of blood sugar levels and gene expression in the liver were predominantly controlled by non-additive interactions, whereas body weight was predominantly controlled by additive interactions. Remarkably, the expression level of nearly 25% of all genes in the liver was controlled by non-additive interactions. The non-additive interactions typically acted to return trait values to the levels detected in control mice, thus contributing to a reduction in trait variation. We also demonstrated that not accounting for non-additive interactions significantly underestimated the phenotypic effect of a genetic variant on a particular genetic background, suggesting that many previously identified risk loci may have significantly larger effects on disease susceptibility in a subset of individuals. These studies highlight the importance of understanding interactions between genetic variants to better understand disease risk and personalize clinical care.

Coordinated transcriptional control of adipocyte triglyceride lipase (Atgl) by transcription factors Sp1 and peroxisome proliferator-activated receptor γ (PPARγ) during adipocyte differentiation

The breakdown of stored fat deposits into its components is a highly regulated process that maintains plasma levels of free fatty acids to supply energy to cells. Insulin-mediated transcription of Atgl, the enzyme that mediates the rate-limiting step in lipolysis, is a key point of this regulation. Under conditions such as obesity or insulin resistance, Atgl transcription is often misregulated, which can contribute to overall disease progression. The mechanisms by which Atgl is induced during adipogenesis are not fully understood. We utilized computational approaches to identify putative transcriptional regulatory elements in Atgl and then tested the effect of these elements and the transcription factors that bind to them in cultured preadipocytes and mature adipocytes. Here we report that Atgl is down-regulated by the basal transcription factor Sp1 in preadipocytes and that the magnitude of down-regulation depends on interactions between Sp1 and peroxisome proliferator-activated receptor γ (PPARγ). In mature adipocytes, when PPARγ is abundant, PPARγ abrogated transcriptional repression by Sp1 at the Atgl promoter and up-regulated Atgl mRNA expression. Targeting the PPARγ-Sp1 interaction could be a potential therapeutic strategy to restore insulin sensitivity by modulating Atgl levels in adipocytes.

Zinc finger protein 407 overexpression upregulates PPAR target gene expression and improves glucose homeostasis in mice

The peroxisome proliferator-activated receptor (PPAR) family of nuclear receptors is central to the pathophysiology and treatment of metabolic disease through the receptors' ability to regulate the expression of genes involved in glucose homeostasis, adipogenesis, and lipid metabolism. However, the mechanism by which PPAR is regulated remains incompletely understood. We generated a transgenic mouse strain (ZFP-TG) that overexpressed Zfp407 primarily in muscle and heart. Transcriptome analysis by RNA-Seq identified 1,300 differentially expressed genes in the muscle of ZFP-TG mice, among which PPAR target genes were significantly enriched. Among the physiologically important PPARγ target genes, Glucose transporter (Glut)-4 mRNA and protein levels were increased in heart and muscle. The increase in Glut4 and other transcriptional effects of Zfp407 overexpression together decreased body weight and lowered plasma glucose, insulin, and HOMA-IR scores relative to control littermates. When placed on high-fat diet, ZFP-TG mice remained more glucose tolerant than their wild-type counterparts. Cell-based assays demonstrated that Zfp407 synergistically increased the transcriptional activity of all PPAR subtypes, PPARα, PPARγ, and PPARδ. The increased PPAR activity was not associated with increased PPAR mRNA or protein levels, suggesting that Zfp407 posttranslationally regulates PPAR activity. Collectively, these results demonstrate that Zfp407 overexpression improved glucose homeostasis. Thus, Zfp407 represents a new drug target for treating metabolic disease.

Contrasting genetic architectures in different mouse reference populations used for studying complex traits

Quantitative trait loci (QTLs) are being used to study genetic networks, protein functions, and systems properties that underlie phenotypic variation and disease risk in humans, model organisms, agricultural species, and natural populations. The challenges are many, beginning with the seemingly simple tasks of mapping QTLs and identifying their underlying genetic determinants. Various specialized resources have been developed to study complex traits in many model organisms. In the mouse, remarkably different pictures of genetic architectures are emerging. Chromosome Substitution Strains (CSSs) reveal many QTLs, large phenotypic effects, pervasive epistasis, and readily identified genetic variants. In contrast, other resources as well as genome-wide association studies (GWAS) in humans and other species reveal genetic architectures dominated with a relatively modest number of QTLs that have small individual and combined phenotypic effects. These contrasting architectures are the result of intrinsic differences in the study designs underlying different resources. The CSSs examine context-dependent phenotypic effects independently among individual genotypes, whereas with GWAS and other mouse resources, the average effect of each QTL is assessed among many individuals with heterogeneous genetic backgrounds. We argue that variation of genetic architectures among individuals is as important as population averages. Each of these important resources has particular merits and specific applications for these individual and population perspectives. Collectively, these resources together with high-throughput genotyping, sequencing and genetic engineering technologies, and information repositories highlight the power of the mouse for genetic, functional, and systems studies of complex traits and disease models.

