Bone marrow stromal cell-derived hepcidin has antimicrobial and immunomodulatory activities

Bone marrow stromal cells (BMSCs) have immunomodulatory activities in numerous species and have been used in clinical trials. BMSCs also make antibacterial agents. Since hepcidin is known to have antimicrobial effects in fish, we wondered if it might also be used as an antimicrobial agent by mammalian BMSCs. In the present study, we show hepcidin expression in both mouse (mBMSC) and human BMSCs (hBMSC). We observed a hBMSC hepcidin-dependent degradation of ferroportin in HEK-293 reporter cells in vitro. In human and mouse bone marrows (BM) we detected hepcidin-positive BMSCs in close proximity to hematopoietic progenitors. The conditioned culture medium of hBMSCs significantly reduced bacterial proliferation that was partially blocked by a hepcidin-neutralizing antibody. Similarly, medium in which hepcidin-deficient (Hamp-/-) mouse BMSCs had been grown was significantly less effective in reducing bacterial counts than the medium of wild-type cells. In a zymosan-induced peritonitis mouse model we found that mBMSC-derived hepcidin reduced the number of invading polymorphonuclear (PMN) cells in the peritoneal cavity. Our results show that BMSC-derived hepcidin has antimicrobial properties in vitro and also reduces inflammation in vivo. We conclude that hepcidin should be added to the expanding arsenal of agents available to BMSCs to fight infections and inflammation.

A 3-Dimensional-Printed Hand Model for Home-Based Acquisition of Fracture Fixation Skills Without Fluoroscopy

OBJECTIVE

To design a low cost ($40), realistic and fluoroscopy-free percutaneous Kirschner wire hand fracture fixation training instrument kit for home-based skill acquisition during the COVID-19 pandemic.

DESIGN

A 3D-printed hand was designed from a computed tomography scan of a healthy hand. These data were used to create replaceable hand and wrist bones and reusable silicone molds for a replica of the soft tissue envelope. The model is currently being integrated into the simulation curriculum at 2 integrated plastic surgery residency programs for training in percutaneous wire fixation of hand fractures.

SETTING

Brown University, Warren Alpert Medical School of Brown University. Department of Surgery, Division of Plastic and Reconstructive Surgery. Large academic quaternary referral institution. Yale University, Yale School of Medicine. Department of Surgery, Division of Plastic and Reconstructive Surgery. Large academic quaternary referral institution.

PARTICIPANTS

PGY 1-4 plastic surgery residents preparing to meet ACGME Accreditation for Graduate Medical Education hand surgery specific milestones.

RESULTS

A realistic and durable 3D model with interchangeable bones allows trainees to practice the key motor skills necessary for successful fixation of hand and wrist fractures with K-wires in a home-based setting.

CONCLUSIONS

A low cost, realistic and durable 3D hand model with interchangeable bones allows easy integration into any home-based hand surgery curriculum. With 3D printers and programming becoming more prevalent and affordable, such models offer a means of low-cost and safe instruction of residents in fracture fixation with no harm to patients.

A 3D printed suturing trainer for medical students

BACKGROUND

Medical students must be able to suture competently upon graduation. To learn suturing technique, students must have access to practice materials. The purpose of this pilot study was to develop a novel suturing trainer and to evaluate its ability to provide realistic and accessible suturing practice. A cohort of senior students at one institution compared the device with standard suture-training media (porcine feet and sponges).

METHODS

Using 3D printing and silicone casting, a novel suturing trainer was developed and a cohort of senior medical students trialed the device in a standardised suturing workshop. Participants evaluated the novel suturing trainer, porcine feet and sponges for simulating human tissue with regard to: (i) tissue layers; (ii) tissue texture; (iii) ability to perform interrupted suturing; (iv) running subcuticular suturing; and (v) knot tying.

RESULTS

Compared with porcine feet and sponges, the suturing trainer had significantly higher mean scores (p < 0.001) for the simulation of human tissue layers and texture, as well as for the ability to facilitate the practice of interrupted suturing, running suturing and knot tying. All (n = 32) participants identified the silicone trainer as the best tool upon which to practice suturing, and 92% (n = 23) responded that their suturing skills would improve if the silicone trainer replaced porcine feet and sponges.

