Lymphatic System Development and Function.

PURPOSE OF REVIEW: This review delves into recent advancements in understanding generalized and organ-specific lymphatic development. It emphasizes the distinct characteristics and critical anomalies that can impair lymphatic function. By exploring developmental mechanisms, the review seeks to illuminate the profound impact of lymphatic malformations on overall health and disease progression. RECENT FINDINGS: The introduction of genome sequencing, single-cell transcriptomic analysis, and advanced imaging technologies has significantly enhanced our ability to identify and characterize developmental defects within the lymphatic system. As a result, a wide range of lymphatic anomalies have been uncovered, spanning from congenital abnormalities present at birth to conditions that can become life-threatening in adulthood. Additionally, recent research highlights the heterogeneity of lymphatics, revealing organ-specific developmental pathways, unique molecular markers, and specialized physiological functions specific to each organ. A deeper understanding of the unique characteristics of lymphatic cell populations in an organ-specific context is essential for guiding future research into lymphatic disease processes. An integrated approach to translational research could revolutionize personalized medicine, where treatments are precisely tailored to individual lymphatic profiles, enhancing effectiveness and minimizing side effects.

Clinical Course of Bio Naive Ulcerative Colitis Patients Five Years After Initiation of Adalimumab in a Nationwide Cohort.

Background: There is limited data on the long-term clinical outcomes of bio-naïve ulcerative colitis (UC) patients who are initiated on adalimumab (ADA). Our study aims to evaluate the clinical course of a nationwide cohort of bio naïve UC patients who were started on ADA, and then followed for 5 years after initiation of the drug. Methods: We conducted a retrospective cohort study using the US Veteran Affairs Healthcare System (VAHS). Bio naïve UC patients were followed for 5 years after initiation of ADA. The primary outcome was to determine the time to discontinuation of ADA and if patients achieved endoscopic remission by the end of follow-up. Results: A total of 387 patients were included among whom 193 (49.87%) had pancolitis. The highest rate of ADA discontinuation was within the first year, with the elderly having a higher rate of discontinuation (HR 1.67, 95% CI: 1.14-2.45) and those on concomitant immunomodulators having a lower rate of discontinuation (HR 0.70, 95% CI: 0.48-1.03). In total, 125 (32.30%) patients remained on ADA at the end of their maximum follow-up. 54 (43.90%) achieved endoscopic remission. Conclusion: Among bio-naive UC patients who were started on ADA, a third were still on the drug at the end of 5 years and half had endoscopic remission. The rate of discontinuation was highest within the first year of initiation, but patients continued to stop the drug over the course of follow-up.

Congenital Vascular and Lymphatic Diseases.

Over the past several centuries, the integration of contemporary medical techniques and innovative technologies, like genetic sequencing, have played a pivotal role in enhancing our comprehension of congenital vascular and lymphatic disorders. Nonetheless, the uncommon and complex characteristics of these disorders, especially considering their formation during the intrauterine stage, present significant obstacles in diagnosis and treatment. Here, we review the intricacies of these congenital abnormalities, offering an in-depth examination of key diagnostic approaches, genetic factors, and therapeutic methods.

ADAM9 promotes type I interferon-mediated innate immunity during encephalomyocarditis virus infection.

Viral myocarditis, an inflammatory disease of the heart, causes significant morbidity and mortality. Type I interferon (IFN)-mediated antiviral responses protect against myocarditis, but the mechanisms are poorly understood. We previously identified A Disintegrin And Metalloproteinase domain 9 (ADAM9) as an important factor in viral pathogenesis. ADAM9 is implicated in a range of human diseases, including inflammatory diseases; however, its role in viral infection is unknown. Here, we demonstrate that mice lacking ADAM9 are more susceptible to encephalomyocarditis virus (EMCV)-induced death and fail to mount a characteristic type I IFN response. This defect in type I IFN induction is specific to positive-sense, single-stranded RNA (+ ssRNA) viruses and involves melanoma differentiation-associated protein 5 (MDA5)-a key receptor for +ssRNA viruses. Mechanistically, ADAM9 binds to MDA5 and promotes its oligomerization and thereby downstream mitochondrial antiviral-signaling protein (MAVS) activation in response to EMCV RNA stimulation. Our findings identify a role for ADAM9 in the innate antiviral response, specifically MDA5-mediated IFN production, which protects against virus-induced cardiac damage, and provide a potential therapeutic target for treatment of viral myocarditis.

