Regulatory mechanisms for natriuretic peptide signalling in sheep granulosa cells.

Natriuretic peptides (NPs) have been reported to have critical roles in follicular development and oocyte maturation in rodents. This study aimed to extend our current understanding of NP-mediated signalling pathways and mechanisms of action in the follicles of a monovulatory species. Ovine granulosa cells (GCs) and theca cells (TCs) were cultured under conditions designed to allow gonadotrophin-stimulated cell differentiation. Gene expression analysis was performed by qualitative (q)PCR for NPs and NPRs (between 16 and 96 h of culture) and VEGF120 and VEGF164 (between 16 and 144 h of culture). A qualitative analysis of the production of NP/NPR family members and NP ligand/receptor associations was carried out utilising a highly sensitive immunological approach known as 'proximity ligation assay' (PLA). All NPRs were observed in GCs, while NPRA was absent in TCs. In GCs, gene expression of NPRA, NPRB and NPRC was apparent but only active BNP and CNP and not ANP, were detected. Also in GCs, ANP but not CNP was able to significantly (P < 0.05) reduce oestradiol and increase (P < 0.05) progesterone. Inhibition of VEGF164 by ANP and CNP (P < 0.01) after 48 h of culture preceded up-regulation of VEGF120 by ANP (P < 0.01) after 144 h, but not CNP. Taken together, these findings appear to demonstrate that NP responsiveness in the GC compartment of sheep follicles is multi-facilitated, utilising both autocrine and paracrine stimulation pathways.

Embryo cell allocation patterns are not altered by biopsy but can be linked with further development.

It has been suggested that first embryo cleavage can be related with the embryonic-abembryonic axis at blastocyst stage in mice. Thus, cells of the 2-cell embryo might be already biased to form the inner cell mass or trophectoderm. This study was conducted to observe the possible effects of embryo biopsy on cell allocation patterns during embryo preimplantation in two different mouse strains and the effects of these patterns on further development. First, one blastomere of the 2-cell embryo was injected with a lipophilic tracer and cell allocation patterns were observed at blastocyst stage. Blastocysts were classified into orthogonal, deviant or random pattern. For the first experiment, embryos were biopsied at 8-cell stage and total cell counts (TCC) were annotated. Furthermore, non-biopsied blastocysts were transferred into foster mothers. Then, pups and their organs were weighed two weeks after birth. Random pattern was significantly recurrent (≈60%), against orthogonal (<22%) and deviant (<22%) patterns among groups. These patterns were not affected by biopsy procedure. However, TCC on deviant embryos were reduced after biopsy. Moreover, no differences were found between patterns for implantation rates, litter size, live offspring and organ weights (lungs, liver, pancreas and spleen). However, deviant pups presented heavier hearts and orthogonal pups presented lighter kidneys among the group. In conclusion, these results suggest that single blastomere removal does not disturb cell allocation patterns during pre-implantation. Nonetheless, the results suggest that embryos following different cell allocation patterns present different coping mechanisms against in vitro manipulations and further development might be altered.

Pre-translational regulation of luteinizing hormone receptor in follicular somatic cells of cattle.

Differential regulation of LHR in theca cells (TC) and granulosa cells (GC) is important for normal follicular development. Unlike TC, GC only acquire LH-responsiveness during the later stages of antral follicle development. This study tested the hypothesis that differential LH-responsiveness in these two cell types may be due, in part, to shifts in cellular patterns of alternatively spliced LHR mRNA transcripts which may not be obvious from analysis of total LHR gene expression. It also further explored the role of translation inhibition by an LHR binding protein (LHBP), normally associated with the production of endogenous cholesterol. LHR mRNA variation arises as a result of the alternative splicing of two variable deletion sites (VDS) designated 5' VDS and 3' VDS, and it was proposed that differences in cell sensitivity to LH may be due in part to variations in the pattern of the mRNA expression of the receptor variants. The outcomes of the present study support a dynamic multi-facetted regulation of LHR during pre-translation. Not only did the ratio between variants change during antral follicle growth and in vitro cell differentiation but also between TC and GC. Regulation could also be linked to LH concentration feedback mechanisms as the absence of LH caused cultured TC to markedly up-regulate amounts of LHR mRNA. In both TC and GC, LHR mRNA was greatly reduced after treatment to block mevalonate production in the de novo cholesterol pathway, adding further support for a regulatory mechanism linked to enriched cellular amounts of mevalonate kinase.

