A hybrid nanoparticle-protein hydrogel system for prolonged local anesthesia

Local anesthetics are effective in relieving pain, but their duration of action is short. Therefore, the development of injectable sustained release systems to prolong the effect of local anesthetics has been of interest. In such systems delivering conventional local anesthetics, it has been challenging to achieve long durations of effect, particularly without incurring tissue toxicity. To overcome these challenges, we created a platform comprising a protein hydrogel incorporating hydrophobic local anesthetic (bupivacaine) nanoparticles. The nanoparticles were prepared by anti-solvent precipitation stabilized with bovine serum albumin (BSA), followed by crosslinking with glutaraldehyde (GA). The resulting BSA hydrogels prolonged release of bupivacaine in vitro. When bupivacaine nanoparticles within crosslinked BSA were injected at the sciatic nerve in rats, a duration of nerve block of 39.9 h was obtained, compared to 5.5 h for the commercial bupivacaine liposome suspension EXPAREL®. Tissue reaction was benign. We further demonstrated that this system could control the release of the amphiphilic drug diphenhydramine and the hydrophobic paclitaxel.

Robotic-assisted laparoscopic Malone appendicostomy: a 6-year perspective

PURPOSE

A robotic-assisted laparoscopic approach to appendicostomy offers the benefits of a minimally invasive approach to patients who would typically necessitate an open procedure, those with a larger body habitus, and those requiring combined complex colorectal and urologic reconstructive procedures. We present our experience performing robotic-assisted appendicostomies with a focus on patient selection, perioperative factors, and functional outcomes.

METHODS

A retrospective review of patients who underwent a robotic-assisted appendicostomy/neoappendicostomy at our institution was performed.

RESULTS

Twelve patients underwent robotic-assisted appendicostomy (n = 8) and neoappendicostomy (n = 4) at a range of 8.8-25.8 years. Five patients had a weight percentile > 50% for their age. Seven patients underwent combined procedures. Median operative time for appendicostomy/neoappendicostomy only was 185.0 min. Complications included surgical site infection (n = 3), stricture requiring minor operative revision (n = 2), conversion to an open procedure due to inadequate appendiceal length (prior to developing our technique for robotic neoappendicostomies; n = 1), and granuloma (n = 1). At a median follow-up of 10.8 months (range 1.7-74.3 months), 91.7% of patients were consistently clean with antegrade enemas.

DISCUSSION

Robotic-assisted laparoscopic appendicostomy and neoappendicostomy with cecal flap is a safe and effective operative approach. A robotic approach can potentially overcome the technical difficulties encountered in obese patients and can aid in patients requiring both a Malone and a Mitrofanoff in a single, combined minimally invasive procedure.

Late Diagnosis of Hirschsprung Disease: Clinical Presentation and Long-Term Functional Outcomes

PURPOSE

Hirschsprung Disease (HD) is typically diagnosed in the neonatal period. A small subset of patients have a prolonged course of abdominal distention and constipation prior to diagnosis. Late HD is defined as having been diagnosed at greater than or equal to one year of age. The literature is limited and offers conflicting data on the implications of a late diagnosis. We aim to investigate the presentation, operative approach, and functional outcomes of a large cohort of patients with a late HD diagnosis.

METHODS

All patients with a late diagnosis of HD (after 1 year of age) at our institution between 1997 and 2021 were included.

RESULTS

Twenty-eight patients were diagnosed with HD at a median age of 3.4 years. Chronic constipation, failure to thrive, and enterocolitis occurred in 100 %, 31 %, and 14 %, respectively. All patients underwent contrast enema and biopsies during their workup, identifying primarily rectosigmoid disease (n = 27) and total colonic aganglionosis (n = 1). Surgical intervention was performed in 27 patients, with 4 patients (15 %) needing a stoma (3 with plan for staged pull-through, 1 long-term stoma) and 23 patients (85 %) undergoing a single-stage pull-through. Postoperative complications included Hirschsprung-associated enterocolitis (n = 5), ostomy prolapse and revision (n = 2), abdominal distention requiring ileostomy creation (n = 2), redo pull-through (n = 2), retroperitoneal hematoma (n = 1), and cecostomy tube placement (n = 1). At a median follow-up of 5.4 years, 83 % of eligible patients achieved fecal continence with 43 % needing laxatives for persistent constipation.

