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Kevin K Brown

Publications and source records attributed to Kevin K Brown.

At least 19 recordsLinked to original sources
PubMed2026

Idiopathic pulmonary fibrosis risk loci in East Asian populations mirror those of European populations.

RATIONALE: Common and rare variants that are associated with the risk of developing idiopathic pulmonary fibrosis (IPF) have been identified predominantly in European ancestry populations. OBJECTIVES: To better understand the genetic variants that contribute to IPF in individuals with Asian ancestry, we conducted a genome-wide association study of IPF in East Asian populations. METHODS: We included 1026 patients with IPF and compared them to 1723 unaffected controls of Japanese and Korean ancestry. Genome-wide association analysis was conducted in the Japanese and Korean ancestry cohorts separately and combined using meta-analysis. Restricted maximum likelihood was used to estimate the SNP-based heritability and local ancestry of chromosome 11 was inferred for each subject. MEASUREMENTS AND MAIN RESULTS: We identified loci on chromosomes 4 (FAM13A; rs7690839), 5 (TERT; rs7734992), 6 (DSP; rs2076295), and 11 (MUC5B; rs35705950) that were significantly associated with risk of IPF. Importantly, the sentinel variants in each of these loci are the same as, or in strong linkage disequilibrium with, the risk variants that have been observed in studies of European ancestry populations. In aggregate, common variants (not including the MUC5B promoter variant) account for approximately 25% of the risk of developing IPF in these East Asian ancestry cohorts. Moreover, local ancestry analysis indicates that the presence of MUC5B promoter variant in the East Asian population is not a result of admixture with European ancestry populations. CONCLUSIONS: We conclude that the IPF risk loci in East Asian populations are shared with those of European ancestry populations, although their risk allele frequencies and effect sizes differ. These findings indicate shared genetic risk factors of IPF across ancestries.

Aged↗
PubMed2006

Gene expression profiling of familial and sporadic interstitial pneumonia.

RATIONALE: Idiopathic interstitial pneumonia (IIP) and its familial variants are progressive and largely untreatable disorders with poorly understood molecular mechanisms. Both the genetics and the histologic type of IIP play a role in the etiology and pathogenesis of interstitial lung disease, but transcriptional signatures of these subtypes are unknown. OBJECTIVES: To evaluate gene expression in the lung tissue of patients with usual interstitial pneumonia or nonspecific interstitial pneumonia that was either familial or nonfamilial in origin, and to compare it with gene expression in normal lung parenchyma. METHODS: We profiled RNA from the lungs of 16 patients with sporadic IIP, 10 with familial IIP, and 9 normal control subjects on a whole human genome oligonucleotide microarray. RESULTS: Significant transcriptional differences exist in familial and sporadic IIPs. The genes distinguishing the genetic subtypes belong to the same functional categories as transcripts that distinguish IIP from normal samples. Relevant categories include chemokines and growth factors and their receptors, complement components, genes associated with cell proliferation and death, and genes in the Wnt pathway. The role of the chemokine CXCL12 in disease pathogenesis was confirmed in the murine bleomycin model of lung injury, with C57BL/6(CXCR4+/-) mice demonstrating significantly less collagen deposition than C57BL/6(CXCR4+/+) mice. Whereas substantial differences exist between familial and sporadic IIPs, we identified only minor gene expression changes between usual interstitial pneumonia and nonspecific interstitial pneumonia. CONCLUSIONS: Taken together, our findings indicate that differences in gene expression profiles between familial and sporadic IIPs may provide clues to the etiology and pathogenesis of IIP.

Adult↗
PubMed2006

Fibroblast foci are not discrete sites of lung injury or repair: the fibroblast reticulum.