Resistin is elevated following traumatic joint injury and causes matrix degradation and release of inflammatory cytokines from articular cartilage in vitro.

OBJECTIVE: Resistin is a secreted factor that is elevated in rheumatoid arthritis (RA) and believed to drive joint inflammation in vivo. This study was undertaken to determine if resistin is present in the joint following joint injury and to elucidate the role of resistin in cartilage degradation. METHODS: The level of resistin was measured in paired synovial fluid (SF) and serum samples from patients following joint injury (anterior cruciate ligament, ACL or meniscus tear). Localization of resistin was visualized by immunohistochemistry of synovial tissue and cartilage from healthy and OA donors. Mouse and human cartilage cultures were used to assess the effect of resistin on cartilage metabolism. RESULTS: In trauma patients, resistin levels declined with increasing time post injury. The resistin levels were highest in samples collected up to 1 week following traumatic injury (SF: 2980 pg/ml, serum: 7901 pg/ml) and lowest in samples collected 6-26 years post injury (SF: 686 pg/ml, serum: 5682 pg/ml). Resistin was shown to be expressed in macrophage-like cells in both healthy and OA synovial tissue. Treatment of mouse cartilage cultures with recombinant resistin led to a dose dependent loss of proteoglycan and induction of inflammatory cytokine and PGE(2) production. Recombinant resistin inhibited proteoglycan synthesis in human cartilage explants. CONCLUSION: Resistin is elevated both systemically and locally in the weeks immediately following joint injury and has a direct effect on cartilage matrix turnover and cytokine production. Resistin may play a role in the early stages of trauma-induced OA and may represent a new therapeutic target to slow joint destruction in OA.

Leptin in the bovine corpus luteum: receptor expression and effects on progesterone production.

In cattle, leptin has been implicated in the control of ovarian function and has been shown to modulate steroid production by theca and granulosa cells in a number of species. However, a direct effect of leptin on bovine luteal function has not been demonstrated. This study was conducted to determine if the leptin receptor (OB-R) is expressed in the bovine corpus luteum (CL), and to examine the effects of leptin on progesterone production by dispersed luteal cells in vitro. RT-PCR was used to detect the presence of OB-R and, more specifically, the long, biologically active isoform (OB-Rb), in CL, collected on days 2-18 of the oestrous cycle (n=18). The effects of leptin on progesterone production were investigated in dispersed luteal cells prepared from CL collected on days 5 and 8 (n=14) of the cycle. The dispersed luteal cells were cultured for 24 hr with recombinant human leptin and/or LR3-IGF-1 and/or LH. OB-Rs, in particular, OB-Rb, were expressed in the CL at all stages of development. Progesterone production by luteal cells was increased (P<0.001) by treatment with LH (10 ng/ml) but treatment with leptin alone had no effect. However, in the presence of IGF-1 (100 ng/ml), leptin (10 ng/ml) caused a significant (P<0.005) increase in progesterone production. In conclusion, we have shown that the leptin receptor is expressed in the bovine CL and have demonstrated a modulatory effect of leptin on luteal progesterone production in vitro.

Effect of copper and thiomolybdates on bovine theca cell differentiation in vitro.