Endothelial cell expression of a STING gain-of-function mutation initiates pulmonary lymphocytic infiltration.

Patients afflicted with Stimulator of interferon gene (STING) gain-of-function mutations frequently present with debilitating interstitial lung disease (ILD) that is recapitulated in mice expressing the STINGV154M mutation (VM). Prior radiation chimera studies revealed an unexpected and critical role for non-hematopoietic cells in initiating ILD. To identify STING-expressing non-hematopoietic cell types required for the development of ILD, we use a conditional knockin (CKI) model and direct expression of the VM allele to hematopoietic cells, fibroblasts, epithelial cells, or endothelial cells. Only endothelial cell-targeted VM expression results in enhanced recruitment of immune cells to the lung associated with elevated chemokine expression and the formation of bronchus-associated lymphoid tissue, as seen in the parental VM strain. These findings reveal the importance of endothelial cells as instigators of STING-driven lung disease and suggest that therapeutic targeting of STING inhibitors to endothelial cells could potentially mitigate inflammation in the lungs of STING-associated vasculopathy with onset in infancy (SAVI) patients or patients afflicted with other ILD-related disorders.

Effectiveness of Tofacitinib in Patients With Ulcerative Colitis: A Nationwide Veterans Administration Cohort Study.

INTRODUCTION: There is paucity of data on the effectiveness and safety of tofacitinib among elderly patients with ulcerative colitis (UC). METHODS: Through a retrospective cohort study among the US National Veterans Affairs Healthcare System, we evaluated effectiveness among the elderly (≥65) and young (<65) patients with UC initiated on tofacitinib. RESULTS: Among 158 patients (53 elderly, 105 young), effectiveness at 12 months was 50.94% in the elderly and 33.33% in the young ( P = 0.032). DISCUSSION: In a nationwide cohort of patients with UC initiating tofacitinib, effectiveness was seen in half of the elderly patients.

Incidence of Pneumonia, Related Hospitalization, and Mortality Among Younger Unvaccinated IBD Patients in a Nationwide Cohort.

BACKGROUND AND GOALS: Community Acquired Pneumonia (CAP) is among the most common infections among Inflammatory Bowel Disease (IBD) patients. Our aim was to determine the absolute and relative risk of CAP, related hospitalization, and death among younger (age < 65) unvaccinated IBD patients exposed and unexposed to immunosuppressive medications. MATERIALS AND METHODS: We conducted a retrospective cohort study among a nationwide cohort of younger IBD unvaccinated patients in the VAHS. Exposure was administration of any immunosuppressive medication. The primary outcome was the first occurrence of pneumonia; secondary outcomes being pneumonia related hospitalization and mortality. We reported event rate per 1000 person-years, hazard ratio, and 95% confidence intervals (CIs) for each outcome. RESULTS: Among a total of 26,707 patients, 513 patients developed pneumonia. Mean age in years (SD) was 51.67 (11.34) for the exposed and 45.91 (12.34) for the unexposed group. The overall crude incidence rate was 3.2 per 1000 patient-years (PYs) [4.04/1000 PYs in the exposed versus 1.45/1000 PYs in the unexposed]. The overall crude incidence rates for pneumonia-related-hospitalization and mortality 1.12 and 0.09 per 1000 PYs, respectively. In Cox regression, the exposed group was associated with an increased risk of pneumonia (AHR 2.85; 95% CI: 2.21 to 3.66, P < 0.001) and pneumonia-related-hospitalization (AHR 3.46; 95% CI: 2.20 to 5.43, P < 0.001). CONCLUSIONS: Overall incidence of CAP among younger unvaccinated IBD patients was 3.2 per 1000 PYs. The overall associated hospitalization rates were low, however, higher amongst those exposed to immunosuppressive medications. This data will help patients and physicians make informed decisions regarding pneumococcal vaccine recommendations.

Expression of a STING Gain-of-function Mutation in Endothelial Cells Initiates Lymphocytic Infiltration of the Lungs.

