Stephanie L. Kwei

Acute anoxia-induced alterations in MAP2 immunoreactivity and neuronal morphology in rat hippocampus

Cerebral ischemia induces major neuronal morphological alterations. It is not clear, however, whether this is directly caused by O2 deprivation. To determine the effect of hypoxia on cytoskeletal structures and neuronal morphology, we performed experiments and examined anoxia-induced changes in microtubule-associated protein 2 (MAP2) and cell morphology in hippocampal slices in vitro. Anoxia (measured PO2 = 0 Torr) induced a marked loss in dendritic MAP2 immunoreactivity and cell swelling of hippocampal neurons by 2 h after O2 reinstitution. These changes were severe in CA1 and CA3 neurons and comparatively mild in dentate gyrus neurons. Quantitative analysis showed that 10 min of anoxia induced a 30% loss of MAP2-positive dendrites but this increased to 70% after 30 min of anoxia. A concurrent major increase in somata area of about 100% and 200% was observed in CA1 and CA3 neurons respectively. Somata area in the lower dentate gyrus, however, increased either insignificantly or by only 30% for the respective periods of anoxia. These results suggest that deprivation of O2 can by itself induce a major loss in dendritic MAP2 immunoreactivity and changes in cell morphology in hippocampal neurons. These alterations occur rapidly after hypoxia, and the severity of these changes is directly related to the duration of anoxia and brain region in the hippocampus.

Radiation therapy and expander-implant breast reconstruction: an analysis of timing and comparison of complications.

BackgroundThe optimal timing of expander-implant exchange in the setting of postmastectomy radiation therapy (PMRT) remains unclear with prior reports yielding inconsistent and variable results. The purpose of this study was to characterize complications associated with the sequencing of expander-implant breast reconstruction before or after PMRT and to compare the outcomes between early (<4 months) and late (>4 months) expander-implant exchange in the subset of patients who received PMRT before exchange. Materials and MethodsThe medical records of all patients PMRT in the setting of tissue expander-implant breast reconstruction between June 2004 and June 2011 at our institution were reviewed retrospectively. Patients were first classified as having undergone expander-implant exchange before the initiation of PMRT or after the completion of PMRT. Patients who underwent expander-implant exchange after PMRT were then classified as having undergone exchange early (<4 months after PMRT) or late (>4 months after PMRT). All complications requiring additional surgery or hospitalization were recorded. ResultsFifty-five eligible patients were identified as having undergone 56 two-stage tissue expander-implant breast reconstructions. Twenty-two reconstructions underwent exchange before PMRT and 34 reconstructions underwent exchange after PMRT. There was no significant difference in overall complication rate (54.55% vs 47.06%, P = 0.785) or reconstruction failure rate (13.64% vs 20.59%, P = 0.724) between the 2 cohorts. Twenty reconstructions underwent exchange less than 4 months after PMRT and 14 underwent exchange more than 4 months after PMRT. There was no significant difference in overall complication rate (40% vs 57.14%, P = 0.487) or failure rate (25% vs 14.29%, P = 0.672) between the 2 groups. Trends suggest a higher rate of infection in patients who underwent exchange earlier (30% vs 14.29%, P = 0.422) and a higher rate of capsular contracture in patients who underwent exchange later (5% vs 21.43%, P = 0.283); however, statistical significance was not reached. ConclusionsOur findings suggest that neither the sequencing nor timing of expander-implant exchange in the setting of PMRT affects overall complication or reconstruction failure rate. However, the timing of exchange may impact the type of complication encountered. Further investigation is necessary to determine an optimal time for expander-implant exchange.

