Orchidectomy-induced alterations in volumetric bone density, cortical porosity and strength of femur are attenuated by dietary conjugated linoleic acid in aged guinea pigs

• Published in: Bone (New York, N.Y.) Vol. 73; pp. 42 - 50
• Main Authors: DeGuire, Jason R, Mak, Ivy L, Lavery, Paula, Agellon, Sherry, Wykes, Linda J, Weiler, Hope A
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2015
• Subjects: Absorptiometry, Photon; Aged guinea pig; Animals; Bone Density; Bone–muscle interactions; Conjugated linoleic acid; Dietary Fats - administration & dosage; DXA; Femur - physiology; Guinea Pigs; Linoleic Acids, Conjugated - administration & dosage; Male; Orchidectomy; Orchiectomy; Orthopedics; Porosity; Aged guinea pig; Lumbar spine; W break; LS; Tt.Ar; Cortical area/total area; Tb.Sp; Young's modulus; RBC; Micro-computed tomography; σ max; vBMD; Areal bone mineral density; Trabecular thickness; Orchidectomy; μCT; FSR; PUFA; iCa; Polyunsaturated fatty acid; Dual-energy X-ray absorptiometry; Energy at break; Ct.Ar; Distance between fulcrum; DXA; IL-6; Trabecular area; Strain; Bone mineral content; 25OHD; ε max; Bone–muscle interactions; Tb.Th; DPD; d max; Maximum flexure load; Trabecular separation; Fractional synthesis rate; Conjugated linoleic acid; E; Distance from neutral axis to outer perimeter; Ionized calcium; PGE 2; Tb.N; WB; L; Interleukin-6; Trabecular number; BV/TV; ORX; Bone volume/total volume; Deoxypyridinoline; BMC; Whole body; Maximum extension at maximum flexure load; 25-Hydroxyvitamin D; F max; Cortical thickness; c; Tartrate-resistant acid phosphatase; Red blood cell; Stress; Ct.Ar./Tt.Ar; Cortical area; Ct.Th; aBMD; TRACP; Cortical porosity; CLA; Ct.Po; Prostaglandin E 2; Volumetric bone mineral density; Wbreak; PGE2; dmax; σmax; εmax; Fmax
• ISSN: 8756-3282; 1873-2763
• DOI: 10.1016/j.bone.2014.12.005

Abstract Age-related osteoporosis and sarcopenia are ascribed in part to reductions in anabolic hormones. Dietary conjugated linoleic acid (CLA) improves lean and bone mass, but its impact during androgen deficiency is not known. This study tested if CLA would attenuate the effects of orchidectomy (ORX)-induced losses of bone and lean tissue. Male guinea pigs (n = 40; 70–72 weeks), were randomized into four groups: 1) SHAM + Control diet, 2) SHAM + CLA diet, 3) ORX + Control diet, 4) ORX + CLA diet. Baseline blood sampling and dual-energy X-ray absorptiometry (DXA) scans were conducted, followed by surgery 4 days later with the test diets started 7 days after baseline sampling. Serial blood sampling and DXA scans were repeated 2, 4, 8 and 16 weeks on the test diets. Body composition and areal BMD (aBMD) of whole body, lumbar spine, femur and tibia were measured using DXA. At week 16, muscle protein fractional synthesis rate (FSR), volumetric BMD (vBMD), microarchitecture and bone strength were assessed. Body weight declined after SHAM and ORX surgery, with slower recovery in the ORX group. Dietary CLA did not affect weight or lean mass, but attenuated gains in fat mass. Lean mass was stable in SHAM and reduced in ORX by 2 weeks with whole body and femur bone mineral content (BMC) reduced by 4 weeks; CLA did not alter BMC. By week 16 ORX groups had lower free testosterone and myofibrillar FSR, yet higher cortisol, osteocalcin and ionized calcium with no alterations due to CLA. ORX + Control had higher prostaglandin E2 (PGE2 ) and total alkaline phosphatase compared to SHAM + Control whereas ORX + CLA were not different from SHAM groups. Femur metaphyseal vBMD was reduced in ORX + CTRL with the reduction attenuated by CLA. Femur cortical thickness (Ct.Th.) and biomechanical strength were reduced and cortical porosity (Ct.Po.) elevated by ORX and attenuated by CLA. This androgen deficient model with a sarcopenic-osteoporotic phenotype similar to aging men responded to dietary CLA with significant benefits to femur density and strength.