Search

To design and establish a prospective biospecimen repository that integrates multi-omics assays with clinical data to study mechanisms of controlled injury and healing.Elective surgery is an opportunity to understand both the systemic and focal responses accompanying controlled and well-characterized injury to the human body. The overarching goal of this ongoing project is to define stereotypical responses to surgical injury, with the translational purpose of identifying targetable pathways involved in healing and resilience, and variations indicative of aberrant peri-operative outcomes.Clinical data from the electronic medical record combined with large-scale biological data sets derived from blood, urine, fecal matter, and tissue samples are collected prospectively through the peri-operative period on patients undergoing 14 surgeries chosen to represent a range of injury locations and intensities. Specimens are subjected to genomic, transcriptomic, proteomic, and metabolomic assays to describe their genetic, metabolic, immunologic, and microbiome profiles, providing a multidimensional landscape of the human response to injury.The highly multiplexed data generated includes changes in over 28,000 mRNA transcripts, 100 plasma metabolites, 200 urine metabolites, and 400 proteins over the longitudinal course of surgery and recovery. In our initial pilot dataset, we demonstrate the feasibility of collecting high quality multi-omic data at pre- and postoperative time points and are already seeing evidence of physiologic perturbation between timepoints.This repository allows for longitudinal, state-of-the-art geno-mic, transcriptomic, proteomic, metabolomic, immunologic, and clinical data collection and provides a rich and stable infrastructure on which to fuel further biomedical discovery.

Hypersecretion of amylin, a β-cell hormone that regulates satiation, is common in individuals with prediabetes and is associated with pancreatic amyloid deposition and type-2 diabetes. Evidence has emerged that increased circulating levels of amyloid-forming human amylin may potentially impair brain function. Because mouse amylin is non-amyloidogenic, we generated transgenic mice with conditional pancreatic expression of amyloid-forming human amylin to study how in vivo knockdown of human amylin expression influences brain function during the development of type-2 diabetes. Males and females were fed a high-fat diet starting at 3 months of age to induce amylin hypersecretion and glucose dysregulation. Males developed hyperglycemia at 5 months of age, whereas females showed glucose dysregulation 3-4 months later. At 5 months of age, human amylin-expressing male mice were randomly assigned to either amylin downregulation group (by peritoneal tamoxifen injection) or control group (maintained amylin expression) (n = 10/group). Two months later, we assessed brain function with the novel object recognition test and performed comparative non-targeted metabolomics and global RNA-seq analyses of hippocampal tissue. Mice with downregulated human amylin show enhanced recognition memory index (p < 0.001) and lower blood glucose levels (p < 0.001) compared to those that continued to express human amylin. This was associated with increased hippocampal levels of glycolysis metabolites, including lactic acid (p < 0.01), glucose-6-phosphate (p = 0.06), and fructose (p = 0.07). Hippocampal gene-expression patterns between the two mouse groups revealed extensive compensatory changes in gene expression related to glucose metabolism. In conclusion, amylin downregulation in diabetic mice improves systemic glucose homeostasis and memory. Molecular processes associated with improved memory involve increased hippocampal glycolytic fluxes and compensatory gene expression.

The mechanisms of the Dietary Approaches to Stop Hypertension (DASH) diet on various health markers remain unclear. The objective of this study was to identify plasma and urine metabolites altered by DASH that may elucidate mechanisms of benefit and suggest biomarkers to facilitate research and monitoring. We tested metabolomics differences in a controlled feeding study of 20 people consuming a Control diet for one wk followed by 2 wks of random assignment to Control or DASH. Fasting plasma and 24-hour urine samples collected at the end of each wk were profiled for metabolites using non-targeted GC/MS and amino acids and acylcarnitines were measured in plasma using a targeted panel. Linear models compared metabolite levels between DASH and Control during the final two randomized feeding wks [nominal pTable 1. Nontargeted and targeted metabolites (Selected metabolites are shown here) in DASH and Control.

