Isocaloric soy protein feeding ameliorates both epithelial and interstitial changes in the Han:SPRD-cy rat independent of a hypocholesterolemic effect. The histologic benefit is associated with changes in polyunsaturated fatty acid metabolism that may influence both inflammatory and proliferative pathways.

Flaxseed ameliorates Han:SPRD-cy rat polycystic kidney disease through moderation of the associated chronic interstitial nephritis. The diet alters renal content of polyunsaturated fatty acids in a manner that may promote the formation of less inflammatory classes of renal prostanoids.

As whole flaxseed is beneficial in the treatment of experimental renal disease, we undertook a study to determine whether previously documented benefits of whole flaxseed could be reproduced with dietary low-lignan flax oil (FO), a rich source of alpha-linolenic acid, in experimental polycystic kidney disease. Male offspring of Han:SPRD-cy heterozygous rats were fed a synthetic diet containing FO or corn oil (CO) for 8 wk from the time of weaning. Renal inflammation, fibrosis, proliferation, cystic change, and oxidized-LDL were assessed morphometrically. Hepatic and renal lipid composition was assessed using GC. FO feeding produced hepatic and renal enrichment of n-3 PUFA and an increase in C18:>C18 PUFA ratios (18-carbon PUFA compared to longer-chain PUFA), with a reduction in proportion of hepatic long-chain PUFA. The FO-based diet was associated with lower mean cystic change by 29.7% (P = 0.018), fibrosis by 21.7% (P = 0.017), macrophage infiltration by 31.5% (P < 0.0001), epithelial proliferation by 18.7% (P = 0.0035), and ox-LDL detection by 31.4% (P < 0.0001) in Han:SPRD-cy heterozygotes. Serum creatinine was significantly lower in FO-fed diseased animals. A small hypocholesterolemic effect was noted in all animals fed FO. FO feeding moderates renal injury, modifies the profile of substrates available for elongation to eicosanoid precursors, and inhibits the elongation of C18 PUFA in this model. The consumption of FO-based products may prove a more practical way of obtaining health benefit than attempts to increase dietary content of unrefined seed.

CLA reduces renal production of PGE2, without reduced availability of the precursor fatty acid, AA. Short-term feeding of CLA to Han:SPRD-cy rats also has significant renal anti-inflammatory and antifibrotic effects. As inflammation and fibrosis are important components of the progression of chronic renal injury, CLA may be a useful agent in dietary amelioration of renal disease.

No abstract

CLA has been shown to induce or suppress excess liver lipid accumulation in various animal models. Interestingly, the state of insulin resistance may be an important modulator of this effect. The objective of the current study was to determine how feeding a dietary CLA mixture would affect liver lipid accumulation in insulin-resistant/obese and lean rats in relation to liver function, lipidemia, liver TAG and phospholipid FA composition, and expression of hepatic markers of FA transport, oxidation, and synthesis. Six-week-old fa/fa and lean Zucker rats (n = 20/genotype) were fed either a 1.5% CLA mixture or a control diet for 8 wk. CLA supplementation reduced liver lipid concentration of fa/fa rats by 62% in concurrence with improved liver function (lower serum alanine aminotransferase and alkaline phosphatase) and favorable modification of the serum lipoprotein profile (reduced VLDL and LDL and elevated HDL) compared with controlfed fa/fa rats. The fa/fa genotype had two-thirds the amount of CLA (as % total FA) incorporated into liver TAG and phospholipids compared with the lean genotype. In both genotypes, CLA altered the hepatic FA profile (TAG greater than phospholipids) and these changes were explained by a desaturase enzyme index. Liver-FA-binding protein and acyl CoA oxidase, markers of FA transport and oxidation, respectively, were expressed at higher levels in CLA-fed fa/fa rats. In summary, these results illustrate a strong relationship between the state of insulin resistance and liver lipid metabolism and suggest that CLA acts to favorably modify lipid metabolism in fa/fa Zucker rats.

Flaxseed derivatives, including both oil and flax lignan, modify progression of renal injury in animal models, including Han:SPRD-cy polycystic kidney disease (PKD). Gender is a significant factor in the rates of progression of many forms of human renal disease, but the role of gender in the response to nutrition intervention in renal disease is unexplored. In this study, male and female Han:SPRD-cy rats or normal littermates were fed either corn oil (CO) or flax oil (FO) diets, with or without 20 mg/kg of the diet flax lignan secoisolaricinoresinol dyglycoside (SDG). Renal injury was assessed morphometrically and biochemically. Renal and hepatic PUFA composition was assessed by GC and renal PGE2 release by ELISA. FO preserved body weight in PKD males, with no effect in females. SDG reduced weight in both normal and PKD females. FO reduced proteinuria in both male and female PKD. FO reduced cystic change and renal inflammation in PKD males but reduced cystic change, fibrosis, renal inflammation, tissue lipid peroxides, and epithelial proliferation in PKD females. SDG reduced renal inflammation in all animals and lipid peroxides in PKD females. A strong interaction between SDG and FO was observed in renal FA composition of female kidneys only, suggesting increased conversion of C18 PUFA to C20 PUFA. FO reduced renal release of PGE2 in both genders. Gender influences the effects of flaxseed derivatives in Han:SPRD-cy rats. Gender-based responses to environmental factors, such as dietary lipid sources and micronutrients, may contribute to gender-based differences in disease progression rates.

The hyperinsulinemic-normoglycemic clamp technique reduced postoperative negative outcomes by suppressing apoptosis. This phenomenon appears to be linked with higher substrate availability and altered cytokine secretion profile and may provide a long-term benefit of this therapy on liver resection patients.