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Acute phase proteins became an interesting point of investigations also in veterinary medicine. In the last several years, there has been considerable progress in studies on the understanding of their functions, and influences on the organism. The benefit to laboratory and clinical diagnosis of diseases has been established also. In general, the acute phase response is a result of proinflammatory cytokines being secreted into the circulation from sites of infection or inflammatory lesions. Among the many pathophysiological responses of an animal to stimulation, there is an increased production and secretion of some plasma proteins from the liver, which are known in generally as acute phase proteins. Despite the uniform nature of the acute phase response, there are numerous differences in the production of acute phase proteins between various animal species. In bovine medicine, the principle acute phase protein to be used is haptoglobin in conjunction with serum amyloid A, which are elevated in some important bovine inflammatory diseases such as laminitis, metritis, or mastitis, as well as in some physiological conditions. Investigations over the last decade have shown that the quantification of their concentrations in plasma or serum can provide valuable diagnostic information in the detection, prognosis and monitoring of disease. Moreover, monitoring the blood concentrations of acute phase proteins can provide additional information on the progression of the inflammatory reaction. The circulating concentration of these proteins is related to the severity of the underlying condition and thus quantification of their concentrations provides a ready means of evaluating the presence and extent of the disease processes causing the response.
The acute-phase protein serum amyloid A (SAA) is present in the bloodstream at the concentration below 1 µM under physiological conditions, but its level increases significantly during the acute-phase response following infection or inflammatory condition. A consequence of the long-term elevated SAA concentration is deposition of normally soluble serum amyloid A in the form of insoluble fibrils, impairing tissue structure and function. These deposits cause development of a secondary type amyloidosis, called amyloid A protein (AA) amyloidosis, which results in a death of thousands of people per annum around the world. The ability of SAA to form amyloids seems to be connected with the N-terminal portion of the molecule. The capacity of the synthetic peptides derived from the N-terminal sequence of human or mice SAA to form fibrils in vitro proves that the most amyloidogenic region is embedded within the protein’s first 15 amino acids. We decided therefore to use peptides consisting of 11–15 amino acids and the sequence derived from the N-terminus of the parent aggregating protein as a research tool for investigation of the molecular recognition and self-assembly mechanisms that promote the formation of SAA amyloid fibrils deposits. In this study, we tested the hypothesis that non-aggregating very short peptides derived from SAA sequence would interact with the analogous region in the protein molecule or its aggregation-prone N-terminal fragment, and block its assembly into oligomers and amyloid fibrils. We designed and synthesized a peptide with the sequence 1RSFFS5, derived from the human SAA primary structure, and then tested it as a potential inhibitor of the aggregation process of SAA protein. The hypothesis about the role of aromatic interactions in amyloid fibril formation led us to test another peptide: 17LVFF20, which is derived from the sequence of Aβ. We tested propensity of the N-terminal segment (1–15) of mice SAA for amyloid fibrils formation, incubating it either alone or together with the potential inhibitors. Thioflavin T (ThT) fluorescence test was used to detect amyloid fibrils formation. These tests confirmed that the designed peptides are able to diminish propensity of the aggregation-prone SAA peptides to form amyloid fibrils. There are currently no effective medical treatment of diseases associated with the systemic amyloidosis. We believe that results of the presented project open up new possibilities in designing compounds that are able to prevent formation of amyloid deposits and could be a starting point for the design of peptidomimetic molecules more suitable as potential drugs. The work was supported by grant NCN nr 2011/03/N/NZ5/01460 and grant BMN No 538-8440-1042-12.
The aim of this study was to compare the concentrations of two acute phase proteins, haptoglobin (Hp) and serum amyloid A (SAA), in serum and milk of Holstein-Friesian dairy cows grouped according to somatic cell count (SCC) thresholds (<100,000; <400,000; >400,000 cells/ml) in composite milk samples. The SCC was assessed quantitatively by FOSSOMATIC 90 analyser, serum and milk Hp and SAA concentrations were determined using commercial ELISA kits (Tridelta Development, Ltd., Wicklow, Ireland). We have found significantly higher Hp and SAA concentrations in the group with SCC >400,000 cells/ml compared to groups with lower SCC thresholds in composite milk samples. In contrast, significant differences were not recorded between the groups in serum Hp and SAA concentrations. The concentrations of Hp in serum and milk were found to be correlated (r = 0.69, P = 0.0003), whereas there was a lower correlation trend in the case of serum versus milk concentrations of SAA (r = 0.43, P = 0.0478). High significant correlations were observed either between milk haptoglobin values and SCC or milk serum amyloid A concentrations and SCC (r = 0.83, r = 0.81, P<0.0001; respectively). An increase in SCC in cows suffereing from mastitis has been accompained by strong elevation of the milk Hp and SAA, significantly correlated with serum Hp (r = 0.64, P = 0.0014) and poorly correlated with SAA values determined in serum (r = 0.43, P = 0.0478). According to the results obtained in this study we can conclude that measurements of the acute phase proteins, haptoglobin and serum amyloid A predominantly in milk, may be useful tool in diagnosing mastitis and may be a useful marker of milk quality.
The objective of this study was to examine the clinical significance of selected indicators of immune response (IL-lß, 1L-4, IL-6. SAA, and Hp) in short-term combined intoxication exposure of pigs to low doses of deoxynivalenol, T-2 toxin, and zearalenone present in naturally contaminated feedstuffs during grain growth. Statistically significant differences were not noted after 14 d of feeding diets contaminated with the above mycotoxins. The mycotoxins did not induce inflammatory processes. The subclinical form of combined mycotoxicosis could be due to incorrect immunological response. The identification of the underlying cause would support the development of new methods for the prevention of combined mycotoxicosis.
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