BACKGROUND: Usual interstitial pneumonia (UIP), the pathologic correlate of idiopathic pulmonary fibrosis, contains characteristic discrete areas of fibroblasts, myofibroblasts, and newly formed collagen, termed "fibroblast foci." These lesions are argued to represent isolated sites of recurrent acute lung injury and suggested to be the mechanism of disease progression. We hypothesized that, rather than isolated, these lesions are part of an organized neoplasm. METHODS: Morphometric analysis of pentachrome-stained histologic sections of UIP was performed. Using point-counting technique on serial sections, fibroblast foci, arteries, and macrophage clusters were identified and we determined their individual "connectiveness" by estimating the Euler number. Two-dimensional micrographs were collated into a three-dimensional array from which a visual three-dimensional reconstruction could be constructed. Clonality analysis was performed using human androgen receptor gene methylation assay. RESULTS: Blood vessels show significant connectivity with a Euler number of 2, whereas macrophage clusters exhibited no connectivity. The fibroblast foci showed a high level of interconnection with Euler numbers ranging from 19 to 39. The computer generated three-dimensional models provide a visual confirmation of this connectiveness. Human androgen receptor gene methylation assay analysis of the foci showed balanced methylation consistent with polyclonality. CONCLUSIONS: The fibroblast foci of UIP are the leading edge of a complex reticulum that is highly interconnected and extends from the pleura into the underlying parenchyma. It is a reactive, rather than a malignant, process.

Disease Progression↗
PubMed2006

Human lung project: evaluating variance of gene expression in the human lung.

Nondiseased tissue is an important reference for microarray studies of pulmonary disease. We obtained 23 single lungs from multiorgan donors at time of procurement. Donors varied in age, sex, smoking history, and ethnicity. Lungs were dissected into upper and lower lobe peripheral sections for RNA extraction. Microarray analysis was performed using Affymetrix Hu-133 Plus 2.0 arrays. We observed that the relative variability of gene expression increased rapidly from technical (lowest), to regional, to population (highest). In addition, age and sex have measurable effects on gene expression. Gene expression variability is heterogeneously distributed among biologic categories. We conclude that gene expression variability is greater between individuals than within individuals and that population variability is the most important factor in the study design of microarray experiments of the human lung. Classes of genes with high population variability are biologically important and provide a novel perspective into lung physiology and pathobiology. Our study represents the first comprehensive analysis of nondiseased lung tissue. The generation of this robust dataset has important implications for the design and implementation of future comparative expression analysis with pulmonary disease states.

Adult↗
PubMed2006

Acute interstitial pneumonia and acute exacerbations of idiopathic pulmonary fibrosis.

Acute interstitial pneumonia (AIP) and acute exacerbations of idiopathic pulmonary fibrosis (AEIPF) are similar respiratory disorders characterized by the rapid development of progressive dyspnea and cough. Both frequently lead to respiratory failure and death. Pathologically, each is characterized by the presence of a diffuse alveolar damage (DAD) pattern; in AIP, DAD is the sole pattern, whereas in AEIPF DAD is superimposed upon a background usual interstitial pneumonia. They differ in that patients with AEIPF have preexisting idiopathic pulmonary fibrosis, whereas patients with AIP have no predisposing disorders to account for their disease. Because both presentations overlap with multiple other causes of acute lung injury, a comprehensive evaluation is necessary to rule out disorders such as overwhelming infection or congestive heart failure. Although a confident diagnosis can be achieved without it, a surgical lung biopsy is necessary to provide a definitive diagnosis. Despite minimal evidence, glucocorticoids are frequently begun once microbiological evaluation confirms the absence of infection. Despite therapy, the case fatality rate ranges up to 70% for both, with most patients dying in the first 2 weeks. Survivors of the acute event can recover to their previous baseline; however, most AIP survivors will stabilize with some functional impairment, whereas in those with AEIPF, progressive fibrosis with functional deterioration is the rule.

Acute Disease↗
PubMed2006

Chronic cough due to nonbronchiectatic suppurative airway disease (bronchiolitis): ACCP evidence-based clinical practice guidelines.

