Evolution of HIV Health Care Workforce Needs in the U.S. Mountain West During the COVID-19 Pandemic: A Mixed Method Study.

ABSTRACT: The COVID-19 pandemic drastically affected health care delivery for vulnerable populations. Many facilities shifted services to telemedicine, and people with HIV or at risk of acquiring HIV experienced interruptions in care. Simultaneously, traditional training approaches to help providers adapt were disrupted. Using a mixed method approach to examine changes over time, we integrated data on trainee needs collected by the Mountain West AIDS Education and Training Center (AETC): a 10-state needs assessment survey in 2020; feedback from a 2020 community of practice; aggregate training data from 2000 to 2022; and a second survey in 2022. HIV care providers' training needs evolved from wanting support on telemedicine and COVID-19 patient care issues, to a later focus on mental health and substance use, social determinants of health, and care coordination. This integrative analysis demonstrates the vital role that AETCs can play in addressing evolving and emergent public health challenges for the HIV workforce.

Facilitators and barriers to adopting or expanding medications for opioid use disorder provision in rural Colorado jails: a qualitative analysis.

BACKGROUND: Opioid use disorder (OUD) is common among individuals who are incarcerated. However, OUD treatment services are sparse in smaller county jails found in many rural areas, which limits a healthy and supportive jail environment. This study assesses the facilitators of and barriers to medications for opioid use disorder (MOUD) adoption or expansion in rural Colorado jails. A qualitative descriptive design was implemented during the summer of 2022 using semi-structured interviews with jail staff, sheriffs, and contracted personnel. Interview questions focused on facilitators of existing MOUD services and barriers to adopting or expanding services. To identify the facilitators and barriers, data were coded using thematic analysis. RESULTS: Seven jails were included in the study. Representatives from each jail participated in the seven interviews, which often included multiple participants per interview. Three of the jails had established routine practices for MOUD administration. Two jails occasionally administered MOUD or had plans in place to be able to administer, while the remaining two did not offer any MOUD. While administrative support, collaborative partnerships, and jail nurses facilitated MOUD use, barriers were more prevalent, including physical space limitations, distance to services, lack of providers in the area, staffing and training issues, funding/budget issues, and perceived risk of diversion. CONCLUSION: Making MOUD available to people who are incarcerated is an important and timely step in enhancing the jail environment, especially in rural areas that often lack access to MOUD. As states look to require MOUD availability for people who are incarcerated, facilitators to MOUD adoption/expansion can be leveraged while strategies are needed to overcome barriers.

Best Practices for Telehealth in Nurse-Led Care Settings-A Qualitative Study.

The COVID-19 pandemic in the US prompted a sudden shift to telehealth in nurse-led care sites which provide services to diverse geolocations. Using a lens of intersectionality, this study characterizes provider and patient-perceived best and promising practices emerging from geographical variation. The aim of this study was to identify best practices of implementing telehealth in nurse-led care models in Colorado through patient and provider experiences of the sudden implementation of telehealth that can enhance health equity. In this exploratory/descriptive qualitative study, a purposive sample of 18 providers and 30 patients were interviewed using a guide informed by the RE-AIM implementation and evaluation framework to capture the contextual experiences related to the sudden shift to telehealth. Textual theme analysis and reflexive team strategies guided the interpretation. Four primary themes of perceived best practices were identified: using multiple modalities, tailoring triage and scheduling, cultivating safety through boundaries and expectations, and differentiating established versus new patient relationships. The findings suggest that telehealth is a flexible and powerful tool to enhance the delivery of equitable care through nurse-led care models within diverse communities such as the one represented in this study. Nurse leaders are positioned to participate in innovative research and create policies and protocols to ensure telehealth is a viable resource to deliver equitable, safe, and accessible high-quality healthcare.

Perinatal Telehealth: Meeting Patients Where They Are.

INTRODUCTION: Prior to the coronavirus disease 2019 (COVID-19) pandemic, studies of innovative telehealth perinatal care models showed similar clinical outcomes and perceived quality of care between groups receiving a combination of virtual video and in-person visits. However, these studies included primarily White, English-speaking participants, excluding those who were economically disenfranchised or did not speak English. The purpose of this qualitative study was to describe perinatal patients' and providers' experiences with telehealth during and after the acute phase of the COVID-19 pandemic to inform future utilization of telehealth to drive the delivery of high-quality, accessible, and equitable perinatal care to diverse communities. METHODS: This descriptive qualitative study included a purposive sample of 14 patients and 17 providers who received or provided perinatal care via telehealth in either a certified nurse-midwifery practice or the nurse-family partnership care model between March 2020 and April 2022. Maximum variation sampling offered a diverse population based on race, ethnicity, and rurality. Researchers conducted 2 rounds of semistructured interviews with a focus on understanding social and geographic context. RESULTS: Six themes were identified through inductive analysis: (1) unexpected advantages of telehealth, (2) patient empowerment, (3) providers' fear of adverse outcomes, (4) concern for equitable care, (5) strategies to enhance the telehealth experience, and (6) strategies to address access to perinatal telehealth. Patients appreciated the increased ease and reduced cost of accessing visits, which led to fewer missed appointments. Health care providers saw great opportunity in telehealth but expressed concerns about accessibility for patients with language barriers or limited resources. DISCUSSION: This study provides insight into priorities for continued telehealth utilization focused on providing equitable access to perinatal care. Rather than returning to practices from before the COVID-19 pandemic formed from longstanding routines and perceived limitations, providers are encouraged to capitalize on the rapid innovations in telehealth to build a more effective, equitable, and patient-centered approach to perinatal care.

