Bone and cellular immune system of multiparous sows are insensitive to ovariectomy and nutritive calcium shortage

Research in osteoporosis, which is a complex systemic disease, demands suitable large animal models. In pigs, most research has been done in growing minipigs, which probably are not ideal models for postmenopausal osteoporosis. Therefore, our aim was to analyze the effects of ovariectomy (OVX) and nutritive calcium shortage on multiparous Large White sows. 32 animals were randomly assigned to 4 groups in a cross design with OVX vs. sham and physiological calcium supplementation (0.75% calcium) vs. dietary calcium shortage (0.3% calcium). The observation period was 10 months with blood sampling every 2 months for hematological, immunological, and biochemical bone marker measurements. At the termination of the experiment, animals were sacrificed. Samples of trabecular bone of distal radius, proximal tibia, and sixth lumbar vertebra were subjected to micro-computed tomography imaging and ashed afterwards. Dual X-ray absorptiometry scans of the proximal femora were performed with prepared bones being placed in a water bath for mimicking soft tissue. Analyses of bone marker and cytokine profile kinetics, distribution of leukocyte subpopulations, and morphometrical and densitometrical analyses showed no evidence of any impact of OVX or calcium shortage. In conclusion, the skeleton of adult sows of a conventional breed is seemingly protected from effects of OVX and calcium shortage.

Heparin and EDTA as anticoagulant differentially affect cytokine mRNA level of cultured porcine blood cells

Cytokine mRNA expression profiles serve to characterize immune cell activation in different test systems. Both, diluted whole blood and isolated PBMC are widely applied for these studies. Comprehensive data regarding the suitability of different anticoagulants for profiling cytokine expression are not available for the pig. Therefore the aim of this study was to compare the effect of two commonly used anticoagulants (heparin and EDTA) on the cytokine expression pattern of porcine blood cells. IL-1alpha, IL-2, IL-4, IL-6, IL-10 and IFN-gamma mRNA levels were detected ex-vivo and upon in-vitro stimulation in diluted porcine whole blood and isolated PBMC by real-time PCR. The cells were stimulated with ConA or LPS, known to act on different target cells and implying different signalling pathways. Additionally the integrity of the isolated RNA was investigated. Ex-vivo cytokine expression pattern of fresh whole blood were not affected by the investigated anticoagulants. In contrast, stimulation of cultured diluted whole blood or PBMC resulted in significant differences depending on the applied anticoagulant. Using EDTA we found a significantly decreased capacity of whole blood to express cytokines. However, isolated PBMC from EDTA anticoagulated blood showed a higher cytokine expression capacity than PBMC from heparinized blood. Comparing diluted whole blood and PBMC we found that cultured porcine whole blood responded better to bacterial products than isolated PBMC, probably because sufficient auxiliary plasma derived factors such as LPS-binding protein, are present. However, isolated PBMC showed a higher T-cell response than diluted whole blood. In conclusion, our findings underline that each application demands a specific assay system.

Clenbuterol Affects the Expression of Messenger RNA for Interleukin 10 in Peripheral Leukocytes from Horses Challenged Intrabronchially with Lipopolysaccharides

On four occasions, four horses with heaves and four horses with small airway inflammatory diseases inhaled 0.9% saline based aerosol mixtures with or without lipopolysaccharides (LPS). Prior to the first saline and LPS inhalation, horses were untreated, while three and a half days prior to the third and forth inhalation horses had received 0.8 microg/kg clenbuterol intravenously twice daily. The messenger RNA (mRNA) expression of tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-4, IL-6, IL-8, IL-10 and interferon- gamma (IFN- gamma) was investigated by RT-PCR, all of which were expressed in the white blood cells of samples collected. Inhalation of LPS only changed the cytokine expression profile of IL-10, IL-4 and TNF-alpha mRNA which were higher after challenge with LPS. However in those horses that were treated with clenbuterol the LPS-induced IL-10 mRNA expression was shown to be suppressed. Further changes in IL-4 and TNF-alpha were not significant. Thus the results of this study indicated that clenbuterol can modulate the expression of IL-10 mRNA in peripheral white blood cells in those horses with small airway diseases that have been exposed to LPS.