Transgenerational inheritance of metabolic disease

Metabolic disease encompasses several disorders including obesity, type 2 diabetes, and dyslipidemia. Recently, the incidence of metabolic disease has drastically increased, driven primarily by a worldwide obesity epidemic. Transgenerational inheritance remains controversial, but has been proposed to contribute to human metabolic disease risk based on a growing number of proof-of-principle studies in model organisms ranging from Caenorhabditis elegans to Mus musculus to Sus scrofa. Collectively, these studies demonstrate that heritable risk is epigenetically transmitted from parent to offspring over multiple generations in the absence of a continued exposure to the triggering stimuli. A diverse assortment of initial triggers can induce transgenerational inheritance including high-fat or high-sugar diets, low-protein diets, various toxins, and ancestral genetic variants. Although the mechanistic basis underlying the transgenerational inheritance of disease risk remains largely unknown, putative molecules mediating transmission include small RNAs, histone modifications, and DNA methylation. Due to the considerable impact of metabolic disease on human health, it is critical to better understand the role of transgenerational inheritance of metabolic disease risk to open new avenues for therapeutic intervention and improve upon the current methods for clinical diagnoses and treatment.

Zinc finger protein 407 (ZFP407) regulates insulin-stimulated glucose uptake and glucose transporter 4 (Glut4) mRNA

The glucose transporter GLUT4 facilitates insulin-stimulated glucose uptake in peripheral tissues including adipose, muscle, and heart. GLUT4 function is impaired in obesity and type 2 diabetes leading to hyperglycemia and an increased risk of cardiovascular disease and neuropathy. To better understand the regulation of GLUT4 function, a targeted siRNA screen was performed and led to the discovery that ZFP407 regulates insulin-stimulated glucose uptake in adipocytes. The decrease in insulin-stimulated glucose uptake due to ZFP407 deficiency was attributed to a reduction in GLUT4 mRNA and protein levels. The decrease in GLUT4 was due to both decreased transcription of Glut4 mRNA and decreased efficiency of Glut4 pre-mRNA splicing. Interestingly, ZFP407 coordinately regulated this decrease in transcription with an increase in the stability of Glut4 mRNA, resulting in opposing effects on steady-state Glut4 mRNA levels. More broadly, transcriptome analysis revealed that ZFP407 regulates many peroxisome proliferator-activated receptor (PPAR) γ target genes beyond Glut4. ZFP407 was required for the PPARγ agonist rosiglitazone to increase Glut4 expression, but was not sufficient to increase expression of a PPARγ target gene reporter construct. However, ZFP407 and PPARγ co-overexpression synergistically activated a PPARγ reporter construct beyond the level of PPARγ alone. Thus, ZFP407 may represent a new modulator of the PPARγ signaling pathway.

Fat depot-specific gene signature and ECM remodeling of Sca1(high) adipose-derived stem cells

Stem cell antigen-1 (Sca1 or Ly6A/E) is a cell surface marker that is widely expressed in mesenchymal stem cells, including adipose-derived stem cells (ASCs). We hypothesized that the fat depot-specific gene signature of Sca1(high) ASCs may play the major role in defining adipose tissue function and extracellular matrix (ECM) remodeling in a depot-specific manner. Herein we aimed to characterize the unique gene signature and ECM remodeling of Sca1(high) ASCs isolated from subcutaneous (inguinal) and visceral (epididymal) adipose tissues. Sca1(high) ASCs are found in the adventitia and perivascular areas of adipose tissues. Sca1(high) ASCs purified with magnetic-activated cell sorting (MACS) demonstrate dendrite or round shape with the higher expression of cytokines and chemokines (e.g., Il6, Cxcl1) and the lower expression of a glucose transporter (Glut1). Subcutaneous and visceral fat-derived Sca1(high) ASCs particularly differ in the gene expressions of adhesion and ECM molecules. While the expression of the major membrane-type collagenase (MMP14) is comparable between the groups, the expressions of secreted collagenases (MMP8 and MMP13) are higher in visceral Sca1(high) ASCs than in subcutaneous ASCs. Consistently, slow but focal MMP-dependent collagenolysis was observed with subcutaneous adipose tissue-derived vascular stromal cells, whereas rapid and bulk collagenolysis was observed with visceral adipose tissue-derived cells in MMP-dependent and -independent manners. These results suggest that the fat depot-specific gene signatures of ASCs may contribute to the distinct patterns of ECM remodeling and adipose function in different fat depots.

Maternal nutrition induces pervasive gene expression changes but no detectable DNA methylation differences in the liver of adult offspring

AIMS

Epidemiological and animal studies have shown that maternal diet can influence metabolism in adult offspring. However, the molecular mechanisms underlying these changes remain poorly understood. Here, we characterize the phenotypes induced by maternal obesity in a mouse model and examine gene expression and epigenetic changes induced by maternal diet in adult offspring.

METHODS

We analyzed genetically identical male mice born from dams fed a high- or low-fat diet throughout pregnancy and until day 21 postpartum. After weaning, half of the males of each group were fed a high-fat diet, the other half a low-fat diet. We first characterized the genome-wide gene expression patterns of six tissues of adult offspring - liver, pancreas, white adipose, brain, muscle and heart. We then measured DNA methylation patterns in liver at selected loci and throughout the genome.

RESULTS

Maternal diet had a significant effect on the body weight of the offspring when they were fed an obesogenic diet after weaning. Our analyses showed that maternal diet had a pervasive effect on gene expression, with a pronounced effect in liver where it affected many genes involved in inflammation, cholesterol synthesis and RXR activation. We did not detect any effect of the maternal diet on DNA methylation in the liver.

CONCLUSIONS

Overall, our findings highlighted the persistent influence of maternal diet on adult tissue regulation and suggested that the transcriptional changes were unlikely to be caused by DNA methylation differences in adult liver.