A tissue quality index: an intrinsic control for measurement of effects of preanalytical variables on FFPE tissue

While efforts are made to improve tissue quality and control preanalytical variables, pathologists are often confronted with the challenge of molecular analysis of patient samples of unknown quality. Here we describe a first attempt to construct a tissue quality index (TQI) or an intrinsic control that would allow a global assessment of protein status based on quantitative measurement of a small number of selected, informative epitopes. Quantitative immunofluorescence (QIF) of a number of proteins was performed on a series of 93 breast cancer cases where levels of expression were assessed as a function of delayed time to formalin fixation. A TQI was constructed based on the combination of proteins that most accurately reflect increased and decreased levels of expression in proportion to delay time. The TQI, defined by combinations of measurements of cytokeratin, ERK1/2 and pHSP-27 and their relationship to cold ischemic time were validated on a second build of the training series and on two independent breast tissue cohorts with recorded time to formalin fixation. We show an association of negative TQI values (an indicator for loss of tissue quality) with increasing cold ischemic time on both validation cohorts and an association with loss of ER expression levels on all three breast cohorts. Using expression levels of three epitopes, we can begin to assess the likelihood of delayed time to fixation or decreased tissue quality. This TQI represents a proof of concept for the use of epitope expression to provide a mechanism for monitoring tissue quality.

SREBP-1c/MicroRNA 33b Genomic Loci Control Adipocyte Differentiation.

ABSTRACT White adipose tissue (WAT) is essential for maintaining metabolic function, especially during obesity. The intronic microRNAs miR-33a and miR-33b, located within the genes encoding sterol regulatory element-binding protein 2 (SREBP-2) and SREBP-1, respectively, are transcribed in concert with their host genes and function alongside them to regulate cholesterol, fatty acid, and glucose metabolism. SREBP-1 is highly expressed in mature WAT and plays a critical role in promoting in vitro adipocyte differentiation. It is unknown whether miR-33b is induced during or involved in adipogenesis. This is in part due to loss of miR-33b in rodents, precluding in vivo assessment of the impact of miR-33b using standard mouse models. This work demonstrates that miR-33b is highly induced upon differentiation of human preadipocytes, along with SREBP-1. We further report that miR-33b is an important regulator of adipogenesis, as inhibition of miR-33b enhanced lipid droplet accumulation. Conversely, overexpression of miR-33b impaired preadipocyte proliferation and reduced lipid droplet formation and the induction of peroxisome proliferator-activated receptor γ (PPARγ) target genes during differentiation. These effects may be mediated by targeting of HMGA2, cyclin-dependent kinase 6 (CDK6), and other predicted miR-33b targets. Together, these findings demonstrate a novel role of miR-33b in the regulation of adipocyte differentiation, with important implications for the development of obesity and metabolic disease.

Endothelial APLNR regulates tissue fatty acid uptake and is essential for apelin’s glucose-lowering effects

Inhibition of FABP4 rescues defective apelin signaling, decreases fatty acid accumulation, and promotes insulin sensitivity. An apelin a day keeps the doctor away Apelin is an atheroprotective protein, which promotes insulin sensitivity and metabolic health, but the details of its signaling are not well understood. Hwangbo et al. discovered that the apelin receptor is predominantly localized in endothelial cells of metabolic organs, such as muscle and adipose tissues, and that it functions, in part, by inhibiting fatty acid binding protein 4 (FABP4) activity. The authors also found that inhibition of FABP4 can reverse the metabolic disease phenotype associated with defective apelin signaling and thus improve fatty acid uptake, glucose utilization, and insulin sensitivity. Treatment of type 2 diabetes mellitus continues to pose an important clinical challenge, with most existing therapies lacking demonstrable ability to improve cardiovascular outcomes. The atheroprotective peptide apelin (APLN) enhances glucose utilization and improves insulin sensitivity. However, the mechanism of these effects remains poorly defined. We demonstrate that the expression of APLNR (APJ/AGTRL1), the only known receptor for apelin, is predominantly restricted to the endothelial cells (ECs) of multiple adult metabolic organs, including skeletal muscle and adipose tissue. Conditional endothelial-specific deletion of Aplnr (AplnrECKO) resulted in markedly impaired glucose utilization and abrogation of apelin-induced glucose lowering. Furthermore, we identified inactivation of Forkhead box protein O1 (FOXO1) and inhibition of endothelial expression of fatty acid (FA) binding protein 4 (FABP4) as key downstream signaling targets of apelin/APLNR signaling. Both the Apln−/− and AplnrECKO mice demonstrated increased endothelial FABP4 expression and excess tissue FA accumulation, whereas concurrent endothelial Foxo1 deletion or pharmacologic FABP4 inhibition rescued the excess FA accumulation phenotype of the Apln−/− mice. The impaired glucose utilization in the AplnrECKO mice was associated with excess FA accumulation in the skeletal muscle. Treatment of these mice with an FABP4 inhibitor abrogated these metabolic phenotypes. These findings provide mechanistic insights that could greatly expand the therapeutic repertoire for type 2 diabetes and related metabolic disorders.

