Distinct effects of dietary flax compared to fish oil, soy protein compared to casein, and sex on the renal oxylipin profile in models of polycystic kidney disease.

Oxylipins are bioactive lipids derived from polyunsaturated fatty acids (PUFA) that are important regulators of kidney function and health. Targeted lipidomic analyses of renal oxylipins from four studies of rodent models of renal disease were performed to investigate the differential effects of dietary flax compared to fish oil, soy protein compared to casein, and sex. Across all studies, dietary fish oil was more effective than flax oil in reducing n-6 PUFA derived oxylipins and elevating eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived oxylipins, whereas dietary flax oil resulted in higher α-linolenic acid (ALA) oxylipins.

Distinct oxylipin alterations in diverse models of cystic kidney diseases.

Cystic kidney diseases are characterized by multiple renal cysts and are the leading cause of inherited renal disease. Oxylipins are bioactive lipids derived from fatty acids formed via cyclooxygenase, lipoxygenase and cytochrome P450 activity, and are important regulators of renal health and disease. Oxylipins are altered in nephronophthisis, a type of cystic kidney disease.

Mixed compared with single-source proteins in high-protein diets affect kidney structure and function differentially in obese fa/fa Zucker rats.

Questions remain regarding the potential negative effects of dietary high protein (HP) on kidney health, particularly in the context of obesity in which the risk for renal disease is already increased. To examine whether some of the variability in HP effects on kidney health may be due to source of protein, obese fa/fa Zucker rats were given HP (35% of energy from protein) diets containing either casein, soy protein, or a mixed source of animal and plant proteins for 12 weeks. Control lean and obese rats were given diets containing casein at normal protein (15% of energy from protein) levels.

Omega-3 Polyunsaturated Fatty Acids and Oxylipins in Neuroinflammation and Management of Alzheimer Disease.

Alzheimer disease (AD) is becoming one of the most prevalent neurodegenerative conditions worldwide. Although the disease progression is becoming better understood, current medical interventions can only ameliorate some of the symptoms but cannot slow disease progression. Neuroinflammation plays an important role in the advancement of this disorder, and n-3 (ω-3) polyunsaturated fatty acids (PUFAs) are involved in both the reduction in and resolution of inflammation.

Lack of Benefit of Early Intervention with Dietary Flax and Fish Oil and Soy Protein in Orthologous Rodent Models of Human Hereditary Polycystic Kidney Disease.

Rationale for dietary advice in polycystic kidney disease (PKD) is based in part on animal studies that have examined non-orthologous models with progressive development of cystic disease. Since no model completely mimics human PKD, the purpose of the current studies was to examine the effects of dietary soy protein (compared to casein) or oils enriched in omega-3 fatty acids (fish or flax oil compared to soy oil) on early disease progression in two orthologous models of PKD. The models studied were Pkd2WS25/- mice as a model of autosomal dominant PKD, and PCK rats as a model of autosomal recessive PKD.

Protein source in a high-protein diet modulates reductions in insulin resistance and hepatic steatosis in fa/fa Zucker rats.

Objective: High-protein diets are being promoted to reduce insulin resistance and hepatic steatosis in metabolic syndrome. Therefore, the effect of protein source in high-protein diets on reducing insulin resistance and hepatic steatosis was examined.

Methods: Fa/fa Zucker rats were provided normal-protein (15% of energy) casein, high-protein (35% of energy) casein, high-protein soy, or high-protein mixed diets with animal and plant proteins.

Advances in Our Understanding of Oxylipins Derived from Dietary PUFAs.

Oxylipins formed from polyunsaturated fatty acids (PUFAs) are the main mediators of PUFA effects in the body. They are formed via cyclooxygenase, lipoxygenase, and cytochrome P450 pathways, resulting in the formation of prostaglandins, thromboxanes, mono-, di-, and tri-hydroxy fatty acids (FAs), epoxy FAs, lipoxins, eoxins, hepoxilins, resolvins, protectins (also called neuroprotectins in the brain), and maresins. In addition to the well-known eicosanoids derived from arachidonic acid, recent developments in lipidomic methodologies have raised awareness of and interest in the large number of oxylipins formed from other PUFAs, including those from the essential FAs and the longer-chain n-3 (ω-3) PUFAs.