Thrombospondin 1 mediates high-fat diet-induced muscle fibrosis and insulin resistance in male mice

Thrombospondin 1 (THBS1 or TSP-1) is a circulating glycoprotein highly expressed in hypertrophic visceral adipose tissues of humans and mice. High-fat diet (HFD) feeding induces the robust increase of circulating THBS1 in the early stages of HFD challenge. The loss of Thbs1 protects male mice from diet-induced weight gain and adipocyte hypertrophy. Hyperinsulinemic euglycemic clamp study has demonstrated that Thbs1-null mice are protected from HFD-induced insulin resistance. Tissue-specific glucose uptake study has revealed that the insulin-sensitive phenotype of Thbs1-null mice is mostly mediated by skeletal muscles. Further assessments of the muscle phenotype using RNA sequencing, quantitative PCR, and histological studies have demonstrated that Thbs1-null skeletal muscles are protected from the HFD-dependent induction of Col3a1 and Col6a1, coupled with a new collagen deposition. At the same time, the Thbs1-null mice display a better circadian rhythm and higher amplitude of energy expenditure with a browning phenotype in sc adipose tissues. These results suggest that THBS1, which circulates in response to a HFD, may induce insulin resistance and fibrotic tissue damage in skeletal muscles as well as the de-browning of sc adipose tissues in the early stages of a HFD challenge. Our study may shed new light on the pathogenic role played by a circulating extracellular matrix protein in the cross talk between adipose tissues and skeletal muscles during obesity progression.

The juxtaparanodal proteins CNTNAP2 and TAG1 regulate diet-induced obesity

Despite considerable effort, the identification of genes that regulate complex multigenic traits such as obesity has proven difficult with conventional methodologies. The use of a chromosome substitution strain-based mapping strategy based on deep congenic analysis overcame many of the difficulties associated with gene discovery and led to the finding that the juxtaparanodal proteins CNTNAP2 and TAG1 regulate diet-induced obesity. The effects of a mild Cntnap2 mutation on body weight were highly dependent on genetic background, as both obesity-promoting and obesity-resistant effects of Cntnap2 were observed on different genetic backgrounds. The more severe effect of complete TAG1 deficiency, by decreasing food intake, completely prevented the weight gain normally associated with high-fat-diet feeding. Together, these studies implicate two novel proteins in the regulation of diet-induced obesity. Moreover, as juxtaparanodal proteins have previously been implicated in various neurological disorders, our results suggest a potential genetic and molecular link between obesity and diseases such as autism and epilepsy.

Increased mitochondrial oxidative phosphorylation in the liver is associated with obesity and insulin resistance

Obesity is the result of excess energy intake relative to expenditure, however little is known about why some individuals are more prone to weight gain than others. Inbred strains of mice also vary in their susceptibility to obesity and therefore represent a valuable model to study the genetics and physiology of weight gain and its co-morbidities such as type 2 diabetes. C57BL/6J mice are susceptible to obesity and insulin resistance when fed an obesogenic diet, whereas A/J mice are resistant despite increased caloric intake. Analysis of B6- and A/J-derived chromosome substitution strains and congenic strains revealed a complex genetic and physiological basis for this phenotype. To improve our understanding of the molecular mechanisms underlying susceptibility to metabolic disease we analyzed global gene expression patterns in 6C1 and 6C2 congenic strains. 6C1 is susceptible whereas 6C2 is resistant to diet-induced obesity. In addition, we demonstrate that 6C1 is glucose intolerant and insulin resistant relative to 6C2. Pathway analysis of global gene expression patterns in muscle, adipose, and liver identified expression level differences between 6C1 and 6C2 in pathways related to basal transcription factors, endocytosis, and mitochondrial oxidative phosphorylation (OxPhos). The OxPhos expression differences were subtle but evident in each complex of the electron transport chain and were associated with a marked increase in mitochondrial oxidative capacity in the livers of the obese strain 6C1 relative to the obesity-resistant strain 6C2. These data suggests the importance of hepatic mitochondrial function in the development of obesity and insulin resistance.

Deep congenic analysis identifies many strong, context-dependent QTLs, one of which, Slc35b4, regulates obesity and glucose homeostasis

Although central to many studies of phenotypic variation and disease susceptibility, characterizing the genetic architecture of complex traits has been unexpectedly difficult. For example, most of the susceptibility genes that contribute to highly heritable conditions such as obesity and type 2 diabetes (T2D) remain to be identified despite intensive study. We took advantage of mouse models of diet-induced metabolic disease in chromosome substitution strains (CSSs) both to characterize the genetic architecture of diet-induced obesity and glucose homeostasis and to test the feasibility of gene discovery. Beginning with a survey of CSSs, followed with genetic and phenotypic analysis of congenic, subcongenic, and subsubcongenic strains, we identified a remarkable number of closely linked, phenotypically heterogeneous quantitative trait loci (QTLs) on mouse chromosome 6 that have unexpectedly large phenotypic effects. Although fine-mapping reduced the genomic intervals and gene content of these QTLs over 3000-fold, the average phenotypic effect on body weight was reduced less than threefold, highlighting the "fractal" nature of genetic architecture in mice. Despite this genetic complexity, we found evidence for 14 QTLs in only 32 recombination events in less than 3000 mice, and with an average of four genes located within the three body weight QTLs in the subsubcongenic strains. For Obrq2a1, genetic and functional studies collectively identified the solute receptor Slc35b4 as a regulator of obesity, insulin resistance, and gluconeogenesis. This work demonstrated the unique power of CSSs as a platform for studying complex genetic traits and identifying QTLs.

