Faculty Bibliography

Purpose: To compare outcomes following IVC stent placement covering versus not covering the renal veins
Material(s) and Method(s): Consecutive patients who underwent IVC stent placement for venous obstruction at a single quaternary care center between 1999 and 2018 were retrospectively identified. These 144 patients were divided into two cohorts based on imaging: 48 patients with an IVC stent implanted across the renal veins (covered) and 96 patients with an IVC stent sparing renal veins (uncovered). Baseline and post-procedural eGFR values were calculated using the CKD-EPI Creatinine Equation (2021)1. Baseline demographics and eGFR were compared between the two groups using Student's t-tests and chi² tests. Changes in average eGFR from baseline were calculated and differences between the cohorts were assessed using Student's t-tests. Kaplan-Meier methods were used to assess the primary patency of the stents in both groups. The covered and uncovered groups did not differ significantly on sex (P = 0.68), race (P = 0.12), age (P = 0.40), or underlying thrombophilia or malignancy (P = 0.11).
Result(s): The average baseline eGFR was 79 mL/min +/- 27 mL/min in the covered group and 86 mL/min +/- 25 mL/min in the uncovered group (P = 0.16). There were no statistically significant differences in changes in eGFR from baseline between the two cohorts following IVC stent placement (Table 1). No patients in either cohort developed renal vein thrombosis following IVC stent placement based on imaging and clinical follow-up. There were no statistically significant differences in primary patency between the two groups with a 2-year primary patency rate of 61% in the covered group and 70% in the uncovered group (P=0.11).
Conclusion(s): In this single-center, retrospective cohort study, renal function, thrombosis, and patency outcomes following IVC stent placement did not differ significantly based on the relation of the IVC stent to the renal veins. This suggests that IVC stent placement across the renal veins is safe and effective for treating symptomatic stenosis in the perirenal IVC. [Formula presented]
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BACKGROUND:Tibial nonunion remains a considerable burden for patients and the surgeons who treat them. In recent years, alternatives to autogenous grafts for the treatment of tibial nonunions have been sought. The purpose of this study was to evaluate the efficacy of autogenous iliac crest bone graft (ICBG) in the treatment of tibial shaft nonunions. MATERIAL AND METHODS/METHODS:Sixty-nine patients were identified who underwent ICBG for repair of atrophic or oligotrophic tibial nonunion and had complete data with at least one year of follow-up (mean 27.9 months). Surgical treatments consisted of revision/supplemental fixation ± ICBG. Surgical approaches for graft placement were either posterolateral (PL), anterolateral (AL), or direct medial (DM). Healing status, time to union, postoperative pain, and functional outcomes were assessed. RESULTS:Bony union was achieved by 97.1% (67/69) of patients at a mean time of 7.8 ± 3.2 months postoperatively. There was no significant difference in mean time to union between the three surgical approach groups: (PL (44.9%) = 7.3 months, AL (20.3%) = 9.2 months, DM (34.8%) = 7.6 months; p = 0.22). Intraoperative cultures obtained at the time of nonunion surgery were positive in 27.5% of patients (19/69). Positive cultures were associated with need for secondary surgery as 8/19 patients (42.1%) with positive cultures required re-operation. Two out of four patients that developed iliac donor site hematomas/infections requiring washout had positive intraoperative cultures as well. There was no difference in final SMFA among the three surgical approach groups. CONCLUSIONS:Autogenous ICBG remains the gold standard in the management of persistent tibial nonunions regardless of surgical approach. There is a small risk for complication at the iliac crest donor site. Given the high union rate, autogenous iliac crest bone grafting for tibial nonunion remains the gold standard for this difficult condition. LEVEL OF EVIDENCE/METHODS:Level III.

