Olfactory receptor Olfr78 (prostate-specific G protein-coupled receptor PSGR) expression in arterioles supplying skeletal and cardiac muscles and in arterioles feeding some murine organs.

The olfactory receptor Olfr78 (prostate-specific G protein-coupled receptor PSGR) is a member of the G protein-coupled receptor family mediating olfactory chemosensation, but it is additionally expressed in other tissues. Olfr78 expressed in kidney participates in blood pressure regulation, and in prostate it plays a role in the development of cancer. We here screened many organs/tissues of transgenic mice co-expressing ß-galactosidase with Olfr78. X-gal-positive cells were detectable in smooth muscle cells of numerous arterioles of striated muscles (heart ventricles and skeletal muscles of various embryological origin). In addition, in most organs where we found expression of Olfr78 mRNA, X-gal staining was restricted to smooth muscle cells of small blood vessels. The dominant expression of Olfr78 in arteriolar smooth muscle cells supports the concept of an important role in blood pressure regulation and suggests a participation in the fine tuning of blood supply especially of striated muscles. This should be considered when targeting Olfr78 in other contexts such as prostate cancer.

Activation of the mouse odorant receptor 37 subsystem coincides with a reduction of novel environment-induced activity within the paraventricular nucleus of the hypothalamus.

Within the main olfactory system of mammals, a unique subsystem exists that is comprised of sensory neurons expressing odorant receptors (ORs) of the OR37 subfamily. These receptors are exclusive for mammals and are highly conserved across species. The mouse OR37 receptor subtypes A, B and C were shown to be activated by the long-chain aliphatic aldehydes pentadecanal, hexadecanal and heptadecanal, respectively. The search for biological sources of these compounds showed that bodily secretions from conspecifics activated the OR37A, B and C glomerulus. At the same time, the activity of cells in a target region of projection neurons from OR37 glomeruli, the paraventricular nucleus of the hypothalamus (PVN), was reduced compared with controls (clean test box). A large number of the activated cells in the PVN of mice that were placed into a clean test box were corticotropin-releasing hormone cells, indicating an induction of the stress axis due to the novel environment. The much lower number of activated cells of mice in a box enriched with bodily secretions from conspecifics indicated a reduced stress response. As bodily secretions from conspecifics activated the OR37 system and simultaneously reduced stress-induced activation of the PVN, it was tested whether the ligands for OR37 receptors could induce this effect. Indeed, a similarly reduced activity in the PVN was found in mice kept in a clean test box and exposed to a mixture of the OR37 ligands delivered via an air stream. These data indicate that the OR37 system may play a role in mediating a phenomenon called social buffering.

Endocrine Modulation of Olfactory Responsiveness: Effects of the Orexigenic Hormone Ghrelin.

Finding food sources is a prerequisite for an acute food intake. This process is initiated by ghrelin released from X/A-like cells of the gastrointestinal tract. Because food finding often depends on olfaction, the question arises whether ghrelin may affect the responsiveness of the olfactory system. Monitoring odor-induced activation of the mouse olfactory epithelium via Egr1 expression revealed that after a nasal application of ghrelin, more sensory neurons responded upon odor exposure indicating an increased responsiveness. The higher reactivity of olfactory neurons was accompanied with an increased activity of receptor-specific glomeruli. In search for mechanisms underlying the ghrelin-mediated sensitization of olfactory neurons, it was shown that Ghsr1a, the ghrelin receptor gene, but not the hormone itself was expressed in the olfactory epithelium. Further analysis of isolated cells revealed that the receptor was in fact expressed in mature olfactory sensory neurons. Treatment with a ghrelin receptor antagonist abolished the ghrelin effect, strengthening the notion that ghrelin and its receptor are responsible for the enhanced neuronal responsiveness. In contrast to the effects of the "hunger" hormone ghrelin, the short-term "satiety" hormone PYY3-36 did not affect olfactory responsiveness. The results demonstrate that ghrelin, which signals acute hunger, renders the olfactory system more responsive to odors.

Identification of a natural source for the OR37B ligand.