Patients afflicted with STING gain-of-function mutations frequently present with debilitating interstitial lung disease ( ILD ) that is recapitulated in mice expressing the STING V154M mutation ( VM ). Prior radiation chimera studies revealed an unexpected and critical role for non-hematopoietic cells in the initiation of ILD. To identify STING-expressing non-hematopoietic cell types relevant to ILD, we generated a conditional knock-in ( CKI ) model in which expression of the VM allele was directed to hematopoietic cells, fibroblasts, epithelial cells, or endothelial cells. Only endothelial cell-targeted expression of the mutant allele resulted in the recruitment of immune cells to the lung and the formation of bronchus-associated lymphoid tissue, as seen in the parental VM strain. These findings reveal the importance of endothelial cells as instigators of STING-driven lung disease and suggest that therapeutic targeting of STING inhibitors to endothelial cells could potentially mitigate inflammation in the lungs of SAVI patients or patients afflicted with other ILD-related disorders. Summary: Patients with STING gain-of-function (GOF) mutations develop life-threatening lung autoinflammation. In this study, Gao et al. utilize a mouse model of conditional STING GOF to demonstrate a role for endothelial STING GOF in initiating immune cell recruitment into lung tissues of SAVI mice.

Impact of gut microbiome in the development and treatment of pancreatic cancer: Newer insights.

The gut microbiome plays an important role in the variation of pharmacologic response. This aspect is especially important in the era of precision medicine, where understanding how and to what extent the gut microbiome interacts with drugs and their actions will be key to individualizing therapy. The impact of the composition of the gut microbiome on the efficacy of newer cancer therapies such as immune checkpoint inhibitors and chimeric antigen receptor T-cell treatment has become an active area of research. Pancreatic adenocarcinoma (PAC) has a poor prognosis even in those with potentially resectable disease, and treatment options are very limited. Newer studies have concluded that there is a synergistic effect for immunotherapy in combination with cytotoxic drugs, in the treatment of PAC. A variety of commensal microbiota can affect the efficacy of conventional chemotherapy and immunotherapy by modulating the tumor microenvironment in the treatment of PAC. This review will provide newer insights on the impact that alterations made in the gut microbial system have in the development and treatment of PAC.

Quantitative analysis of metabolic fluxes in brown fat and skeletal muscle during thermogenesis.

Adaptive thermogenesis by brown adipose tissue (BAT) dissipates calories as heat, making it an attractive anti-obesity target. Yet how BAT contributes to circulating metabolite exchange remains unclear. Here, we quantified metabolite exchange in BAT and skeletal muscle by arteriovenous metabolomics during cold exposure in fed male mice. This identified unexpected metabolites consumed, released and shared between organs. Quantitative analysis of tissue fluxes showed that glucose and lactate provide ~85% of carbon for adaptive thermogenesis and that cold and CL316,243 trigger markedly divergent fuel utilization profiles. In cold adaptation, BAT also dramatically increases nitrogen uptake by net consuming amino acids, except glutamine. Isotope tracing and functional studies suggest glutamine catabolism concurrent with synthesis via glutamine synthetase, which avoids ammonia buildup and boosts fuel oxidation. These data underscore the ability of BAT to function as a glucose and amino acid sink and provide a quantitative and comprehensive landscape of BAT fuel utilization to guide translational studies.

Interaction between age and gender on survival outcomes in extramedullary multiple myeloma over the past two decades.

