Evolution of neoplastic cell lineages in Barrett oesophagus

It has been hypothesized that neoplastic progression develops as a consequence of an acquired genetic instability and the subsequent evolution of clonal populations with accumulated genetic errors. Accordingly, human cancers and some premalignant lesions contain multiple genetic abnormalities not present in the normal tissues from which the neoplasms arose. Barrett oesophagus (BE) is a premalignant condition which predisposes to oesophageal adenocarcinoma (EA) that can be biopsied prospectively over time because endoscopic surveillance is recommended for early detection of cancer. In addition, oesophagectomy specimens frequently contain the premalignant epithelium from which the cancer arose. Neoplastic progression in BE is associated with alterations in TP53 (also known as p53) and CDKN2A (also known as p16) and non-random losses of heterozygosity (LOH). Aneuploid or increased 4N populations occur in more than 90-95% of EAs, arise in premalignant epithelium and predict progression. We have previously shown in small numbers of patients that disruption of TP53 and CDKN2A typically occurs before aneuploidy and cancer. Here, we determine the evolutionary relationships of non-random LOH, TP53 and CDKN2A mutations, CDKN2A CpG-island methylation and ploidy during neoplastic progression. Diploid cell progenitors with somatic genetic or epigenetic abnormalities in TP53 and CDKN2A were capable of clonal expansion, spreading to large regions of oesophageal mucosa. The subsequent evolution of neoplastic progeny frequently involved bifurcations and LOH at 5q, 13q and 18q that occurred in no obligate order relative to each other, DNA-content aneuploidy or cancer. Our results indicate that clonal evolution is more complex than predicted by linear models.

Inactivation of p16 in human mammary epithelial cells by CpG island methylation

Proliferation of human mammary epithelial cells (HMEC) is limited to a few passages in culture due to an arrest in G1 termed selection or mortality stage 0, M0. A small number of cells spontaneously escape M0, continue to proliferate in culture, and then enter a second mortality stage, M1, at which they senesce. Evidence that M0 involves the Rb pathway comes from the observation that expression of human papillomavirus type 16 E7 alleviates the M0 proliferation block, and we further show that the Rb-binding region of E7 is required to allow cells to bypass M0. In contrast, E6 does not prevent HMEC from entering M0 but, rather, is involved in M1 bypass. Here we show that inactivation of the D-type cyclin-dependent kinase inhibitor p16INK4A is associated with escape from the M0 proliferation block. Early-passage HMEC express readily detectable amounts of p16 protein, whereas normal or E6-expressing HMEC that escaped M0 expressed markedly reduced amounts of p16 mRNA and protein. This initial reduction of p16 expression was associated with limited methylation of the p16 promoter region CpG island. At later passages, a further reduction in p16 expression occurred, accompanied by increased CpG island methylation. In contrast, reduction of p16 expression did not occur in E7-expressing HMEC that bypassed M0, due to inactivation of Rb. These observations in the E6-expressing HMEC correlate well with the finding that CpG island methylation is a mechanism of p16 inactivation in the development of human tumors, including breast cancer.

Members of the olfactory receptor gene family are contained in large blocks of DNA duplicated polymorphically near the ends of human chromosomes

We have identified three new members of the olfactory receptor (OR) gene family within a large segment of DNA that is duplicated with high similarity near many human telomeres. This segment is present at 3q, 15q, and 19p in each of 45 unrelated humans sampled from various populations. Additional copies are present polymorphically at 11 other subtelomeric locations. The frequency with which the block is present at some locations varies among populations. While humans carry seven to 11 copies of the OR-containing block, it is located in chimpanzee and gorilla predominantly at a single site, which is not orthologous to any of the locations in the human genome. The observation that sequences flanking the OR-containing segment are duplicated on larger and different sets of chromosomes than the OR block itself demonstrates that the segment is part of a much larger, complex patchwork of subtelomeric duplications. The population analyses and structural results suggest the types of processes that have shaped these regions during evolution. From its sequence, one of the OR genes in this duplicated block appears to be potentially functional. Our findings raise the possibility that functional diversity in the OR family is generated in part through duplications and inter-chromosomal rearrangements of the DNA near human telomeres.