In search for biological sources of the long-chain fatty aldehydes (penta-, hexa-, and heptadecanal), which we recently identified as ligands for members of the mouse odorant receptor subfamily OR37, the headspace of secretions and excretions from mice was analyzed by gas chromatography and mass spectrometry. In urine, skin swabs, and saliva, these components were not detectable. However, in fecal pellets, a substantial amount of hexadecanal, the OR37B ligand, was found. Accordingly, exposure of mice to feces induced an activation of the OR37B glomerulus, whereas the OR37A and the OR37C glomerulus were not responsive. The amount of hexadecanal deposited with feces varied significantly; however, it was independent of the amount of feed. In many species, feces is covered with secretion from anal glands. Due to the size and the inaccessibility of these glands in mice, the headspace of anal gland secretion from dog was analyzed by gas chromatography-mass spectrometry, which resulted in a prominent peak for hexadecanal. Exposure of mice to anal gland secretion from dog activated the OR37B glomerulus. Altogether, these data suggest that hexadecanal, a ligand for the receptor OR37B, is produced in anal glands and deposited with feces into the environment.

Case Report: The woman with the big heart-an imaging-guided attempt of surgical reduction.

In a female patient with acute cardiac decompensation, an auxiliary finding of a giant left atrium emerged. The surgical therapy of the atrial reduction, in addition to a mitral valve replacement and a coronary artery bypass grafting, is hereby presented.

Endothelin receptor B-deficient mice are protected from high-fat diet-induced metabolic syndrome.

OBJECTIVE: Endothelin receptor B (ETB) together with ETA mediates cellular effects of endothelin 1 (ET-1), an autocrine and endocrine peptide produced by the endothelium and other cells. It regulates vascular tone and controls kidney function. Metabolic syndrome is due to high caloric intake and is characterized by insulin resistance, dyslipidemia, and white adipose tissue (WAT) accumulation. ETA/ETB antagonism has been demonstrated to favorably influence insulin resistance. Our study explored the role of ETB in metabolic syndrome. METHODS: Wild type (etb+/+) and rescued ETB-deficient (etb-/-) mice were fed a high-fat diet, and energy, glucose, and insulin metabolism were analyzed, and hormones and lipids measured in serum and tissues. Cell culture experiments were performed in HepG2 cells. RESULTS: Compared to etb+/+ mice, etb-/- mice exhibited better glucose tolerance and insulin sensitivity, less WAT accumulation, lower serum triglycerides, and higher energy expenditure. Protection from metabolic syndrome was paralleled by higher hepatic production of fibroblast growth factor 21 (FGF21) and higher serum levels of free thyroxine (fT4), stimulators of energy expenditure. CONCLUSIONS: ETB deficiency confers protection from metabolic syndrome by counteracting glucose intolerance, dyslipidemia, and WAT accumulation due to enhanced energy expenditure, effects at least in part dependent on enhanced production of thyroid hormone/FGF21. ETB antagonism may therefore be a novel therapeutic approach in metabolic syndrome.

Analysis of left ventricular mass in untreated men and in men treated with agalsidase-ß: data from the Fabry Registry.

PURPOSE: The aim of this study was to evaluate the progression of left ventricular hypertrophy in untreated men with Fabry disease and to assess the effects of agalsidase-ß (recombinant human α-galactosidase A) on left ventricular hypertrophy. METHODS: Longitudinal Fabry Registry data were analyzed from 115 men treated with agalsidase-ß (1 mg/kg/2 weeks) and 48 untreated men. Measurements included baseline left-ventricular mass and at least one additional left-ventricular mass assessment over ≥ 2 years. Patients were grouped into quartiles, based on left-ventricular mass slopes. Multivariate logistic regression analyses identified factors associated with left ventricular hypertrophy progression. RESULTS: For men in whom treatment was initiated at the age of 18 to <30 years, mean left ventricular mass slope was -3.6 g/year (n = 31) compared with +9.5 g/year in untreated men of that age (n = 15) (P < 0.0001). Untreated men had a 3.4-fold higher risk of having faster increases in left-ventricular mass compared with treated men (odds ratio: 3.43; 95% confidence interval: 1.05-11.22; P = 0.0415). A baseline age of ≥ 40 years was also associated with left--ventricular hypertrophy progression (odds ratio: 5.03; 95% confidence interval: 1.03-24.49; P = 0.0457) compared with men younger than 30 years. CONCLUSION: Agalsidase-ß treatment for ≥2 years may improve or stabilize left-ventricular mass in men with Fabry disease. Further investigations may determine whether early intervention and stabilization of LVM are correlated with clinical outcomes.