Ancestral paternal genotype controls body weight and food intake for multiple generations

Current treatments have largely failed to slow the rapidly increasing world-wide prevalence of obesity and its co-morbidities. Despite a strong genetic contribution to obesity (40-70%), only a small percentage of heritability is explained with current knowledge of monogenic abnormalities, common sequence variants and conventional modes of inheritance. Epigenetic effects are rarely tested in humans because of difficulties arranging studies that distinguish conventional and transgenerational inheritance while simultaneously controlling environmental factors and learned behaviors. However, growing evidence from model organisms implicates genetic and environmental factors in one generation that affect phenotypes in subsequent generations. In this report, we provide the first evidence for paternal transgenerational genetic effects on body weight and food intake. This test focused on the obesity-resistant 6C2d congenic strain, which carries the Obrq2a(A/J) allele on an otherwise C57BL/6J background. Various crosses between 6C2d and the control C57BL/6J strain showed that the Obrq2a(A/J) allele in the paternal or grandpaternal generation was sufficient to inhibit diet-induced obesity and reduce food intake in the normally obesity-susceptible, high food intake C57BL/6J strain. These obesity-resistant and reduced food intake phenotypes were transmitted through the paternal lineage but not the maternal lineage with equal strength for at least two generations. Eliminating social interaction between the father and both his offspring and the pregnant dam did not significantly affect food intake levels, demonstrating that the phenotype is transmitted through the male germline rather than through social interactions. Persistence of these phenotypes across multiple generations raises the possibility that transgenerational genetic effects contribute to current metabolic conditions.

Diet-induced hepatocellular carcinoma in genetically predisposed mice

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide, with approximately 70% of cases resulting from hepatitis B and C viral infections, aflatoxin exposure, chronic alcohol use or genetic liver diseases. The remaining approximately 30% of cases are associated with obesity, type 2 diabetes and related metabolic diseases, although a direct link between these pathologies and HCCs has not been established. We tested the long-term effects of high-fat and low-fat diets on males of two inbred strains of mice and discovered that C57BL/6J but not A/J males were susceptible to non-alcoholic steatohepatitis (NASH) and HCC on a high-fat but not low-fat diet. This strain-diet interaction represents an important model for genetically controlled, diet-induced HCC. Susceptible mice showed morphological characteristics of NASH (steatosis, hepatitis, fibrosis and cirrhosis), dysplasia and HCC. mRNA profiles of HCCs versus tumor-free liver showed involvement of two signaling networks, one centered on Myc and the other on NFkappaB, similar to signaling described for the two major classes of HCC in humans. miRNA profiles revealed dramatically increased expression of a cluster of miRNAs on the X chromosome without amplification of the chromosomal segment. A switch from high-fat to low-fat diet reversed these outcomes, with switched C57BL/6J males being lean rather than obese and without evidence for NASH or HCCs at the end of the study. A similar diet modification may have important implications for prevention of HCCs in humans.

Resistance to diet-induced obesity in mice with a single substituted chromosome

Obesity and its comorbidities are taking an increasing toll on human health. Key pathways that were identified with single gene variants in humans and model organisms have led to improved understanding and treatment of rare cases of human obesity. However, similar progress remains elusive for the more common multifactorial cases of metabolic dysfunction and disease. A survey of mouse chromosome substitution strains (CSSs) provided insight into the complex genetic control of diet-induced obesity and related conditions. We now report a survey of 60 traits related to obesity and metabolic syndrome in mice with a single substituted chromosome as well as selected traits measured in congenic strains derived from the substituted strain. We found that each strain that was resistant to diet-induced obesity had a distinct phenotype that uniquely modeled different combinations of traits related to metabolic disease. For example, the chromosome 6 CSS remained insulin resistant in the absence of obesity, demonstrating an atypical relationship between body weight and insulin resistance. These results provide insights into the genetic control of constant components of this mouse model of diet-induced metabolic disease as well as phenotypes that vary depending on genetic background. A better understanding of these genotype-phenotype relationships may enable a more individualized diagnosis and treatment of obesity and the metabolic syndrome.

pak2a mutations cause cerebral hemorrhage in redhead zebrafish

The zebrafish is a powerful model for studying vascular development, demonstrating remarkable conservation of this process with mammals. Here, we identify a zebrafish mutant, redhead (rhd(mi149)), that exhibits embryonic CNS hemorrhage with intact gross development of the vasculature and normal hemostatic function. We show that the rhd phenotype is caused by a hypomorphic mutation in p21-activated kinase 2a (pak2a). PAK2 is a kinase that acts downstream of the Rho-family GTPases CDC42 and RAC and has been implicated in angiogenesis, regulation of cytoskeletal structure, and endothelial cell migration and contractility among other functions. Correction of the Pak2a-deficient phenotype by Pak2a overexpression depends on kinase activity, implicating Pak2 signaling in the maintenance of vascular integrity. Rescue by an endothelial-specific transgene further suggests that the hemorrhage seen in Pak2a deficiency is the result of an autonomous endothelial cell defect. Reduced expression of another PAK2 ortholog, pak2b, in Pak2a-deficient embryos results in a more severe hemorrhagic phenotype, consistent with partially overlapping functions for these two orthologs. These data provide in vivo evidence for a critical function of Pak2 in vascular integrity and demonstrate a severe disease phenotype resulting from loss of Pak2 function.

