Identification of transcription factors responsible for dysregulated networks in human osteoarthritis cartilage by global gene expression analysis.

OBJECTIVE: Osteoarthritis (OA) is the most prevalent joint disease. As disease-modifying therapies are not available, novel therapeutic targets need to be discovered and prioritized for their importance in mediating the abnormal phenotype of cells in OA-affected joints. Here, we generated a genome-wide molecular profile of OA to elucidate regulatory mechanisms of OA pathogenesis and to identify possible therapeutic targets using integrative analysis of mRNA-sequencing data obtained from human knee cartilage. DESIGN: RNA-sequencing (RNA-seq) was performed on 18 normal and 20 OA human knee cartilage tissues. RNA-seq datasets were analysed to identify genes, pathways and regulatory networks that were dysregulated in OA. RESULTS: RNA-seq data analysis revealed 1332 differentially expressed (DE) genes between OA and non-OA samples, including known and novel transcription factors (TFs). Pathway analysis identified 15 significantly perturbed pathways in OA with ECM-related, PI3K-Akt, HIF-1, FoxO and circadian rhythm pathways being the most significantly dysregulated. We selected DE TFs that are enriched for regulating DE genes in OA and prioritized these TFs by creating a cartilage-specific interaction subnetwork. This analysis revealed eight TFs, including JUN, Early growth response (EGR)1, JUND, FOSL2, MYC, KLF4, RELA, and FOS that both target large numbers of dysregulated genes in OA and are themselves suppressed in OA. CONCLUSIONS: We identified a novel subnetwork of dysregulated TFs that represent new mediators of abnormal gene expression and promising therapeutic targets in OA.

Statistical shape modeling of proximal femoral shape deformities in Legg-Calvé-Perthes disease and slipped capital femoral epiphysis.

INTRODUCTION: The current understanding of morphological deformities of the hip such as femoroacetabular impingement (FAI), Legg-Calvé-Perthes disease (LCPD), and slipped capital femoral epiphysis (SCFE) is based on two-dimensional metrics, primarily involving the femoral head, that only partially describe the complex skeletal morphology. OBJECTIVE: This study aimed to improve the three-dimensional (3-D) understanding of shape variations during normal growth, and in LCPD and SCFE, through statistical shape modeling. DESIGN: Thirty-two patients with asymptomatic, LCPD, and SCFE hips, determined from physical and radiographic examinations, were scanned using 3-D computed tomography (CT) at a voxel size of (0.5-0.9 mm)(2) in-plane and 0.63 mm slice thickness. Statistical shape modeling was performed on segmented proximal femoral surfaces to determine modes of variation and shape variables quantifying 3-D shape. In addition, conventional variables were determined for all femora. RESULTS: Proximal femur shape was described by eight modes of variation and corresponding shape variables. Statistical shape variables were distinct with age and revealed coordinated, growth-associated differences in neck length-to-width ratio, femoral head medialization, and trochanter protrusion. After size and age-based shape adjustment, diseased proximal femora were characterized by shape variables distinct from those of asymptomatic hips. The shape variables defined morphology in health and disease, and were correlated with certain conventional variables of shape, including neck-shaft angle, head diameter, and neck diameter. CONCLUSION: 3-D quantitative analyses of proximal femoral bone shape during growth and in disease are useful for furthering the understanding of normal and abnormal shape deviations which affect cartilage biomechanics and risk of developing osteoarthritis.

New tricks with old dogs: personalised medicine and clinical trials.

We provide a didactic example of how clinical trials can accommodate individualised patient information relative to design and analysis.

Sonographic monitoring of mass effect in stroke patients treated with hypothermia. Correlation with intracranial pressure and matrix metalloproteinase 2 and 9 expression.

Severe stroke leads to subsequent cerebral oedema. Patients with severe stroke develop midline shift (MLS) which can be measured by transcranial duplex sonography (TCD). We measured MLS with TCD in 30 patients with large infarction in the territory of the middle cerebral artery (MCA). All of the examined patients had intracranial pressure (ICP) measure devices and the ICP at the time of the TCD was recorded. MLS was also determined on CT scan on day 4. Ten of the 30 patients were treated with hypothermia. We also determined matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) in serum by zymography. MLS measured by TCD correlated significantly with MLS on CT. In addition there was a strong correlation between the ICP measured at the time of TCD and MLS. In patients treated with hypothermia MLS was less pronounced. MMP9 and MMP2 showed a characteristic time course and had strong associations with MLS. We confirm earlier reports that TCD is a reliable noninvasive method for serially monitoring patients with intracranial lesions. Hypothermia reduces MMP9 activity as well as MLS. TCD may reduce the need for repetitive CT scans in neurological critically ill patients.