Short-term fasting of mice elevates circulating fibroblast growth factor 23 (FGF23).

AIMS: Phosphate and vitamin D homeostasis are controlled by fibroblast growth factor 23 (FGF23) from bone suppressing renal phosphate transport and enhancing 24-hydroxylase (Cyp24a1), thereby inactivating 1,25(OH)2 D3 . Serum FGF23 is correlated with outcomes in several diseases. Fasting stimulates the production of ketone bodies. We hypothesized that fasting can induce FGF23 synthesis through the production of ketone bodies. METHODS: UMR106 cells and isolated neonatal rat ventricular myocytes (NRVM) were treated with ketone body ß-hydroxybutyrate. Mice were fasted overnight, fed ad libitum, or treated with ß-hydroxybutyrate. Proteins and further blood parameters were determined by enzyme-linked immunoassay (ELISA), western blotting, immunohistochemistry, fluorometric or colorimetric methods, and gene expression by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: ß-Hydroxybutyrate stimulated FGF23 production in UMR106 cells in a nuclear factor kappa-light-chain enhancer of activated B-cells (NFκB)-dependent manner, and in NRVMs. Compared to fed animals, fasted mice exhibited higher ß-hydroxybutyrate and FGF23 serum levels (based on assays either detecting C-terminal or intact, biologically active FGF23 only), cardiac, pancreatic, and thymic Fgf23 and renal Cyp24a1 expression, and lower 1,25(OH)2 D3 serum concentration as well as renal Slc34a1 and αKlotho (Kl) expression. In contrast, Fgf23 expression in bone and serum phosphate, calcium, plasma parathyroid hormone (PTH) concentration, and renal Cyp27b1 expression were not significantly affected by fasting. CONCLUSION: Short-term fasting increased FGF23 production, as did administration of ß-hydroxybutyrate, effects possibly of clinical relevance in view of the increasing use of FGF23 as a surrogate parameter in clinical monitoring of diseases. The fasting state of patients might therefore affect FGF23 tests.

Untypical connectivity from olfactory sensory neurons expressing OR37 into higher brain centers visualized by genetic tracing.

The OR37 subfamily of odorant receptors(ORs) exists exclusively in mammals. In contrast to ORs in general, they are highly conserved within and across species.These unique features raise the question, whether olfactory information gathered by the OR37 sensory cells is processed in specially designated brain areas. To elucidate the wiring of projection neurons from OR37 glomeruli into higher brain areas, tracing experiments were performed.The application of DiI onto the ventral area of the olfactory bulb, which harbors the OR37 glomeruli, led to the labeling of fibers not only in the typical olfactory cortical regions,but also in the medial amygdala and the hypothalamus. To visualize the projections from a defined OR37 glomerulus more precisely, transgenic mice were studied in which olfactory sensory neurons co-express the receptor subtype OR37C and the transsynaptic tracer wheat germ agglutinin(WGA). WGA became visible not only in the OR37C sensory neurons and the corresponding OR37C glomerulus,but also in cell somata located in the mitral/tufted cell layer adjacent to the OR37C glomerulus, indicating a transfer of WGA onto projection neurons. In the brain, WGA immunoreactivity was not detectable in typical olfactory cortical areas, but instead in distinct areas of the medial amygdala.Detailed mapping revealed that the WGA immunoreactivity was restricted to the posterior-dorsal subnucleus of the medial amygdala. In addition, WGA immunoreactivity was visible in some well-circumscribed areas of the hypothalamus.These results are indicative for a unique connectivity from OR37C sensory cells into higher brain centers.

Mammalian-specific OR37 receptors are differentially activated by distinct odorous fatty aldehydes.