CONCLUSION

Recognizing a late presentation of HD requires a high index of suspicion. Patients with a late diagnosis did not experience an increased rate of permanent stoma, complications, or redo surgery compared to rates reported for the larger HD population. Similar long-term functional outcomes were achieved compared to the larger HD population.

LEVEL OF EVIDENCE

IV.

Amputation Rates and Associated Social Determinants of Health in the Most Populous US Counties

Importance

Social Determinants of Health (SDOH) have been found to be associated with health outcome disparities in patients with peripheral artery disease (PAD). However, the association of specific components of SDOH and amputation has not been well described.

Objective

To evaluate whether individual components of SDOH and race are associated with amputation rates in the most populous counties of the US.

Design, Setting, and Participants

In this population-based cross-sectional study of the 100 most populous US counties, hospital discharge rates for lower extremity amputation in 2017 were assessed using the Healthcare Cost and Utilization Project State Inpatient Database. Those data were matched with publicly available demographic, hospital, and SDOH data. Data were analyzed July 3, 2022, to March 5, 2023.

Main outcome and Measures

Amputation rates were assessed across all counties. Counties were divided into quartiles based on amputation rates, and baseline characteristics were described. Unadjusted linear regression and multivariable regression analyses were performed to assess associations between county-level amputation and SDOH and demographic factors.

Results

Amputation discharge data were available for 76 of the 100 most populous counties in the United States. Within these counties, 15.3% were African American, 8.6% were Asian, 24.0% were Hispanic, and 49.6% were non-Hispanic White; 13.4% of patients were 65 years or older. Amputation rates varied widely, from 5.5 per 100 000 in quartile 1 to 14.5 per 100 000 in quartile 4. Residents of quartile 4 (vs 1) counties were more likely to be African American (27.0% vs 7.9%, P < .001), have diabetes (10.6% vs 7.9%, P < .001), smoke (16.5% vs 12.5%, P < .001), be unemployed (5.8% vs 4.6%, P = .01), be in poverty (15.8% vs 10.0%, P < .001), be in a single-parent household (41.9% vs 28.6%, P < .001), experience food insecurity (16.6% vs 12.9%, P = .04), or be physically inactive (23.1% vs 17.1%, P < .001). In unadjusted linear regression, higher amputation rates were associated with the prevalence of several health problems, including mental distress (β, 5.25 [95% CI, 3.66-6.85]; P < .001), diabetes (β, 1.73 [95% CI, 1.33-2.15], P < .001), and physical distress (β, 1.23 [95% CI, 0.86-1.61]; P < .001) and SDOHs, including unemployment (β, 1.16 [95% CI, 0.59-1.73]; P = .03), physical inactivity (β, 0.74 [95% CI, 0.57-0.90]; P < .001), smoking, (β, 0.69 [95% CI, 0.46-0.92]; P = .002), higher homicide rate (β, 0.61 [95% CI, 0.45-0.77]; P < .001), food insecurity (β, 0.51 [95% CI, 0.30-0.72]; P = .04), and poverty (β, 0.46 [95% CI, 0.32-0.60]; P < .001). Multivariable regression analysis found that county-level rates of physical distress (β, 0.84 [95% CI, 0.16-1.53]; P = .03), Black and White racial segregation (β, 0.12 [95% CI, 0.06-0.17]; P < .001), and population percentage of African American race (β, 0.06 [95% CI, 0.00-0.12]; P = .03) were associated with amputation rate.

Conclusions and Relevance

Social determinants of health provide a framework by which the associations of environmental factors with amputation rates can be quantified and potentially used to guide interventions at the local level.

On-Demand Opioid Effect Reversal with an Injectable Light-Triggered Polymer-Naloxone Conjugate

Misuse of opioids can lead to a potential lethal overdose. Timely administration of naloxone is critical for survival. Here, we designed a polymer-naloxone conjugate that can provide on-demand phototriggered opioid reversal. Naloxone was attached to the polymer poly(lactic-co-glycolic acid) via a photocleavable coumarin linkage and formulated as injectable nanoparticles. In the absence of irradiation, the formulation did not release naloxone. Upon irradiation with blue (400 nm) light, the nanoparticles released free naloxone, reversing the effect of morphine in mice. Such triggered events could be performed days and weeks after the initial administration of the nanoparticles and could be performed repeatedly.