Subfertility that will respond to appropriate copper supplementation is a widespread problem in the national dairy herd. The aims of this study were to determine the effect of copper and/or copper chelating thiomolybdates on LH-induced differentiation by looking at the effects on androgen production, steroidogenic enzymes (cytochrome P450 17alpha-hydroxylase and cytochrome P450 side-chain cleavage) and lysyl oxidase mRNA expression in cultured theca cells maintained under serum-free conditions. The effect of thiomolybdates and copper on LH differentiation was investigated by supplementing (ammonium) tetrathiomolybdate to optimum theca cell culture media at 0-100 microg/ml, copper (chloride) at equimolar concentrations (0-51.6 microg/ml) or equimolar combinations of both media. Lysyl oxidase mRNA expression was investigated with semi-quantitative RT-PCR, whilst expression of cytochrome P450 17alpha-hydroxylase and cytochrome P450 side-chain cleavage mRNA was examined using real time PCR. Both PCRs used bovine specific primers and cell lysates obtained from bovine theca cells cultured for 6 days and in the presence or absence of the 100 microg/ml dose of thiomolybdate and equimolar copper thiomolybdate. Thiomolybdate depressed androstenedione production in a dose-dependent manner at doses greater than 1 microg/ml at 96 h (P<0.05); doses above 20 microg/ml were all greatly reduced at all time points and at 192 h when related to numbers of cells (P<0.001). Copper alone had no effect at physiological doses, but the use of the equimolar copper thiomolybdate reversed the effect of tetrathiomolybdates on androstenedione production at the 20 microg/ml dose. Thiomolybdate supplementation, with and without copper, had no significant effect on the level of lysyl oxidase or cytochrome P450 side-chain cleavage expression. However, cytochrome P450 17alpha-hydroxylase expression was significantly increased (P<0.05) by tetrathiomolybdate, possibly due to a local regulatory system. In conclusion, these results demonstrate that thiomolybdates can prevent LH-induced differentiation of bovine theca cells in vitro and that these effects can be ameliorated by copper supplementation. Our results also indicate that it is unlikely that the effects of thiomolybdate are mediated at the transcriptional level and further work is required to determine if thiomolybdate exerts its effects through post-translation processing or some other unrelated mechanism. Overall, these data support the hypothesis that copper responsive subfertility results from perturbation of the normal pattern of ovarian steroidogenesis.

Ultrasonographic and radiographic results from a two-year controlled trial of immediate or one-year-delayed addition of infliximab to ongoing methotrexate therapy in patients with erosive early rheumatoid arthritis.

OBJECTIVE: To compare the impact of immediate and delayed introduction of anti-tumor necrosis factor therapy on inflammation and structural damage in methotrexate (MTX)-treated patients with early rheumatoid arthritis (RA). METHODS: Twenty-four patients with erosive early RA (duration < 3 years) who were receiving MTX were randomized to receive infliximab 5 mg/kg or placebo infusions at weeks 0, 2, and 6, and then every 8 weeks through week 46. Beginning at week 54 and thereafter, all patients received infliximab 5 mg/kg. Metacarpophalangeal joints were scanned using high-frequency ultrasonography and power Doppler imaging. Radiographs were evaluated using the modified Sharp/van der Heijde scoring system. RESULTS: From baseline to week 54, total synovial thickness was significantly improved in the infliximab + MTX group compared with the placebo + MTX group (median reduction 95.8% versus 37.5%; P = 0.005), as was the total color Doppler area (CDA; vascularity assessment) (median reduction 100% and 47.1%, respectively; P = 0.025). From week 0 to week 110, no significant between-group difference was observed in the change from baseline for total synovial thickening or the total CDA. At week 54, greater progression in the Sharp/van der Heijde score was apparent in patients receiving placebo + MTX compared with those receiving infliximab + MTX. Although radiographic progression in the placebo + MTX group was greatly reduced in the second year (after initiation of infliximab therapy), marked differences were observed between the infliximab + MTX group (median change in the Sharp/van der Heijde score 4.0) and the placebo + MTX group (median change 14.5) from baseline to week 110 (P = 0.076). CONCLUSION: The results indicate that the efficacy of 2 years of combination therapy with infliximab + MTX for inhibiting cumulative structural damage was superior to that of 1 year of treatment with MTX alone followed by the addition of infliximab.