OBJECTIVES: To review the role of nonbronchiectatic suppurative airway disease (bronchiolitis) in the spectrum of causes of cough and its management. DESIGN/METHODOLOGY: A MEDLINE search (through May 2004) for studies published in the English language since 1980 on human subjects using the medical subject heading terms "cough," "causes of cough," "etiology of cough," "interstitial lung disease," "bronchiolitis," "bronchiolitis obliterans," "diffuse panbronchiolitis," and "inflammatory bowel disease" was performed. Case series and prospective descriptive clinical trials were selected for review. Any references from these studies that were pertinent to the topic were also obtained. RESULTS/CONCLUSIONS: In patients with cough in whom other more common causes of cough have been excluded, incomplete or irreversible airflow limitation, small airways disease seen on high-resolution CT scan, or purulent secretions seen on bronchoscopy, should suggest nonbronchiectatic suppurative airways disease (bronchiolitis) as a potential primary cause. Successful management depends on the identification of the specific underlying disorder.

Bronchiolitis↗
PubMed2006

Chronic cough due to chronic interstitial pulmonary diseases: ACCP evidence-based clinical practice guidelines.

OBJECTIVES: To review the role of chronic interstitial pulmonary disease in the spectrum of causes of cough and its management. DESIGN/METHODOLOGY: A MEDLINE search (through May 2004) for studies published in the English language since 1980 on human subjects using the medical subject heading terms "cough," "causes of cough," "etiology of cough," "interstitial lung disease," "idiopathic pulmonary fibrosis," "sarcoidosis," and "hypersensitivity pneumonitis" was performed. Case series and prospective descriptive clinical trials were selected for review. Any references from these studies that were pertinent to the topic were also obtained. RESULTS/CONCLUSIONS: In patients with cough, chronic interstitial pulmonary disease should be considered as a primary cause only after more common causes, such as upper airway cough syndrome and gastroesophageal reflux, have been excluded. Successful management depends on identification of the specific disorder.

Chronic Disease↗
PubMed2006

Update in the diagnosis and management of pulmonary vasculitis.

The term vasculitis encompasses a number of distinct clinicopathologic disease entities, each of which is characterized pathologically by cellular inflammation and destruction of the blood vessel wall, and clinically by the types and locations of the affected vessels. While multiple classification schemes have been proposed to categorize and simplify the approach to these diseases, ultimately their diagnosis rests on the identification of particular patterns of clinical, radiologic, laboratory, and pathologic features. While lung involvement is most commonly seen with the primary idiopathic, small-vessel or antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides of Wegener granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome, one should remember that medium-vessel vasculitis (ie, classic polyarteritis nodosa), large-vessel vasculitis (ie, Takayasu arteritis), primary immune complex-mediated vasculitis (ie, Goodpasture syndrome), and secondary vasculitis (ie, systemic lupus erythematosus) can all affect the lung. However, for the purpose of this review, we will focus on the ANCA-associated vasculitides.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2006

Mycophenolate mofetil is safe, well tolerated, and preserves lung function in patients with connective tissue disease-related interstitial lung disease.

BACKGROUND: Interstitial lung disease (ILD) frequently complicates connective tissue diseases (CTDs). Glucocorticoids and immunomodulatory agents are regarded as mainstays of therapy for CTD-related ILD; however, apart from those studies that have evaluated certain medications for patients with scleroderma, few studies have been performed. In this study, our objectives were to examine the safety and tolerability of mycophenolate mofetil (MMF) and to determine its impact on lung function in patients with CTD-ILD. METHODS: In this retrospective observational study, we analyzed patients at our center who ever received MMF for CTD-ILD. We examined the frequency and severity of side effects associated with MMF and used longitudinal data analytic methods to determine the ability of MMF to maintain lung function over time. RESULTS: Twenty-eight patients were treated with MMF over 35.9 patient-years. The most common underlying CTD diagnosis was scleroderma (n = 9). The most common reason for initiating MMF was an adverse effect of a prior immunomodulatory agent. Six patients had clinically significant side effects related to MMF; all resolved with dose reduction. Compared to before MMF, the mean daily prednisone dose while patients were receiving MMF was lower (10 mg/d vs 15 mg/d, p = 0.09). In addition, since starting MMF, the average percentage of predicted forced vital capacity (FVC), average percentage of predicted total lung capacity, and average percentage of predicted diffusing capacity of the lung for carbon monoxide for the cohort increased by 2.3%, 4.0%, and 2.6%, respectively. CONCLUSION: MMF appears to be safe and well tolerated in patients with CTD-ILD. Larger-scale studies are needed to further evaluate the efficacy of MMF in this patient population.