Spectrum of lymphatic anomalies in patients with RASA1-related CM-AVM

BACKGROUND

Capillary malformation-arteriovenous malformation (CM-AVM) is characterized by multifocal fast-flow capillary malformations, sometimes with arteriovenous malformations/fistulas, skeletal/soft tissue overgrowth, telangiectasias, or Bier spots. Lymphatic abnormalities are infrequently reported. We describe seven patients with CM-AVM and lymphatic anomalies.

METHODS

Following IRB approval, we identified patients with CM-AVM and lymphatic anomalies seen at the Vascular Anomalies Center at Boston Children's Hospital from 2003 to 2023. We retrospectively reviewed records for clinical, genetic, laboratory, and imaging findings.

RESULTS

We found seven patients with CM-AVM and lymphatic abnormalities. Five patients were diagnosed prenatally: four with pleural effusions (including one suspected chylothorax) and one with ascites. Pleural effusions resolved after neonatal drainage in three patients and fetal thoracentesis in the fourth; however, fluid rapidly reaccumulated in this fetus causing hydrops. Ascites resolved after neonatal paracentesis, recurred at 2 months, and spontaneously resolved at 5 years; magnetic resonance lymphangiography for recurrence at age 19 years suggested a central conducting lymphatic anomaly (CCLA), and at age 20 years a right spermatic cord/scrotal lymphatic malformation (LM) was detected. Chylous pericardial effusion presented in a sixth patient at 2 months and disappeared after pericardiocentesis. A seventh patient was diagnosed with a left lower extremity LM at 16 months. Six patients underwent genetic testing, and all had RASA1 mutation. RASA1 variant was novel in three patients (c.1495delinsCTACC, c.434_451delinsA, c.2648del), previously reported in two (c.2603+1G>A, c.475_476del), and unavailable in another. Median follow-up age was 5.8 years (4 months-20 years).

CONCLUSION

CM-AVM may be associated with lymphatic anomalies, including pericardial/pleural effusions, ascites, CCLA, and LM.

Methyl-Branched Liposomes as a Depot for Sustained Drug Delivery

Inadequate drug loading and control of payload leakage limit the duration of the effect of liposomal drug carriers and may cause toxicity. Here, we report a liposome system as a depot for sustained drug delivery whose design is inspired by the low permeability of Archaeal membranes to protons and solutes. Incorporating methyl-branched phospholipids into lipid bilayers decreased payload diffusion across liposomal membranes, thereby enhancing the drug load capacity by 10-16% and reducing the release of small molecules in the first 24 h by 40-48%. The in vivo impact of this approach was demonstrated by injection at the sciatic nerve. Methyl-branched liposomes encapsulating the anesthetic tetrodotoxin (TTX) achieved markedly prolonged local anesthesia lasting up to 70 h, in comparison to the 16 h achieved with liposomes containing conventional lipids. The present work demonstrates the usefulness of methyl-branched liposomes to enhance liposomal depot systems for sustained drug delivery.

Surgical Resection of Vulvar Labial Venous Malformations: A Single Center Experience

BACKGROUND

Venous malformations (VMs) involving the vulva are rare but often cause debilitating pain, aesthetic concern, and functional impairment. Treatment with medical therapy, sclerotherapy, operative resection, or a combination thereof may be considered. The optimal therapeutic approach remains unclear. We report our experience resecting labial VMs in a large cohort of patients.

METHODS

A retrospective review of patients who underwent partial or complete resection of a labial VM was conducted.

RESULTS

Thirty-one patients underwent forty-three resections of vulvar VMs between 1998 and 2022. Physical examination and imaging demonstrated: 16% of patients had focal labial lesions, 6% had multifocal labial lesions, and 77% had extensive labial lesions. Indications for intervention included pain (83%), appearance (21%), functional impairment (17%), bleeding (10%), and cellulitis (7%). Sixty-one percent of patients underwent a single resection, 13% multiple partial resections, and 26% a combination of sclerotherapy and operative resection(s). Median age was 16.3 years at first operation. All patients requiring multiple operations had extensive VMs. Median blood loss was 200 mL. Postoperative complications included wound infection/dehiscence (14%), hematoma (2%), and urinary tract infection (2%). The median follow-up assessment was 14 months: 88% of patients had no complaints and 3 patients were experiencing recurrent discomfort.