Background Traumatic brachial plexus injury (BPI) can result in debilitating sequelae of the upper extremity. Presently, therapeutic decisions are based on the mechanism of injury, serial physical examination, electromyography, nerve conduction, and imaging studies. While magnetic resonance imaging is the current imaging modality of choice for BPI, ultrasound is a promising newcomer that is inexpensive, accessible, and available at point of care. Objective To evaluate ultrasound as a diagnostic tool in the assessment of traumatic adult BPI through a systematic review. Methods An electronic literature search was completed in MEDLINE, EMBASE, CINAHL, and Cochrane databases up to July 2016. Two independent reviewers completed the screening and data extraction. Methodological quality of studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Statistical analysis was used to estimate pooled sensitivities and study heterogeneity. Results Seven studies were included. Four studies compared the detection of pre- and postganglionic lesions at different levels (C5-T1) to surgical exploration as the reference standard. Sensitivity of lesion detection was greater in the upper and middle spinal nerves: C5 (93%, confidence interval [CI] = 78%-100%), C6 (94%, CI = 82%-100%), and C7 (95%, CI = 86%-100%) than in the lower: C8 (71%, CI = 36%-95%) and T1 (56%, CI = 29%-81%). Conclusion Individual studies demonstrate ultrasound as an effective diagnostic tool for traumatic adult BPI. Sensitivity of lesion detection was noted to be greater in the upper and middle (C5-C7) than in the lower spinal nerves (C8, T1). Further standardized studies should be performed to confirm the utility of ultrasound in the diagnosis of traumatic adult BPI.

BACKGROUND Nerve repair may be effective in improving function following obstetrical brachial plexus injury. No previous review has directly compared nerve repair to nonoperative management for similar patients, and no previous analysis has been adequately powered to determine whether nerve repair reduces impairment. METHODS Electronic databases were searched (MEDLINE, Embase, CINAHL, and Cochrane Central). Eligible studies were randomized controlled trials, observational studies, and case series (n > 9); included patients younger than 2 years undergoing nerve repair or nonoperative management of obstetrical brachial plexus injury; and reported functional impairment. Two reviewers independently screened articles using objective a priori criteria. Bias was assessed for each study. Overall quality of evidence was evaluated for each outcome. RESULTS Among nine cohort studies including 222 patients, nerve repair significantly reduced functional impairment compared with nonoperative management (relative risk, 0.58; 95 percent CI, 0.43 to 0.79; p < 0.001; I = 0 percent; absolute risk reduction, 19 percent; number needed to treat, six). Findings are consistent with comparison of similar patients from case series. With operative management, no deaths were reported; major adverse events were reported in 1.5 percent, and minor adverse events were reported in 5.0 percent of cases. Among demographic (all severities) samples managed nonoperatively, residual impairment remains in 27 percent (19 to 36 percent). CONCLUSIONS Nerve repair reduces functional impairment in obstetrical brachial plexus injury. Nonoperative management in patients with a deficit at 3 months of age leads to a high proportion of functional impairment. Mortality is not a common risk of modern pediatric microsurgical nerve repair. Residual impairment with nonoperative management is underestimated in the reported literature. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, IV.

BACKGROUND Residual size discrepancy between the affected and unaffected limbs is a distinct but not well-understood consequence of an obstetrical brachial plexus injury. This study aimed to document the extent of limb length differences in children with obstetrical brachial plexus injury compared with typically developing children. The effects of age, growth patterns, severity, and surgical intervention were also explored. Also, this study examined the reliability of the clinical measurement technique. METHODS A prospective cohort of 179 children with obstetrical brachial plexus injury was systematically evaluated for limb length and girth by a multidisciplinary team. Clinical measurements were obtained at regular intervals until 12 months and then yearly. A control group of typically developing children aged 6 months to 17 years had limb length and girth measured on one occasion. RESULTS Interrater reliability of clinical measurement techniques demonstrated high consistency, with an intraclass correlation of 0.90 (p < 0.0001). Limb measurements were recorded at nine time points. Paired t tests of children with and without surgical intervention found significant differences between affected and unaffected sides in arm, forearm, and total length as early as the 1-month measurement and at most other time points (p < 0.05). The 3-month total limb length difference was a statistically significant predictor of 12-month limb length difference (p < 0.05). CONCLUSIONS Obstetrical brachial plexus injury significantly affects the length of the arm and forearm. Early detectable limb length deficits are associated with the likelihood of requiring surgical reconstruction. Clinical limb length measurement can be performed reliably and noninvasively.

