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Whitney DG, Alford AI, Devlin MJ, Li Y, Caird MS. Intersite reliability of vertebral bone marrow lipidomics-derived lipid composition among children with varying degrees of bone fragility undergoing routine orthopedic surgery. Bone 2021; 143:115633. [PMID: 32927104 PMCID: PMC7770023 DOI: 10.1016/j.bone.2020.115633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/30/2020] [Accepted: 09/09/2020] [Indexed: 01/18/2023]
Abstract
BACKGROUND Lipidomics, a branch of metabolomics, is an attractive technique to characterize bone marrow lipid composition, which may be associated with skeletal acquisition and homeostasis. However, the reliability of lipidomics-derived lipid composition of the bone marrow is unknown, especially for pediatric populations with bone fragility. The purpose of this study was to evaluate the intersite reliability and standard error of measurement (SEM) of vertebral bone marrow lipid composition at the thoracic (T11/T12) and lumbar (L1/L2) spine determined by targeted lipidomics among children with varying degrees of bone fragility undergoing routine orthopedic surgery. METHODS Children aged between 12 and 19 years of age, with a confirmed diagnosis of adolescent idiopathic scoliosis or neuromuscular scoliosis and cerebral palsy, and undergoing routine posterior spinal fusion surgery at our institution were initially included in this study. Transpedicular vertebral body bone marrow samples were taken from thoracic (T) or lumbar (L) vertebrae. Further inclusion criteria involved having bone marrow extracted from both T11 and T12 (n = 24) or L1 and L2 (n = 19). Lipid composition was measured using a targeted lipidomics technique and examined as the saturated, monounsaturated, and polyunsaturated index and as individual fatty acids. Relative and absolute test-retest reliability was assessed using the intraclass correlation coefficient (ICC) and SEM. RESULTS For the T11/T12 analysis: the ICC and SEM were 0.59 and 1.7% for the saturated index, 0.31 and 6.2% for the monounsaturated index, and 0.44 and 6.1% for the polyunsaturated index; the ICC showed a considerable range for individual fatty acids from 0.07 (fatty acid 20:2) to 0.82 (15:0) with 62.1% of the fatty acids having poor reliability (i.e., ICC < 0.50). For the L1/L2 analysis: the ICC and SEM were 0.50 and 2.4% for the saturated index, -0.12 and 6.0% for the monounsaturated index, and 0.00 and 4.9% for the polyunsaturated index; the ICC showed a considerable range for individual fatty acids from -0.34 (18:1_n-9) to 0.88 (15:0 and 18:3_n-3) with 79.3% of the fatty acids having poor reliability. CONCLUSIONS The intersite test-retest reliability was poor-to-moderate for index measures and generally poor for individual fatty acids for the thoracic and lumbar spine. At this time, it is not recommended to pool bone marrow adipose tissue across vertebral sites for bone marrow adiposity research or clinical monitoring for pediatric populations with bone fragility.
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Affiliation(s)
- Daniel G Whitney
- Department of Physical Medicine and Rehabilitation, University of Michigan, 325 E. Eisenhower, Ann Arbor, MI 48108, United States of America; Institute for Healthcare Policy and Innovation, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109, United States of America.
| | - Andrea I Alford
- Department of Orthopaedic Surgery, University of Michigan, A. Alfred Taubman Biomedical Sciences Research Building, Room 2009, Ann Arbor, MI 48109, United States of America
| | - Maureen J Devlin
- Department of Anthropology, University of Michigan, 1085 S. University Ave., Ann Arbor, MI 48109, United States of America
| | - Ying Li
- Department of Orthopaedic Surgery, University of Michigan, A. Alfred Taubman Biomedical Sciences Research Building, Room 2009, Ann Arbor, MI 48109, United States of America
| | - Michelle S Caird
- Department of Orthopaedic Surgery, University of Michigan, A. Alfred Taubman Biomedical Sciences Research Building, Room 2009, Ann Arbor, MI 48109, United States of America
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McGrath C, Little-Letsinger SE, Sankaran JS, Sen B, Xie Z, Styner MA, Zong X, Chen W, Rubin J, Klett EL, Coleman RA, Styner M. Exercise Increases Bone in SEIPIN Deficient Lipodystrophy, Despite Low Marrow Adiposity. Front Endocrinol (Lausanne) 2021; 12:782194. [PMID: 35145475 PMCID: PMC8822583 DOI: 10.3389/fendo.2021.782194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/20/2021] [Indexed: 01/12/2023] Open
Abstract
Exercise, typically beneficial for skeletal health, has not yet been studied in lipodystrophy, a condition characterized by paucity of white adipose tissue, with eventual diabetes, and steatosis. We applied a mouse model of global deficiency of Bscl2 (SEIPIN), required for lipid droplet formation. Male twelve-week-old B6 knockouts (KO) and wild type (WT) littermates were assigned six-weeks of voluntary, running exercise (E) versus non-exercise (N=5-8). KO weighed 14% less than WT (p=0.01) and exhibited an absence of epididymal adipose tissue; KO liver Plin1 via qPCR was 9-fold that of WT (p=0.04), consistent with steatosis. Bone marrow adipose tissue (BMAT), unlike white adipose, was measurable, although 40.5% lower in KO vs WT (p=0.0003) via 9.4T MRI/advanced image analysis. SEIPIN ablation's most notable effect marrow adiposity was in the proximal femoral diaphysis (-56% KO vs WT, p=0.005), with relative preservation in KO-distal-femur. Bone via μCT was preserved in SEIPIN KO, though some quality parameters were attenuated. Running distance, speed, and time were comparable in KO and WT. Exercise reduced weight (-24% WT-E vs WT p<0.001) but not in KO. Notably, exercise increased trabecular BV/TV in both (+31%, KO-E vs KO, p=0.004; +14%, WT-E vs WT, p=0.006). The presence and distribution of BMAT in SEIPIN KO, though lower than WT, is unexpected and points to a uniqueness of this depot. That trabecular bone increases were achievable in both KO and WT, despite a difference in BMAT quantity/distribution, points to potential metabolic flexibility during exercise-induced skeletal anabolism.
