Computed Tomography Measured Psoas Cross Sectional Area Is Associated With Bone Mineral Density Measured by Dual Energy X-Ray Absorptiometry.

Dual-energy X-ray absorptiometry (DEXA) is the gold standard for osteoporosis screening and diagnosis. However, abdominal conventional computed tomography (CT) scan is widely available and multiple studies validated its use as a screening tool for osteoporosis compared to DEXA. The aim of this study was to determine the reliability of measuring core muscle size at the L3-L4 intervertebral disk space and estimate the relationship between core muscle size and bone mineral density (BMD) measured by DEXA. Retrospective chart review was performed on patients who underwent a DEXA scan for osteoporosis and a conventional abdominal CT scan within one-year apart. Total cross-sectional area (CSA) and Hounsfield Unit (HU) density of core muscles (psoas, paraspinal, and abdominal wall muscles) were measured. The association between psoas, paraspinal, abdominal, and central muscle CSA and Bone Mineral density (BMD) at L3, L4, total Lumbar Spine (LS), and right (R) and left (L) hip was estimated in crude and adjusted for age and sex linear regression models. Sixty patients (37 females, 23 males) met the inclusion criteria. The average interval between DEXA and abdominal CT scans was 3.6 months (range 0.1-10.2). Psoas muscle density was significantly positively associated with R hip BMD in both crude and adjusted models (ß = 20.2, p = 0.03; ß = 18.5, p = 0.01). We found a significant positive linear association between psoas muscle CSA and HU density with BMD of LS, R, and L hip in both crude and adjusted models. The strongest significant positive linear association was observed between total abdominal CSA and R hip BMD in crude and age and sex adjusted (ß = 85.3, p = 0.01; ß = 63.9, p = 0.02, respectively). CT scans obtained for various clinical indications can provide valuable information regarding BMD. This is the first study investigating association between BMD with central muscle density and CSA, and it demonstrated their significant positive the association.

Sagittal Fragment Rotation and Ogden Type-I Classification Are Hallmarks of Combined Tibial Tubercle Fracture and Patellar Tendon Injury.

BACKGROUND: Tibial tubercle fractures (TTFs) are uncommon injuries, comprising <3% of all proximal tibial fractures. These fractures occasionally occur in conjunction with a patellar tendon injury (PTI). We aimed to identify risk factors associated with combined TTF and PTI. METHODS: A retrospective review was performed of patients presenting to a single, tertiary children's hospital with TTF between 2012 and 2023. Demographic data, operative details, radiographs, and injury patterns were analyzed. Radiographs were assessed for the epiphyseal union stage (EUS), Ogden classification, and fracture patterns. Multiple logistic regression models were used to assess the impact of body mass index, comminution, fracture fragment rotation, EUS, bilateral injury, and Ogden classification on injury type. RESULTS: We identified 262 fractures in 252 patients (mean age, 13.9 ± 1.31 years). Of the patients, 6% were female and 48% were Black. Of the 262 fractures, 228 (87%) were isolated TTFs and 34 (13%) were TTFs with PTI. Multivariable analysis demonstrated fragment rotation on lateral radiographs (p < 0.0001) and Ogden Type-I classification (p < 0.0001) to be the most predictive risk factors for a combined injury. Rotation was associated with a substantial increase in the odds of a combined injury, with an odds ratio of 22.1 (95% confidence interval [CI], 6.1 to 80.1). Ogden Type-I fracture was another significant risk factor, with an odds ratio of 10.2 (95% CI, 3.4 to 30.4). CONCLUSIONS: The Ogden classification and fragment rotation are the most useful features for distinguishing between isolated TTF and combined TTF with PTI. This is the first study to identify risk factors for TTF combined with PTI. Surgeons may use this information to aid in preoperative planning. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Absence of the complement regulatory molecule CD59a leads to exacerbated neuropathology after traumatic brain injury in mice.

BACKGROUND: Complement represents a crucial mediator of neuroinflammation and neurodegeneration after traumatic brain injury. The role of the terminal complement activation pathway, leading to generation of the membrane attack complex (MAC), has not been thoroughly investigated. CD59 is the major regulator of MAC formation and represents an essential protector from homologous cell injury after complement activation in the injured brain. METHODS: Mice deleted in the Cd59a gene (CD59a-/-) and wild-type littermates (n = 60) were subjected to focal closed head injury. Sham-operated (n = 60) and normal untreated mice (n = 14) served as negative controls. The posttraumatic neurological impairment was assessed for up to one week after trauma, using a standardized Neurological Severity Score (NSS). The extent of neuronal cell death was determined by serum levels of neuron-specific enolase (NSE) and by staining of brain tissue sections in TUNEL technique. The expression profiles of pro-apoptotic (Fas, FasL, Bax) and anti-apoptotic (Bcl-2) mediators were determined at the gene and protein level by real-time RT-PCR and Western blot, respectively. RESULTS: Clinically, the brain-injured CD59a-/- mice showed a significantly impaired neurological outcome within 7 days, as determined by a higher NSS, compared to wild-type controls. The NSE serum levels, an indirect marker of neuronal cell death, were significantly elevated in CD59a-/- mice at 4 h and 24 h after trauma, compared to wild-type littermates. At the tissue level, increased neuronal cell death and brain tissue destruction was detected by TUNEL histochemistry in CD59a-/- mice within 24 hours to 7 days after head trauma. The analysis of brain homogenates for potential mediators and regulators of cell death other than the complement MAC (Fas, FasL, Bax, Bcl-2) revealed no difference in gene expression and protein levels between CD59a-/- and wild-type mice. CONCLUSION: These data emphasize an important role of CD59 in mediating protection from secondary neuronal cell death and further underscore the key role of the terminal complement pathway in the pathophysiology of traumatic brain injury. The exact mechanisms of complement MAC-induced secondary neuronal cell death after head injury require further investigation.