Curcumin and cancer: barriers to obtaining a health claim.

Curcumin is a highly pleiotropic molecule found in the rhizomes of Curcuma longa (turmeric). It is responsible for the yellow color of turmeric and has been shown to inhibit the proliferation of cancer cells and to be of use in preventing or treating a number of diseases. Curcumin has been shown to modulate multiple cell-signaling pathways simultaneously, thereby mitigating or preventing many different types of cancers, including multiple myeloma and colorectal, pancreatic, breast, prostate, lung, head, and neck cancers, in both animal models and humans.

Cholesterol-lowering properties of oat β-glucan and the promotion of cardiovascular health: did Health Canada make the right call?

In 2010, Health Canada approved a heath claim acknowledging the link between increased oats (Avena sativa)-soluble fibre consumption and a reduction in total serum cholesterol levels. The approval also recognized the relationship between decreased total blood cholesterol concentration and a reduced risk of coronary heart disease. The functional food ingredient believed to be responsible for the hypocholesterolemic property of oats is β-glucan, a highly viscous, soluble fibre composed of d-glucose monomers linked by a combination of β-(1→4) and β-(1→3) glycosidic bonds.

Dietary restriction in moderately obese rats improves body size and glucose handling without the renal and hepatic alterations observed with a high-protein diet.

Obesity is increasing worldwide, and high-protein (HP) diets are widely used for weight loss. However, the overall safety of HP diets is not well established in obese individuals, who make up a significant proportion of the population. To evaluate the health effects of an HP diet in obesity, obesity-prone (OP) Sprague-Dawley rats were given high-fat diets for 12 weeks to induce obesity.

Dietary flax oil rich in α-linolenic acid reduces renal disease and oxylipin abnormalities, including formation of docosahexaenoic acid derived oxylipins in the CD1-pcy/pcy mouse model of nephronophthisis.

The CD1-pcy/pcy mouse model of nephronophthisis displays reduced renal docosahexaenoic acid (DHA) levels and alterations in renal cyclooxygenase and lipoxygenase oxylipins derived from n-6 fatty acids. Since dietary flax oil ameliorates disease progression, its effect on renal fatty acids and oxylipins was examined. Sixteen weeks of feeding resulted in reduced disease progression and enrichment of renal phospholipid α-linolenic acid (ALA) and eicosapentaenoic acid, reduction in arachidonic acid (AA), but no change in linoleic acid (LA) or DHA.

Cyclooxygenase product inhibition with acetylsalicylic acid slows disease progression in the Han:SPRD-Cy rat model of polycystic kidney disease.

Renal cyclooxygenase (COX) derived eicosanoids are elevated and lipoxygenase (LOX) products are reduced in the Han:SPRD-Cy rat model of polycystic kidney disease (PKD). Selective COX2 inhibition reduces kidney disease progression, but COX1 levels also are elevated in this model. Since the effect of reducing the products of both COX isoforms and the role of LOX products is not known, weanling normal and diseased Han:SPRD-cy littermates were given either low dose acetylsalicylic acid (ASA), nordihydroguaiaretic (NDGA) or no treatment for eight weeks.

Renal cyclooxygenase and lipoxygenase products are altered in polycystic kidneys and by dietary soy protein and fish oil treatment in the Han:SPRD-Cy rat.

Scope: Dietary fish oil (FO) and soy protein (SP) are two interventions that slow disease progression in the Han:SPRD-Cy rat model of polycystic kidney disease (PKD). Inhibition of cyclooxygenase (COX)-derived eicosanoids also reduces disease progression, but the role of lipoxygenase (LOX) products in this disease is not known.

Methods And Results: Since dietary FO and SP have been shown to alter eicosanoid formation via differing mechanisms, Han:SPRD-Cy rats were given diets containing either casein protein (CP) or SP, and soy oil (SO) or FO.