Lymphatic abnormalities are associated with RASA1 gene mutations in mouse and man.

Mutations in gene RASA1 have been historically associated with capillary malformation-arteriovenous malformation, but sporadic reports of lymphatic involvement have yet to be investigated in detail. To investigate the impact of RASA1 mutations in the lymphatic system, we performed investigational near-infrared fluorescence lymphatic imaging and confirmatory radiographic lymphangiography in a Parkes-Weber syndrome (PKWS) patient with suspected RASA1 mutations and correlated the lymphatic abnormalities against that imaged in an inducible Rasa1 knockout mouse. Whole-exome sequencing (WES) analysis and validation by Sanger sequencing of DNA from the patient and unaffected biological parents enabled us to identify an early-frameshift deletion in RASA1 that was shared with the father, who possessed a capillary stain but otherwise no overt disease phenotype. Abnormal lymphatic vasculature was imaged in both affected and unaffected legs of the PKWS subject that transported injected indocyanine green dye to the inguinal lymph node and drained atypically into the abdomen and into dermal lymphocele-like vesicles on the groin. Dermal lymphatic hyperplasia and dilated vessels were observed in Rasa1-deficient mice, with subsequent development of chylous ascites. WES analyses did not identify potential gene modifiers that could explain the variability of penetrance between father and son. Nonetheless, we conclude that the RASA1 mutation is responsible for the aberrant lymphatic architecture and functional abnormalities, as visualized in the PKWS subject and in the animal model. Our unique method to combine investigatory near-infrared fluorescence lymphatic imaging and WES for accurate phenoptyping and unbiased genotyping allows the study of molecular mechanisms of lymphatic involvement of hemovascular disorders.

Investigational lymphatic imaging at the bedside in a pediatric postoperative chylothorax patient.

Chylothorax is a rare but serious complication in children who undergo heart surgery. Its pathogenesis is poorly understood, and invasive surgical treatments are considered only after conservative management fails. Current diagnostic imaging techniques, which could aid decision making for earlier surgical intervention, are difficult to apply. Herein, we deployed near-infrared fluorescence (NIRF) lymphatic imaging to allow the visualization of abnormal lymphatic drainage in an infant with postoperative chylothorax to guide the choice of surgical management. A 5-week-old male infant, who developed chylothoraces after undergoing Norwood surgery for hypoplastic left heart syndrome, was intradermally administered trace doses of indocyanine green in both feet and the left hand. NIRF imaging was then performed at the bedside to visualize lymphatic drainage patterns. Imaging results indicated impeded lymphatic drainage from the feet toward the trunk with no fluorescence in the chest indicating no leakage of peripheral lymph at the thoracic duct. Instead, lymph drainage occurred from the axilla directly into the pleural cavity. As a result of imaging, left pleurodesis was performed to stop the pleural effusion with the result of temporary decrease of left chest tube drainage. Although additional studies are required to understand normal and abnormal lymphatic drainage patterns in infants, we showed the potential of using NIRF lymphatic imaging at the bedside to visualize the lymphatic drainage pathway to guide therapy. Timely management of chylothorax may be improved by using NIRF imaging to understand lymphatic drainage pathways.

Hyperbaric Oxygen Therapy versus placebo for post-concussion syndrome (HOT-POCS): A randomized, double-blinded controlled pilot study.

Post-Concussion Syndrome (PCS) refers to the persistence of physical, cognitive, and emotional symptoms following mild traumatic brain injury (mTBI)/concussion, occurring in roughly 15-30% of individuals. Hyperbaric oxygen therapy (HBOT) has been suggested as a potential treatment for PCS; however, the evidence to date is mixed due to inconsistencies in the treatment protocol and focus on veterans with combat-related injuries, which may not be generalizable to the general population. The goal of Hyperbaric Oxygen Therapy for Post-Concussion Syndrome (HOT-POCS) is to assess the efficacy and safety of HBOT for the treatment of PCS in the civilian population. This randomized, controlled pilot study will be using a standardized HBOT protocol (20 sessions of 100% O2 at 2.0 atm absolute [ATA]) compared with a true placebo gas system that mimics the oxygen composition at room air (20 sessions of 10.5% O2 and 89.5% nitrogen at 2.0 ATA) in a cohort of 100 adults with persistent post-concussive symptoms 3-12 months following injury. Change in symptoms on the Rivermead Post-concussion Questionnaire (RPQ) will be the primary outcome of interest. Secondary outcomes include the rate of adverse events, change in the quality of life, and change in cognitive function. Exploratory outcome measures will include changes in physical function and changes in cerebral brain perfusion and oxygen metabolism on MRI brain imaging. Overall, the HOT-POCS study will compare the efficacy of a standardized HBOT treatment protocol against a true placebo gas for the treatment of PCS within 12 months after injury.

A randomized controlled trial comparing two types of pneumatic compression for breast cancer-related lymphedema treatment in the home.