Bench-to-bedside review: Burn-induced cerebral inflammation--a neglected entity?

Severe burn injury remains a major burden on patients and healthcare systems. Following severe burns, the injured tissues mount a local inflammatory response aiming to restore homeostasis. With excessive burn load, the immune response becomes disproportionate and patients may develop an overshooting systemic inflammatory response, compromising multiple physiological barriers in the lung, kidney, liver, and brain. If the blood-brain barrier is breached, systemic inflammatory molecules and phagocytes readily enter the brain and activate sessile cells of the central nervous system. Copious amounts of reactive oxygen species, reactive nitrogen species, proteases, cytokines/chemokines, and complement proteins are being released by these inflammatory cells, resulting in additional neuronal damage and life-threatening cerebral edema. Despite the correlation between cerebral complications in severe burn victims with mortality, burn-induced neuroinflammation continues to fly under the radar as an underestimated entity in the critically ill burn patient. In this paper, we illustrate the molecular events leading to blood-brain barrier breakdown, with a focus on the subsequent neuroinflammatory changes leading to cerebral edema in patients with severe burns.

Inhibition of complement C5a prevents breakdown of the blood-brain barrier and pituitary dysfunction in experimental sepsis.

INTRODUCTION: Septic encephalopathy secondary to a breakdown of the blood-brain barrier (BBB) is a known complication of sepsis. However, its pathophysiology remains unclear. The present study investigated the effect of complement C5a blockade in preventing BBB damage and pituitary dysfunction during experimental sepsis. METHODS: Using the standardised caecal ligation and puncture (CLP) model, Sprague-Dawley rats were treated with either neutralising anti-C5a antibody or pre-immune immunoglobulin (Ig) G as a placebo. Sham-operated animals served as internal controls. RESULTS: Placebo-treated septic rats showed severe BBB dysfunction within 24 hours, accompanied by a significant upregulation of pituitary C5a receptor and pro-inflammatory cytokine expression, although gene levels of growth hormone were significantly attenuated. The pathophysiological changes in placebo-treated septic rats were restored by administration of neutralising anti-C5a antibody to the normal levels of BBB and pituitary function seen in the sham-operated group. CONCLUSIONS: Collectively, the neutralisation of C5a greatly ameliorated pathophysiological changes associated with septic encephalopathy, implying a further rationale for the concept of pharmacological C5a inhibition in sepsis.

Decreased Lean Psoas Cross-Sectional Area Is Associated With Increased 1-Year All-Cause Mortality in Male Elderly Orthopaedic Trauma Patients.

OBJECTIVES: To investigate the association between lean psoas cross-sectional area (CSA) and 1-year all-cause mortality in elderly patients sustaining pelvic and long bone fractures. DESIGN: Retrospective cohort. SETTING: Level I trauma center. PATIENTS: Elderly trauma patients admitted from 2007 to 2014. METHODS: We reviewed demographic and clinical data, injury mechanism, fracture OTA/AO classification, and mortality. Axial computed tomography images were used to measure lean psoas CSA at the L3-L4 disk space. Cox proportional hazard regression analysis was used to estimate 1-year mortality association with psoas CSA in crude and adjusted for age, body mass index, Injury Severity Score, medical comorbidities, and discharge destination in total population and stratified by sex. MAIN OUTCOME MEASUREMENT: One-year all-cause mortality defined as death within 12 months from date of hospitalization. RESULTS: Five hundred fifty-eight patients (54% female, 46% male) were analyzed. The pelvis was most commonly fractured (37.81%). A statistically significant association was observed between decreased lean psoas CSA and 1-year mortality in total population {hazard ratio [HR] = 0.93 [95% confidence interval (CI) = 0.90-0.96], P < 0.0001}. Stratification by gender revealed a statistically significant mortality HR in male patients [HR = 0.89 (95% CI = 0.84-0.96), P = 0.002]. We did not find a statistically significant mortality HR in female patients [HR = 0.95 (95% CI = 0.89-1.01), P = 0.103]. CONCLUSIONS: In this cohort of elderly orthopaedic trauma patients, decreased lean psoas CSA was associated with increased 1-year all-cause mortality in total population and males. Further investigation of the association of sarcopenia with mortality in the elderly is warranted. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Common PIK3CA mutants and a novel 3' UTR mutation are associated with increased sensitivity to saracatinib.