DISCUSSION

The silicone suturing device provides a more realistic and accessible suture learning experience than porcine feet and sponges. Further validation is required to assess its long-term effectiveness in medical education.

Complex wound closure by plastic surgery following resection of spinal neoplasms minimizes postoperative wound complications in high-risk patients

OBJECTIVE

Wound breakdown and infection are common postoperative complications following resection of spinal neoplasms. Accordingly, it has become common practice at some centers for plastic surgeons to assist with closure of large posterior defects after spine tumor resection. In this study, the authors tested the hypothesis that plastic surgery closure of complex spinal defects improves wound outcomes following resection of spinal neoplastic disease.

METHODS

Electronic medical records of consecutive patients who underwent resection of a spinal neoplasm between June 2015 and January 2019 were retrospectively reviewed. Patients were separated into two subpopulations based on whether the surgical wound was closed by plastic surgery or neurosurgery. Patient demographics, preoperative risk factors, surgical details, and postoperative outcomes were collected in a central database and summarized using descriptive statistics. Outcomes of interest included rates of wound complication, reoperation, and mortality. Known preoperative risk factors for wound complication in spinal oncology were identified based on literature review and grouped categorically. The presence of each category of risk factors was then compared between groups. Univariate and multivariate linear regressions were applied to define associations between individual risk factors and wound complications.

RESULTS

One hundred six patients met inclusion criteria, including 60 wounds primarily closed by plastic surgery and 46 by neurosurgery. The plastic surgery population included more patients with systemic metastases (58% vs 37%, p = 0.029), prior radiation (53% vs 17%, p < 0.001), prior chemotherapy (37% vs 15%, p = 0.014), and sacral region tumors (25% vs 7%, p = 0.012), and more patients who underwent procedures requiring larger incisions (7.2 ± 3.6 vs 4.5 ± 2.6 levels, p < 0.001), prolonged operative time (413 ± 161 vs 301 ± 181 minutes, p = 0.001), and greater blood loss (906 ± 1106 vs 283 ± 373 ml, p < 0.001). The average number of risk factor categories present was significantly greater in the plastic surgery group (2.57 vs 1.74, p < 0.001). Despite the higher relative risk, the plastic surgery group did not experience a significantly higher rate of wound complication (28% vs 17%, p = 0.145), reoperation (17% vs 9%, p = 0.234), or all-cause mortality (30% vs 13%, p = 0.076). One patient died from wound-related complications in each group (p = 0.851). Regression analyses identified diabetes, multilevel instrumentation, and BMI as the factors associated with the greatest wound complications.

CONCLUSIONS

Involving plastic surgery in the closure of spinal wounds after resection of neoplasms may ameliorate expected increases in wound complications among higher-risk patients.

Partial Suture Fusion in Nonsyndromic Single-Suture Craniosynostosis

INTRODUCTION

Partial synostosis of cranial sutures has been shown to have clinical and diagnostic significance. However, there is limited published information about how suture fusion progresses over time. In this study, we evaluate patients with nonsyndromic single-suture synostosis. We aim to define the incidence of partial versus complete suture fusion and whether a correlation exists between the degree of suture fusion and age.

METHODS

Two hundred fifty-four patients with nonsyndromic single-suture synostosis were evaluated. Preoperative computed tomography (CT) scans were rendered in 3-dimensions, all sutures were visualized and assessed for patency or fusion, and length of fusion was measured. Findings were grouped according to suture type (sagittal, coronal, metopic, or lambdoid), the degree of fusion (full, >50%, or <50%), and patient age at time of CT scan (0-90, 91-180, 181-360, or >360 days). Data were analyzed to correlate patient age versus the degree of suture fusion.