Aged↗
PubMed2006

Unique characteristics of systemic sclerosis sine scleroderma-associated interstitial lung disease.

STUDY OBJECTIVES: To describe the characteristics of systemic sclerosis sine scleroderma (ssSSc)-associated interstitial lung disease (ILD) presenting as idiopathic interstitial pneumonia (IIP). DESIGN: Retrospective review of six patients with ssSSc-associated ILD diagnosed after referral for evaluation of IIP. MEASUREMENT AND RESULTS: All patients were white, their mean age was 56 years (range, 37 to 86), and gender was evenly divided. Sclerodactyly, skin thickening, and digital edema were absent in all patients. All patients had scattered telangiectasia, and four patients had Raynaud phenomenon with abnormal nailfold capillaroscopy findings. All described gastroesophageal reflux, and three patients had esophageal dysmotility by esophagography. All had restrictive pulmonary physiology and a reduced diffusion capacity. High-resolution CT revealed nonspecific interstitial pneumonia (NSIP) or usual interstitial pneumonia (UIP) radiographic patterns. Of the three patients who underwent surgical lung biopsy, two patients had NSIP and one patient had UIP pathologic patterns. Five patients had asymptomatic pericardial effusions and elevated pulmonary artery pressures by echocardiography. All patients had nucleolar-staining anti-nuclear antibodies (ANAs), and one patient was anti-Scl-70 positive. All five anti-Scl-70-negative patients were anti-Th/To positive, and the anti-Scl-70-positive patient was anti-Th/To negative. CONCLUSIONS: In the presentation of an IIP, the presence of a nucleolar-staining ANA, telangiectasia, Raynaud phenomenon with abnormal capillaroscopy findings, gastroesophageal reflux, or pericardial disease suggests underlying systemic sclerosis. These findings should aid clinicians in the evaluation and treatment of patients with otherwise undefined ILD.

Adult↗
PubMed2006

Pulmonary vasculitis.

Pulmonary vasculitis describes a number of distinct disorders that are pathologically characterized by the destruction of blood vessels. The clinical manifestations of each disorder are defined by the size, type, and location of the affected vasculature. The clinical approach to these disorders rests upon an astute clinician considering the diagnosis and identifying the specific patterns of clinical, radiologic, laboratory, and pathologic abnormalities. Lung involvement is most commonly seen with the primary, idiopathic, small-vessel, or antineutrophil cytoplasmic antibody-associated vasculitides; Wegener's granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome. However, primary, idiopathic medium and large-vessel vasculitis, primary immune complex-mediated vasculitis, and secondary vasculitis are all capable of presenting with lung involvement. In this article, we focus on the more common, antineutrophil cytoplasmic antibody-associated disorder, vasculitides.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2006

Anti-th/to-positivity in a cohort of patients with idiopathic pulmonary fibrosis.

OBJECTIVE: To evaluate the presence and clinical relevance of anti-Th/To-positivity in patients with idiopathic pulmonary fibrosis (IPF). METHODS: Antinuclear antibody (ANA) testing was performed in 285 patients with a clinical diagnosis of IPF and surgical lung biopsy-proven usual interstitial pneumonia. Twenty-five subjects (8.8%) were found to have a positive ANA with a nucleolar-staining pattern and were followed for 10 years. Immunoprecipitation analysis indicated that 13 of the 25 subjects had autoantibodies against Th/To antigen. RESULTS: All subjects presented with worsening dyspnea. Pulmonary physiology and gas exchange did not differ between those with and those without a positive ANA, those with and without a nucleolar-staining ANA, and those with and without anti-Th/To antibody positivity. Retrospective review of the clinical record revealed that none of the 25 subjects with a nucleolar-staining ANA had the characteristic cutaneous features of systemic sclerosis (SSc). Four of the 13 Th/To-positive subjects had 3 of 5 criteria of limited cutaneous SSc (CREST variant), and 9 met proposed criteria for SSc sine scleroderma. None of the 12 Th/To-negative subjects had 3 or more criteria of limited cutaneous SSc (CREST variant), and only one met proposed criteria for SSc sine scleroderma. Of the 25 subjects with nucleolar-staining ANA, cumulative survival was similar between those who were Th/To-positive and those who were Th/To-negative (log-rank test, p = 0.73). Cumulative survival was similar between the 13 Th/To-positive subjects and all other 272 IPF subjects (log-rank test, p = 0.34). CONCLUSION: Our findings indicate that a nucleolar-staining ANA is a common finding in patients with IPF, and that antibodies against Th/To are responsible for the majority of these. Given the high specificity of Th/To-positivity for SSc, our data suggest that these subjects may have SSc sine scleroderma, and that their prognosis is no different from those with IPF.