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Affiliation(s)
- Cody McGrath
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Sarah E. Little-Letsinger
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jeyantt Srinivas Sankaran
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Buer Sen
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zhihui Xie
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Martin A. Styner
- Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Xiaopeng Zong
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Weiqin Chen
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Janet Rubin
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
| | - Eric L. Klett
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
- Department of Nutrition, Gillings School of Global Public Health, UNC, Chapel Hill, NC, United States
| | - Rosalind A. Coleman
- Department of Nutrition, Gillings School of Global Public Health, UNC, Chapel Hill, NC, United States
| | - Maya Styner
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
- *Correspondence: Maya Styner,
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Whitney DG, Devlin MJ, Alford AI, Caird MS. Pattern of bone marrow lipid composition measures along the vertebral column: A descriptive study of adolescents with idiopathic scoliosis. Bone 2021; 142:115702. [PMID: 33099030 PMCID: PMC9426858 DOI: 10.1016/j.bone.2020.115702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/03/2020] [Accepted: 10/18/2020] [Indexed: 11/21/2022]
Abstract
BACKGROUND There is evidence that the extent of vertebral bone marrow adiposity increases caudally along the vertebral column in children and adolescents. However, no studies have examined the lipid composition of bone marrow along the vertebral column, which may uniquely influence bone acquisition and metabolism during growth independent of the amount of bone marrow adipose tissue. The goal of this study was to characterize the pattern of lipid composition index measures from the thoracic to lumbar spine (T11-L4) among a sample of adolescents with idiopathic scoliosis (AIS) undergoing routine orthopedic surgical care for scoliosis correction. METHODS Adolescents between 14 and 18 years of age, with a confirmed diagnosis of AIS, and undergoing routine posterior spinal fusion surgery at our institution were initially included for this descriptive study. The surgery yielded transpedicular vertebral body marrow samples from T11 through L4; 11 participants had bone marrow samples from T11 through L2 and 4 of the 11 participants had marrow samples from T11 through L4. Lipid composition index measures, including the saturated, monounsaturated, and polyunsaturated index, were measured using a targeted lipidomics technique. Linear regression equation for the slope (m) and Pearson correlation coefficient (r) was computed to assess the pattern of lipid composition index measures along the vertebral column from T11 to L2 (n = 11) and extended analysis to L4. Exploratory analyses were performed to examine the association between the pattern of lipid composition measures (individual slopes) and physical characteristics for T11-L2. RESULTS For T11-L2, the slope of the saturated index was near 0 (r = 0.08; P = 0.92), whereas the slopes of the unsaturated indices were approximately opposite of one another: the monounsaturated index exhibited a -0.55 change (r = 0.58; P = 0.42) per vertebra and the polyunsaturated index exhibited a 0.52 change (r = 0.72; P = 0.28) per vertebra in the caudal direction from T11-L2. For T11-L4, there were modest changes in slope for the saturated (m = 0.12; r = 0.30; P = 0.57) and monounsaturated (m = -0.68; r = 0.74; P = 0.09) indices, while the polyunsaturated index slope remained similar (m = 0.56; r = 0.89; P = 0.02). Age, sex, height, body mass, and BMI were not associated with the pattern of any of the lipid composition index measures. CONCLUSIONS Study findings in this small sample of individuals with AIS suggest that the bone marrow saturated index may be relatively stable across T11-L4, while the monounsaturated index may decrease by 0.55-0.68% per vertebra and the polyunsaturated index may increase by 0.52-0.56% per vertebra in the caudal direction.
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Affiliation(s)
- Daniel G Whitney
- Department of Physical Medicine and Rehabilitation, University of Michigan, 325 E. Eisenhower, Ann Arbor, MI 48108, United States of America; Institute for Healthcare Policy and Innovation, University of Michigan, 2800 Plymouth Rd., Ann Arbor, MI 48109, United States of America.
| | - Maureen J Devlin
- Department of Anthropology, University of Michigan, 1085 S. University Ave., Ann Arbor, MI 48109, United States of America
| | - Andrea I Alford
- Department of Orthopaedic Surgery, University of Michigan, A. Alfred Taubman Biomedical Sciences Research Building, Room 2009, Ann Arbor, MI 48109, United States of America
| | - Michelle S Caird
- Department of Orthopaedic Surgery, University of Michigan, A. Alfred Taubman Biomedical Sciences Research Building, Room 2009, Ann Arbor, MI 48109, United States of America
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