BACKGROUND:Psychological, emotional, and mental distress affects many patients who experience early pregnancy loss (EPL). A common concern is that the patient's actions or choices caused the loss. Understanding the cause of EPL may improve the distress of EPL patients and their partners. Chromosomal abnormalities leading to a significant portion of EPL. Cell-free DNA (cfDNA) testing, a non-invasive test providing high quality information about the chromosomal makeup of a fetus, may offer assurance that a fetal abnormality caused the loss, and provide more certainty or closure in processing EPL. CfDNA may be a useful adjunct to patient-centered care in the setting of EPL. This commentary explores the possibility of cfDNA testing in lessening the emotional distress that often accompanies EPL. METHODS:The peer reviewed literature was explored for manuscripts addressing (1) the potential for cfDNA serum testing for patients experiencing EPL and screening products of conception to determine the cause of EPL; and/or (2) the impact that information might have on the psychological morbidity of EPL for patients and their partners. Themes generated from extracted data were used to generate key questions for future research. RESULTS:Preliminary findings suggest fetal fraction values are instrumental in the success of cfDNA testing, and a successful cfDNA testing experience can have a positive impact on patients. CONCLUSIONS:Ultimately, we conclude cfDNA testing could have a positive impact in patient care and improve the well-being of patients undergoing the emotional toll of EPL by reducing feelings of guilt and providing closure to those who learn the loss was associated with chromosomal abnormality. Further trials and studies that explore the intersection of mental health of EPL on patients should explore the efficacy of cfDNA testing as an adjunct to patient-centered care in these cases.

OBJECTIVE:Millions of babies have been conceived by IVF, yet debate about its safety to offspring continues. We hypothesized that superovulation and in vitro fertilization (IVF) promote genomic changes, including altered telomere length (TL) and activation of the retrotransposon LINE-1 (L1), and tested this hypothesis in a mouse model. MATERIAL AND METHODS/METHODS:Experimental study analyzing TL and L1 copy number in C57BL/6 J mouse blastocysts in vivo produced from natural mating cycles (N), in vivo produced following superovulation (S), or in vitro produced following superovulation (IVF). We also examined the effects of prolonged culture on TL and L1 copy number in the IVF group comparing blastocysts cultured 96 h versus blastocysts cultured 120 h. TL and L1 copy number were measured by Real Time PCR. RESULTS:TL in S (n = 77; Mean: 1.50 ± 1.15; p = 0.0007) and IVF (n = 82; Mean: 1.72 ± 1.44; p < 0.0001) exceeded that in N (n = 16; Mean: 0.61 ± 0.27). TL of blastocysts cultured 120 h (n = 15, Mean: 2.14 ± 1.05) was significantly longer than that of embryos cultured for 96 h (n = 67, Mean: 1.63 ± 1.50; p = 0.0414). L1 copy number of blastocysts cultured for 120 h (n = 15, Mean: 1.71 ± 1.49) exceeded that of embryos cultured for 96 h (n = 67, Mean: 0.95 ± 1.03; p = 0.0162). CONCLUSIONS:Intriguingly ovarian stimulation, alone or followed by IVF, produced embryos with significantly longer telomeres compared to in vivo, natural cycle-produced embryos. The significance of this enriched telomere endowment for the health and longevity of offspring born from IVF merit future studies.

Thoracic aortic aneurysms (TAA) in Marfan syndrome, caused by fibrillin-1 mutations, are characterized by elevated cytokines and fragmentated elastic laminae in the aortic wall. This study explored whether and how specific fibrillin-1-regulated miRNAs mediate inflammatory cytokine expression and elastic laminae degradation in TAA. miRNA expression profiling at early and late TAA stages using a severe Marfan mouse model (Fbn1^mgR/mgR) revealed a spectrum of differentially regulated miRNAs. Bioinformatic analyses predicted the involvement of these miRNAs in inflammatory and extracellular matrix-related pathways. We demonstrate that upregulation of pro-inflammatory cytokines and matrix metalloproteinases is a common characteristic of mouse and human TAA tissues. miR-122, the most downregulated miRNA in the aortae of 10-week-old Fbn1^mgR/mgR mice, post-transcriptionally upregulated CCL2, IL-1β and MMP12. Similar data were obtained at 70 weeks of age using Fbn1^C1041G/+ mice. Deficient fibrillin-1-smooth muscle cell interaction suppressed miR-122 levels. The marker for tissue hypoxia HIF-1α was upregulated in the aortic wall of Fbn1^mgR/mgR mice, and miR-122 was reduced under hypoxic conditions in cell and organ cultures. Reduced miR-122 was partially rescued by HIF-1α inhibitors, digoxin and 2-methoxyestradiol in aortic smooth muscle cells. Digoxin-treated Fbn1^mgR/mgR mice demonstrated elevated miR-122 and suppressed CCL2 and MMP12 levels in the ascending aortae, with reduced elastin fragmentation and aortic dilation. In summary, this study demonstrates that miR-122 in the aortic wall inhibits inflammatory responses and matrix remodeling, which is suppressed by deficient fibrillin-1-cell interaction and hypoxia in TAA.