PURPOSE: Pneumatic compression devices (PCDs) are used in the home setting as adjunctive treatment for lymphedema after acute treatment in a clinical setting. PCDs range in complexity from simple to technologically advanced. The objective of this prospective, randomized study was to determine whether an advanced PCD (APCD) provides better outcomes as measured by arm edema and tissue water reductions compared to a standard PCD (SPCD) in patients with arm lymphedema after breast cancer treatment. METHODS: Subjects were randomized to an APCD (Flexitouch system, HCPCS E0652) or SPCD (Bio Compression 2004, HCPCS E0651) used for home treatment 1 h/day for 12 weeks. Pressure settings were 30 mmHg for the SPCD and upper extremity treatment program (UE01) with standard pressure for the APCD. Thirty-six subjects (18 per group) with unilateral upper extremity lymphedema with at least 5% arm edema volume at the time of enrollment, completed treatments over the 12-week period. Arm volumes were determined from arm girth measurements and suitable model calculations, and tissue water was determined based on measurements of the arm tissue dielectric constant (TDC). RESULTS: The APCD-treated group experienced an average of 29% reduction in edema compared to a 16% increase in the SPCD group. Mean changes in TDC values were a 5.8% reduction for the APCD group and a 1.9% increase for the SPCD group. CONCLUSION: This study suggests that for the home maintenance phase of treatment of arm lymphedema secondary to breast cancer therapy, the adjuvant treatment with an APCD provides better outcomes than with a SPCD.

Hyperbaric Oxygen Therapy in Sports Musculoskeletal Injuries.

Hyperbaric oxygen therapy (HBOT) is a well-established treatment for a variety of conditions. Hyperbaric oxygen therapy is the administration of 100% oxygen breathing in a pressure vessel at higher than atmospheric pressure (1 atmosphere absolute = 101 kPa). Typically, treatment is given daily for between 1 and 2 h at pressures of 2.0 to 2.8 ATA, depending on the indication. Sporting injuries are often treated over 3 to 10 sessions. Hyperbaric oxygen therapy has been documented to be effective and is approved in 14 medical indications by the Undersea and Hyperbaric Medical Society, including, but not limited to, carbon monoxide poisoning, compromised skin grafts and flaps, crush injuries, necrotizing soft tissue infections, and nonhealing ulcers with arterial insufficiencies. Recently, HBOT for sports musculoskeletal injuries is receiving increased attention. Hyperbaric oxygen therapy may allow injured athletes to recover faster than normal rehabilitation methods. Any reduction in collegiate and professional athletes' rehabilitation period can be financially significant for top-level sports teams; however, further research is required to confirm HBOT's benefits on sports musculoskeletal injuries. The purpose of this review to discuss the current understanding of HBOT as a treatment modality for common musculoskeletal injuries in sport medicine. Moreover, we will highlight the advantages and disadvantages of this modality, as well as relevant clinical and research applications.

A phase 2B randomised trial of hyperbaric oxygen therapy for ulcerative colitis patients hospitalised for moderate to severe flares.

BACKGROUND: Hyperbaric oxygen has been reported to improve disease activity in hospitalised ulcerative colitis (UC) patients. AIM: To evaluate dosing strategies with hyperbaric oxygen for hospitalised UC patients. METHODS: We enrolled UC patients hospitalised for acute flares (Mayo score 6-12). Initially, all patients received 3 days of hyperbaric oxygen at 2.4 atmospheres (90 minutes with two air breaks) in addition to intravenous steroids. Day 3 responders (reduction of partial Mayo score ≥ 2 points and rectal bleeding score ≥ 1 point) were randomised to receive a total of 5 days vs 3 days of hyperbaric oxygen. RESULTS: We treated 20 patients with hyperbaric oxygen (75% prior biologic failure). Day 3 response was achieved in 55% (n = 11/20), with significant reductions in stool frequency, rectal bleeding and CRP (P < 0.01). A more significant reduction in disease activity was observed with 5 days vs 3 days of hyperbaric oxygen (P = 0.03). Infliximab or colectomy was required in only three patients (15%) despite a predicted probability of 80% for second-line therapy. Day 3 hyperbaric oxygen responders were less likely to require re-hospitalisation or colectomy by 3 months vs non-responders (0% vs 66%, P = 0.002). No treatment-related adverse events were observed. CONCLUSION: Hyperbaric oxygen appears to be effective for optimising response to intravenous steroids in UC patients hospitalised for acute flares, with low rates of re-hospitalisation or colectomy at 3 months. An optimal clinical response is achieved with 5 days of hyperbaric oxygen. Larger phase 3 trials are needed to confirm efficacy and obtain labelled approval.

Near-infrared fluorescence lymphatic imaging in a patient treated for venous occlusion.