The capacity of the mammalian olfactory system to detect an enormous collection of different chemical compounds is based on a large repertoire of odorant receptors (ORs). A small group of these ORs, the OR37 family, is unique due to a variety of special features. Members of this subfamily are exclusively found in mammals, they share a high degree of sequence homology and are highly conserved during evolution. It is still elusive which odorants may activate these atypical receptors. We have reasoned that compounds from skin, hairs, or skin glands might be potential candidates. We have exposed mice to such compounds and monitored activation of glomeruli through the expression of the activity marker c-fos in juxtaglomerular cells surrounding ventrally positioned glomeruli in the olfactory bulb (OB). Employing this methodology it was found that stimulation with long-chain alkanes elicits activation in the ventral part of the OB, however, none of the OR37 glomeruli. Analyses of long-chain hydrocarbon compounds with different functional groups revealed that long-chain aliphatic aldehydes elicited an activation of defined OR37 glomeruli, each of them responding preferentially to an aldehyde with different chain lengths. These results indicate that OR37 receptors may be tuned to distinct fatty aldehydes with a significant degree of ligand specificity.

Internalization of odorant-binding proteins into the mouse olfactory epithelium.

The detection of odorants in vertebrates is mediated by chemosensory neurons that reside in the olfactory epithelium of the nose. In land-living species, the hydrophobic odorous compounds inhaled by the airstream are dissolved in the nasal mucus by means of specialized globular proteins, the odorant-binding proteins (OBPs). To assure the responsiveness to odors of each inhalation, a rapid removal of odorants from the microenvironment of the receptor is essential. In order to follow the fate of OBP/odorant complexes, a recombinant OBP was fluorescently labeled, loaded with odorous compounds, and applied to the nose of a mouse. Very quickly, labeled OBP appeared inside the sustentacular cells of the epithelium. This uptake occurred only when the OBP was loaded with appropriate odorant compounds. A search for candidate transporters that could mediate such an uptake process led to the identification of the low density lipoprotein receptor Lrp2/Megalin. In the olfactory epithelium, megalin was found to be specifically expressed in sustentacular cells and the Megalin protein was located in their microvilli. In vitro studies using a cell line that expresses megalin revealed a rapid internalization of OBP/odorant complexes into lysosomes. The uptake was blocked by a Megalin inhibitor, as was the internalization of OBPs into the sustentacular cells of the olfactory epithelium. The results suggest that a Megalin-mediated internalization of OBP/odorant complexes into the sustentacular cells may represent an important mechanism for a rapid and local clearance of odorants.

Glucocorticoids dexamethasone and prednisolone suppress fibroblast growth factor 23 (FGF23).

Fibroblast growth factor 23 (FGF23) is a hormone mainly secreted by bone cells. Its most prominent effects are the regulation of renal phosphate reabsorption and calcitriol (active vitamin D, 1,25(OH)2D3) formation, effects dependent on its co-receptor αKlotho. Besides these actions, further paracrine and endocrine effects exist. The production of FGF23 is regulated by 1,25(OH)2D3, parathyroid hormone, dietary phosphate intake, iron status, as well as inflammation. Glucocorticoids are hormones with anti-inflammatory properties and are, therefore, widely used for acute and chronic inflammatory diseases, autoimmune disorders, and malignancies. The present study explored whether glucocorticoids influence the production of FGF23 in vitro as well as in mice. Fgf23 transcription was analyzed by semi-quantitative real-time PCR. Serum concentrations of FGF23 and 1,25(OH)2D3 were measured by ELISA. Urinary phosphate and Ca2+ excretion were determined in metabolic cages. As a result, in UMR106 rat osteoblast-like cells and in MC3T3-E1 cells, both, dexamethasone and prednisolone, downregulated Fgf23 transcription and FGF23 protein synthesis. Dexamethasone increased Dmp1 and Phex (encoding FGF23-regulating genes) as well as Nfkbia (encoding NFκB inhibitor IκBα) transcription in UMR106 cells. In mice, a single injection of dexamethasone or prednisolone was followed by a significant decrease of serum C-terminal and intact FGF23 concentration and bone Fgf23 mRNA expression within 12 h. These effects were paralleled by increased renal phosphate excretion and enhanced 1,25(OH)2D3 formation. We conclude that a single glucocorticoid treatment strongly downregulates the FGF23 plasma concentration. KEY MESSAGES: Glucocorticoids dexamethasone and prednisolone suppress the formation of bone-derived hormone fibroblast growth factor 23 (FGF23) in vitro. The effect is accompanied by an upregulation of Dmp1, Phex, and IκBα, negative regulators of FGF23, in UMR106 osteoblast-like cells. Glucocorticoid receptor antagonist RU-486 attenuates the effect of dexamethasone on FGF23, Dmp1, and Phex. In mice, a single glucocorticoid dose suppresses FGF23 and enhances 1,25(OH)2D3 (active vitamin D).