Allelic mutations of the sodium channel SCN8A reveal multiple cellular and physiological functions

Allelic mutations of Scn8a in the mouse have revealed the range of neurological disorders that can result from alternations of one neuronal sodium channel. Null mutations produce the most severe phenotype, with motor neuron failure leading to paralysis and juvenile lethality. Two less severe mutations cause ataxia, tremor, muscle weakness, and dystonia. The electrophysiological effects have been studied at the cellular level by recording from neurons from the mutant mice. The data demonstrate that Scn8a is required for the complex spiking of cerebellar Purkinje cells and for persistent sodium current in several classes of neurons, including some with pacemaker roles. The mouse mutations of Scn8a have also provided insight into the mode of inheritance of channelopathies, and led to the identification of a modifier gene that affects transcript splicing. These mutations demonstrate the value of mouse models to elucidate the pathophysiology of human disease.

Three ENU-induced neurological mutations in the pore loop of sodium channel Scn8a (Na(v)1.6) and a genetically linked retinal mutation, rd13

The goal of The Jackson Laboratory Neuroscience Mutagenesis Facility is to generate mouse models of human neurological disease. We describe three new models obtained from a three-generation screen for recessive mutations. Homozygous mutant mice from lines nmf2 and nmf5 exhibit hind limb paralysis and juvenile lethality. Homozygous nmf58 mice exhibit a less severe movement disorder that includes sustained dystonic postures. The mutations were mapped to the distal region of mouse Chromosome (Chr) 15. Failure to complement a mutant allele of a positional candidate gene, Scn8a, demonstrated that the mutations are new alleles of Scn8a. Missense mutations of evolutionarily conserved residues of the sodium channel were identified in the three lines, with the predicted amino acid substitutions N1370T, I1392F, and L1404H. These residues are located within the pore loop of domain 3 of sodium channel Na(v)1.6. The lethal phenotypes suggest that the new alleles encode proteins with partial or complete loss of function. Several human disorders are caused by mutation in the pore loop of domain 3 of paralogous sodium channel genes. Line nmf5 contains a second, independent mutation in the rd13 locus that causes a reduction in cell number in the outer nuclear layer of the retina. rd13 was mapped to the distal 4 Mb of Chr 15. No coding or splice site mutations were detected in Pde1b, a candidate gene for rd13. The generation of three independent Scn8a mutations among 1100 tested G3 families demonstrates that the Scn8a locus is highly susceptible to ENU mutagenesis. The new alleles of Scn8a will be valuable for analysis of sodium channel physiology and disease.

High-resolution mapping of the sodium channel modifier Scnm1 on mouse chromosome 3 and identification of a 1.3-kb recombination hot spot

Variation between inbred strains of mice can be used to identify modifier genes affecting the susceptibility to inherited disease. The medJ allele of the sodium channel Scn8a contains a splice site mutation that results in sodium channel deficiency. The severity of the neurological disorder is determined by the modifier locus Scnm1. The wild-type allele of the modifier results in correct splicing of 10% of Scn8amedJ pre-mRNA and a dystonic phenotype. The susceptible allele of the modifier in strain C57BL/6J results in 5% correctly spliced transcripts and a lethal phenotype. A mapping cross with C3H using 26 new markers and 2304 affected F2 animals localized the modifier gene to a 950-kb interval on mouse chromosome 3. Fine mapping of recombination breakpoints revealed a recombination hot spot of 1.3 kb. The ratio of genetic to physical distance in the hot spot is 85 cM/Mb, two orders of magnitude higher than the mouse genome average of 0.5 cM/Mb. The role of the modifier in other disorders in human and mouse can be tested with linked markers described here.

SCNM1, a putative RNA splicing factor that modifies disease severity in mice

The severity of many inherited disorders is influenced by genetic background. We describe a modifier interaction in C57BL/6Jmice that converts a chronic movement disorder into a lethal neurological disease. The primary mutation (medJ) changes a splice donor site of the sodium channel gene Scn8a (Nav1.6). The modifier mutation is characteristic of strain C57BL/6Jand introduces a nonsense codon into sodium channel modifier 1 (SCNM1), a zinc finger protein and a putative splice factor. An internally deleted SCNM1 protein is also predicted as a result of exon skipping associated with disruption of a consensus exonic splicing enhancer. The effect of the modifier mutation is to reduce the abundance of correctly spliced sodium channel transcripts below the threshold for survival. Our finding that genetic variation in a putative RNA splicing factor influences disease susceptibility in mice raises the possibility that a similar mechanism modifies the severity of human inherited disorders.

TSRC1, a widely expressed gene containing seven thrombospondin type I repeats

The thrombospondin type 1 repeat domain is found in nearly 100 mammalian proteins with diverse biological functions that include cellular adhesion, angiogenesis, and patterning of the developing nervous system. We have characterized a novel thrombospondin type 1 repeat containing gene, TSRC1, encoding a predicted protein with seven thrombospondin repeats, six of which are clustered at the C-terminus. The 17 coding exons and two nontranslated exons of TSRC1 span 10 kb of genomic DNA. The human and mouse genes encode proteins of 1074 and 1036 amino acids, respectively, with 76% amino acid sequence identity. Thirty of the extra amino acids in the human protein are encoded by exon 6. Mouse Tsrc1 is expressed in all fetal and adult tissues tested. Three conserved noncoding sequence elements with potential regulatory function are located in intron 1. Mouse Tsrc1 was genetically mapped to chromosome 3 within the nonrecombinant region for the sodium channel modifier locus Scnm1. The sensitive and resistant alleles of Scnm1 did not differ in Tsrc1 protein sequence, transcript length, or transcript abundance. Human TSRC1 is located on chromosome 1q21 within an 11.7 Mb segment of conserved synteny. TSRC1 and the closely linked gene ADAM15 appear to be derived by a chromosomal inversion that interrupted an ancestral ADAMTS gene.