Sustained improvement over two years in physical function, structural damage, and signs and symptoms among patients with rheumatoid arthritis treated with infliximab and methotrexate.

OBJECTIVE: To evaluate the efficacy and safety of repeated administration of infliximab plus methotrexate (MTX) over a 2-year period in patients with rheumatoid arthritis (RA) who previously experienced an incomplete response to MTX. METHODS: Four hundred twenty-eight patients were randomly assigned to receive MTX plus placebo or infliximab at a dose of 3 or 10 mg/kg plus MTX for 54 weeks, with an additional year of followup. The protocol was later amended to allow for continued treatment during the second year. Of 259 patients who entered the second year of treatment, 216 continued to receive infliximab plus MTX for 102 weeks. Ninety-four of these 259 patients experienced a gap in therapy of >8 weeks before continuing therapy. Infusions were administered at weeks 0, 2, and 6, followed by treatment every 4 weeks or every 8 weeks (alternating with placebo infusions in the interim 4-week visits) at a dose of 3 or 10 mg/kg for a total of 102 weeks (including the gap in therapy). For safety and efficacy assessments, data on the patients who were randomized to receive treatment, irrespective of whether treatment was administered for 102 weeks, were evaluated using all actual observations available. The efficacy measures included the Health Assessment Questionnaire (HAQ) (physical function), Short Form 36 health survey (SF-36) (health-related quality of life), total radiographic scores (structural damage), and the American College of Rheumatology 20% improvement criteria (ACR20) (signs and symptoms). RESULTS: The infliximab plus MTX regimens resulted in significantly greater improvement in HAQ scores (P < or = 0.006) and SF-36 physical component summary scores (P < or = 0.011) compared with the MTX-only group. There also was stability in the SF-36 mental component summary score among patients who received the infliximab plus MTX regimens. Median changes from baseline to week 102 in the total radiographic score were 4.25 for patients who received the MTX-only regimen and 0.50 for patients who received the infliximab plus MTX regimen. The proportion of patients achieving an ACR20 response at week 102 varied from 40% to 48% for the infliximab plus MTX groups compared with 16% for the MTX-only group. CONCLUSION: Throughout 102 weeks of therapy, infliximab plus MTX provided significant, clinically relevant improvement in physical function and quality of life, accompanied by inhibition of progressive joint damage and sustained improvement in the signs and symptoms of RA among patients who previously had an incomplete response to MTX alone.

Comparison of ultrasonographic assessment of synovitis and joint vascularity with radiographic evaluation in a randomized, placebo-controlled study of infliximab therapy in early rheumatoid arthritis.

OBJECTIVE: To investigate sensitive ultrasonographic imaging methods for detection of synovial thickness and vascularity to discriminate between patients with early rheumatoid arthritis (RA) receiving infliximab + methotrexate (MTX) versus placebo + MTX over 18 weeks, and to compare the relationship between synovial thickening and vascularity at baseline and radiologic damage to joints of the hands and feet at 54 weeks. METHODS: Patients with early RA (duration <3 years) receiving stable dosages of MTX were randomly assigned to receive blinded infusions of 5 mg/kg infliximab (n = 12) or placebo (n = 12) at weeks 0, 2, 6, and then every 8 weeks until week 46. At baseline and week 18, clinical assessments were performed, and metacarpophalangeal joints were assessed by high-frequency ultrasonography and power Doppler ultrasonography measurements. Radiographs of the hands and feet taken at baseline and at 54 weeks were evaluated using the van der Heijde modification of the Sharp method (vdH-Sharp score). RESULTS: Using changes in the total vdH-Sharp score over 54 weeks and changes in synovial thickening and joint vascularity at 18 weeks, we were able to distinguish those patients receiving infusions of infliximab + MTX from those receiving placebo + MTX. Sonographic measurements of synovial thickening and vascularity at baseline in the placebo + MTX group demonstrated clear relationships with the magnitude of radiologic joint damage at week 54. Infliximab + MTX treatment abolished these relationships. CONCLUSION: The delay or reversal of inflammatory and joint-destructive mechanisms in patients with early RA was already apparent following 18 weeks of treatment with infliximab + MTX and was reflected in radiologic changes at 54 weeks.