Progressive region-specific de novo methylation of the p16 CpG island in primary human mammary epithelial cell strains during escape from M(0) growth arrest

CpG island methylation plays an important role in normal cellular processes, such as genomic imprinting and X-chromosome inactivation, as well as in abnormal processes, such as neoplasia. However, the dynamics of de novo CpG island methylation, during which a CpG island is converted from an unmethylated, active state to a densely methylated, inactive state, are largely unknown. It is unclear whether the development of de novo CpG island methylation is a progressive process, in which a subset of CpG sites are initially methylated with a subsequent increase in methylation density, or a single event, in which the initial methylation event encompasses the entire CpG island. The tumor suppressor gene p16/CDKN2a/INK4a (p16) is inactivated by CpG island methylation during neoplastic progression in a variety of human cancers. We investigated the development of methylation in the p16 CpG island in primary human mammary epithelial cell strains during escape from mortality stage 0 (M(0)) growth arrest. The methylation status of 47 CpG sites in the p16 CpG island on individual DNA molecules was determined by sequencing PCR clones of bisulfite-treated genomic DNA. The p16 CpG island was initially methylated at a subset of sites in three discrete regions in association with p16 transcriptional repression and escape from M(0) growth arrest. With continued passage, methylation gradually increased in density and methylation expanded to sites in adjacent regions. Thus, de novo methylation in the p16 CpG island is a progressive process that is neither site specific nor completely random but instead is region specific. Our results suggest that early detection of methylation in the CpG island of the p16 gene will require methylation analysis of the three regions and that the identification of region-specific methylation patterns in other genes may be essential for an accurate assessment of methylation-mediated transcriptional silencing.

Molecular characterization of the human gene encoding an abundant 61 kDa protein specific to the retinal pigment epithelium

The retinal pigment epithelium (RPE) of the eye expresses an abundant 61 kDa protein (RPE65), that is developmentally regulated and tissue-specific. In our efforts toward understanding the specialized functions and development of the RPE, and the origins of inherited retinal degenerations, we have characterized the human gene encoding the 61 kDa protein. This is the first structural characterization of a gene transcribed specifically in the RPE. The gene maps to human chromosome 1p31. The sequence encoding the transcript spans over 20 kb, and is interrupted by 13 introns. A putative transcription start site lies 54 bp upstream of the initiation codon. A single transcript of approximately 2.9 kb is present in human RPE, and is not detected in other tissues. The deduced 533 amino acid sequence of the human protein is 98.7% identical to the bovine, but shows no significant similarity to any other entry in the databases. Expression of the 61 kDa protein appears to depend on the presence of environmental cues, since the corresponding transcripts are rapidly lost from RPE cells established in culture. Down regulation may occur post-transcriptionally, since AU-rich elements proposed to target RNA for rapid degradation are present throughout the 3'-untranslated region. The tissue-specific expression, high abundance, evolutionary conservation, developmental regulation, and sequence of the 3'-untranslated region suggest that the 61 kDa protein is the product of a functionally important gene whose expression is tightly regulated.

p16INK4a expression is frequently decreased and associated with 9p21 loss of heterozygosity in sporadic melanoma

The product of the p16/INK4a/CDKN2/MTS1 tumor-suppressor gene acts as a negative cell cycle regulator by inhibiting G1 cyclin-dependent kinases that phosphorylate the retinoblastoma protein. p16 is inactivated in a wide range of human malignancies, including familial melanoma. However, its expression and function in sporadic melanoma has not been extensively investigated. We studied p16 expression in 62 archival melanomas and 30 archival nevi and lentigines by immunohistochemistry. Eighteen of 26 (69%) superficial spreading melanomas, 17 of 28 (61%) nodular melanomas, all of three lentigo maligna melanomas, and all of five melanoma metastases were found to harbor less than 10% p16-positive tumor cells. In contrast, only six of 24 (25%) nevi had less than 10% positive cells. No correlation between tumor thickness and loss of p16 expression was found. Using DNA from micro-dissected tumor and matched normal tissues, five of seven (71%) p16-negative melanoma cases had 9p21 loss of heterozygosity (LOH), and one of these 9p21 LOH cases had promoter region hypermethylation of the remaining p16 allele. These data demonstrate that partial or complete loss of p16 expression is prevalent in sporadic melanoma and is frequently associated with 9p21 LOH.

