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Background: To document the role of sub-clinical infections in disc disorders and investigate the existence of microbiome in intervertebral discs (IVD).Methods: Genomic DNA from 24 lumbar IVDs [8-MRI normal discs (ND) from brain dead yet alive organ donors, 8-disc herniation (DH), 8-disc degeneration (DD)] was subjected to 16SrRNA sequencing for profiling the diversity of human disc microbiome in health and disease. The disc microbiome was further compared to established human gut and skin microbiomes.Results: All healthy MRI normal discs from brain dead yet alive organ donors also had a rich bacterial presence. A total of 424 different species (355-ND, 346-DD, and 322-DH) were detected, with 42.75% OTUs being classified at kingdom level, 44% at the phylum level, 22.62% at genus level, and 5.5% at species level. Varying biodiversity and abundance between healthy and diseased discs were documented with protective bacteria being abundant in normal discs, and putative pathogens abundant in DD and DH. Propionibacterium acnes had a similar but lower abundance to other pathogens in all three groups ND (3.07%), DD (3.88%), DH (1.56%). Fifty-eight bacteria were common between gut and IVD microbiomes, 29 between skin and IVD microbiomes, and six common to gut/skin/IVD.Conclusion: Our study challenges the hitherto concept of sterility in healthy IVD and documented a microbiome even in MRI normal healthy discs. The varying abundance of bacteria between ND, DD, and DH documents 'dysbiosis' as a possible etiology of DD. Many known pathogens were identified in greater abundance than Propionibacterium acnes, and there was evidence for the presence of the gut/skin/spine microbiome axis. [ABSTRACT FROM AUTHOR]

Background Context: The true understanding of aging and disc degeneration (DD) is still elusive. MRI has not helped our attempts to understand the health and disease status of the discs as it reflects mainly the end morphologic changes and not the changes at a molecular level. Understanding degeneration at a molecular level through proteomics might allow differentiation from normal aging and also aid in the development of biomarkers for early diagnosis and preventive therapies.Purpose: To utilize proteomics to understand the molecular basis of healthy, aging, and degenerating discs and conclusively differentiate normal aging and degeneration.Study Design: Proteomic analysis of human intervertebral disc samples.Methods: L4-L5 disc samples from three groups were acquired and subjected to proteomic analysis. Samples from individuals aged in the second, third, and fourth decades were used to represent young healthy discs (Group A). Those from MRI normal donors aged in the fifth, sixth, and seventh decades represented normal aging (Group B). Five degenerated discs obtained from patients at surgery represented degeneration (Group C). The entire proteome map and alteration in protein expressions were further analyzed using bioinformatics analysis. This was a self-funded project.Results: There were 84 common proteins. Specific proteins numbered 225 in A, 315 in B, and 283 in C. By gene ontology biological process identification, Group A predominated with extracellular matrix organization, cytoskeletal structural and normal metabolic proteins. Group B differed in having additional basal expression of immune response, complement inhibitors, and senescence proteins. Group C was different, with upregulation of proteins associated with oxidative stress response, positive regulators of apoptosis, innate immune response, complement activation and defense response to gram positive bacteria indicating ongoing inflammaging.Conclusions: Our study documented diverse proteome signatures between the young, aging and degenerating discs. Inflammaging was the main differentiator between normal biological aging and DD.Clinical Significance: Multiple inflammatory molecules unique to DD were identified, allowing the possibility of developing specific biomarkers for early diagnosis and thereby provide evidence-based metrics for preventive measures rather than surgical intervention and also to monitor progress of the disease. [ABSTRACT FROM AUTHOR]

Background Context: Small leucine-rich proteoglycans (SLRPs) play an essential role in extracellular matrix (ECM) organization and function. Recently, dysregulation of SLRPs has been implicated in degenerative disc disease (DDD). An in-depth analysis using high-throughput proteomic sequencing might provide valuable information on their implications in health and disease.Purpose: To utilize proteomics for analyzing the expression of SLRPs in fetal, healthy adult, and degenerated discs, to identify possible molecular targets to halt or reverse the degenerative process.Study Design: Experimental analysis.Methods: Proteomic signatures of 8 magnetic resonance imaging (MRI) normal lumbar discs (ND) [harvested from brain dead alive organ donors] were compared to 8 fetal disc samples (FD) [harvested from fetal spines devoid of congenital anomalies following spontaneous or medical termination of pregnancy] and 8 degenerate discs (DD) [collected from patients undergoing fusion surgery]. The various functional pathways along with the differential expression of SLRPs and the associated changes in collagens, large proteoglycans (LLRPs), matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) have been analyzed further using bioinformatics. This project was self-funded by the Ganga Orthopedic Research and Education Foundation.Results: ESI-LC-MS/MS analysis revealed a total of 1,029 proteins in FD, 1,785 proteins in ND, and 1,775 proteins in DD. Fetal disc proteins were engaged mainly in ribosomal pathways (indicating active proliferation and regenerative potential). The healthy adult discs (ND) primarily participated in ECM maintenance and basic metabolic pathways, whereas the unique proteins of DD group were involved in inflammatory (Complement and coagulation cascades, Systemic Lupus Erythematosus and Leukocyte transendothelial migration) pathways and infective (Staphylococcus aureus infection, Prion diseases, Amoebiasis, Pertussis, and Legionellosis) channels which favor the recent concepts of inflammaging and subclinical infection as causes of DDD. Analysis of SLRPs revealed the upregulation of Biglycan in FDs and downregulation of Lumican, Decorin, Prolargin, and Chondroadherin in the DD group. The universal decrease in the abundance of SLRPs in the DD group was associated with an increase in MMPs and a reduction in TIMPs, collagen and LLRP content.Conclusions: Our study documents the influence of SLRPs in the maintenance of disc health and also the need for future research in using them for disc regeneration.Clinical Significance: The various SLRPs that we identified are all known to have a beneficial influence on ECM integrity and a negative effect on the degenerative process at different stages in the evolution of degeneration. Biglycan, which is abundantly present in a fetus, may be suitable for regenerative therapy, and the other SLRPs like Lumican, Prolargin, Decorin, and Chondroadherin may serve the same purpose and/or as biomarkers. [ABSTRACT FROM AUTHOR]