C8 medium chain triglycerides benefit energy metabolism and modulate inflammatory lipids in cats with chronic kidney disease.

Chronic kidney disease (CKD) is characterized by inflammation and irreversible damage to the structure and function of kidneys. The kidneys require large amounts of energy to maintain their structural integrity and function, and in CKD there is a disruption of renal energy metabolism due to decreased oxidative phosphorylation and mitochondrial function. The canonical medium-chain fatty acids (MCFAs) are caproic (C6:0), caprylic (C8:0), and capric (C10:0) acids, while lauric acid (C12:0) is considered an intermediate fatty acid. The purpose of this study was to assess circulating markers of energy status and inflammation in felines with CKD when fed trioctanoin (C8 MCT), a medium-chain triglyceride (MCT), in the presence of fish oil. The C8 MCTs are hydrolyzed into MCFAs, which are more efficiently digested, transported to the liver, and absorbed into mitochondria than intermediate or long chain fatty acids. They also generate higher levels of ketone bodies such as beta-hydroxybutyrate (BHB), which is a preferred source of energy for kidneys. Various lipid metabolites and BHB contribute to energy metabolism and modulate inflammation. The subjects were cats with naturally occurring CKD (at least International Renal Interest Society (IRIS) stage one with symmetric dimethylarginine (SDMA) ≥14.0 μg/dL for at least 3 mo; n = 16) housed at Hill's Pet Nutrition Center. In a cross-over study, based on sex and age cats were assigned to the order of feeding of a control food (dry food for management of renal disease) and test food. On an as-fed basis, pork fat was decreased from 12.3% in the control food to 4.3% in the test food, allowing for the addition of 8% C8 MCTs. Fasting blood and urine were collected after feeding each food for 8 wk. Analyses included assessing plasma metabolomics, serum and urine biochemistries, and complete blood counts. Fasting levels of circulating BHB were increased by the test food and carnitine adducts showed a bidirectional effect, as compared to control food (P < 0.05). There were also decreases in inflammatory lipid mediators including dihydro- and hexosylceramides, lysophospholipids, and phosphatidylcholines with test food (P < 0.05 vs control), suggesting reduced inflammatory signals. These results indicate feeding C8 MCTs to cats with CKD increases available energy from ketones and decreases lipids involved in inflammation, supporting a beneficial role of C8 MCTs in the nutritional management of CKD in cats.