Relationship between serum lipid profile, clinical and clinicopathological findings in 59 dogs with inflammatory protein-losing enteropathy

Introduction: Alterations of lipid metabolism have been described in people with inflammatory bowel disease (IBD) [1]. IBD patients exhibit lower total cholesterol (TC) and low-density lipoproteins (LDL), variables high-density lipoproteins (HDL), and higher triglycerides (TG) levels compared to healthy controls [1-3]. Moreover, low cholesterol and high triglycerides are independently associated with more severe disease [1,2]. In veterinary medicine, disorders of lipid metabolism have been described secondary to various diseases [4-6]. However, scattered information in dogs with inflammatory protein-losing enteropathy (iPLE) exists. Aim: The aims of this study were to describe serum lipid profiles and to identify possible associations with selected clinical and clinicopathological findings in dogs with iPLE. Materials and Methods: Fifty-nine owned-dogs of various breed and age with newly-diagnosed iPLE were prospectively enrolled. Dogs responding to dietary trials were excluded. Signalment, body condition score (BCS), chronic enteropathy clinical activity index (CCECAI), serum concentrations of C-reactive protein (CRP), paraoxonase-1 (PON-1), triglycerides, cholesterol, protein and lipoprotein classes obtained by electrophoretic separation were studied. Dogs were further assigned to 2 therapeutic subgroups (P=prednisolone; NP=no prednisolone). Results: Median age (min-max), body weight, BCS, CCECAI, CRP, PON-1, cholesterol, triglycerides and total protein (TP) were 88 months (6-156), 13,4 kg (2,4-47,5), 4 (1-6), 9 (3-17), 5,2 mg/L (0-48,4), 77 U/L (10,4-241), 117 mg/dL (61-327), 83 mg/dL (30-172) and 4,1 g/dL (2-7,4), respectively. Median HDL (min-max), VLDL, LDL and chylomicrons were 54,0% (18,7-82,7), 7% (1,2-37,1), 33,8% (7,7-64,3) and 2,2% (0,4-22,8), respectively. HDL, LDL and very low-density lipoproteins (VLDL) were the predominant lipoprotein class in 45, 12 and 2 dogs, respectively. Significant associations among BCS or CCECAI and lipoprotein classes were not found. Positive correlations were found between HDL and TP, cholesterol, PON-1, and between VLDL and cholesterol, CRP. Negative correlations were found between LDL and body weight, TP, cholesterol, PON-1, and between HDL and CRP. The lowest HDL and the highest LDL values were observed in dogs with decreased PON-1 and/or increased CRP. Concentration of different lipoprotein classes of group P (n=14) did not significantly differ from those of group NP (n=45). Conclusions: The positive correlation between HDL and PON-1 (a negative acute phase protein with antioxidant properties) and the negative correlation with CRP (the major inflammatory protein in dogs), suggest a possible anti-inflammatory and antioxidant role of HDL in iPLE dogs, whereas LDL and VLDL appear increased in dogs with iPLE even if further studies are needed to provide more useful information on this subject.