Vascular matrix adhesion and the blood-brain barrier.

The integrity of the cerebral microvasculature depends on the interaction between its component cells and the extracellular matrix, as well as reorganized cell-cell interactions. In the central nervous system, matrix adhesion receptors are expressed in the microvasculature and by neurons and their supporting glial cells. Cells within cerebral microvessels express both the integrin and dystroglycan families of matrix adhesion receptors. However, the functional significance of these receptors is only now being explored. Endothelial cells and astrocytes within cerebral capillaries co-operate to generate and maintain the basal lamina and the unique barrier functions of the endothelium. Integrins and the dystroglycan complex are found on the matrix-proximate faces of both endothelial cells and astrocyte end-feet. Pericytes rest against the basal lamina. In the extravascular compartment, select integrins are expressed on neurons, microglial cells and oligodendroglia. Significant alterations in both cellular adhesion receptors and their matrix ligands occur during focal cerebral ischaemia, which support their functional significance in the normal state. We propose that matrix adhesion receptors are essential for the maintenance of the integrity of the blood-brain permeability barrier and that modulation of these receptors contributes to alterations in the barrier during brain injury.

Angiotensin type 1 receptor blockage improves ischemic injury following transient focal cerebral ischemia.

Following cerebral ischemia, i.v. infusion of angiotensin II increases cerebral edema and mortality. Angiotensin type 1 receptor blockage should therefore improve acute cerebral ischemia. Left middle cerebral artery occlusion (120 min) followed by reperfusion was performed with the thread method under halothane anesthesia in Sprague-Dawley rats. Olmesartan (angiotensin type 1 receptor blocker; 0.01 or 0.1mumol/kg/h) was infused i.p. for 7 days following middle cerebral artery occlusion followed by reperfusion. Stroke index score, infarct volume, specific gravity, and brain angiotensin II and matrix metalloproteinases were quantified in the ischemic and non-ischemic hemispheres. Olmesartan treatment improved stroke index score, infarct volume, and cerebral edema in our cerebral ischemia model. In particular, stroke index score, infarct volume, and cerebral edema were reduced even with a low dose of olmesartan that did not decrease blood pressure. Paralleling these effects on cerebral ischemia, olmesartan treatment also reduced the reactive upregulation in brain angiotensin II, matrix metalloproteinase-2, matrix metalloproteinase-9, and membrane type 1-matrix metalloproteinase in the ischemic area. Angiotensin type 1 receptor stimulation may be one of the important factors that cause cerebral edema following cerebral ischemia, and that its inhibition may be of therapeutic advantage in cerebral ischemia.

A note on the genome scan meta-analysis statistic.

Wise and colleagues (Ann. Hum. Genet. (1999) 63: 263-72) introduced a rank-based statistical technique for meta-analysis of genome scans, the Genome Scan Meta-Analysis (GSMA) method. We provide an alternative derivation of the null distribution of the GSMA statistic, with extensions, and we suggest approximations to the distribution of the GSMA statistic that may be useful in applications.

Reference centiles for serum ferritin and percentage of transferrin saturation, with application to mutations of the HFE gene.

BACKGROUND: The gene that causes most cases of hereditary hemochromatosis is designated HFE. Individuals with mutations in the HFE gene may have increased serum iron, transferrin saturation, and ferritin concentrations relative to individuals with the wild-type genotype. METHODS: We generated reference centiles for percentage of transferrin saturation and serum ferritin concentrations in normal (wild-type), healthy Caucasian adults. We then examined transferrin and ferritin concentrations relative to these centiles in 81 individuals homozygous for the major hemochromatosis mutation C282Y and 438 individuals with the compound heterozygous HFE genotype C282Y/H63D. RESULTS: Serum ferritin concentrations, but not percentage of transferrin saturation, in normal, healthy women tended to increase sharply as they progressed through menopause. Transferrin and serum ferritin centiles for normal, healthy females were lower than the corresponding centiles in normal, healthy males. C282Y homozygotes had abnormally high transferrin saturation and serum ferritin values relative to the wild types. Compound heterozygotes appeared to be a mixture of individuals with unexceptional transferrin and ferritin values and those with abnormally large values similar to the homozygotes, with equal proportions of each. CONCLUSIONS: There are age- and sex-related differences in reference centiles for the percentage of transferrin saturation and serum ferritin concentrations in normal, healthy adults. Individuals homozygous for the C282Y mutation in the HFE gene have abnormal transferrin saturation and serum ferritin values relative to the reference population; penetrance with the compound heterozygotes, as reflected by abnormal transferrin and ferritin values, is less than with the homozygotes.