CONCLUSIONS

Surgical resection is a safe and effective approach to treating vulvar labial VMs. Patients with focal or multifocal VMs can be successfully treated with a single resection, whereas patients with an extensive VM may require multiple partial resections or combined sclerotherapy and resection(s) to achieve long-term control.

TYPE OF STUDY

Retrospective Study.

LEVEL OF EVIDENCE

IV.

Ablation of Venous Malformations by Photothermal Therapy with Intravenous Gold Nanoshells

Venous malformations (VMs) consist of hugely enlarged and dysmorphic veins. These lesions cause significant disfigurement, pain, and complications such as bleeding and coagulopathy. Pharmacotherapy for the treatment of VMs has limited efficacy and potentially limiting toxicity. Current treatment for patients with VMs entails life-long pharmacotherapy or surgical procedures. Here we explored whether intravenously administered agents can be used to destroy VMs by photothermal therapy (PTT), using gold nanoshells (AuNSs) that generated heat following irradiation with near-infrared (NIR) light. In a murine model of VMs, intravenous AuNSs accumulated within the VMs. Irradiation of the VMs induced marked regression and even elimination. Nanoparticle-based photothermal therapy can provide effective therapy for VMs, which are otherwise relatively refractory to treatment.

Benzonatate as a local anesthetic

INTRODUCTION

Benzonatate is an FDA-approved antitussive agent that resembles tetracaine, procaine, and cocaine in its chemical structure. Based on structural similarities to known local anesthetics and recent findings of benzonatate exerting local anesthetic-like effects on voltage-gated sodium channels in vitro, we hypothesized that benzonatate will act as a local anesthetic to yield peripheral nerve blockade.

METHODS

Benzonatate was injected at the sciatic nerve of Sprague-Dawley rats. Sensory and motor blockade were assessed using a modified hot plate test and a weight-bearing test, respectively. Additionally, the effect of co-injection with tetrodotoxin and Tween 80 (a chemical permeation enhancer) was examined. Myotoxicity of benzonatate was assessed in vivo by histological analysis.

RESULTS

Benzonatate produced a concentration-dependent sensory and motor nerve blockade with no appreciable systemic effects. Co-injection with tetrodotoxin or Tween 80 produced prolongation of sensory nerve blockade. Histologic assessment showed significant inflammation and myotoxicity from benzonatate injection, even at low concentrations.

CONCLUSION

This study demonstrates that benzonatate does act as a local anesthetic at the peripheral nerve, with sensory and motor nerve blockade. Benzonatate interacts with tetrodotoxin and Tween 80 to prolong nerve blockade. However, benzonatate causes significant myotoxicity, even at subtherapeutic concentrations.

Primary and secondary vaginal reconstruction with autologous buccal mucosa and intravaginal wound vacuum therapy

BACKGROUND

Vaginal reconstruction with autologous buccal mucosa graft offers a promising alternative to the use of skin grafts and vascularized intestinal segments. Given the novelty of this procedure, the optimal approach to postoperative wound management remains unclear with current practices often requiring many months of vaginal stents/molds. This study aims to evaluate a newly developed negative pressure intravaginal wound vacuum placed at the conclusion of the vaginoplasty with the goals of facilitating graft take and healing.

METHODS

A retrospective review of patients (age 12-21 years) who underwent eight primary and secondary vaginoplasty procedures using autologous buccal mucosa coupled with intravaginal wound vacuum placement was performed.

RESULTS

Vaginal reconstruction with fenestrated full-thickness buccal mucosa graft and intravaginal wound vacuum placement was successfully performed eight times in seven patients at a median age of 15.6 years. Four patients underwent robotic vaginal pull-through with buccal mucosa serving as an interposition graft, and four patients underwent vaginoplasty with buccal graft alone. All cases had excellent engraftment at time of wound vacuum removal on postoperative day seven and had healthy-appearing buccal mucosa at a mean follow-up of 148 days. Postoperatively, one patient developed a stricture at the anastomosis between native vagina and buccal mucosa graft, requiring a second buccal mucosa graft six months after the first operation.

CONCLUSIONS

The use of autologous buccal mucosa graft for primary and secondary vaginal reconstruction coupled with intravaginal wound vacuum therapy offers a promising new approach. Negative pressure wound vacuum therapy may provide a more optimal wound healing environment for improved outcomes.