Molecular and pathological effects of a modifier gene on deficiency of the sodium channel Scn8a (Na(v)1.6)

Scn8a encodes an abundant, widely distributed voltage-gated sodium channel found throughout the central and peripheral nervous systems. Mice with different mutant alleles of Scn8a provide models of the movement disorders ataxia, dystonia, tremor and progressive paralysis. We previously reported that the phenotype of the hypomorphic allele of Scn8a, medJ, is dependent upon an unlinked modifier locus, Scnm1. Strain C57BL/6J carries a sensitive allele of the modifier locus that results in juvenile lethality. We now provide evidence that the modifier acts on the splicing efficiency of the mutant splice donor site. Mutant mice display either 90% or 95% reduction in the proportion of correctly spliced mRNA, depending on modifier genotype. The abundance of the channel protein, Na(v)1.6, is also reduced by an order of magnitude in medJ mice, resulting in delayed maturation of nodes of Ranvier, slowed nerve conduction velocity, reduced muscle mass and reduction of brain metabolic activity. medJ mice provide a model for the physiological effects of sodium channel deficiency and the molecular mechanism of bigenic disease.

Mutations of voltage-gated sodium channels in movement disorders and epilepsy

Spontaneous and induced mutations of neuronal Na+ channels in human patients and mutant mice result in a broad range of neurological-disease. Epilepsy, a disorder of neuronal hyperexcitability, has been associated with delayed inactivation of SCN2A in mice, and with altered kinetics of SCN1A in human patients. Movement disorders including tremor, ataxia, dystonia and paralysis have been observed in mice with mutations of SCN8A. Electrophysiological recordings from neurons isolated from mice with mutations in individual channels reveal the contributions of each channel to in vivo firing patterns. In addition to monogenic disease, Na+ channel mutations are likely to contribute to polygenic disease susceptibility and to normal variation in neuronal function. Advances in molecular methods coupled with genomic sequences from the Human Genome Project will permit identification of many new patient mutations and generation of animal models to dissect their physiological and cellular consequences.

Development and validation of the ITG Health-Related Quality-of-Life Short-Form measure for use in patients with coronary artery disease. Integrated Therapeutics Group

BACKGROUND

Available coronary artery disease (CAD)-specific health-related quality-of-life (HRQL) measures are not ideally suited for routine clinical practice. We report development of a valid and reliable CAD-specific short-form measure.

HYPOTHESIS

The Integrated Therapeutics Group (ITG) CAD-specific short-form HRQL measure is reliable and valid for assessing the health status of patients with CAD.

METHODS

In all, 409 patients (mean age 62.4 years) completed the 24-item CAD-specific HRQL questionnaire. Factor analysis was used to identify the scaling of the 24 CAD-specific items. Analysis of variance was used to reduce the number of items within each scale, and reliability (Cronbach's alpha), discriminant validity, and ceiling and floor effects of short-form scales were evaluated. Short-form scales were compared with the longer scales using relative validity coefficients. The CAD severity was assessed using New York Heart Association criteria, physician assessment, electrocardiogram results, the number of myocardial infarctions, and the number of CAD-specific medications. Clinical validity of short-form scales was then assessed based on their ability to discriminate across severity levels of these clinical criteria.

RESULTS

Four scales were identified: Extent of Chest Pain, Functioning and Well-Being, Activities Level-Physical, and Activities Level-Social. The 24-item questionnaire was reduced to a 13-item short form, with reliability exceeding 0.70 for all four scales. Relative validity estimates comparing short-form to original scales ranged from 0.68 to 2.58. Mean scores varied significantly (p < 0.05) by clinical severity, supporting the discriminant validity of the ITG CAD short-form scales.

CONCLUSIONS

The ITG CAD short form (used alone or with a general HRQL measure) is valid and practical for assessing patients with CAD.

Evaluation of a short form for measuring health-related quality of life among pediatric asthma patients

BACKGROUND

This study was undertaken to derive and validate a short form parent-completed questionnaire to measure health-related quality of life (HRQL) in pediatric asthma patients.

OBJECTIVE

The objectives of this study were to (1) use stepwise analysis to derive a shorter questionnaire from the original long-form questionnaire and (2) determine the tradeoff in precision between the long- and short-form surveys.

