Sex-specific effects of injury and beta-adrenergic activation on metabolic and inflammatory mediators in a murine model of post-traumatic osteoarthritis

OBJECTIVE

Metabolic processes are intricately linked to the resolution of innate inflammation and tissue repair, two critical steps for treating post-traumatic osteoarthritis (PTOA). Based on lipolytic and immunoregulatory actions of norepinephrine, we hypothesized that intra-articular β-adrenergic receptor (βAR) stimulation would suppress PTOA-associated inflammation in the infrapatellar fat pad (IFP) and synovium.

DESIGN

We used the βAR agonist isoproterenol to perturb intra-articular metabolism 3.5 weeks after applying a non-invasive single-load compression injury to knees of 12-week-old male and female mice. We examined the acute effects of intra-articular isoproterenol treatment relative to saline on IFP histology, multiplex gene expression of synovium-IFP tissue, synovial fluid metabolomics, and mechanical allodynia.

RESULTS

Injured knees developed PTOA pathology characterized by heterotopic ossification, articular cartilage loss, and IFP atrophy and fibrosis. Isoproterenol suppressed the upregulation of pro-fibrotic genes and downregulated the expression of adipose genes and pro-inflammatory genes (Adam17, Cd14, Icam1, Csf1r, and Casp1) in injured joints of female (but not male) mice. Analysis of published single-cell RNA-seq data identified elevated catecholamine-associated gene expression in resident-like synovial-IFP macrophages after injury. Injury substantially altered synovial fluid metabolites by increasing amino acids, peptides, sphingolipids, phospholipids, bile acids, and dicarboxylic acids, but these changes were not appreciably altered by isoproterenol. Intra-articular injection of either isoproterenol or saline increased mechanical allodynia in female mice, whereas neither substance affected male mice.

CONCLUSIONS

Acute βAR activation altered synovial-IFP transcription in a sex and injury-dependent manner, suggesting that women with PTOA may be more sensitive than men to treatments targeting sympathetic neural signaling pathways.

Imaging mass cytometry reveals tissue-specific cellular immune phenotypes in the mouse knee following ACL injury

Objective

To develop an imaging mass cytometry method for identifying complex cell phenotypes, inter-cellular interactions, and population changes in the synovium and infrapatellar fat pad (IFP) of the mouse knee following a non-invasive compression injury.

Design

Fifteen male C57BL/6 mice were fed a high-fat diet for 8 weeks prior to random assignment to sham, 0.88 ​mm, or 1.7 ​mm knee compression displacement at 24 weeks of age. 2-weeks after loading, limbs were prepared for histologic and imaging mass cytometry analysis, focusing on myeloid immune cell populations in the synovium and IFP.

Results

1.7 ​mm compression caused anterior cruciate ligament (ACL) rupture, development of post-traumatic osteoarthritis, and a 2- to 3-fold increase in cellularity of synovium and IFP tissues compared to sham or 0.88 ​mm compression. Imaging mass cytometry identified 11 myeloid cell subpopulations in synovium and 7 in IFP, of which approximately half were elevated 2 weeks after ACL injury in association with the vasculature. Notably, two monocyte/macrophage subpopulations and an MHC IIhi population were elevated 2-weeks post-injury in the synovium but not IFP. Vascular and immune cell interactions were particularly diverse in the synovium, incorporating 8 unique combinations of 5 myeloid cell populations, including a monocyte/macrophage population, an MHC IIhi population, and 3 different undefined F4/80+ myeloid populations.

Conclusions

Developing an imaging mass cytometry method for the mouse enabled us to identify a diverse array of synovial and IFP vascular-associated myeloid cell subpopulations. These subpopulations were differentially elevated in synovial and IFP tissues 2-weeks post injury, providing new details on tissue-specific immune regulation.