Patient and Provider Perceptions of COVID-19-Driven Telehealth Use From Nurse-Led Care Models in Rural, Frontier, and Urban Colorado Communities.

The purpose of this study was to characterize the patient and provider engagement in the sudden telehealth implementation that occurred with the onset of the COVID-19 pandemic. Patients and providers from 3 nurse-led models of care (federally qualified health centers, nurse midwifery practices, and the Nurse-Family partnership program) in Colorado were surveyed. Data from the Patient Attitude toward Telehealth survey and Provider Perceptions about Telehealth were collected. Patient respondents (n = 308) who resided primarily in rural or frontier communities were female, white, and Hispanic. Patients in urban areas used telehealth more frequently than in rural or frontier areas (P < .001). Rural/Frontier patients had significantly lower attitude scores than urban patients across each of 5 domains assessed. Telehealth modality differed across location (P < .023), with video calls, used more frequently by urban providers, and phone calls used by rural/frontier providers. Our data highlight differences in telehealth access and attitudes across rurality. These findings may contribute to future policy while addressing barriers to telehealth access and delivery.

Effects of a QI intervention on pediatric asthma treatment using patient outcomes and workflow in an emergency department.

OBJECTIVE: Evaluate a nurse-initiated quality improvement (QI) intervention aimed at enhancing asthma treatment in a pediatric emergency department (ED), utilizing outcomes and workflow. METHODS: We evaluated the impact of QI interventions for pediatric patients presenting to the ED with asthma with pre-post analysis. A pediatric asthma score (PAS) of >8 indicated moderate to severe asthma. This secondary analysis of the electronic health record (EHR), evaluated on 1) patient outcomes (time to clinical treatment, ED length of stay [EDLOS], admissions and discharges home), 2) clinical workflow. RESULTS: We compared 886 visits occurring between 01/01/2015 and 09/27/2015 (pre-implementation period) with 752 visits between 01/01/2016 and 09/27/2016 (post-implementation). Time to first documentation of PAS was decreased post-intervention (p<.001) by >30 min (75 ± 57 to 39 ± 54 min). There were significant decreases in time to treatment with both steroid and bronchodilator administration (both p<.001). EDLOS did not significantly change. Based on acuity level, those discharged home from the ED with high acuity (PAS score ≥8), had a significant decrease in time to initial PAS, steroid and bronchodilator use and EDLOS. Of those with high acuity who were admitted to the hospital, there was a difference pre- to post-implementation, in time to first PAS (p<.05), but not to treatment. Workflow visualization provided additional insights and detailed (task level) comparisons of the timing of ED activities. CONCLUSIONS: Nurse-initiated ED interventions, can significantly improve the timeliness of pediatric asthma evaluation and treatment. Examining workflow along with the outcomes, can better inform QI evaluations and clinical management.

Preventing intimate partner violence among foreign-born Latinx mothers through relationship education during nurse home visiting.

AIMS: This study aimed to examine the effectiveness of an augmented home visiting programme in preventing intimate partner violence among Latinx mothers by nativity. BACKGROUND: Intimate partner violence diminishes home visit programmes' effectiveness. Immigrant Latinx mothers are especially vulnerable and need culturally tailored prevention. METHODS: We performed secondary analyses of 33 US-born and 86 foreign-born Latinx mothers at baseline and 1- and 2-year follow-up in a longitudinal randomized controlled trial of the Nurse-Family Partnership programme augmented with nurse-delivered Within My Reach relationship education curriculum and violence screening and referrals in Oregon. We estimated proportional odds models via generalized estimating equations on total physical and sexual victimization and/or perpetration forms (an ordinal variable), adjusting for intervention, wave, age and education. RESULTS: The intervention-nativity interaction was not significant (p = .953). Foreign-born status was associated with lower reported violence at baseline (adjusted odds ratio: 0.29, 95% confidence interval: 0.13-0.67, p = .004). This association was marginally significant at 1-year follow-up (0.43, 0.17-1.08, p = .072) and not significant at 2-year follow-up (0.75, 0.33-1.67, p = .475). CONCLUSIONS: This augmented programme was not effective for Latinx mothers by nativity. Their nativity gap diminished over time. IMPLICATIONS FOR NURSING MANAGEMENT: Nursing leaders should support culturally tailored home visiting programmes to detect and prevent intimate partner violence affecting Latinx immigrants. CLINICAL TRIAL REGISTRATION: This study is registered at www. CLINICALTRIALS: gov NCT01811719. The full trial protocol can be accessed at https://clinicaltrials.gov/ct2/show/NCT01811719.