METHODS

One hundred eighty-one pediatric asthma patients were enrolled from 4 sites. A parent of each patient completed a general and an asthma-specific questionnaire during routine office visits from June 1995 to January 1997. The questionnaire included the Child Health Questionnaire Parent Form 50, a general HRQL survey, and a 17-item asthma-specific battery assessing daytime symptoms, nighttime symptoms, and functional limitations. All scales were scored from 0 to 100, with higher scores indicating better HRQL. Analysis of variance models were used to derive short-form scales from the 17-item long-form scales, and the final asthma-specific short-form scale structure was confirmed with use of stepwise regression. Scale reliability was assessed with Cronbach's alpha. Validity of the short-form questionnaire was assessed by comparing mean scale scores according to the level of asthma severity defined by several clinical criteria. Asthma severity was assessed with use of percent predicted FEV(1), frequency and type of symptoms, parent rating of disease severity, physician rating of disease severity, and resource use (emergency department use and hospitalizations). The relative validity of each of the short-form scales was measured by comparing the proportion of variance explained by each of the short-form scales compared with the respective long-form scales.

RESULTS

The 17-item asthma-specific battery was reduced to 8 items, the Integrated Therapeutics Group Child Asthma Short Form. The daytime and nighttime symptom scales for each contain 2 items and the functional limitations scale 4 items. Reliability was greater than 0.70 for each of the short-form scales. The absence of ceiling and floor effects indicates each scale's ability to detect changes at both low and high levels of functioning. Lower (poorer) mean HRQL scores for severe cases compared with mild cases, for all disease severity indicators, demonstrated clinical validity. Relative validity estimates, comparing the proportion of explained variance of the short-form scales with that of the long-form scales, ranged from 0. 85 to 1.20, indicating a similar ability to measure change.

CONCLUSIONS

This study documents the development of a brief, multidimensional, 8-item questionnaire for measuring HRQL in pediatric asthma patients. The brevity of the questionnaire makes it practical for use in practice settings and to monitor patients.

The member satisfaction survey as a measure of health plan accountability

In its 1996 study of St. Louis area health maintenance organization members, Gateway Purchasers for Health closely analyzed member responses to the National Committee for Quality Assurance's annual member health care survey. The analysis of specific questions regarding overall satisfaction levels and member health status afforded insight into the factors that contribute to an individual's reported satisfaction with health care services and into variations by subgroups within the population. Ultimately, consumer information that allows choice of a health plan that best suits specific needs and preferences will drive accountability, quality, and value in the health care market.

The effectiveness of one-on-one nurse education on the outcomes of high-risk adult and pediatric patients with asthma

The effects of an asthma self-management program on asthma outcomes were evaluated in adult and pediatric patients with asthma who were considered at high risk (i.e., those who were not in control of their disease as determined by resource utilization, medication use, or lack of use). The program consisted of one-on-one nurse-to-patient ("nurse champion") education and subsequent assessment of asthma outcomes using the Asthma Quality Assessment System (AQAS) questionnaire, which measured asthma severity, patient quality of life, asthma awareness and knowledge, confidence in managing asthma, use of peak flow meters, asthma symptoms, medication use, lost work or school days, and affect of asthma. Over the course of six months, nurse champions educated 201 patients from four managed care plans and collected data at baseline and during four follow-up sessions. Adult patients and pediatric patient caregivers reported significant improvements in quality of life, and clinical and process measures. Significant increases in asthma knowledge were observed immediately after patient education, including greater than 89% increase in the proportion of patients who reported that they know "a lot" about the "things that cause asthma symptoms." Significant decreases were also found in work or school days missed, urgent care utilization, and hospital admission rates. Appropriate preventive care visits increased by more than 40%. These results indicate that the nurse champion program was associated with an improvement in asthma outcomes in high-risk adult and pediatric patients and warrant further evaluation in controlled studies. Incorporating one-on-one education programs into asthma management is an effective and rapid means of improving asthma outcomes.

Effects of an asthma management program on the asthmatic member: patient-centered results of a 2-year study in a managed care organization

OBJECTIVE

To report the results of a 2-year pilot program of asthma education based on National Heart, Lung, and Blood Institute treatment guidelines.

PATIENTS AND METHODS

Asthmatic members (n = 6698) of a managed care organization received education about their condition directly or through their primary care physician. Medical and pharmacy administrative claims data were reviewed to measure acute asthma events and prescribed therapies in the first (the baseline) and second years of the study. The claims data were augmented by member surveys from a stratified random sample of 2734 asthmatic patients who were members (6 years of age or older) in the baseline year.

RESULTS

Compared with the first year, asthmatic members received fewer inpatient services and the proportion of asthmatic members prescribed oral inhaled corticosteroids increased 30% in the second year. Health-related quality of life, measured with validated general and disease-specific instruments; satisfaction with the quality of care; exposure to patient education; knowledge of the disease; and member's confidence in their ability to manage their disease showed statistically significant improvements during the follow-up year of the program for both adult and child asthmatic members.

CONCLUSION

For asthmatic members of this health plan, a comprehensive asthma health management program improved processes of care and outcomes.

The responsiveness of disease-specific and generic health measures to changes in the severity of asthma among adults