Characterization of the Cytokine Pattern of Porcine Bone Marrow-Derived Cells Treated with 1alpha,25(OH)2D3

The biologically active form of vitamine D(3) [1alpha,25(OH)(2)D(3)] has recently been described not only to influence bone metabolism but also to exert immunomodulating activities, which may have an impact on bone formation/resorption as well. In this study, we analysed the effects of 1alpha,25(OH)(2)D(3) on the cytokine pattern of porcine bone marrow-derived cells from piglets aged 1-3 weeks. After culture for 1 week, the number of osteoclasts was determined, with tartrate-resistant acid phosphatase (TRAP)-positive, multinucleated cells being considered osteoclasts. Cultured bone marrow cell-derived mRNA was subjected to semiquantitative RT-PCR specific for a panel of porcine cytokines (IL-1alpha, IL-6, IL-8, IL-10, and TNF-alpha). In addition, an immunofluorescence analysis using anti-porcine mAbs specific for IL-1beta, IL-2, IL-4, IL-6, IL-12, TNF-alpha, and IFN-gamma was performed. In order to prove the existence of a porcine homologue of the receptor activator of NF-kappaB ligand (RANKL) bone marrow cell- as well as porcine white blood cell-derived mRNA was investigated by RT-PCR using primer pairs specific for murine RANKL. Cell culture supernatant was analysed for soluble RANKL by means of an ELISA designed for quantification of human RANKL. By means of RT-PCR, expression of IL-1alpha, IL-6, IL-8, IL-10 and TNF-alpha mRNA could be found in cells cultured with and without 1alpha,25(OH)(2)D(3). Immunofluorescence analysis revealed that IL-1, IL-6, and TNF-alpha were produced by both stromal cells and osteoclasts. Besides its known osteoclastogenic effects, 1alpha,25(OH)(2)D(3) tended to downregulate the respective cytokines, but significantly upregulated RANKL expression. The homology between the porcine RANKL-specific sequence and the corresponding human RANKL sequence was 79%. The data found support the idea that porcine bone marrow cell cultures may provide a suitable alternative to murine systems in human osteological research.

Quantitative simultaneous multiplex real-time PCR for the detection of porcine cytokines

We have established an easy real-time PCR assay, which allows the precise quantification of changes in the expression level of 6 relevant porcine cytokines, and 3 housekeeping genes. This assay simultaneously detects 9 sequences by measuring 3 x 3 targets in a triplex-format. The mRNA of the lymphokines IL-2, IL-4, IL-10, and IFN-gamma, of the proinflammatory cytokines IL-1alpha and IL-6, and of the housekeeping genes are quantified using TaqMan-probes by means of standard dilution series on the iCycler iQ. The standard consists of equal aliquots of the experimental cDNAs under investigation. Simultaneously the most suitable combination of 3 out of the four housekeeping genes beta-actin, HPRT, GAPDH, and cyclophilin can be selected, and their averaged expression values constitute a normalisation factor. The raw data of all targets of interest is then calculated relative to this normalisation factor, making eventual changes of the relative expression level of the single housekeeping genes controllable and quantifiable. We have applied this assay to quantify changes in the cytokine mRNA levels of porcine stimulated with various concentrations of LPS and ConA, known to induce different cytokine expression patterns. We have shown, that even small differences in the expression level (less than 2-fold) can be precisely quantified, and reveal statistically significant changes, when using the normalisation factor. This assay will be useful for studying changes in the expression of relevant porcine cytokines and will help to further improve the investigation of immune responses in the pig.

Porcine dermatitis and nephropathy syndrome (PDNS) is associated with a systemic cytokine expression profile indicative of proinflammation and a Th1 bias