Background— Molecular tools may provide insight into cardiovascular risk. We assessed whether metabolites discriminate coronary artery disease (CAD) and predict risk of cardiovascular events. Methods and Results— We performed mass–spectrometry–based profiling of 69 metabolites in subjects from the CATHGEN biorepository. To evaluate discriminative capabilities of metabolites for CAD, 2 groups were profiled: 174 CAD cases and 174 sex/race-matched controls (“initial”), and 140 CAD cases and 140 controls (“replication”). To evaluate the capability of metabolites to predict cardiovascular events, cases were combined (“event” group); of these, 74 experienced death/myocardial infarction during follow-up. A third independent group was profiled (“event-replication” group; n=63 cases with cardiovascular events, 66 controls). Analysis included principal-components analysis, linear regression, and Cox proportional hazards. Two principal components analysis–derived factors were associated with CAD: 1 comprising branched-chain amino acid metabolites (factor 4, initial P =0.002, replication P =0.01), and 1 comprising urea cycle metabolites (factor 9, initial P =0.0004, replication P =0.01). In multivariable regression, these factors were independently associated with CAD in initial (factor 4, odds ratio [OR], 1.36; 95% CI, 1.06 to 1.74; P =0.02; factor 9, OR, 0.67; 95% CI, 0.52 to 0.87; P =0.003) and replication (factor 4, OR, 1.43; 95% CI, 1.07 to 1.91; P =0.02; factor 9, OR, 0.66; 95% CI, 0.48 to 0.91; P =0.01) groups. A factor composed of dicarboxylacylcarnitines predicted death/myocardial infarction (event group hazard ratio 2.17; 95% CI, 1.23 to 3.84; P =0.007) and was associated with cardiovascular events in the event-replication group (OR, 1.52; 95% CI, 1.08 to 2.14; P =0.01). Conclusions— Metabolite profiles are associated with CAD and subsequent cardiovascular events.

Background: Skeletal muscle structure and function are dependent on intact innervation. Prolonged muscle denervation results in irreversible muscle fiber atrophy, connective tissue hyperplasia, and deterioration of muscle spindles, specialized sensory receptors necessary for proper skeletal muscle function. The protective effect of temporary sensory innervation on denervated muscle, before motor nerve repair, has been shown in the rat. Sensory-protected muscles exhibit less fiber atrophy and connective tissue hyperplasia and maintain greater functional capacity than denervated muscles. The purpose of this study was to determine whether temporary sensory innervation also protects muscle spindles from degeneration. Methods: Rat tibial nerve was transected and repaired with either the saphenous or the original transected nerve. Negative controls remained denervated. After 3 to 6 months, the electrophysiologic response of the nerve to stretch in the rat gastrocnemius muscle was measured (n = 3 per group). After the animals were euthanized, the gastrocnemius muscle was removed, sectioned, stained, and examined for spindle number (n = 3 per group) and morphology (one rat per group). Immunohistochemical assessment of muscle spindle innervation was examined in four additional animals. Results: Significant deterioration of muscle spindles was seen in denervated muscle, whereas in muscle reinnervated with the tibial or the saphenous nerve, spindle number and morphology were improved. Histologic and functional evidence of spindle reinnervation by the sensory nerve was obtained. Conclusion: These findings add to the known means by which motor or sensory nerves exert protective effects on denervated muscle, and further promote the use of sensory protection for improving the outcome after peripheral nerve injury.

The prognostic factors that determine outcome in patients with necrotizing fasciitis remain poorly understood. The aim of this study was to analyze the variables that affect the mortality and morbidity of patients with necrotizing fasciitis and to create a simple method for estimating the probability of mortality.The authors undertook a retrospective review of all patients with necrotizing fasciitis treated in three tertiary care hospitals in Ontario, Canada, between January of 1994 and June of 2001. Demographic, comorbid illness, and disease-specific data were collated and analyzed for associations with outcome. Using logistic regression analysis, probability estimates for the prediction of mortality were developed, based on three contributing independent factors.Ninety-nine patients satisfied the inclusion criteria. Overall mortality was 20 percent. Sixteen patients suffered from amputation or organ loss. The most common comorbidities were diabetes (30 percent), immunocompromised status (17 percent), and chickenpox (11 percent). Advanced age (odds ratio, 1.04; 95 percent confidence interval, 1.01 to 1.08; p = 0.012), streptococcal toxic shock syndrome (odds ratio, 10.54; 95 percent confidence interval, 2.80 to 39.44; p0.001), and immunocompromised status (odds ratio, 3.97; 95 percent confidence interval, 1.04 to 15.19; p = 0.044) were independent predictors of mortality and were used to design a formula for the probability of mortality.Age, streptococcal toxic shock syndrome, and immune status are significant determinants of mortality and can predict the probability of death from necrotizing fasciitis soon after admission. This objective information can guide clinicians in communication with patients and in making clinical decisions.