Angiotensin-converting enzyme inhibition with enalapril slows progressive intima-media thickening of the common carotid artery in patients with non-insulin-dependent diabetes mellitus.

BACKGROUND AND PURPOSE: Whether angiotensin-converting enzyme (ACE) inhibitors have any clinically significant antiatherogenic effects in humans remains unproven. We undertook a prospective randomized clinical trial of 98 patients with non-insulin-dependent diabetes mellitus (NIDDM) to examine the efficacy of ACE inhibition with enalapril for preventing intima-media (IM) thickening of the carotid wall as measured ultrasonographically. METHODS: Ninety-eight NIDDM patients were randomly assigned either to enalapril at 10 mg/d (n=48) or to a control group (n=50); the planned duration of the trial was 2 years. All patients were seen at baseline (study entry) and 2 subsequent formal annual evaluations, in addition to standard clinical management for NIDDM. IM thickening and vascular lumen diameters were determined for all patients on the basis of baseline and 2 subsequent annual evaluations with carotid ultrasonography. We performed an intent-to-treat analysis to assess changes in IM thickening over the course of the study. RESULTS: Annual IM thickening measurements of the right and left common carotid arteries were 0.01+/-0.02 and 0.01+/-0.02 mm/y in the enalapril-treated group and 0.02+/-0.03 and 0.02+/-0.02 mm/y in the control group, respectively (P<0.05). From regression analysis, annual IM thickening was found to be predicted by enalapril use, sex, and insulin use (F(3,94)=3.86, P=0.012). When we controlled for these other variables, enalapril use reduced annual IM thickening of right and left common carotid arteries by 0.01+/-0.004 mm/y relative to the control group over the course of this study. CONCLUSIONS: Long-term treatment with an ACE inhibitor (enalapril) slows progressive IM thickening of the common carotid artery in NIDDM patients.

Rapid differential endogenous plasminogen activator expression after acute middle cerebral artery occlusion.

BACKGROUND AND PURPOSE: During focal cerebral ischemia, the microvascular matrix (ECM), which participates in microvascular integrity, is degraded and lost when neurons are injured. Loss of microvascular basal lamina antigens coincides with rapid expression of select matrix metalloproteinases (MMPs). Plasminogen activators (PAs) may also play a role in ECM degradation by the generation of plasmin or by MMP activation. METHODS: The endogenous expressions of tissue-type plasminogen activator (tPA), urokinase (uPA), and PA inhibitor-1 (PAI-1) were quantified in 10-microm frozen sections from ischemic and matched nonischemic basal ganglia and in the plasma of 34 male healthy nonhuman primates before and after middle cerebral artery occlusion (MCA:O). RESULTS: Within the ischemic basal ganglia, tissue uPA activity and antigen increased significantly within 1 hour after MCA:O (2P<0.005). tPA activity transiently decreased 2 hours after MCA:O (2P=0.01) in concert with an increase in PAI-1 antigen (2P=0.001) but otherwise did not change. The transient decrease in free tPA antigen was marked by an increase in the tPA-PAI-1 complex (2P<0.001). No significant relations to neuronal injury or intracerebral hemorrhage were discerned. CONCLUSIONS: The rapid increase in endogenous PA activity is mainly due to significant increases in uPA, but not tPA, within the ischemic basal ganglia after MCA:O. This increase and an increase in PAI-1 coincided with latent MMP-2 generation and microvascular ECM degeneration but not neuronal injury.

Suboptimum hemicraniectomy as a cause of additional cerebral lesions in patients with malignant infarction of the middle cerebral artery.