Although lower extremity edema/lymphedema can result from venous and/or lymphatic abnormalities, effective treatment depends upon understanding their relative contributions to the condition. Herein we use near-infrared fluorescence lymphatic imaging in a 16 year-old female diagnosed with unilateral lymphedema of the right leg and previously treated with left iliac vein stenting in an attempt to alleviate lymphedema. The imaging shows that abnormal lymphatic anatomy, rather than venous occlusion, was likely responsible for unilateral swelling.

An abnormal lymphatic phenotype is associated with subcutaneous adipose tissue deposits in Dercum's disease.

OBJECTIVE: Investigational, near-infrared fluorescence (NIRF) lymphatic imaging was used to assess lymphatic architecture and contractile function in participants diagnosed with Dercum's disease, a rare, poorly understood disorder characterized by painful lipomas in subcutaneous adipose tissues. METHODS: After informed consent and as part of an FDA-approved feasibility study to evaluate lymphatics in diseases in which their contribution has been implicated, three women diagnosed with Dercum's disease and four control subjects were imaged. Each participant received multiple intradermal and subcutaneous injections of indocyanine green (ICG, total dose ≤400 µg) in arms, legs, and/or trunk. Immediately after injection, ICG was taken up by the lymphatics and NIRF imaging was conducted. RESULTS: The lymphatics in the participants with Dercum's disease were intact and dilated, yet sluggishly propelled lymph when compared to control lymphatics. Palpation of regions containing fluorescent lymphatic pathways revealed tender, fibrotic, tubular structures within the subcutaneous adipose tissue that were associated with painful nodules, and, in some cases, masses of fluorescent tissue indicating that some lipomas may represent tertiary lymphoid tissues. CONCLUSIONS: These data support the hypothesis that Dercum's disease may be a lymphovascular disorder and suggest a possible association between abnormal adipose tissue deposition and abnormal lymphatic structure and function.

Evidence for SH2 domain-containing 5'-inositol phosphatase-2 (SHIP2) contributing to a lymphatic dysfunction.

The lymphatic vasculature plays a critical role in a number of disease conditions of increasing prevalence, such as autoimmune disorders, obesity, blood vascular diseases, and cancer metastases. Yet, unlike the blood vasculature, the tools available to interrogate the molecular basis of lymphatic dysfunction/disease have been lacking. More recently, investigators have reported that dysregulation of the PI3K pathway is involved in syndromic human diseases that involve abnormal lymphatic vasculatures, but there have been few compelling results that show the direct association of this molecular pathway with lymphatic dysfunction in humans. Using near-infrared fluorescence lymphatic imaging (NIRFLI) to phenotype and next generation sequencing (NGS) for unbiased genetic discovery in a family with non-syndromic lymphatic disease, we discovered a rare, novel mutation in INPPL1 that encodes the protein SHIP2, which is a negative regulator of the PI3K pathway, to be associated with lymphatic dysfunction in the family. In vitro interrogation shows that SHIP2 is directly associated with impairment of normal lymphatic endothelial cell (LEC) behavior and that SHIP2 associates with receptors that are associated in lymphedema, implicating its direct involvement in the lymphatic vasculature.

Lymphatic abnormalities in the normal contralateral arms of subjects with breast cancer-related lymphedema as assessed by near-infrared fluorescent imaging.

Current treatment of unilateral breast cancer-related lymphedema (BCRL) is only directed to the afflicted arm. Near-infrared fluorescent imaging (NIRF) of arm lymphatic vessel architecture and function in BCRL and control subjects revealed a trend of increased lymphatic abnormalities in both the afflicted and unafflicted arms with increasing time after lymphedema onset. These pilot results show that BCRL may progress to affect the clinically "normal" arm, and suggest that cancer-related lymphedema may become a systemic, rather than local, malady. These findings support further study to understand the etiology of cancer-related lymphedema and lead to better diagnostics and therapeutics directed to the systemic lymphatic system.

Near-infrared fluorescence imaging of lymphatics in head and neck lymphedema.

BACKGROUND: Lymphedema is a complication that may occur after surgical resection and radiation treatment in a number of cancer types and is especially debilitating in regions where treatment options are limited. Although upper and lower extremity lymphedema may be effectively treated with manual lymphatic drainage (MLD) therapies and devices that use compression to direct proximal flow of lymph fluids, head and neck lymphedema is more challenging. METHODS AND RESULTS: Herein, we describe the compassionate use of an investigatory technique of near-infrared (NIR) fluorescence imaging to understand the lymphatic anatomy and function, help direct MLD, and use 3-dimensional (3D) surface profilometry to monitor response to therapy in a patient with head and neck lymphedema after surgery and radiation treatment. CONCLUSION: NIR fluorescence imaging provides a mapping of functional lymph vessels for direction of efficient MLD therapy in the head and neck. Additional studies are needed to assess the efficacy of MLD therapy when directed by NIR fluorescence imaging.