A Comparison of Superomedial versus Inferior Pedicle Reduction Mammaplasty Using Three-Dimensional Analysis.

A COMPARISON OF SUPEROMEDIAL VERSUS INFERIOR PEDICLE REDUCTION MAMMOPLASTY USING THREE-DIMENSIONAL ANALYSIS. Victor Z. Zhu, Ajul Shah, Rachel Lentz, Tracy Sturrock, Alexander F. Au, Stephanie L. Kwei. Section of Plastic and Reconstructive Surgery, Department of Surgery, Yale University, School of Medicine, New Haven, CT. Reduction mammoplasty using the inferior pedicle (IP) technique continues to be more commonly performed than the superomedial pedicle (SMP). This study uses three-dimensional (3D) imaging to compare postoperative linear and volumetric changes in SMP and IP breast reductions. Reduction mammoplasty was performed using either a SMP or IP, with a Wise-pattern skin incision. Patients in each cohort were matched based on total postoperative breast size, BMI, and age. Postoperative 3D photographs were taken at 1-3 months and 6-12 months. Measurements included: sternal notch to nipple distance, areola surface area, total breast volume, breast projection, proportion superior pole volume, proportion medial pole volume, and tissue shifting over time. There were 13 SMP patients (26 breasts) and 14 IP patients (28 breasts). There were significant differences at 1-3 months between the cohorts in sternal notch to nipple distance (21.6+0.4cm SMP vs. 24.1+0.3cm IP, p<0.01), and proportion superior pole volume (53.9+1.2% SMP vs. 57.3+1.1% IP, p=0.04). The sternal notch to nipple distance (21.6+0.4cm SMP vs. 24.6+0.4cm IP, p<0.01) remained different between the two cohorts at 6-12 months; however, there was no difference in superior pole fullness at this time point. There was a significant difference in proportion medial pole volume (38.1+2.0% SMP vs. 45.8+1.4% IP, p<0.01). There were changes in volumetric distribution over time in both cohorts, with decreased proportion medial pole volume in the SMP cohort, and increased proportion medial pole volume in the IP cohort (p<0.01) over time. Areola surface area increased significantly more over time in the IP cohort than the SMP cohort (2.87+0.77cm IP vs. 0.01+0.57cm SMP, p<0.01). There is no difference between the SMP and IP technique in proportion superior pole volume or breast projection within the 12-month postoperative period; however, the IP technique demonstrated greater proportion medial pole volume and increased areolar surface area over time.

Adipocyte hypertrophy and lipid dynamics underlie mammary gland remodeling after lactation

Adipocytes undergo pronounced changes in size and behavior to support diverse tissue functions, but the mechanisms that control these changes are not well understood. Mammary gland-associated white adipose tissue (mgWAT) regresses in support of milk fat production during lactation and expands during the subsequent involution of milk-producing epithelial cells, providing one of the most marked physiological examples of adipose growth. We examined cellular mechanisms and functional implications of adipocyte and lipid dynamics in the mouse mammary gland (MG). Using in vivo analysis of adipocyte precursors and genetic tracing of mature adipocytes, we find mature adipocyte hypertrophy to be a primary mechanism of mgWAT expansion during involution. Lipid tracking and lipidomics demonstrate that adipocytes fill with epithelial-derived milk lipid. Furthermore, ablation of mgWAT during involution reveals an essential role for adipocytes in milk trafficking from, and proper restructuring of, the mammary epithelium. This work advances our understanding of MG remodeling and tissue-specific roles for adipocytes.During mammary gland involution, the organ undergoes extensive remodeling. Here, the authors explore the role of mammary gland adipose tissue (mgWAT) in this process and demonstrate that adipocyte hypertrophy and lipid trafficking underlie mgWAT expansion and epithelial regression.