BACKGROUND: Extramedullary multiple myeloma (MM) (EMM) is a rare and aggressive subentity of MM that can be present at diagnosis or develop anytime during the disease course. There is a paucity of data on the clinical characteristics and overall epidemiology of EMM. Furthermore, there is a scarcity of data on how the interaction of age and gender influences the survival of EMM. AIM: To evaluate the clinical characteristics of patients with EMM over the past 2 decades and to identify epidemiologic characteristics that may impact overall prognosis. METHODS: A total of 858 patients diagnosed with EMM, between 2000 and 2017, were ultimately enrolled in our study by retrieving the Surveillance, Epidemiology, and End Results database. We analyzed demographics, clinical characteristics, and overall mortality (OM) as well as cancer-specific mortality (CSM) of EMM. Variables with a P value < 0.1 in the univariate Cox regression were incorporated into the multivariate Cox model to determine the independent prognostic factors, with a hazard ratio (HR) of greater than 1 representing adverse prognostic factors. RESULTS: From a sample of 858 EMM, the male gender (63.25%), age range 60-79 years (51.05%), and non-Hispanic whites (66.78%) were the most represented. Central Nervous System and the vertebral column was the most affected site (33.10%). Crude analysis revealed higher OM in the age group 80+ [HR = 6.951, 95% confidence interval (95%CI): 3.299-14.647, P = 0], Non-Hispanic Black population (HR = 1.339, 95%CI: 1.02-1.759, P = 0.036), Bones not otherwise specified (NOS) (HR = 1.74, 95%CI: 1.043-2.902, P = 0.034), and widowed individuals (HR = 2.107, 95%CI: 1.511-2.938, P = 0). Skin involvement (HR = 0.241, 95%CI: 0.06-0.974, P = 0.046) and a yearly income of $75000+ (HR = 0.259, 95%CI: 0.125-0.538, P = 0) had the lowest OM in the crude analysis. Crude analysis revealed higher CSM in the age group 80+, Non-Hispanic Black, Bones NOS, and widowed. Multivariate cox proportional hazard regression analyses only revealed higher OM in the age group 80+ (HR = 9.792, 95%CI: 4.403-21.774, P = 0) and widowed individuals (HR = 1.609, 95%CI: 1.101-2.35, P = 0.014). Multivariate cox proportional hazard regression analyses of CSM also revealed higher mortality of the same groups. Eyes, mouth, and ENT involvement had the lowest CSM in the multivariate analysis. There was no interaction between age and gender in the adjusted analysis for OM and CSM. CONCLUSION: EMM is a rare entity. To our knowledge, there is a scarcity of data on the clinical characteristics and prognosis factors of patients with extramedullary multiple myeloma. In this retrospective cohort, using a United States-based population, we found that age, marital status, and tumor site were independent prognostic factors. Furthermore, we found that age and gender did not interact to influence the mortality of patients with EMM.

Interaction between Age and Primary Site on Survival Outcomes in Primary GI Melanoma over the Past Decade.

BACKGROUND: Primary malignant melanomas of the Gastrointestinal mucosa are uncommon. Most cases of gastrointestinal (GI) melanomas are secondary, arising from metastasis at distant sites. The purpose of this study is to assess to what extent the interaction between independent prognostic factors (age and tumor site) of primary GI melanoma influence survival. Furthermore, we also aimed to investigate the clinical characteristics, survival outcomes, and independent prognostic factors of patients with primary GI melanoma in the past decade. METHODS: A total of 399 patients diagnosed with primary GI melanoma, between 2008 and 2017, were enrolled in our study by retrieving data from the Surveillance, Epidemiology, and End Results (SEER) database. We analyzed demographics, clinical characteristics, and overall mortality (OM) as well as cancer-specific mortality (CSM) of primary GI melanoma. Variables with a p value < 0.1 in the univariate Cox regression were incorporated into the multivariate Cox model (model 1) to determine the independent prognostic factors, with a hazard ratio (HR) of greater than 1 representing adverse prognostic factors. Furthermore, we analyzed the effect of the interaction between age and primary location on mortality (model 2). RESULTS: Multivariate cox proportional hazard regression analyses revealed higher OM in age group 80+ (HR = 5.653, 95% CI 2.212-14.445, p = 0), stomach location of the tumor (HR = 2.821, 95% CI 1.265-6.292, p = 0.011), regional lymph node involvement only (HR = 1.664, 95% CI 1.051-2.635, p < 0.05), regional involvement by both direct extension and lymph node involvement (HR = 1.755, 95% CI 1.047-2.943, p < 0.05) and distant metastases (HR = 4.491, 95% CI 3.115-6.476, p = 0), whereas the lowest OM was observed in patients with small intestine melanoma (HR = 0.383, 95% CI 0.173-0.846, p < 0.05). Multivariate cox proportional hazard regression analyses of CSM also revealed higher mortality of the same groups and lower CSM in small intestine and colon melanoma excluding the rectum. For model 2, considering the interaction between age and primary site on mortality, higher OM was found in age group 80+, followed by age group 40-59 then age group 60-79, regional lymph node involvement only, regional involvement by both direct extension and lymph node involvement and distant metastases. The small intestine had a lower OM. The rectum as primary location and the age range 40-59 interacted to lower the OM (HR = 0.14, 95% CI 0.02-0.89, p = 0.038). Age and primary gastric location did not interact to affect the OM. For the CSM, taking into account the interaction between age and the primary location, higher mortality was found in the same groups and the colon location. The primary colon location also interacted with the age group 40-59 to increase the CSM (HR = 1.38 × 109, 95% CI 7.80 × 107-2.45 × 1010, p = 0). CONCLUSIONS: In this United States population-based retrospective cohort study using the SEER database, we found that only the age range 40-59 interacted with the rectum and colon to lower and increase mortality respectively. Primary gastric location, which was the single most important location to affect mortality, did not interact with any age range to influence mortality. With those results, we hope to shed some light on this rare pathology with a very dismal prognosis.