Long-term effects of enzyme replacement therapy on fabry cardiomyopathy: evidence for a better outcome with early treatment.

BACKGROUND: Enzyme replacement therapy with recombinant alpha-galactosidase A reduces left ventricular hypertrophy and improves regional myocardial function in patients with Fabry disease during short-term treatment. Whether enzyme replacement therapy is effective in all stages of Fabry cardiomyopathy during long-term follow-up is unknown. METHODS AND RESULTS: We studied 32 Fabry patients over a period of 3 years regarding disease progression and clinical outcome under enzyme replacement therapy. Regional myocardial fibrosis was assessed by magnetic resonance imaging late-enhancement technique. Echocardiographic myocardial mass was calculated with the Devereux formula, and myocardial function was quantified by ultrasonic strain-rate imaging. In addition, exercise capacity was measured by bicycle stress test. All measurements were repeated at yearly intervals. At baseline, 9 patients demonstrated at least 2 fibrotic left ventricular segments (severe myocardial fibrosis), 11 had 1 left ventricular segment affected (mild fibrosis), and 12 were without fibrosis. In patients without fibrosis, enzyme replacement therapy resulted in a significant reduction in left ventricular mass (238+/-42 g at baseline, 202+/-46 g at 3 years; P for trend <0.001), an improvement in myocardial function (systolic radial strain rate, 2.3+/-0.4 and 2.9+/-0.6 seconds(-1), respectively; P for trend=0.045), and a higher exercise capacity obtained by bicycle stress exercise (106+/-14 and 122+/-26 W, respectively; P for trend=0.014). In contrast, patients with mild or severe fibrosis showed a minor reduction in left ventricular hypertrophy and no improvement in myocardial function or exercise capacity. CONCLUSIONS: These data suggest that treatment of Fabry cardiomyopathy with recombinant alpha-galactosidase A should best be started before myocardial fibrosis has developed to achieve long-term improvement in myocardial morphology and function and exercise capacity.

Impact of myocardial fibrosis in patients with symptomatic severe aortic stenosis.

BACKGROUND: In this prospective follow-up study, the effect of myocardial fibrosis on myocardial performance in symptomatic severe aortic stenosis was investigated, and the impact of fibrosis on clinical outcome after aortic valve replacement (AVR) was estimated. METHODS AND RESULTS: Fifty-eight consecutive patients with isolated symptomatic severe aortic stenosis underwent extensive baseline characterization before AVR. Standard and tissue Doppler echocardiography and cardiac magnetic resonance imaging (late-enhancement imaging for replacement fibrosis) were performed at baseline and 9 months after AVR. Endomyocardial biopsies were obtained intraoperatively to determine the degree of myocardial fibrosis. Patients were analyzed according to the severity of interstitial fibrosis in cardiac biopsies (severe, n=21; mild, n=15; none, n=22). The extent of histologically determined cardiac fibrosis at baseline correlated closely with New York Heart Association functional class and markers of longitudinal systolic function (all P<0.001) but not global ejection fraction or aortic valve area. Nine months after AVR, the degree of late enhancement remained unchanged, implying that AVR failed to reduce the degree of replacement fibrosis. Patients with no fibrosis experienced a marked improvement in New York Heart Association class from 2.8+/-0.4 to 1.4+/-0.5 (P<0.001). Only parameters of longitudinal systolic function predicted this functional improvement. Four patients with severe fibrosis died during follow-up, but no patient from the other groups died. CONCLUSIONS: Myocardial fibrosis is an important morphological substrate of postoperative clinical outcome in patients with severe aortic stenosis and was not reversible after AVR over the 9 months of follow-up examined in this study. Because markers of longitudinal systolic function appear to indicate sensitively both the severity of myocardial fibrosis and the clinical outcome, they may prove valuable for preoperative risk assessment in patients with aortic stenosis.

Gene switching and odor induced activity shape expression of the OR37 family of olfactory receptor genes.