TYPE OF STUDY

Retrospective Study LEVELS OF EVIDENCE: Level IV.

Diagnosis, Management, and Outcome of Aortitis at a Single Center

BACKGROUND

Aortitis is a rare condition with inflammatory or infectious etiology that can be difficult to diagnose due to the highly variable clinical presentation and nonspecific symptoms. However, current literature on the diagnosis, management, and prognosis of aortitis is extremely scarce.

METHODS

We retrospectively reviewed all patients' charts who were diagnosed with giant cell arteritis, Takayasu arteritis, or noninfectious aortitis presenting at a single center between January 1, 2009, and April 17, 2015. Data collected included demographics, medical history, comorbidities, laboratory and imaging data, management, and outcome.

RESULTS

Among the included 15 patients presenting with aortitis at our center, 53% were diagnosed with Takayasu arteritis, 33% with idiopathic inflammatory aortitis, and 13% with giant cell arteritis. All patients received steroid treatment, 67% received adjunctive immunosuppressants or immunomodulators, and 33% underwent interventional procedures. Based on clinical presentation and laboratory and imaging findings at the last follow-up visit for each patient, 67% showed improvement, 27% had no change in disease activity, and 7% had a progression of the disease.

CONCLUSIONS

Takayasu arteritis was found to be more common than idiopathic inflammatory aortitis and giant cell arteritis among our 15 cases diagnosed with aortitis. All patients received medical therapy and 33% received interventional procedures, leading to 67% improvement of disease activity or related complications. This article also offers a comprehensive review of the diagnosis, management, and outcome of aortitis, supplementing the very limited literature on this disease.

A Unique Case of Aortic Thrombosis With Elevated Lipoprotein(a)

Aortic thrombosis is a rare condition that can be caused by atherosclerosis, aneurysms, thrombophilia, vasculitis, trauma, and malignancy. Symptoms vary based on thrombus size and site of embolization. It can lead to devastating complications including acute limb ischemia, myocardial infarction, stroke, and other target organ ischemia. Diagnosis is based on clinical presentation, imaging findings, and relevant laboratory work-up. Although not well defined, management for aortic thrombosis includes surgical intervention, such as thromboembolectomy, and conservative measures, such as anticoagulation. Here, we present a unique case of aortic thrombosis causing acute lower limb ischemia with elevated lipoprotein(a) and other comorbidities. Based on our literature review, our article is the first to establish the connection between elevated lipoprotein(a) and aortic thrombosis in the nonaneurysmal aorta.

Calcipotriol Targets LRP6 to Inhibit Wnt Signaling in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy in need of more effective treatment approaches. One potential therapeutic target is Wnt/β-catenin signaling, which plays important roles in PDAC tumor initiation and progression. Among Wnt inhibitors with suitable in vivo biologic activity is vitamin D, which is known to antagonize Wnt/β-catenin signaling in colorectal cancer and have antitumor activity in PDAC. For this study, the relationship between vitamin D signaling, Wnt/β-catenin activity, and tumor cell growth in PDAC was investigated through the use of calcipotriol, a potent non-hypercalcemic vitamin D analogue. PDAC tumor cell growth inhibition by calcipotriol was positively correlated with vitamin D receptor expression and Wnt/β-catenin activity. Furthermore, vitamin D and Wnt signaling activity were found to be reciprocally linked through feedback regulation. Calcipotriol inhibited autocrine Wnt/β-catenin signaling in PDAC cell lines in parallel with decreased protein levels of the low-density lipoprotein receptor-related protein 6 (LRP6), a requisite coreceptor for ligand-dependent canonical Wnt signaling. Decrease in LRP6 protein seen with calcipotriol was mediated through a novel mechanism involving transcriptional upregulation of low-density lipoprotein receptor adaptor protein 1 (LDLRAP1). Finally, changes in LRP6 or LDLRAP1 expression directly altered Wnt reporter activity, supporting their roles as regulators of ligand-dependent Wnt/β-catenin signaling.

IMPLICATIONS

This study provides a novel biochemical target through which vitamin D signaling exerts inhibitory effects on Wnt/β-catenin signaling, as well as potential biomarkers for predicting and following tumor response to vitamin D-based therapy.