Porcine dermatitis and nephropathy syndrome (PDNS) is broadly discussed as a porcine circovirus type 2 (PCV2)-associated disease, although PCV2, in contrast to postweaning multisystemic wasting syndrome (PMWS), has to date not been proven to be the aetiologic agent. In order to better understand the complex immunopathology of PDNS, the systemic cytokine expression profiles of (i) five pigs suffering from PDNS, (ii) five animals suffering from naturally acquired PMWS and (iii) five controls were investigated at mRNA and protein levels by means of multiplex real-time RT-PCR and flow cytometric intracellular cytokine detection, respectively. IL-1alpha, IL-6 and IFN-gamma mRNA expressions were found to be elevated in PDNS pigs. At the protein level, an increased capacity of peripheral blood mononuclear cells to produce IL-2, IL-4, IL-6, IL-12, TNF-alpha and IFN-gamma was evident. Hematological investigations revealed a hypochromic anemia while basophils and monocytes were relatively and neutrophils absolutely increased in PDNS pigs. PCV2 antibody levels did not differ significantly between PDNS and PMWS affected animals. Taken results together, the cytokine profile of the PDNS affected animals together with hematological data pointed towards a proinflammatory condition supporting a Th1 bias. Cytokine data of PMWS affected animals exhibited only minor non-significant differences when compared to controls, only IL-10 was significantly decreased at the mRNA level.

Systemic cytokine profile in feeder pigs suffering from natural postweaning multisystemic wasting syndrome (PMWS) as determined by semiquantitative RT–PCR and flow cytometric intracellular cytokine detection

Postweaning multisystemic wasting syndrome (PMWS) is an economically important disease in pigs caused by porcine circovirus type 2 (PCV2). Development of this disease is presumably associated with an impairment of the immune system. We, therefore, investigated the systemic expression of relevant cytokines (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p40, TNF-alpha, IFN-gamma) and IL-2Ralpha at mRNA (semiquantitative RT-PCR) and at protein level (flow cytometric intracellular cytokine detection after short-time stimulation of peripheral blood mononuclear cells) in 10 feeder pigs aged 14 weeks suffering from natural PMWS and in 10 clinically healthy pen-mates. Hematological examination revealed a significant (p < 0.001) relative lymphopenia in the diseased animals when compared to reference pigs. IL-1alpha and IL-10 mRNA levels were notably increased in the affected pigs, whereas IL-2 and IL-2Ralpha (CD25) mRNA levels tended to be down-regulated. IL-8, TNF-alpha and IFN-gamma mRNA expressions appeared to be slightly increased. Intracellular cytokine levels as measured by flow cytometry revealed an increase of IL-1beta, IL-2, and IL-6, whereas IL-12 and TNF-alpha expressions were not affected. IFN-gamma was slightly decreased in the diseased animals. In conclusion, despite the assumption, that the cellular immune response to PMWS as a virus-induced disease should be characterized by either a Th1 driven cytokine profile or a cytokine profile indicative of T cell immunosuppression, our results did not support that hypothesis. Nevertheless, data from intracellular cytokine detection suggest an even increased percentage of the remaining lymphocytes capable to produce IL-2 upon in vitro stimulation, which is in contrast to the slightly diminished IL-2 mRNA levels reflecting the in vivo situation at least at the mRNA level.

Delay in processing porcine whole blood affects cytokine expression

Quantification of cytokine messenger ribonucleic acid (mRNA) in blood samples has become an important tool in the investigation of immune cell activation in a variety of clinical settings. It has been shown that the method of sample collection and processing influences the levels of several cytokine mRNAs. Therefore, it is generally accepted that blood samples for analysis of cytokine expression be processed as soon as possible and under standardised conditions. Since immediate sample processing is not always possible, we investigated the effect of different storage conditions (room temperature (Rt) and 4 degrees C) and storage times (1, 2, 4, 6 and 24 h) on the mRNA level of different cytokines (IL-1alpha, IL-2, IL-6, IL-8, IL-10, IFN-gamma), as well as the IL-2 receptor (IL-2R) in porcine whole blood samples (n=8). Quantification of cytokine expression was performed using simultaneous reverse transcription PCR (RT-PCR) combined with the expression of the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a reference. Our data demonstrate that delays in sample processing longer than 1 h result in significant changes of the mRNA levels of individual cytokines. Expression of the monokines IL-1alpha, IL-6 and IL-10 were increased by storage at both room temperature and 4 degrees C. Expression of IL-8 was increased only in the samples stored at room temperature, and expression of IFN-gamma was raised exclusively in the samples stored at 4 degrees C. We conclude that porcine blood samples should be processed within 2 h to prevent undesired stimulatory effects on the cytokine expression pattern. However, if only selected cytokines are investigated, the undesired effects of prolonged storage can be selectively suppressed by choosing the appropriate temperature of sample storage.