Outcomes from the medication assisted treatment pilot program for adults with opioid use disorders in rural Colorado.

BACKGROUND: As Colorado ranked among the top nationally in non-medical use of opioids, a pilot medication for opioid use disorder (MOUD) program was developed to increase the number of NPs and PAs providing MOUD in order to bring this evidence- based treatment to 2 counties showing disproportionally high opioid overdose deaths. Over the first 18 months, the MOUD Pilot Program led to 15 new health care providers receiving MOUD waiver training and 1005 patients receiving MOUD from the 3 participating organizations. Here we evaluate patient centered clinical and functional outcomes of the pilot MOUD program implemented in 2 rural counties severely affected by the opioid crisis. METHODS: Under state-funded law (Colorado Senate Bill 17-074), three rural agencies submitted de-identified patient-level data at baseline (N = 1005) and after 6 months of treatment (N = 190, 25%) between December 2017 and January 2020. The Addiction Severity Index, PhQ9 and GAD-7 with McNemar-Bowker, and Wilcoxon Signed Rank tests analysis were used to measure patient outcomes across after participation in the program. . RESULTS: Patients in treatment reported using less heroin (52.1% vs 20.4%), opioids (22.3% vs 11.0%), and alcohol (28.6% vs 13.1%, all P < 0.01). Patients reported improved health (53.4% vs. 68.2%, P = 0.04), less frequency of disability (8.69 vs. 6.51, P = 0.02), symptoms (29.8% vs 21.3%), pain (67.5% to 53.6), worry (45.3% vs 62.3%), anxiety (49.7% vs 23.2%), depression (54.1% vs 23.3%, all P < 0.02) after treatment. CONCLUSIONS: This study shows decreased substance use, improved physical and mental health, and reduced symptoms after 6 months of MOUD. Although more research on retention and long-term effects is needed, data shows improved health outcomes after 6 months of MOUD. Lessons learned from implementing this pilot program informed program expansion into other rural areas in need to address some of Colorado' major public health crises.

Multicenter Study Evaluating Nitrous Oxide Use for Labor Analgesia at High- and Low-Altitude Institutions.

BACKGROUND: Nitrous oxide (N2O) has been used nationally as an analgesic in many clinical settings. While neuraxial analgesia is still the most commonly used labor analgesic in the United States, there is increasing use of N2O in labor. Given the reduction in the partial pressure of gases at a higher altitude, N2O has been reported to have reduced analgesic properties. However, there is no study to date evaluating the impact of altitude on labor analgesia and N2O. METHODS: We conducted a multicenter retrospective data analysis of a N2O registry collected from 4 institutions over a 3-year period. We compared the impact of altitude on 50% N2O administration for labor analgesia, conversion rates to another analgesic modality, as well as collected side effect frequencies and conversion predictors. Multivariable regression models were used to compare clinical characteristics and outcomes between parturients at high and low altitudes, while adjusting for race, ethnicity, education, and age (logistic and linear regressions for categorical and quantitative outcomes, respectively). RESULTS: A total of 1856 laboring parturients (age 18-50) were included in the analysis. The odds of converting from 50% N2O to another analgesic modality had no statistically significant difference between high- versus low-altitude institutions (adjusted odds ratio [aOR], 1.13; 95% confidence interval [CI], 0.90-1.42; P = .3). Yet, when parturients at low altitude converted from N2O, they were more likely (aOR, 3.03; 95% CI, 1.59-5.88) to choose neuraxial analgesia instead of another analgesic modality when compared to high-altitude parturients. This is possibly due to higher epidural rates at the low-altitude institutions. When parturients at high altitude did convert into another modality, they were more likely (aOR, 2.19; 95% CI, 1.14-4.21) to convert due to inadequate pain relief compared to low-altitude parturients; however, missing data may have affected this finding. Laboring individuals at low altitude were significantly more likely to experience side effects (aOR, 2.13; 95% CI, 1.45-3.12). Those requiring labor augmentation, assisted vaginal, or cesarean delivery converted to neuraxial analgesia significantly more often than those that delivered via spontaneous vaginal delivery (P < .05) in both high- and low-altitude groups. CONCLUSIONS: This is the first study evaluating 50% N2O as a labor analgesic at high altitude. As expected, we found lower side effects at high altitude, likely due to the lower partial pressure of N2O. However, there was not a statistically significant increase in conversion from N2O to another analgesic modality at high altitude and no clinically significant differences in neonatal outcomes.