Vein graft adaptation and fistula maturation in the arterial environment

Veins are exposed to the arterial environment during two common surgical procedures, creation of vein grafts and arteriovenous fistulae (AVF). In both cases, veins adapt to the arterial environment that is characterized by different hemodynamic conditions and increased oxygen tension compared with the venous environment. Successful venous adaptation to the arterial environment is critical for long-term success of the vein graft or AVF and, in both cases, is generally characterized by venous dilation and wall thickening. However, AVF are exposed to a high flow, high shear stress, low-pressure arterial environment and adapt mainly via outward dilation with less intimal thickening. Vein grafts are exposed to a moderate flow, moderate shear stress, high-pressure arterial environment and adapt mainly via increased wall thickening with less outward dilation. We review the data that describe these differences, as well as the underlying molecular mechanisms that mediate these processes. Despite extensive research, there are few differences in the molecular pathways that regulate cell proliferation and migration or matrix synthesis, secretion, or degradation currently identified between vein graft adaptation and AVF maturation that account for the different types of venous adaptation to arterial environments.

Surgery in the age of biologics

Since the introduction of the first anti-tumor necrosis factor antibodies in the late 1990s, biologic therapy has revolutionized the medical treatment of patients with inflammatory bowel disease (IBD). Nevertheless, surgery continues to play a significant role in treating IBD patients. Rates of intestinal resection in patients with Crohn's disease or colectomy in ulcerative colitis are reducing but not substantially over the long term. An increasing variety of biologic medications are now available to treat IBD patients in various clinical situations. Consequently, a number of questions persist about how biologic medications affect the need for surgery and overall course in IBD patients. Given the trend for earlier and more frequent use of biologic medications in IBD patients, a working knowledge of the effects of these medications on surgical decision-making and outcomes is essential for the practicing colorectal surgeon and gastroenterologist. This review seeks to summarize the relevant literature surrounding biologic use and IBD surgery with a focus on the effect of biologics on the frequency, type and complications of surgery in this 'age of biologics'.

Systematic review and meta-analysis of robotic versus open hepatectomy

BACKGROUND

To date, there are few studies comparing the outcomes of robotic hepatectomy (RH) versus open hepatectomy (OH). We report the first systematic review and meta-analysis comparing the outcomes of RH versus OH.

METHODS

A systemic review was performed of all comparative studies of RH versus OH that reported the perioperative outcome(s) of interest.

RESULTS

Seven retrospective cohort studies were included. There was no significant difference in patients' baseline characteristics. RH was associated with a longer operation time (mean difference (MD) 61.47 min; 95% confidence interval (CI) (7.03, 115.91); P = 0.03), shorter hospital stay (MD -2.57 days; 95% CI (-3.31, -1.82); P < 0.001), lower costs, less overall (risk ratio (RR) 0.63; 95% CI (0.46, 0.86); P = 0.004), minor (RR 0.64; 95% CI (0.43, 0.95); P = 0.03) and major (RR 0.45; 95% CI (0.22, 0.94); P = 0.03) post-operative complications compared to OH.

CONCLUSION

RH had superior perioperative outcomes and was not cost prohibitive compared to OH, but had longer operation times.

Clinical phenotype of juvenile-onset primary open-angle glaucoma linked to chromosome 1q

PURPOSE

Recent reports have suggested that a gene responsible for juvenile-onset primary open-angle glaucoma exists on the long arm of chromosome 1 (1q). This report describes a previously unpublished family (UM:JG3) in which juvenile-onset glaucoma is segregating in an autosomal dominant manner. The clinical features in this family were compared with those seen in other pedigrees with this condition. Linkage analysis was performed to evaluate whether a glaucoma-causing gene in UM:JG3 is linked to genetic markers on chromosome 1q.

METHODS

Affected family members, their siblings, children, and spouses were examined to identify the presence of glaucoma. Linkage studies were performed using short tandem repeat polymorphisms from chromosome 1q. Results of these studies were compared with those found for other families in which juvenile-onset primary open-angle glaucoma is linked genetically to the same chromosome 1q region.