Olfactory sensory neurons (OSNs) which express distinct odorant receptor (OR) genes are spatially arranged within the mouse olfactory epithelium. Towards an understanding of the mechanisms which determine these patterns, representative OR genes which are typically expressed in the unique central patch of the epithelium were investigated. Inside the patch, numerous OSNs which initially selected a representative gene from this OR group finally expressed another gene from the group, indicating that OSNs inside the patch 'switch' between these genes. If an OSN successively chose genes from the same OR gene cluster, these originated from the same parental chromosome. A deletion of the olfactory cyclic nucleotide-gated ion channel altered the distribution pattern of distinct OSN populations; they were no longer located exclusively inside the patch. Together, the results indicate that OSNs inside the patch initially sample several OR genes for expression; for their correct patterning in the OE, odor-induced activity appears to play a critical role.

A validated disease severity scoring system for Fabry disease.

Fabry disease is a lysosomal storage disorder with onset of adverse signs and symptoms usually during childhood and progressive life-threatening decline in organ functions. A validated and feasible Fabry disease severity scoring system (DS3) is needed to reliably quantify the disease burden, monitor disease progression and treatment response, and compare disease status among patient cohorts in clinical studies. We developed a new Fabry DS3 and tested its reliability and validity using a combination of expert consensus formation and statistical techniques. Relevant Fabry disease domains and items were identified, inclusion of items was refined and scaling of scores for individual assessments was optimized to maximize the correlation between the instrument's total score and the assigned clinical global impression of severity (CGI-S scores). Furthermore, the minimum clinically important difference in each of the instrument's domains was estimated and the DS3's quantitative content validity was judged. The current Fabry DS3 working model has 5 domains; 4 clinical domains (Peripheral Nervous System, Renal, and Cardiac, each with 3 items, Central Nervous System with 2 items) and a patient-reported domain (Patient-Reported domain with one item). The domain score is obtained by averaging the scores for all domain items. The Content Validity Index and Feasibility Index were shown to be good; 0.96 and 0.97, respectively. There was no significant inter-rater difference and the level of concordance was high. Correlation with the CGI-S was R(2)=0.89 indicating excellent criterion and construct (convergent) validity. In summary, initial estimations of validity, reliability and feasibility for the new Fabry DS3 instrument suggest that it is a feasible and reliable means of assessing disease severity and progression over time and comparing inter-patient severity of Fabry disease. Our results demonstrate that the Fabry DS3 correlates highly with the clinical assessment by Fabry disease experts.

The patch-like pattern of OR37 receptors is formed by turning off gene expression in non-appropriate areas.

Olfactory sensory neurons (OSNs) expressing the same odorant receptor (OR) gene are generally widely dispersed throughout the olfactory epithelium (OE). In contrast, OSNs expressing any member from the special OR37 subfamily are concentrated in a small patch in the centre of the OE. To evaluate whether transcription of OR37 genes is only possible in the patch region, or if they can generally be chosen also in non-appropriate areas, a transgenic approach was employed that permanently labelled all cells which ever transcribed a representative OR37 gene. It was found that - in addition to cells inside the patch - numerous cells outside were labelled, indicating that they had transcribed the OR37 gene, but then turned it off while choosing another OR gene. Permanent expression of the OR37 gene was exclusively maintained in the patch. The results suggest that mechanisms acting downstream of an initial OR gene choice restrict OR37 expression to the patch.

Evaluation of Myocardial Gene Expression Profiling for Superior Diagnosis of Idiopathic Giant-Cell Myocarditis and Clinical Feasibility in a Large Cohort of Patients with Acute Cardiac Decompensation.