Pathological MAPK activation-mediated lymphatic basement membrane disruption causes lymphangiectasia that is treatable with ravoxertinib.

Lymphangiectasia, an anomalous dilation of lymphatic vessels first described in the 17th century, is frequently associated with chylous effusion, respiratory failure, and high mortality in young patients, yet the underlying molecular pathogenesis and effective treatments remain elusive. Here, we identify an unexpected causal link between MAPK activation and defective development of the lymphatic basement membrane that drives lymphangiectasia. Human pathological tissue samples from patients diagnosed with lymphangiectasia revealed sustained MAPK activation within lymphatic endothelial cells. Endothelial KRASG12D-mediated sustained MAPK activation in newborn mice caused severe pulmonary and intercostal lymphangiectasia, accumulation of chyle in the pleural space, and complete lethality. Pathological activation of MAPK in murine vasculature inhibited the Nfatc1-dependent genetic program required for laminin interactions, collagen crosslinking, and anchoring fibril formation, driving defective development of the lymphatic basement membrane. Treatment with ravoxertinib, a pharmacological inhibitor of MAPK, reverses nuclear-to-cytoplasmic localization of Nfatc1, basement membrane development defects, lymphangiectasia, and chyle accumulation, ultimately improving survival of endothelial KRAS mutant neonatal mice. These results reveal defective lymphatic basement membrane assembly and composition as major causes of thoracic lymphangiectasia and provide a potential treatment.

A Rare Case of Junctional Bradycardia Secondary to Oral Phenytoin.

Phenytoin is a commonly used anti-seizure agent, which stabilizes neuronal membranes by blocking voltage-gated sodium channels to inhibit the propagation of action potentials during convulsions. However, phenytoin has also been shown to have antiarrhythmic effects as it can prolong the effective refractory period of ventricular pacemaker cells. Adverse cardiac effects such as junctional bradycardia are usually seen with intravenous use. Cardiovascular dysfunction is not well recognized in oral phenytoin toxicity. Here we present a case of junctional bradycardia due to oral phenytoin toxicity, which resolved spontaneously with the discontinuation of phenytoin. This case report will serve to increase awareness of the adverse cardiovascular effects of oral phenytoin toxicity to improve the recognition and treatment of these adverse effects.

Safety of Recombinant Zoster Vaccine in Patients with Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Patients with inflammatory bowel disease [IBD] have an increased risk of contracting herpes zoster [HZ] infection. However, vaccination rates for HZ are low among IBD patients. A contributing factor may be fear of an IBD flare associated with vaccination. Our aim here was to evaluate if recombinant zoster vaccine [RZV] is associated with an IBD flare. METHODS: This was a retrospective cohort study using data from the Veterans Affairs Healthcare System [VAHS]. The exposure of interest was receiving RZV. We randomly matched such exposed patients with unexposed individuals. The primary outcome was the first episode of IBD flare within 90 days of the index date. Baseline characteristics were compared between groups using a t-test for continuous variables and Chi-square test for categorical variables. Conditional logistic regression was used to estimate the odds ratio [OR] and 95% confidence interval [CI]. RESULTS: Among the eligible study cohort, 1677 patients received RZV. Thirty-six patients, 20 in the exposed group and 16 in the unexposed group, had a confirmed flare by chart review. The 90-day cumulative incidence of IBD flare was not different between the vaccinated and unvaccinated groups [1.2% among those exposed vs 1.0% among those unexposed, p = 0.503]. The OR for IBD flare associated with RZV vaccination was 1.25 [95% CI: 0.65-2.41]. CONCLUSION: In a nationwide cohort of stable IBD patients, administration of RZV was not associated with the risk of IBD flare within 90 days. These findings should motivate further use of this highly effective vaccine.