RESULTS

The UM:JG3 family includes 22 affected individuals over five generations, including 12 still living. The average age at diagnosis for living affected individuals was 26 years. An association between myopia and glaucoma was observed in this family, but the glaucoma was not associated with iris processes or other structural anomalies. The clinical course of disease and response to treatment were similar to other families with this disease. The disease phenotype in this family is linked to markers on chromosome 1q with a maximum lod score of 3.52 at a recombination fraction of 0.00 for marker D1S433. Haplotype analysis suggests the gene responsible for glaucoma in this family is located in an 8-cM region between markers D1S445 and D1S218.

CONCLUSIONS

The glaucoma in UM:JG3 is linked to markers on chromosome 1q, with a candidate interval smaller than that in previous reports. In individuals with juvenile-onset open-angle glaucoma linked to chromosome 1q, the phenotype can range from mild ocular hypertension to blindness, resulting from marked elevations in intraocular pressure, with age at diagnosis ranging from 6 to 62 years. However, most affected individuals display a characteristic phenotype that includes onset in the first three decades of life, unusually high intraocular pressures, and the need for surgical therapy to prevent loss of vision. Whether differences in expression among families is due to allelic heterogeneity remains to be determined.

The mouse aortocaval fistula recapitulates human arteriovenous fistula maturation

Several models of arteriovenous fistula (AVF) have excellent patency and help in understanding the mechanisms of venous adaptation to the arterial environment. However, these models fail to exhibit either maturation failure or fail to develop stenoses, both of which are critical modes of AVF failure in human patients. We used high-resolution Doppler ultrasound to serially follow mice with AVFs created by direct 25-gauge needle puncture. By day 21, 75% of AVFs dilate, thicken, and increase flow, i.e., mature, and 25% fail due to immediate thrombosis or maturation failure. Mature AVF thicken due to increased amounts of smooth muscle cells. By day 42, 67% of mature AVFs remain patent, but 33% of AVFs fail due to perianastomotic thickening. These results show that the mouse aortocaval model has an easily detectable maturation phase in the first 21 days followed by a potential failure phase in the subsequent 21 days. This model is the first animal model of AVF to show a course that recapitulates aspects of human AVF maturation.

Characterization of the human type 2 neuropeptide Y receptor gene (NPY2R) and localization to the chromosome 4q region containing the type 1 neuropeptide Y receptor gene

Neuropeptide Y (NPY) signals through a family of G-protein-coupled receptors present in the brain and sympathetic neurons. To further our understanding of the genetic elements involved in the regulation of NPY receptor expression, we have cloned and characterized the human gene encoding the type 2 NPY receptor (Y2 receptor, HGMW-approved symbol NPY2R).2 The transcript spans 9 kb of genomic sequence and is encoded on two exons. As in the type 1 NPY receptor (Y1 receptor) gene, the 5'-untranslated region of the Y2 receptor is interrupted by an intervening sequence ( approximately 4.5 kb). However, the Y2 receptor gene does not contain an intron analogous to that present in the coding region of the Y1 receptor. The predicted transcript size ( approximately 4.5 kb) is consistent with the size observed by Northern analysis. The 381-amino-acid sequence deduced from the open reading frame is identical to that encoded by the cDNA. The Y2 receptor gene maps to human chromosome 4q31, the same region containing the Y1 receptor locus, suggesting that these subtypes may have arisen by gene duplication despite their structural differences.

Novel trabecular meshwork inducible glucocorticoid response mutation in an eight-generation juvenile-onset primary open-angle glaucoma pedigree

OBJECTIVE

This study aimed to update a large kindred with juvenile-onset primary open-angle glaucoma (POAG) first described in 1940 and to identify the underlying genetic cause of the disease.

DESIGN

Molecular genetic study of a single kindred, including clinical examination, retrospective review of clinical and family history records, linkage analysis, and mutation screening.

PARTICIPANTS

The retrospective review included 957 members of a single large family. The linkage study included 40 members of 1 branch of the family in which juvenile-onset POAG is segregating in an autosomal-dominant pattern. Mutation screening included 15 at-risk family members with juvenile-onset POAG, probands of 40 families with adult-onset POAG, probands of 11 additional unrelated juvenile-onset POAG families, and 43 unrelated normal control subjects.

INTERVENTION

Clinical and family history records were obtained, ophthalmologic examinations were performed, and blood samples were drawn for use in genotyping.