Although plastic surgeons have empirically "known" of the benefits of reduction mammaplasty for their patients, a paucity of outcome studies have been reported. For this study, an attempt to perform a meta-analysis of outcomes in reduction mammaplasty was undertaken. A computer literature search was performed of the MEDLINE database for the period between 1966 and September of 1997 for the Medical Subject Headings mammaplasty and outcome measures. Reference lists were used for additional reports. No trials were identified that met the criteria for meta-analysis. Seventeen publications met less restrictive review criteria that evaluated quality-of-life outcome measures. A systematic evaluation of patient-focused outcome measures demonstrated that consistent improvement in physical symptoms was found across most studies, as was a high degree of patient satisfaction (78 to 95 percent very or moderately satisfied), and some have shown improvement in body image and psychological well-being. However, although this review does identify consistent improvements in patient quality of life after reduction mammaplasty, inconsistencies among study designs do not allow formal meta-analysis.

Regeneration across the nerve allograft in the immunosuppressed host was assessed using electrical and histologic parameters. The Lewis rat (RTIl) served as the recipient animal, and ACI rats (RTIa) provided the donor nerve allografts. Hydrocortisone and azathioprine were used in various dose schedules as the immunosuppressive agents. Animals were immunosuppressed for either 30 or 100 days. Histologic and electrophysiologic measurements of nerve regeneration were assessed at 30, 100, and 180 days. The degree of nerve regeneration was similar in all experimental groups. Short-term, low-dose immunosuppression was as successful as longer-term, higher-dose immunosuppression therapy. The degree of nerve regeneration in all experimental groups was significantly better than that in the fresh, untreated nerve allograft control group (Lewis/ACI) but was not as good as that seen in the autograft control group (Lewis/Lewis).

Microneurovascular techniques make transfer of innervated soft tissue a reality. The present study investigated the sensory potential of four such donor sites: volar wrist, dorsal hand, dorsal foot, and great toe. Normal moving and static two-point discrimination values for these areas are reported. A sensory reeducation protocol demonstrated that even these normal values may be improved with training. This suggests that the full potential of transferred innervated soft tissue may best be achieved by incorporating sensory reeducation routinely in the postoperative rehabilitation program.

Lewis rats (RT1(1] were the recipients of 3-cm nerve grafts from syngeneic Lewis donors or allogeneic ACI (RT1a) donors. Microneurosurgical repair of the nerve graft to the transected sciatic nerve of the recipient animal was performed with 10-0 epineurial sutures. Recipients were randomly allocated to cyclosporin A (CsA) immunosuppressed or untreated groups. Cyclosporin A was administered in the minimal effective dosage to prevent nerve allograft rejection across this major histocompatibility disparity (5 mg/kg per day). Nerve regeneration across the nerve grafts was assessed by sciatic function index (SFI) and toe spread index (TSI) determinations serially and by electrophysiologic, histologic, and morphologic assessments 14 weeks after engraftment. Sciatic nerve regeneration across allogeneic nerve grafts in cyclosporin A immunosuppressed recipients was significantly superior compared to the untreated controls (p less than 0.008) and not significantly different from that across the syngeneic control animals.

The potential use of peripheral nerve allografts would significantly improve the reconstructive potential for patients with major peripheral nerve deficits. This study evaluated the response of the nerve allograft recipient treated with varying dosages of cyclosporin A (CsA) to determine the minimal effective dosage necessary to prevent nerve graft rejection. Lewis rats (RT1l) were the recipients of syngeneic nerve grafts from identical Lewis donors or allogeneic nerve grafts from ACI (RT1a) donors. Nerve grafts were inlaid next to the intact sciatic nerve of the recipient. The immunologic responsiveness of the recipient animal's lymphocytes to a donor-specific antigenic challenge was assessed by the mixed lymphocyte reaction (MLR). In addition, nerve grafts were evaluated histologically. Animals were monitored for cyclosporin A toxicity. It was found that cyclosporin A (5 mg/kg per day) was effective in rendering the recipient animals unresponsive by mixed lymphocyte reaction at 10, 20, and 40 days after engraftment. This dosage was similarly effective in preventing histologic changes characteristic of nerve allograft rejection. This dosage regimen was nontoxic to the animals. Our study ascertained a minimal nontoxic dosage of cyclosporin A that effectively prevented nerve allograft rejection across a major histocompatibility disparity in rats.