Adult↗
PubMed2005

TNF-alpha sensitizes normal and fibrotic human lung fibroblasts to Fas-induced apoptosis.

Pulmonary accumulation of fibroblasts and myofibroblasts in idiopathic pulmonary fibrosis/usual interstitial pneumonia (IFP/UIP) has been linked to (1) increased migration of a circulating pool of fibrocytes, (2) cell proliferation, and (3) resistance to apoptosis. The mechanism of physiologic apoptosis of lung fibroblasts is poorly understood. Using normal and fibrotic human lung fibroblasts and the human lung fibroblast cell line, MRC-5, we examined the regulation of Fas-induced apoptosis by the proinflammatory cytokines TNF-alpha and IFN-gamma. Herein, we show that the basal resistance of lung fibroblasts and myofibroblasts to Fas-induced apoptosis is overcome by sensitization with TNF-alpha. IFN-gamma did not sensitize cells to Fas-induced apoptosis, but exhibited synergistic activity with TNF-alpha. Sensitization by TNF-alpha was observed in MRC-5 cells and in fibroblasts and myofibroblasts from normal and fibrotic human lung, suggesting that this represents a conserved mechanism to engage Fas-induced apoptosis. The mechanism of sensitization was localized at the level of recruitment of the adapter protein, FADD, to the cytoplasmic domain of Fas. Collectively, these findings suggest that fibroblast apoptosis involves two steps, sensitization and induction, and that inadequate pulmonary inflammation in IPF/UIP may favor fibroblast accumulation by reducing sensitization to apoptosis.

Adaptor Proteins, Signal Transducing↗
PubMed2005

The NHLBI lymphangioleiomyomatosis registry: characteristics of 230 patients at enrollment.

RATIONALE: Pulmonary lymphangioleiomyomatosis is a progressive cystic lung disease that is associated with infiltration of atypical smooth muscle-like cells. Previous descriptions of clinical characteristics of subjects with lymphangioleiomyomatosis have been based on a limited number of patients. OBJECTIVES: To describe the clinical characteristics of subjects with pulmonary lymphangioleiomyomatosis, both sporadic and tuberous sclerosis-related forms. METHODS: Over a 3-yr period, from 1998 to 2001, 243 subjects with pulmonary lymphangioleiomyomatosis were enrolled into a national registry; 13 subjects who had already undergone lung transplantation were excluded for the purposes of this report. MEASUREMENTS AND MAIN RESULTS: All 230 subjects were women, aged 18 to 76 yr (mean +/- SE, 44.5 +/- 0.65 yr). The average age at onset of symptoms was 38.9 +/- 0.73 yr and at diagnosis was 41.0 +/- 0.65 yr. Tuberous sclerosis complex was present in 14.8% of subjects. Pulmonary manifestations, most commonly spontaneous pneumothorax, were the primary events leading to the diagnosis in 86.5% of cases. Nearly 55% of the subjects were being treated with a progesterone derivative. An obstructive pattern on pulmonary function testing was observed in 57.3% of the subjects, whereas 33.9% had normal spirometric results. Women with tuberous sclerosis-related lymphangioleiomyomatosis were younger and had less impaired lung function compared with those with the sporadic form. CONCLUSIONS: The age range of women afflicted with pulmonary lymphangioleiomyomatosis is broader than previously appreciated and the degree of pulmonary function can be quite variable, with one-third of subjects having normal spirometry at enrollment into this registry.

Adolescent↗