MAIN OUTCOME MEASURES

Allele sizes of microsatellite repeat genetic markers from the vicinity of the GLC1A glaucoma gene on chromosome 1q were assigned based on size fractionation of DNA fragments generated by polymerase chain reaction (PCR). Linkage was established by the method of lod scores. Mutations were identified by determination of the DNA sequence of PCR products amplified from the trabecular meshwork inducible glucocorticoid response (TIGR) gene. Glaucoma status for purposes of linkage and mutation analysis was based on a combination of ophthalmologic examination, clinical records, family history, and previously published information. For some individuals reported in the pedigree, but not included in the genotyping studies, less information was available as presented in the text and tables.

RESULTS

Autosomal-dominant POAG was confirmed or reported for 78 members of an 8-generation family. Linkage analysis showed significant evidence for linkage of juvenile-onset POAG in one branch of the family to D1S452 (maximum lod score of 6.42 at a recombination fraction of 0.00) and other markers in the vicinity of the GLC1A gene on chromosome 1q. Screening of the TIGR gene identified a mutation that results in substitution of asparagine for isoleucine at codon 477 near the carboxyterminal end of the protein.

CONCLUSIONS

The authors' findings strongly suggest that the juvenile-onset POAG locus in this family is the GLC1A locus and that the underlying cause of the disease is the IIe477Asn TIGR mutation that cosegregates with juvenile-onset POAG in one branch of this large family. Lack of samples from deceased individuals prevented the authors from determining whether reported adult-onset cases in this family could also be attributed to the IIe477Asn TIGR mutation. Absence of the IIe477Asn TIGR mutation from other juvenile- and adult-onset POAG families implies that this TIGR mutation is not a common cause of glaucoma.

Hospital readmission after pulmonary lobectomy is not affected by surgical approach

BACKGROUND

The aim of this study is to identify the predictors of hospital readmission or early unplanned return to clinic within 30 days of discharge after pulmonary lobectomy.

METHODS

The medical records of patients undergoing lobectomy by the thoracic surgery service between January 2009 and July 2012 were reviewed. All lobectomies were included irrespective of the etiology of disease. Multivariate logistic regression methods were used to identify predictors of readmission and or early unplanned return to clinic.

RESULTS

Two hundred thirteen patients underwent a pulmonary lobectomy during the study period (median age, 67 years). Pathologic diagnosis was malignant in 94% of the patients and benign in 6%. Minimally invasive approaches were used in 69% of the patients, whereas open thoracotomy was used in 31%. Median hospital length of stay was 4 days, and postoperative mortality occurred in 1 patient (0.5%). The Charlson comorbidity index was 1 ± 1. Predicted postoperative forced expiratory volume in 1 second and diffusing capacity of the lung for carbon monoxide were 68% ± 18% and 64% ± 17%, respectively. Postoperative complications occurred in 31% of patients; 13% required readmission to the hospital within 30 days of discharge or early unplanned return to clinic. Predictors of readmission or early unplanned return to clinic were unplanned transfer to the intensive care unit (odds ratio, 10.4; 95% confidence interval, 1.1 to 103.5; p = 0.04) and Charlson comorbidity index greater than 0 (odds ratio, 1.5; 95% confidence interval, 1.04 to 2.03; p = 0.03). Readmission or early unplanned return to clinic was independent of surgical approach (p = 0.32).

CONCLUSIONS

Patients who require a postoperative transfer to the intensive care unit or with higher Charlson comorbidity index are at higher risk for hospital readmission after pulmonary lobectomy. Readmission was not affected by the surgical approach. Whether a different strategy to follow-up for these high-risk patients can prevent readmission remains to be determined.

Surgeon-delivered laparoscopic transversus abdominis plane blocks are non-inferior to anesthesia-delivered ultrasound-guided transversus abdominis plane blocks: a blinded, randomized non-inferiority trial

BACKGROUND

The transversus abdominis plane (TAP) block is an important non-narcotic adjunct for post-operative pain control in abdominal surgery. Surgeons can use laparoscopic guidance for TAP block placement (LTAP), however, direct comparisons to conventional ultrasound-guided TAP (UTAPs) have been lacking. The aim of this study is to determine if surgeon placed LTAPs were non-inferior to anesthesia placed UTAPs for post-operative pain control in laparoscopic colorectal surgery.