A Genomic Biomarker for Breast Cancer Development in High-Risk Women

BackgroundFamily history is an important factor contributing to a woman's risk of breast cancer development. This increased risk reflects the participation of inherited genetic components such as breast cancer susceptibility genes. However, many of the genetic components contributing to breast cancer remain unknown, and a number of women with a family history of breast cancer never develop breast cancer despite their high-risk status, while other high-risk woman go on to develop breast cancer. Thus, it is clear that we lack crucial pieces of information to help define a person's true risk of developing breast cancer.Methods and FindingsWe hypothesize that there are many undiscovered germline variations in genes that lead to altered gene expression patterns predictive of breast cancer development in high-risk women. We have developed a genomic model capable of predicting which high-risk women, both BRCA1/2 mutation carriers and BRCAX women, will actually develop breast cancer. Specifically, we use exon-level genome-wide expression profiling of peripheral blood mononuclear cells (PBMCs) to develop a model of disease risk (n=118 samples of either control or high-risk women). From this data, we generate a biomarker consisting of genes that most correlate to cancer development in women with strong family histories of breast cancer. Using an internal independent dataset, our biomarker can predict the high-risk women who will or will not develop cancer with over 85% accuracy. Further, we have validated this model on an independent external cohort (n=36) which was obtained and processed at sites unique to our training dataset. Our genomic biomarker can accurately predict breast cancer development in high-risk women with over 78% accuracy using this external dataset. Therefore, from our analyses, we can calculate with high accuracy an individual woman's true risk of developing breast cancer. This method provides a personalized approach to hereditary breast cancer risk assessment that is not currently available. This personalized risk assessment will aide clinicians in counseling their patients regarding specific management options based on a patient's individual risk of breast cancer. Lastly, these studies have also identified novel genes associated with breast cancer risk, which may provide a basis for targeted therapies that may help modify the risk of breast cancer development in high risk patients.ConclusionsTogether, these studies deliver both a non-invasive biomarker for hereditary breast cancer risk and a characterization of genes that contribute to breast cancer development. Overall, we expect these experiments to identify the genetic changes that underlie breast cancer predisposition, and assist clinicians and patients in determining the appropriate preventative measures based on their personal risk of developing breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4059.

Towards Arabidopsis genome analysis: monitoring expression profiles of 1400 genes using cDNA microarrays

cDNA microarrays containing 1443 Arabidopsis thaliana genes were analyzed for expression profiles in major organs of Arabidopsis plants. Novel expression profiles were identified for many coding sequences with putative gene identifications. Expression patterns of novel sequences provided clues to their possible functions. The results demonstrate how microarrays containing a large number of Arabidopsis genes can provide a powerful tool for plant gene discovery, functional analysis and elucidation of genetic regulatory networks.

A comparison of the approaches to laparoscopic herniorrhaphy

BACKGROUND

There are a variety of accepted techniques for herniorrhaphy. With the advent of laparoscopic general surgery, new endoscopic techniques using the transabdominal and total extraperitoneal approaches have been added to the many options for the repair of inguinal hernia. The purpose of this study was to compare the early results of these approaches at a single institution.

METHODS

Between May 1991 and August 1994, 600 laparoscopic herniorrhaphies were performed on 493 patients. Three hundred hernias were repaired using the transabdominal preperitoneal approach and 300 were repaired using the total extraperitoneal approach. A retrospective review was performed with emphasis on the comparison of recurrence rates and complication rates between these two approaches to laparoscopic herniorrhaphy.

RESULTS

The recurrence rates were 2.0% (6/300) for the transabdominal approach and 0.3% (1/300) for the total extraperitoneal approach. The complication rate for the transabdominal approach was 10.7% and included thigh paresthesias (6), inferior epigastric artery injuries (4), enterotomy (1), bowel obstruction (1), bladder injury (1), and urinary retention (14). The complication rate for the total extraperitoneal approach was 3.7% and included enterotomies (2), bladder injury (1), paresthesia (1), and urinary retention (6). The recurrence, the enterotomies, and the bladder injury in the total extraperitoneal group were all in patients who had previous lower abdominal operations.

CONCLUSIONS

Although both the transabdominal preperitoneal and total extraperitoneal approaches to laparoscopic herniorrhaphy have acceptable recurrence and complication rates, there were significant advantages to the total extraperitoneal approach in our institution. Previous lower abdominal surgery may be a relative contraindication to the total extraperitoneal approach.

Chronic extradural haematomas: indications for surgery

Non-invasive neuro-imaging has led to the detection of minimally symptomatic or asymptomatic chronic extradural haematomas. Our experience and review of the literature suggests that, as in the case of chronic subdural haematomas, there is development of membranes and liquifaction of the clot which may permit drainage of such collections through twist drill or burrholes. The time from development and the neuro-imaging chanes on CT and MRI can suggest the age and nature of the clot and thus permit timing of surgery so that drainage may be accomplished with a minor procedure.