OBJECT: The goal of this study was to determine the frequency of hemicraniectomy-associated lesions and their potential effect on the risk of mortality in patients suffering from malignant infarction of the middle cerebral artery MCA). METHODS: The authors evaluated serial computerized tomography scans obtained in 60 patients with complete infarction of the right MCA who were treated using hemicraniectomy. The maximum diameter of the hemicraniectomy was determined and the hemicraniectomy-associated lesions were classified as ischemic lesions or hemorrhages. The category of hemorrhages was composed of parenchymal, subdural, or epidural/subgaleal hematomas. Parenchymal hemorrhages and infarcts associated with hemicraniectomy occurred with frequency rates of 41.6% and 28.4%, respectively. The occurrence of hemicraniectomy-associated bleeding was related to the size of the hemicraniectomy performed; that is, the smaller the hemicraniectomy, the more often lesions occurred (p < 0.05). Hemicraniectomy-associated bleeding was also related to an increased risk of mortality. CONCLUSIONS: Hemicraniectomy is an effective therapy in patients with malignant infarction of the MCA. However, a hemicraniectomy that is too small in diameter may cause the formation of additional lesions and adversely affect the risk of mortality and the quality of survival. In addition, the size and shape of the edges of the bone defect are important factors relating to its efficacy.

Characterization of Inherited Differences in Transcription of the Human Integrin alpha 2 Gene.

Inherited, single-base substitutions are found at only two positions, C(-)52T and C(-)92G, within the proximal 5'-regulatory region (within -1096 to +48) of the human integrin alpha(2) gene. We recently reported that the T(-)52 substitution results in decreased binding of transcription factor Sp1 to adjacent binding sites, decreased transcription of the alpha(2) gene, and reduced densities of platelet alpha(2)beta(1). In this study, we identify an additional Sp1-binding site at position -107 to -99 and show that the adjacent dimorphic sequence C(-)92G also influences the rate of gene transcription. In the erythroleukemia cell line Dami, transfected promoter-luciferase constructs bearing the G(-)92 sequence exhibit roughly a 3-fold decrease in activity relative to the C(-)92 constructs. In transfected CHRF-288-11 megakaryocytic cells, the corresponding activity decreases by 5-fold. DNase I footprinting of the promoter region with Dami nuclear extracts showed a protected segment at -107 to -99 that can be deprotected by coincubation with molar excess of a consensus Sp1 oligonucleotide. Gel mobility shift assays and supershift assays with specific antibodies indicate that Sp1 binds to this region of the alpha(2) gene promoter. Mutation of the Sp1 binding element within -107 to -99 in constructs containing either C(-)92 or G(-)92 abolishes basal promoter activity and eliminates the binding of Sp1. The G(-)92 sequence has a gene frequency of 0.15 in a typical Caucasian population, and the presence of this allele correlates with reduced densities of platelet alpha(2)beta(1). The combined substitution G(-)92/T(-)52 has an additive influence on gene transcription, resulting in an 8-fold decrease in transfected Dami cells or a 20-fold decrease in transfected CHRF-288-11 cells. In summary, the natural dimorphism C(-)92G within the proximal 5'-regulatory region of the human integrin alpha(2) gene contributes to the regulation of integrin alpha(2)beta(1) expression on megakaryocytes and blood platelets and must thereby modulate collagen-related platelet function in vivo.

Allele-dependent transcriptional regulation of the human integrin alpha2 gene.

Genetically controlled variation in alpha2beta1 expression by human blood platelets was previously described. Sixty-two haplotype sequences corresponding to the proximal 5' regulatory region (-1096 to +1) of the alpha2 gene were compared, and a dimorphic sequence -52C>T was identified that is located precisely between 2 tandem Sp1/Sp3 binding elements previously shown to be absolutely required for transcriptional activity of this gene in epithelial cell lines and the erythroleukemic cell line K562. The gene frequency of -52T in a random Caucasian population is approximately 0.35, and the expression of -52T correlates directly with reduced densities of platelet alpha2beta1. In mobility shift analyses, the -52T substitution attenuates complex formation with both Sp1 and Sp3. When transfected into the erythroleukemia cell line Dami, promoter-luciferase constructs bearing the -52T sequence exhibit a 5-fold decrease in activity relative to the -52C construct. In transfected CHRF-288-11 megakaryocytic cells, the corresponding activity decreases by 10-fold. The -52T sequence appears to be in linkage disequilibrium with the previously defined allele A3 (807C; HPA-5b), known to be associated with diminished expression of platelet alpha2beta1. In summary, a natural dimorphism has been identified within the proximal 5' regulatory region of the human integrin alpha2 gene that is responsible for decreased expression levels of the integrin alpha2beta1 on blood platelets through a mechanism that is probably mediated by the nuclear regulatory proteins Sp1 and Sp3.

Predictive value of lesions for relapses in relapsing-remitting multiple sclerosis.