METHODS

This was a prospective, randomized, patient and observer blinded parallel-arm non-inferiority trial conducted at a single tertiary academic center between 2016 and 2018 on adult patients undergoing laparoscopic colorectal surgery. Narcotic consumption and pain scores were compared for LTAP vs. UTAP for 48 h post-operatively.

RESULTS

60 patients completed the trial (31 UTAP, 29 LTAP) of which 25 patients were female (15 UTAP, 10 LTAP) and the mean ages (SD) were 60.0 (13.6) and 61.5 (14.3) in the UTAP and LTAP groups, respectively. There was no significant difference in post-operative narcotic consumption between UTAP and LTAP at the time of PACU discharge (median [IQR] milligrams of morphine, 1.8 [0-4.5] UTAP vs. 0 [0-8.7] LTAP P = .32), 6 h post-operatively (5.4 [1.8-17.1] UTAP vs. 3.6 [0-12.6] LTAP P = .28), at 12 h post-operatively (9.0 [3.6-29.4] UTAP vs. 7.2 [0.9-22.5] LTAP P = .51), at 24 h post-operatively (9.0 [3.6-29.4] UTAP vs. 7.2 [0.9-22.5] LTAP P = .63), and 48 h post-operatively (39.9 [7.5-70.2] UTAP vs. 22.2 [7.5-63.8] LTAP P = .41). Patient-reported pain scores as well as pre-, intra-, and post-operative course were similar between groups. Non-inferiority criteria were met at all post-op time points up to and including 24 h but not at 48 h.

CONCLUSIONS

Surgeon-delivered LTAPs are safe, effective, and non-inferior to anesthesia-administered UTAPs in the immediate post-operative period.

TRIAL REGISTRY

The trial was registered at clinicaltrials.gov Identifier NCT03577912.

Melanoma in pregnancy

The clinical course of malignant melanoma in pregnancy has been a subject of controversy, but current evidence indicates that it is similar to the clinical course in non-pregnant patients. Early detection and biopsy of localized disease is crucial because early treatment provides an excellent prognosis. Surgical excision is the primary therapy for this disease. As the primary care provider for many women in the reproductive age group, obstetrician-gynecologists have an opportunity to detect these lesions at their earliest stages when they are amenable to cure. Overall, maternal metastases to the fetus and placenta are very rare events and do not warrant elective termination based on the maternal diagnosis. However, a thorough examination of the infant and placenta should be done in all cases of melanoma complicating pregnancy. After treatment, long-term follow-up is recommended. Since most recurrences develop within 3 years after the diagnosis, it remains prudent to recommend that these patients avoid a subsequent pregnancy during this interval.

Modulation of lymphocyte-mediated tissue repair by rational design of heterocyclic aryl hydrocarbon receptor agonists

Aryl hydrocarbon receptor (AHR) is an essential regulator of gut immunity and a promising therapeutic target for inflammatory bowel disease (IBD). Current AHR agonists are inadequate for clinical translation due to low activity, inadequate pharmacokinetics, or toxicity. We synthesized a structurally diverse library and used integrated computational and experimental studies to discover mechanisms governing ligand-receptor interaction and to design potent drug leads PY109 and PY108, which display physiochemical drug-likeness properties, desirable pharmacokinetic profiles, and low toxicity. In a murine model of dextran sulfate sodium-induced colitis, orally administered compounds increase interleukin-22 (IL-22) production and accelerate mucosal healing by modulating mucosal adaptive and innate lymphoid cells. AHR and IL-22 pathway induction was confirmed using RNA sequencing and characterization of the lymphocyte protein-protein interaction network. Significant induction of IL-22 was also observed using human T cells from patients with IBD. Our findings support rationally designed AHR agonists for IBD therapy.

Chronic kidney disease predicts long-term mortality after major lower extremity amputation

Background:

Despite low peri-operative mortality after major lower extremity amputation, long-term mortality remains substantial. Metabolic syndrome is increasing in incidence and prevalence at an alarming rate in the USA.

Aim:

This study was to determine whether metabolic syndrome predicts outcome after major lower extremity amputation.

Patients and Methods:

A retrospective review of charts between July 2005 and June 2010.