Domestic ruminants as models for the elucidation of the mechanisms controlling ovarian follicle development in humans.

It is necessary to understand the basic physiology underlying the complex process of folliculogenesis to address common causes of infertility and to devise innovative strategies to increase the efficiency of assisted reproduction technologies. Availability of suitable ovarian tissue is a major constraint to research in this area in humans, and monovulatory domestic ruminants represent a physiologically relevant model to elucidate basic mechanisms before more focused clinical investigations. This paper reviews the development of several whole animal and cell culture models in ruminants that have allowed basic investigations into the endocrine and local mechanisms regulating preantral and antral follicle development in monovulatory species. Studies on preantral follicle development using the ovarian autograft model have shown, contrary to accepted dogma, that FSH may mediate the rate at which preantral follicles grow and have provided evidence to support the existence of local regulatory feedback mechanisms that influence the rate of primordial follicle initiation and preantral follicle development. Studies on the endocrine control of antral follicle development using the GnRH-antagonist model have shown that a pulsatile mode of LH delivery is not a requirement for normal patterns of follicle development and ovarian hormone secretion. Studies on the local control of somatic cell differentiation using physiological cell culture models have highlighted the essential relationship between somatic cell communication and expression of differentiative markers. We conclude that the domestic ruminant represents a valuable model system for the elucidation of the endocrine and local mechanisms controlling both early and terminal stages of follicle development in monovulatory species. The results of these investigations have direct strategic relevance within clinical medicine.

Temporal relationships between FSH receptor, type 1 insulin-like growth factor receptor, and aromatase expression during FSH-induced differentiation of bovine granulosa cells maintained in serum-free culture.

A serum-free culture system has been developed in ruminants that allows gonadotrophin-responsive induction of oestradiol (E2) production by non-differentiated granulosa cells (GC) from small antral follicles. Critical determinants are dose of FSH and insulin-like growth factor (IGF), and the plating density of the GC. Over the first 16 h of culture when cells remained as a dispersed monolayer, expression declined in FSH receptors (FSHr) (P <0.001), IGF type 1 receptor (IGF-1r) (P <0.08) and p450 arom (CYP19, P <0.001). Characteristic GC clusters formed from 16 h and further enlarged between 24 and 48 h, accompanied by marked increases in FSHr (P <0.01), IGF-1r (P <0.05), and p450 arom (P <0.01) expression, and preceded induction and subsequent peak E2 production, at 96 and 144 h, respectively (P <0.01). In conclusion, isolation and dispersion of GC appears to induce reversion to an immature state resulting in loss of receptor expression. Re-establishment of cell-cell communications in the presence of FSH and IGF results in receptor up-regulation and induction of cellular differentiation.

Expression of lysyl oxidase and effect of copper chloride and ammonium tetrathiomolybdate on bovine ovarian follicle granulosa cells cultured in serum-free media.

Subfertility that will respond to appropriate copper supplementation is a widespread problem in the UK dairy herd and, although characterized by reduced or absent oestrus and reduced conception rates, the exact cause remains unknown. The aim of this study was to investigate the expression of mRNA for the copper-dependent enzyme, lysyl oxidase, and the effect of copper and/or copper chelating thiomolybdates on FSH-induced differentiation of bovine granulosa cells cultured in serum-free media. Expression of lysyl oxidase mRNA was investigated using bovine specific primers and RT-PCR on cell lysates obtained from bovine granulosa cells cultured under optimum conditions for 0, 16, 24, 48, 96, 144 and 192 h. The effect of thiomolybdates and copper were investigated by supplementing optimized granulosa cell culture media with ammonium tetrathiomolybdate at 0, 0.1, 1, 10, 100 and 1000 micro g ml(-1), copper chloride at equimolar concentrations (0, 0.0516, 0.516, 5.16, 51.6, 516 micro g ml(-1)) or equimolar combinations of both media. Lysyl oxidase mRNA was expressed by the granulosa cells throughout the 192 h of culture. Thiomolybdate depressed oestradiol production in a dose-dependent manner at doses > 1 micro g ml(-1) and prevented the characteristic clumped appearance of granulosa cells in this serum-free system. Although the supplementation of copper alone had no effect at physiological doses, the use of the equimolar copper and thiomolybdate media ameliorated the effect of tetrathiomolybdates on both oestradiol production and cellular morphology. In conclusion, the results of the present study indicate that lysyl oxidase is expressed by granulosa cells, that thiomolybdates can prevent FSH-induced differentiation of bovine granulosa cells in vitro and that these effects can be reversed by copper supplementation. Overall, these data support the hypothesis that copper-responsive subfertility results from perturbation of the normal pattern of ovulatory follicle growth and development, an effect that may be mediated, at least in part, via lysyl oxidase activity.

