Project description:The anterior cruciate ligament (ACL) is an essential stabilizer of the tibiofemoral articulation. ACL tears often lead to functional instability and are associated with an increased risk for osteoarthritis. The healing potential of the injured ACL is poorly understood and is considered to be limited. Transcriptome-wide expression profiles of 24 human ACL remnants recovered at the time of surgical reconstruction were analyzed utilizing the Agilent human 8x60K microarray platform. Gene ontology was performed on differentially expressed transcripts based on time-from-injury (acute, <3 months; intermediate, 3-12 months; chronic, >12 months). A subset of transcripts was validated via microfluidic digital polymerase-chain-reaction. Expression of periostin, a highly differentially expressed transcript, was tested by immunohistochemistry. Numerous transcripts covering important functional classifications were differentially expressed by time-from-injury. In acute tears, processes representing angiogenesis were repressed while those representing stem-cell differentiation were elevated. In intermediate tears, processes representing stem-cell proliferation concomitant with cellular component organization/cellular localization were elevated. In chronic tears, processes denoting myosin filament organization were elevated while those representing cellular component organization/cell localization and extracellular matrix organization were repressed. Expression levels of periostin were down-regulated in chronic tears compared to acute (42-fold) and intermediate (29-fold) tears. Immunohistochemistry confirmed a decline in periostin expression in tissues from chronic tears. These findings suggest an initial attempt of the injured ACL to repair, which declines with time-from-injury. These findings have implications for efforts to repair the ACL and may be relevant for reconstruction of the ACL. The functional role of periostin in ACL injuries, and the potential implication for surgical treatment, warrants further investigation. Total RNA obtained frominjured anterior cruciate ligament (ACL) tissues from pateints undergoing ACL surgery.

Project description:Background: Loss of motion and arthrofibrosis after anterior cruciate ligament reconstruction (ACLR) can be a devastating complication for athletes. The cellular and molecular pathogenesis of arthrofibrosis is poorly understood, limiting prevention and treatment options. Synovial inflammation may contribute to post-ACLR arthrofibrosis. Hypothesis/Purpose: We hypothesized that higher synovial immune cell infiltration and inflammatory/catabolic gene expression patterns at the time of ACLR would correlate with poorer motion-related outcomes. Study Design: Case Series Methods: Patients aged 10-18 undergoing primary ACLR were enrolled in a prospective pilot study, and synovial tissue biopsies were obtained during ACLR. Flow cytometry and single cell RNA-sequencing explored synovial cell types/frequencies and gene expression. Principle component analysis followed by clustering grouped patients into distinct immunophenotypes based on their synovial cell composition. Clinical follow-up with knee range of motion (ROM), need for lysis of adhesions, and patient reported outcome measures were collected and compared between immunophenotypes. Results: Enrolled patients (n = 17) underwent ACLR at a median of 37 days post-injury. Analysis revealed three distinct immunophenotypes. Type 1 comprised patients with the longest time between injury and surgery and the lowest hematopoietic and T cell infiltration. Types 2 and 3 had similar times between injury and surgery, and Type 2 had intermediate while Type 3 had the highest hematopoietic and T cell percentages. Type 3 was associated with worse ROM at 2- and 6-weeks post-op; T cell prevalence and ROM were inversely correlated at those time points. The only patient requiring lysis of adhesions for arthrofibrosis was in Type 3. Conclusion: Synovial immune infiltration after ACL injury shows variability between patients that clusters into three immunophenotypes correlating with early ROM and the risk of arthrofibrosis. T cell recruitment and infiltration was the strongest factor correlated with ROM outcomes and presents an exciting venue for future research on post-ACLR arthrofibrosis.

Project description:The anterior cruciate ligament (ACL) is an essential stabilizer of the tibiofemoral articulation. ACL tears often lead to functional instability and are associated with an increased risk for osteoarthritis. The healing potential of the injured ACL is poorly understood and is considered to be limited. Transcriptome-wide expression profiles of 24 human ACL remnants recovered at the time of surgical reconstruction were analyzed utilizing the Agilent human 8x60K microarray platform. Gene ontology was performed on differentially expressed transcripts based on time-from-injury (acute, <3 months; intermediate, 3-12 months; chronic, >12 months). A subset of transcripts was validated via microfluidic digital polymerase-chain-reaction. Expression of periostin, a highly differentially expressed transcript, was tested by immunohistochemistry. Numerous transcripts covering important functional classifications were differentially expressed by time-from-injury. In acute tears, processes representing angiogenesis were repressed while those representing stem-cell differentiation were elevated. In intermediate tears, processes representing stem-cell proliferation concomitant with cellular component organization/cellular localization were elevated. In chronic tears, processes denoting myosin filament organization were elevated while those representing cellular component organization/cell localization and extracellular matrix organization were repressed. Expression levels of periostin were down-regulated in chronic tears compared to acute (42-fold) and intermediate (29-fold) tears. Immunohistochemistry confirmed a decline in periostin expression in tissues from chronic tears. These findings suggest an initial attempt of the injured ACL to repair, which declines with time-from-injury. These findings have implications for efforts to repair the ACL and may be relevant for reconstruction of the ACL. The functional role of periostin in ACL injuries, and the potential implication for surgical treatment, warrants further investigation.

			Action	DRS
	SRR27500500.fastq.gz	Fastqsanger.gz
	SRR27500501.fastq.gz	Fastqsanger.gz
	SRR27500502.fastq.gz	Fastqsanger.gz
	SRR27500503.fastq.gz	Fastqsanger.gz
	SRR27500504.fastq.gz	Fastqsanger.gz

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Early MicroRNA and Metabolite Changes Post-ACL Reconstruction Surgery

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