Results:

Fifty-four patients underwent a total of 60 major lower extremity amputations. Sixty percent underwent below-knee amputation and 40% underwent above-knee amputation. The 30-day mortality was 7% with no difference in level (below-knee amputation, 8%; above-knee amputation, 4%; P = 0.53). The mean follow-up time was 39.7 months. The 5-year survival was 54% in the whole group, and was independent of level of amputation (P = 0.24) or urgency of the procedure (P = 0.51). Survival was significantly decreased by the presence of underlying chronic kidney disease (P = 0.04) but not by other comorbidities (history of myocardial infarction, P = 0.79; metabolic syndrome, P = 0.64; diabetes mellitus, P = 0.56).

Conclusion:

Metabolic syndrome is not associated with increased risk of adverse outcomes after lower extremity amputation. However, patients with chronic kidney disease constitute a sub-group of patients at higher risk of postoperative long-term mortality and may be a group to target for intervention.

Ephrin type-B receptor 4 activation reduces neointimal hyperplasia in human saphenous vein in vitro

BACKGROUND

Vein bypass is an essential therapy for patients with advanced peripheral and coronary artery disease despite development of neointimal hyperplasia. We have shown that stimulation of the receptor tyrosine kinase ephrin type-B receptor 4 (Eph-B4) with its ligand ephrin-B2 prevents neointimal hyperplasia in murine vein grafts. This study determines whether Eph-B4 in adult human veins is capable of phosphorylation and activation of downstream signaling pathways, as well as functional to release nitric oxide (NO) and prevent neointimal hyperplasia in vitro.

METHODS

Discarded human saphenous veins were taken from the operating room and placed in organ culture without or with ephrin-B2/Fc (2 μg/mL) for 14 days, and the neointima/media ratio was measured in matched veins. Primary human umbilical vein endothelial cells were treated with ephrin-B2/Fc (2 μg/mL) and examined with quantitative polymerase chain reaction, Western blot, immunoassays, and for release of NO. Ephrin-B2/Fc (2 μg/mL) was placed on the adventitia of saphenous veins treated with arterial shear stress for 24 hours in a bioreactor and activated Eph-B4 examined with immunofluorescence.

RESULTS

The baseline intima/media ratio in saphenous vein rings was 0.456 ± 0.097, which increased to 0.726 ± 0.142 in untreated veins after 14 days in organ culture but only to 0.630 ± 0.132 in veins treated with ephrin-B2/Fc (n = 19, P = .017). Ephrin-B2/Fc stimulated Akt, endothelial NO synthase and caveolin-1 phosphorylation, and NO release (P = .007) from human umbilical vein endothelial cells (n = 6). Ephrin-B2/Fc delivered to the adventitia stimulated endothelial Eph-B4 phosphorylation after 24 hours of arterial stress in a bioreactor (n = 3).

CONCLUSIONS

Eph-B4 is present and functional in adult human saphenous veins, with intact downstream signaling pathways capable of NO release and prevention of neointimal hyperplasia in vitro. Adventitial delivery of ephrin-B2/Fc activates endothelial Eph-B4 in saphenous veins treated with arterial shear stress in vitro. These results suggest that stimulation of Eph-B4 function may be a candidate strategy for translation to human clinical trials designed to inhibit venous neointimal hyperplasia.

Metabolic syndrome is associated with type II endoleak after endovascular abdominal aortic aneurysm repair

OBJECTIVE

Type II endoleak is usually a benign finding after endovascular abdominal aortic aneurysm repair (EVAR). In some patients, however, type II endoleak leads to aneurysm sac expansion and the need for further intervention. We examined which factors, in particular the components of metabolic syndrome (MetS), would lead to an increase risk of endoleak after EVAR.

METHODS

The medical records of all patients who underwent EVAR between 2002 and 2011 at the Veterans Affairs Connecticut Healthcare System were reviewed. MetS was defined as the presence of three or more of the following: hypertension (blood pressure ≥130 mm Hg/≥90 mm Hg), serum triglycerides ≥150 mg/dL, serum high-density lipoproteins ≤50 mg/dL for women and ≤40 mg/dL for men, body mass index ≥30 kg/m(2), and fasting blood glucose ≥110 mg/dL. Development of endoleak, including specific endoleak type, was determined by review of standard radiologic surveillance.