Iodixanol pharmacokinetics in children.

The objective of this report was to study the elimination pharmacokinetics of iodixanol in children. Iodixanol (Visipaque, Nycomed Inc., Wayne, PA, USA) is a new iso-osmolar iodinated radiocontrast agent. We hypothesized that elimination of this agent would be dependent on age-related differences in renal clearance. Seven centers enrolled 43 patients. Cardiac catheterization was performed in 41 patients and cranial computed tomography in 2. Patients were entered into 5 age groups: newborn to <2 months, 2 to <6 months, 6 months to <1 year, 1 to <3 years, and 3 to 6 months of age that is comparable to normal adults. Prolonged elimination in children <6 months of age is related to renal immaturity.

Evaluation of polymorphisms in the presenilin-1 gene and the butyrylcholinesterase gene as risk factors in sporadic Alzheimer's disease.

The E4 allele of the apolipoprotein E gene (APOE) is a major risk factor for late-onset Alzheimer's disease (LOAD) but is neither necessary nor sufficient to cause the disease. In this study, we investigated polymorphisms in the presenilin-1 (PS-1), and butyrylcholinesterase (BChE) genes, which have been implicated as risk factors for LOAD. Our data-set comprised 177 AD and 118 control patients, all of whom had been histopathologically confirmed following autopsy. We have tested homozygosity for the PS-1 allele 1 and possession of the BChE-K variant in association with APOE epsilon4 as risk factors in LOAD. Our findings support an association between the PS-1 polymorphism and LOAD, finding homozygosity for allele 1 associated with an approximately two-fold increased risk. Our data also show that in subjects greater than 75 years of age possession of both BChE-K and APOE-epsilon4 alleles is associated with an increased risk of LOAD, whilst the risk associated with APOE-epsilon4 allele alone is not significant.

Mutation in an alpha1-antitrypsin enhancer results in an interleukin-6 deficient acute-phase response due to loss of cooperativity between transcription factors.

We previously reported that a mutation in a 3' enhancer region of the alpha1-antitrypsin (AAT) gene is associated with chronic obstructive airways disease (COAD). During the acute-phase response the plasma concentration of AAT increases approximately 3-fold and this effect is mediated primarily by interleukin-6 (IL-6). We demonstrate, by transfection of Hep G2 cells, that the AAT gene contains at least two enhancers, one at the 5' end of the gene which is dominant under basal conditions, and another at the 3' end of the gene which exhibits weak basal activity. However, both enhancers must be present to modulate the IL-6-induced response which is diminished as a consequence of the 3' enhancer mutation. These results suggest that the 3' enhancer modulates the IL-6 response through an interaction with the 5' enhancer. The mutation occurs at a DNA binding site for the ubiquitous transcription factor octamer-1 (Oct-1) and results in a loss of cooperativity between Oct-1 and the tissue-specific transcription factor, NF-IL6 (C/EBPbeta), a member of the C/EBP family of transcription factors. NF-IL6 is a key transcription factor for a major pathway through which IL-6 mediates its effects. These observations provide a novel mechanism for a diminished IL-6-induced response.