Burns and other traumatic injuries represent a substantial biomedical burden. The current standard of care for deep injuries is autologous split-thickness skin grafting (STSG), which frequently results in contractures, abnormal pigmentation, and loss of biomechanical function. Currently, there are no effective therapies that can prevent fibrosis and contracture after STSG. Here, we have developed a clinically relevant porcine model of STSG and comprehensively characterized porcine cell populations involved in healing with single-cell resolution. We identified an up-regulation of proinflammatory and mechanotransduction signaling pathways in standard STSGs. Blocking mechanotransduction with a small-molecule focal adhesion kinase (FAK) inhibitor promoted healing, reduced contracture, mitigated scar formation, restored collagen architecture, and ultimately improved graft biomechanical properties. Acute mechanotransduction blockade up-regulated myeloid CXCL10-mediated anti-inflammation with decreased CXCL14-mediated myeloid and fibroblast recruitment. At later time points, mechanical signaling shifted fibroblasts toward profibrotic differentiation fates, and disruption of mechanotransduction modulated mesenchymal fibroblast differentiation states to block those responses, instead driving fibroblasts toward proregenerative, adipogenic states similar to unwounded skin. We then confirmed these two diverging fibroblast transcriptional trajectories in human skin, human scar, and a three-dimensional organotypic model of human skin. Together, pharmacological blockade of mechanotransduction markedly improved large animal healing after STSG by promoting both early, anti-inflammatory and late, regenerative transcriptional programs, resulting in healed tissue similar to unwounded skin. FAK inhibition could therefore supplement the current standard of care for traumatic and burn injuries.

Cell-extracellular matrix interactions have been studied extensively using cells cultured in vitro. These studies indicate that focal adhesion (FA)-based cell-extracellular matrix interactions are essential for cell anchoring and cell migration. Whether FAs play a similarly important role in vivo is less clear. Here, we summarize the formation and function of FAs in cultured cells and review how FAs transmit and sense force in vitro. Using examples from animal studies, we also describe the role of FAs in cell anchoring during morphogenetic movements and cell migration in vivo. Finally, we conclude by discussing similarities and differences in how FAs function in vitro and in vivo.

BACKGROUND:Left ventricular noncompaction (LVNC) is the third most common pediatric cardiomyopathy characterized by a thinned myocardium and prominent trabeculations. Next-generation genetic testing has led to a rapid increase in the number of genes reported to be associated with LVNC, but we still have little understanding of its pathogenesis. We sought to grade the strength of the gene-disease relationship for all genes reported to be associated with LVNC and identify molecular pathways that could be implicated. METHODS:Following a systematic PubMed review, all genes identified with LVNC were graded using a validated, semi-quantitative system based on all published genetic and experimental evidence created by the Clinical Genome Resource (ClinGen). Genetic pathway analysis identified molecular processes and pathways associated with LVNC. RESULTS:We identified 189 genes associated with LVNC: 11 (6%) were classified as definitive, 21 (11%) were classified as moderate, and 140 (74%) were classified as limited, but 17 (9%) were classified as no evidence. Of the 32 genes classified as definitive or moderate, the most common gene functions were sarcomere function (n=11; 34%), transcriptional/translational regulator (n=6; 19%), mitochondrial function (n=3; 9%), and cytoskeletal protein (n=3; 9%). Furthermore, 18 (56%) genes were implicated in noncardiac syndromic presentations. Lastly, 3 genetic pathways (cardiomyocyte differentiation via BMP receptors, factors promoting cardiogenesis in vertebrates, and Notch signaling) were found to be unique to LVNC and not overlap with pathways identified in dilated cardiomyopathy and hypertrophic cardiomyopathy. CONCLUSIONS:LVNC is a genetically heterogeneous cardiomyopathy. Distinct from dilated or hypertrophic cardiomyopathies, LVNC appears to arise from abnormal developmental processes.