RESULTS

During a 9-year period, 79 male patients (mean age, 73.5 years), underwent EVAR for infrarenal abdominal aortic aneurysm (mean 6.2 cm maximal transverse diameter). MetS was present in 52 patients (66%). The distribution of MetS factors among all patients was hypertension in 86%, hypertriglyceridemia in 72%, decreased high-density lipoprotein in 68%, diabetes in 37%, and a body mass index of ≥30 kg/m(2) in 30%. No survival difference was found between the MetS and non-MetS groups (P = .66). There was no difference in perioperative myocardial infarction or visceral ischemia immediately postoperatively between the two groups. Patients with MetS had a significant increase in acute kidney injury (n = 7, P = .0128). Endoleaks of all types were detected in 26% (n = 20) of all patients; patients with MetS had more endoleaks than patients without MetS (35% vs 7.4%, P = .0039). Of the 19 type II endoleaks, 79% were present at the time of EVAR and only 21% developed during surveillance; 95% had MetS (P = .0007).

CONCLUSIONS

Type II endoleak after EVAR for abdominal aortic aneurysm is associated with MetS. Whether these patients are subject to more subsequent intervention due to sac expansion is unclear. MetS may be a factor to consider in the treatment of type II endoleak.

Tolerance to the anticonvulsant effects of phenobarbital, trimethadione, and clonazepam in kindled rats: cross tolerance to carbamazepine

The kindled-convulsion model was used to assess the development of tolerance and cross tolerance to the anticonvulsant effects of antiepileptic drugs. In Experiment 1, tolerance developed to the anticonvulsant effects of bidaily (one every 48 h) IP injections of phenobarbital, trimethadione, and clonazepam on convulsions elicited 1 h after each injection in kindled rats by amygdala stimulation. In Experiment 2, kindled rats that were tolerant to the anticonvulsant effects of phenobarbital, trimethadione, or clonazepam received bidaily IP injections of carbamazepine, each followed 1 h later by a convulsive amygdala stimulation. There was a statistically significant transfer of tolerance from phenobarbital to carbamazepine, but not from either trimethadione or clonazepam to carbamazepine. Apparently, tolerance to anticonvulsant drugs is most likely to transfer between drugs that are effective against similar kinds of clinical and experimental seizures and have similar putative mechanisms of action.

A PSGL-1 glycomimetic reduces thrombus burden without affecting hemostasis

Events mediated by the P-selectin/PSGL-1 pathway play a critical role in the initiation and propagation of venous thrombosis by facilitating the accumulation of leukocytes and platelets within the growing thrombus. Activated platelets and endothelium express P-selectin, which binds P-selectin glycoprotein ligand-1 (PSGL-1) that is expressed on the surface of all leukocytes. We developed a pegylated glycomimetic of the N terminus of PSGL-1, PEG40-GSnP-6 (P-G6), which proved to be a highly potent P-selectin inhibitor with a favorable pharmacokinetic profile for clinical translation. P-G6 inhibits human and mouse platelet-monocyte and platelet-neutrophil aggregation in vitro and blocks microcirculatory platelet-leukocyte interactions in vivo. Administration of P-G6 reduces thrombus formation in a nonocclusive model of deep vein thrombosis with a commensurate reduction in leukocyte accumulation, but without disruption of hemostasis. P-G6 potently inhibits the P-selectin/PSGL-1 pathway and represents a promising drug candidate for the prevention of venous thrombosis without increased bleeding risk.

Late onset venous thoracic outlet syndrome following clavicle non-union fracture: A case report

A 59-year-old woman was admitted three times over a six-month period with recurrent upper extremity deep venous thrombosis (UEDVT). It was determined that this patient was suffering from an unusual presentation of Paget-Schröetter syndrome secondary to a 20-year-old non-union of a midshaft clavicle fracture. Following thrombolysis the patient underwent resection and plate fixation of the clavicle fracture non-union. Despite the anatomic proximity of the subclavian vessels to the clavicle, vascular complications from fracture are rare. Treatment of midshaft clavicle fractures is often non-operative. Non-union rates are generally less than 10%, and easily treated secondarily without complication. Clavicular pseudo-arthroses from trauma have been implicated in the development of the thoracic outlet syndromes, however, onset 20 years after fracture has never before been reported.