RESULTS

For all patients, 72% had complete and 28% had partial synostosis. Ratios of full to partial fusion for each suture type were as follows: sagittal 97:36, coronal 35:22, metopic 46:4, and lambdoid 4:10. The sagittal, coronal, and metopic groups demonstrated greater probabilities of complete suture fusion as patient age increases (P = .021, P < .001, P = .001, respectively). This trend was also noted when all sutures were considered together by age-group (P < .001).

CONCLUSION

We note a partial suture fusion rate of 28.3%. Our analysis shows a correlation between the extent of suture synostosis and patient age. Finally, we demonstrate that different sutures display different patterns of partial and complete fusion.

Eosinophilic Polymyositis: A Rare Cause of Atraumatic Compartment Syndrome of the Forearm

Background  Eosinophilic polymyositis is a rare disorder in which eosinophils infiltrate muscle and supporting connective tissue structures, resembling autoimmune or immunologically mediated disease. This disorder can be associated with muscle inflammation and death, and can be a cause of atraumatic compartment syndrome. Methods  This is a retrospective chart review of a case report as well as review of pertinent literature. Results  This report presents a rare case of atraumatic compartment syndrome of the forearm caused by eosinophilic polymyositis. It provides a case summary and histological examination of this patient. Conclusion  This is an important case to report because it highlights eosinophilic polymyositis as a unique etiology of compartment syndrome. In appropriate clinical situations where patients do not improve despite standard interventions, one should consider the rare and unusual etiology of compartment syndrome due to eosinophilic polymyositis. Furthermore, primary surgical intervention should not be delayed while waiting to ascertain a definitive diagnosis.

Introduction of Medical Three-Dimensional Printing in Rhode Island

Since the early 2000s, three-dimensional (3D) printing has become a well-rounded, evolving technology which has begun to revolutionize healthcare. 3D printing enables rapid creation and manufacture of individual patient models from original designs or medical imaging data. These models can be used for surgical planning, procedural training for residents and medical students, and the design and manufacture of surgical instruments, implants and prostheses. Current availability of this advanced technology at the Lifespan 3D Printing Lab permits Rhode Island physicians to utilize 3D printing in multiple, diverse settings to help improve their medical practice and optimize healthcare outcomes. This article describes three case-based examples to demonstrate varies used of 3D printing in Medicine.

PREVELENCE OF PRIMARY ALDOSTERONISM IN AN URBAN HYPERTENSIVE POPULATION

OBJECTIVE

To determine the prevalence of primary aldosteronism (PA) in hypertensive patients presenting to the primary care clinic at The Mount Sinai Hospital, regardless of the degree of hypertension and to identify clinical criteria that should prompt screening for PA.

METHODS

An aldosterone:renin ratio (ARR, cutoff ≥20, with plasma aldosterone concentration [PAC] ≥10 and suppressed renin) was used to prospectively screen 296 hypertensive patients (blood pressure [BP] ≥140/90) over the age of 18 from August 2012 through May 2013. Subjects who screened positive then underwent confirmatory oral salt load testing (OSLT).

RESULTS

Of the 296 patients, 14 screened positive for PA, an overall prevalence of 4.7%. Six of the 14 cases underwent confirmatory OSLT, upon which 2 were confirmed positive, for a prevalence of 0.7%. Overall, patients with confirmed PA were more likely to have resistant hypertension (42.9% vs. 18.1% (P = .0334)) and require more antihypertensive agents (2.8 ± 1.2 agents vs. 2.1 ± 1.1 agents, P = .0213). There was a trend toward lower potassium values in the cases.

CONCLUSION

The prevalence of PA in our clinic is much lower than in reports from certain "at-risk" populations. PA screening is indicated in patients with resistant hypertension, regardless of serum potassium levels.

ABBREVIATIONS

ARR = aldosterone:renin ratio ACTH = adrenocorticotropic hormone AVS = adrenal venous sampling BP = blood pressure MRA = mineralocorticoid receptor antagonist OSLT = oral salt load confirmatory test PA = primary aldosteronism PAC = plasma aldosterone concentration PCP = primary care provider PRA = plasma renin activity.