PURPOSE: Dysregulation of the phosphoinositide 3-kinase (PI3K) and Src signaling pathways commonly occur in colorectal cancer. Mutations in the PIK3CA gene are associated with an increase in severity of disease and worse clinical outcomes. Elevated levels of Src have been identified in premalignant lesions and are suggested to play a central role in tumor progression. Because these pathways appear to enhance tumor growth and metastasis, molecularly targeted agents for both pathways are currently being evaluated in early-phase clinical trials. EXPERIMENTAL DESIGN: We used colorectal cancer cell lines and a patient-derived explant model to investigate the efficacy of saracatinib. Mutations in the PIK3CA were evaluated to examine the association between mutations in the PIK3CA gene and sensitivity to saracatinib. RESULTS: We have identified a subset of patients with a PIK3CA (exon 9 and 20) mutation with increased sensitivity to saracatinib. A novel 3' untranslated region (UTR) mutation was also shown to be associated with increased sensitivity to saracatinib and have a reduced affinity for miR-520a and miR-525a. Importantly, we show that Src inhibition reduces the interaction between Src and p85, subsequently decreasing Akt-dependent signaling. CONCLUSION: These results indicate that a personalized approach in targeting Src in PIK3CA-mutant patients with colorectal cancers may prove effective in a subset of patients with this genetic alteration.

ALDH+ tumor-initiating cells exhibiting gain in NOTCH1 gene copy number have enhanced regrowth sensitivity to a γ-secretase inhibitor and irinotecan in colorectal cancer.

The Notch signaling pathway has been shown to be upregulated in colorectal cancer (CRC) and important for the self-renewal of cancer stem cells. In this study, we evaluated the efficacy of PF-03084014, a γ-secretase inhibitor, in combination with irinotecan to identify the effects of treatment on tumor recurrence and the tumor-initiating population in our CRC preclinical explant model. The combination of PF-03084014 and irinotecan had the greatest effect at reducing tumor growth on four CRC tumors when compared with treatment with PF-03084014 or irinotecan alone. The combination significantly reduced tumor recurrence in two CRC explants (CRC001 and CRC036) after treatment was discontinued. Both of these tumors exhibited elevated baseline levels of Notch pathway activation as well as an increase in NOTCH1 gene copy number when compared with the two CRC explants (CRC026 and CRC027) where tumors reappeared quickly after termination of treatment. Isolation and injection of aldehyde dehydrogenase (ALDH(+) and ALDH(-)) cells in an in vivo explant model demonstrated that the ALDH(+) cell population were tumorigenic. Evaluation of the ALDH(+) cells after 28 days of treatment showed that the combination reduced the ALDH(+) population in the tumors that did not regrow. Furthermore, ALDH(+) cells from CRC001 and CRC027 were injected in vivo and treated immediately for 28 days. Two months after treatment, tumors were evident in the combination treatment group for CRC027 but not for CRC036. These results indicate the combination of PF-03084014 and irinotecan may be effective in reducing tumor recurrence in CRC patients whose tumors exhibit elevated levels of the Notch pathway.

Gene array and fluorescence in situ hybridization biomarkers of activity of saracatinib (AZD0530), a Src inhibitor, in a preclinical model of colorectal cancer.

PURPOSE: To evaluate the efficacy of saracatinib (AZD0530), an oral Src inhibitor, in colorectal cancer (CRC) and to identify biomarkers that predict antitumor activity. EXPERIMENTAL DESIGN: Twenty-three CRC cell lines were exposed to saracatinib, and baseline gene expression profiles of three sensitive and eight resistant cell lines in vitro and in vivo were used to predict saracatinib sensitivity in an independent group of 10 human CRC explant tumors using the gene array K-Top Scoring Pairs (K-TSP) method. In addition, fluorescence in situ hybridization (FISH) and immunoblotting determined both Src gene copy number and activation of Src, respectively. RESULTS: Two of 10 explant tumors were determined to be sensitive to saracatinib. The K-TSP classifier (TOX>GLIS2, TSPAN7>BCAS4, and PARD6G>NXN) achieved 70% (7 of 10) accuracy on the test set. Evaluation of Src gene copy number by FISH showed a trend toward significance (P = 0.066) with respect to an increase in Src gene copy and resistance to saracatinib. Tumors sensitive to saracatinib showed an increase in the activation of Src and FAK when compared with resistant tumors. CONCLUSIONS: Saracatinib significantly decreased tumor growth in a subset of CRC cell lines and explants. A K-TSP classifier (TOX>GLIS2, TSPAN7>BCAS4, and PARD6G>NXN) was predictive for sensitivity to saracatinib. In addition, increased activation of the Src pathway was associated with sensitivity to saracatinib. These results suggest that FISH, a K-TSP classifier, and activation of the Src pathway have potential in identifying CRC patients that would potentially benefit from treatment with saracatinib.