A 3D Mammometric Comparison of Implant-Based Breast Reconstruction With and Without Acellular Dermal Matrix (ADM)

This retrospective study utilizes 3D imaging and mammometrics to compare implant-based breast reconstruction with and without the use of ADM. Previous studies have suggested improved aesthetic outcomes with the use of ADM, but none have been able to quantify this difference. Images were obtained at early and late time points following the expander–implant exchange procedure. Measurements included the point of maximum projection, the superior, inferior, medial and lateral volumetric distribution, and the distance from the point of maximum projection to the inframammary fold along the breast meridian. The patients’ demographic information, implant size, and complication rate between the two cohorts were similar. In the early post-operative period, the patients with ADM demonstrated higher medial pole volume; however, this difference did not persist in the late post-operative period. Patients with ADM demonstrated a small but statistically significant greater point of maximum projection and length of lower pole curvature in comparison with the non-ADM cohort. In summary, the results of this study demonstrate improved mammometric measurements when ADM is used in implant-based breast reconstruction, supporting superior aesthetic outcomes in early and late post-operative time points.Level of Evidence IIIThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

A mammometric comparison of modified Robertson versus Wise pattern inferior pedicle reduction mammoplasty

Aim: The advent of 3D photoimaging and mammometrics has allowed for quantitative, volumetric breast analyses. This study uses 3D photoimaging and mammometrics to compare the postoperative morphometric outcomes of the modified Robertson technique to the more traditional Wise pattern inferior pedicle technique. Methods: Inferior pedicle reduction mammoplasty was performed using either a Wise pattern or modified Robertson skin incision. 3D photography and analysis were done at 1-3 months and 6-12 months postoperatively. Results: There were 14 breasts in the modified Robertson group (ROB) and 24 breasts in the Wise pattern group (WISE). There were no significant differences in demographic data or amount of tissue resected. At 6-12 months, the modified Robertson cohort demonstrated increased superior pole fullness (62.9% ROB vs. 58.3% WISE, P = 0.05). The Wise cohort, however, maintained greater maximum breast projection (5.52 cm ROB vs. 6.54 cm WISE, P = 0.01) and increased medial pole fullness (29.6% ROB vs. 46.9% WISE, P < 0.01). There was no difference in tissue shifting from the superior pole to the inferior pole over time (+3.36 superior pole % ROB vs. +1.42 superior pole % WISE, P = 0.28). Areola surface area increased equally in both cohorts (+3.08 cm2 ROB vs. +2.59 cm2 WISE, P = 0.77); however, the final size of the areola was greater in the modified Robertson cohort (26.9 cm2 ROB vs. 21.6 cm2 WISE, P < 0.01). Conclusion: Using 3D mammometrics, we found increased superior pole fullness in the modified Robertson group while the Wise pattern group demonstrated greater medial pole fullness and maximum breast projection. ABSTRACT

Abstract 142: Prevention of Seroma and Post-operative Wound Complications Using Negative Pressure Wound Therapy Devices Following Panniculectomy in Massive Weight-Loss Patients.

PurPose: The majority of chronic wounds occurs in people over age 60 and is increasing at a rate of approximately 10% per year. However, there is still no effective treatment method for such wounds because the mechanism has not been fully elucidated. We have found both high ROS production and MMPs expression in the ischemic wound of young animal, which correlated with high levels of MAPKs. The present study aimed to test the hypothesis that the ROS/MAPK/MMPs signaling axis plays an important role in pathobiological process of chronic wound in elderly by using small interference RNA (siRNA) approach in a novel ischemic wound model.