The objective of the study was to compare the validity of asthma-specific and generic health outcome measures in relation to changes in the severity of asthma and to treatment. Adult patients (n = 142) participating in a randomized placebo-controlled trial at six clinics were assessed at baseline, prior to the withdrawal (placebo) or continuation of treatment with Vanceril and again after 8 weeks. The criterion measures of change in severity included pulmonary function expressed as the percent predicted FEV1, five physician-assessed asthma severity measures (cough, chest tightness, wheezing, shortness of breath and overall condition) and two patient-assessed severity measures (night-time symptoms and overall symptoms). The 8 week change scores were estimated for all generic and specific measures and the results were compared across groups of patients who did and did not change in terms of clinical criteria of disease severity and across treatment groups. The responsiveness of each generic and specific measure was estimated independently using the relative validity (RV) methodology, which compares F-ratios for the mean change scores across measures in analyses of the same comparison groups. RV coefficients estimate how much worse each measure discriminated between comparison groups, relative to the best measure (RV = 1.0). Four standardized asthma-specific measures and a total scale score (based on the Marks questionnaire), an individualized asthma-specific scale measuring limitations in activities most important to each patient (based on the Juniper method) and two newly-developed scales measuring physical and psychosocial symptoms were used as outcome measures, generic health outcome measures included eight functional health and well-being scales as well as the physical and mental health summary scales from the SF-36 health survey. A standardized asthma-specific scale was most valid in discriminating between groups of patients who did and did not change according to all of the clinical criterion variables studied and in discriminating between treated and untreated groups. Different scales performed best, depending on the clinical criterion. The asthma-specific Marks breathlessness scale was significant in all nine comparisons (RV = 0.62-1.0) and was most valid in discriminating between groups in six of nine tests. The overall scale also performed well in all comparisons (RV = 0.58-1.0). The newly-developed physical symptoms scale was significant in discriminating between groups in eight out of nine tests (RV = 0.52-1.0) and was most valid in three of the nine, including the treatment comparison. The psychosocial impact scale discriminated significantly in eight of the nine comparisons (RV = 0.16-0.38), but was less valid than other specific measures. The asthma-specific individualized activities scale discriminated significantly in seven of the nine tests, but performed less well than the other specific measures (RV = 0.21-0.35) and was not significant in the treatment comparison. One or more SF-36 scales discriminated significantly between groups in all nine comparisons. Two of those scales (physical functioning and role-physical) were consistently more valid than the others (RV = 0.17 and 0.58, respectively) and were the only two generic scales that discriminated between groups of patients defined in terms of changes in FEV1 (RV = 0.26-0.58). The SF-36 physical summary scale discriminated significantly between groups in all nine comparisons (RV = 0.19-0.61) and was the most valid generic measure in the treatment comparison (RV = 0.55). The SF-36 mental summary scale was significant only for the two patient-assessed changes in disease severity (RV = 0.31 and 0.32) and for physician-assessed overall severity (RV = 0.12). A comprehensive battery of generic and specific measures is likely to be most useful in understanding the impact of changes in disease severity on the functional health and well-being of adults with asthma, a

Asthma: benchmarking for quality improvement

BACKGROUND

Linked medical and pharmacy claims can be used to identify patients with asthma and benchmark current practice standards.

METHOD

This was a 3-year study of five independent practice association style health maintenance organizations with an annual enrollment of 870,000. More than 28,000 members were identified with claims for asthma.

OBJECTIVE

The intent of this study was to benchmark current asthma practice. Before quality improvement projects can be implemented baseline data are required.

RESULTS

The prevalence of asthma varied by geographic regions. Specialty care was associated with greater use of anti-inflammatory medications and more refills of these drugs. Refill rates for inhaled corticosteroids for all patients was low. Specialty care of asthmatic members was associated with a lower rate of emergency service events and hospitalizations.

CONCLUSIONS

Linked medical and pharmacy claims' databases can be used to benchmark current practice performance and serve as a reference for quality improvement programs. Appropriate use of specialty care may improve asthma outcomes.

Approaches to prostate cancer by managed care organizations

OBJECTIVES

Managed care organizations (MCOs) are developing population-based approaches to illnesses with large numbers of patients, wide variations in care and outcomes, and high costs. This is the first survey that evaluates current prostate cancer approaches by MCOs.

METHODS

Case studies and a survey of corporate medical directors at large MCOs were conducted.

RESULTS

Two approaches, broadly based on disease management strategies for men with prostate cancer, have been implemented in managed care settings on the West Coast. While both have provided comprehensive approaches to the disease, assessment of improvement in outcomes will require longer follow-up. A survey of corporate medical directors of MCOs indicates that population-based disease approaches nationwide for malignant prostate disease lag behind more well-developed efforts for nonmalignant illnesses such as diabetes and asthma.

CONCLUSIONS

Prostate cancer may be a feasible area for development and evaluation of population-based approaches. MCOs have the potential to improve clinical care and outcomes for large numbers of men with prostate cancer. While limitations exist related to specific managed care considerations of data needs and lack of medical and surgical consensus on disease management, programs based on shared decision making have the potential to improve patient care and outcomes.

Patterns of anti-inflammatory therapy in the post-guidelines era: a retrospective claims analysis of managed care members

Published and widely disseminated guidelines for the care and management of asthma characterize asthma as a chronic, inflammatory disease and propose specific recommendations for therapy with inhaled anti-inflammatory medications. In a retrospective analysis of medical and pharmacy claims data of approximately 28,000 asthmatic members from five managed care settings, the dominant pattern of pharmacologic therapy that emerged was the use of bronchodilators without inhaled anti-inflammatory drug therapy. In addition, a significant proportion of asthmatic patients received no prescription drug therapy for asthma. Less than one third of asthmatic patients received any anti-inflammatory therapy and the majority of these received one or two prescriptions per year. Specialist physicians were two to three times more likely than non-specialists during a study period of 1 year to prescribe an anti-inflammatory medication, and were half as likely to have their asthmatic patients experience an emergency department or hospital event. This database analysis suggests that greater conformity with guidelines and/or access to specialist physician care for asthmatic members will lead to improved patient outcomes.