BACKGROUND AND PURPOSE: Recent studies have suggested that enhancing lesions on contrast-enhanced T1-weighted MR images are predictive of impending exacerbations in cases of relapsing-remitting multiple sclerosis. We examined whether enhancing lesions, new enhancing lesions, and new hypointense lesions ("black holes") could accurately predict exacerbations in a cohort of 50 patients with relapsing-remitting multiple sclerosis within a time frame of up to 6 months. METHODS: Data were obtained from 50 patients with relapsing-remitting disease. All patients underwent monthly MR imaging and clinical examinations for a period of 12 months. Putative predictors of clinical relapse were defined from enhancing lesions, new enhancing lesions, and new black hole outcomes, and their operating characteristics were studied. RESULTS: Overall, the positive predictive values (PV+) of enhancing lesions, new enhancing lesions, or new black holes for an exacerbation did not exceed 0.25 and the negative predictive values (PV-) were all near 0.9. The best predictor for new enhancing lesions was the occurrence of new enhancing lesions in each of the previous 3 months (PV+: 0.79 [95% confidence interval, 0.651-0.900]; PV-: 0.83 [95% confidence interval, 0.751-0.887]). Similarly, new black holes were predicted best by the occurrence of new black holes in each of the previous 2 months (PV+: 0.54 [95% confidence interval: 0.372-0.697]; PV-: 0.85 [95% confidence interval, 0.790-0.896]). CONCLUSION: None of the MR markers could predict an impending relapse with any reasonable degree of precision. Rather, the absence of MR markers is associated with a more favorable clinical course (ie, fewer relapses).

Persistent asthma: patient characteristics, courses of asthma, and utility of salmeterol.

Applications of National Asthma and Education and Prevention Program (NAEPP) guidelines for the diagnosis and management of asthma may reduce the morbidity of this disorder. Medical records and questionnaires from a series of 177 outer-city adolescents and adults with persistent asthma were audited according to NAEPP guidelines and for utility of salmeterol (Serevent). Allergic sensitivity and exposure to indoor allergens house-dust mite (66% of patients), fungi (42%), cat (20%) and/or dog (14%) were of dominant importance to persistent asthma. Patients who continued salmeterol over 1 year had reduced severity of disease, improved forced expiratory flow at 25%-75% of vital capacity, and reduced usage of systemic, but not inhaled, corticosteroid.

New hypointense lesions on MRI in relapsing-remitting multiple sclerosis patients.

BACKGROUND: Preliminary observational studies with multiple sclerosis (MS) patients have reported strong correlations between an increase in hypointense lesion load (black holes) on T1-weighted spin echo images, and an increase in disability. OBJECTIVE: We assessed the relationship of hypointense lesions to the clinical course of disease among 50 relapsing-remitting MS patients in the controlled setting of a randomized clinical trial. METHODS: Fifty patients with relapsing-remitting disease were enrolled in a randomized double-blind two-arm (cladribine vs. placebo) clinical trial of 1-year duration. All patients had monthly clinical evaluations and MRIs over the course of the trial. Multivariate techniques were used to identify predictors of clinical severity from information on exacerbations, MRIs, baseline clinical parameters, and demographics. RESULTS: At baseline, clinical severity is weakly related to counts of black holes, with rank correlations between counts and clinical scores (EDSS and SNRS) of absolute magnitude 0.3. Rates of appearance of new black holes over the course of the trial are higher for patients with more severe disease at baseline (EDSS > or = 4) than for the less severe patients. Changes in clinical severity over the course of the trial are best predicted by baseline neurologic scores and numbers of exacerbations, with black holes adding no further improvement in prediction. CONCLUSIONS: Numbers of exacerbations seem more critical to short-term clinical outcomes in relapsing-remitting MS, as reflected by patients' clinical scores, rather than black holes. Various imaging methods and MRI indices capture complementary information relating to MS disease processes. The determination of which processes are affected by different drugs should lead to more effective treatment of MS patients.

Asthma mortality rates among California youths.

Asthma mortality rates for California youths (ages 5-17 years) were examined over the period 1981-1995. Data were analyzed by Poisson regression from the California Departments of Vital Statistics, Finance, and the U.S. Census Bureau. Aggregate statewide mortality demonstrated a 2.01%, statistically insignificant, upward trend without geographic clustering. Stratified race/ ethnicity rates differed significantly, with African-American mortality twice that of the Caucasian population. In addition, an increased number of deaths occurred in households of African-Americans, Caucasians (including Hispanics), and Hispanics with incomes below statewide medians. This study on California youths differs from reports on larger populations with its minimal aggregate increase in asthma mortality, yet mirrors national trends of disproportionate impact on African-Americans and the economically disadvantaged.