AIMS: The diagnostic approach to idiopathic giant-cell myocarditis (IGCM) is based on identifying various patterns of inflammatory cell infiltration and multinucleated giant cells (GCs) in histologic sections taken from endomyocardial biopsies (EMBs). The sampling error for detecting focally located GCs by histopathology is high, however. The aim of this study was to demonstrate the feasibility of gene profiling as a new diagnostic method in clinical practice, namely in a large cohort of patients suffering from acute cardiac decompensation. Methods and Results: In this retrospective multicenter study, EMBs taken from n = 427 patients with clinically acute cardiac decompensation and suspected acute myocarditis were screened (mean age: 47.03 ± 15.69 years). In each patient, the EMBs were analyzed on the basis of histology, immunohistology, molecular virology, and gene-expression profiling. Out of the total of n = 427 patient samples examined, GCs could be detected in 26 cases (6.1%) by histology. An established myocardial gene profile consisting of 27 genes was revealed; this was narrowed down to a specified profile of five genes (CPT1, CCL20, CCR5, CCR6, TLR8) which serve to identify histologically proven IGCM with high specificity in 25 of the 26 patients (96.2%). Once this newly established profiling approach was applied to the remaining patient samples, an additional n = 31 patients (7.3%) could be identified as having IGCM without any histologic proof of myocardial GCs. In a subgroup analysis, patients diagnosed with IGCM using this gene profiling respond in a similar fashion to immunosuppressive therapy as patients diagnosed with IGCM by conventional histology alone. Conclusions: Myocardial gene-expression profiling is a promising new method in clinical practice, one which can predict IGCM even in the absence of any direct histologic proof of GCs in EMB sections. Gene profiling is of great clinical relevance in terms of a) overcoming the sampling error associated with purely histologic examinations and b) monitoring the effectiveness of therapy.

Characterization of connexin31.1-deficient mice reveals impaired placental development.

The gap junction gene Connexin31.1 has been reported to be expressed predominantly in the epidermis of murine skin. To study the function of this gene, we generated mice in which the coding DNA of the Connexin31.1 gene was replaced by lacZ reporter coding DNA. Using beta-galactosidase staining, we have shown that lacZ/Connexin31.1 was expressed in the spinous and granular layers of the epidermis, in cells of olfactory epithelium and in the vomeronasal organ. During embryogenesis, Connexin31.1 was co-expressed with another isoform, Connexin31, in the post-implantation trophoblast cell lineage and, later in gestation, in placental glycogen cells. Although homozygous Connexin31.1-deficient mice were fertile and showed no morphological or functional defects in adult organs expressing this gene, 30% of the offspring expected according to Mendelian inheritance were lost between embryonic days 11.5 and 14.5 and surviving embryos were significantly reduced in weight near the end of pregnancy. Placentas of Connexin31.1-deficient embryos were reduced in weight and showed altered morphology of the spongiotrophoblast and labyrinth layer. The spongiotrophoblast formed a compact barrier at the decidual border that might restrict the maternal blood supply. We conclude that Connexin31.1 is critical for normal placental development but appears to be functionally compensated by other connexin isoforms in the embryo proper and adult mouse.

Functional differences of left ventricular hypertrophy induced by either arterial hypertension or aortic valve stenosis.

The aim of this study was to reveal functional differences of left ventricular (LV) hypertrophy induced by either aortic stenosis (AS) or arterial hypertension (AH) assessed by strain-rate imaging. Twenty patients with AS and 19 patients with AH were enrolled. In the 2 groups, coronary artery disease was ruled out invasively. All subjects underwent echocardiographic studies, including strain-rate imaging studies of LV long- and short-axis function. Eight patients underwent follow-up examinations after aortic valve replacement, and 20 healthy volunteers served as a control group. LV end-diastolic posterior wall thickness was not different between the 2 patient groups (12.7 +/- 2.5 mm in AS vs 12.8 +/- 1.6 mm in AH) but was significantly increased compared with the control group (8.5 +/- 1.1 mm). The LV ejection fraction was within normal limits in all groups but significantly lower in the patient groups (54 +/- 9% in AS, 55 +/- 6% in AH) compared with the control group (66 +/- 3%). Radial and longitudinal systolic strain rates were depressed in patients with AS compared with those with AH and controls (radial 1.6 +/- 0.6 vs 2.6 +/- 0.6 and 3.8 +/- 0.6 s(-1), respectively, p <0.005). After valve replacement, longitudinal strain rate remained unchanged, but radial strain rate gradually increased (1.6 +/- 0.6 vs 2.1 +/- 0.8 s(-1), p = NS). In parallel, the ejection fraction gradually improved and LV hypertrophy gradually diminished. In conclusion, despite the same degree of LV wall thickness, AS and AH have different impacts on the rate of LV deformation.