Analysis of medication patterns for pediatric asthma patients in emergency department: Does the sequence placement of glucocorticoids administration matter?

Objectives: Timely glucocorticoid administration is associated with decreased admission rate and is thus a common quality metric for ED asthma care; less is known about the impact of the timing of glucocorticoids in the context of the sequence of asthma medications administered. Therefore, we investigated the distribution of asthma medication sequences in one ED and analyzed the effect of the sequence placement of glucocorticoids administration on treatment outcomes.Methods: A retrospective study using five-year electronic health record data obtained from an academic urban children's hospital ED was conducted. We clustered the sequences of medication administration using an exact string-matching algorithm to identify the most frequently used asthma medication sequences. Then, we used the identified patterns to perform statistical tests to examine the effect of the sequence placement of glucocorticoids administration on the outcomes length-of-stay and ED disposition.Results: A total of 4,844 encounters were included in our study. The ten most common treatment sequences accounted for 43% of all encounters. Stratified analyses confirmed that treatment sequences pattern was correlated with patient severity, but ED crowding does not impact treatment sequences. In multivariable models, glucocorticoids administration earlier in the treatment sequence was associated with shorter length of stay and lower hospital admission rates.Conclusions: By analyzing medication sequence patterns for the ED encounter of pediatric asthma, we found that the earlier sequence placement of glucocorticoids administration is associated with improved outcomes. Our findings can help inform quality improvement and clinical guideline development related to ED asthma care for children.

Inconsistency in Faculty and Student Perceptions of DNP and PhD Leader Scholarly Activity.

OBJECTIVE: We aimed to quantify faculty and student perceptions of scholarly activities for doctor of nursing practice (DNP) and PhD leaders. BACKGROUND: The American Association of Colleges of Nursing describes DNP as a practice-focused degree and PhD as a research-focused degree. In 2016, the Council on Graduate Education for Administration in Nursing (now Association for Leadership Science in Nursing) published in the Journal of Nursing Administration sample practice objectives for DNP and research objectives for PhD leaders. METHODS: Using the published objectives, we surveyed faculty and students to quantify congruence with the publication and consistency within groups. The data informed intraprofessional education constructed using action research. RESULTS: There was low congruence between faculty and student responses with the article. PhD faculty had the least, and PhD students, the greatest, consistency in survey responses. CONCLUSIONS: Confusion exists within our faculty and students around differentiating PhD and DNP scholarly activities. Data supported need to clarify scholarly role boundaries through intraprofessional education.

From policy to practice: Pilot program increases access to medication for opioid use disorder in rural Colorado.

Medication for opioid use disorder (MOUD) is an important approach to address the opioid crisis, but rural areas have limited access to MOUD. In 2016, Nurse Practitioners (NPs) and Physician Assistants (PAs) became eligible to prescribe buprenorphine. Local and state stakeholders in Colorado, including clinicians, policymakers, law enforcement, and patient advocates, formed a collaborative to develop legislative policy and programs for the opioid epidemic. A pilot MOUD program was developed in 2017 to increase the number of NPs and PAs providing MOUD and to increase access to MOUD in 2 counties with high opioid overdose rates. A central coordinating site selected 3 clinical agencies through an open call for proposals, with review of applications by nursing faculty experts and a community advisory board. We then monitored the number of waivered providers and patients served in targeted counties. Providers at pilot program sites tracked costs, community-level barriers, facilitators of success via monthly reports. Sites were funded for 18 months. Seven MOUD providers were added in County 1, a 350% increase compared to the prior year, and there are now 8 MOUD providers in County 2 where there were previously none. County 1 increased MOUD services from 99 clients in 2017 to 582 in 2018 and 317 during the first half of 2019. County 2 provided MOUD services for 60 new clients in 2018 and 46 in the first half of 2019. Cognitive-behavioral therapy, family therapy, and other approaches were used to increase patient engagement and days without opioid use. Successes included community outreach, referral networks, and provider education to reduce stigma. Barriers to sustainability included 1) reimbursement, 2) stigma, and 3) coordination with hospitals. Policy efforts, legislation, and academic-community collaboration led to an increase in MOUD providers and patients served in rural counties severely affected by the opioid crisis.

Correlates of Physical Activity and Sedentary Behaviors Among Overweight Hispanic School-aged Children.

PURPOSE: The purpose of this study was to explore potential correlates of physical activity and sedentary screen time behaviors among overweight Hispanic school-aged children, ages 7 to 14years. DESIGN AND METHODS: We conducted an exploratory correlation analysis using baseline data of 40 child-parent dyads from the "Mind Exercise Nutrition Do It!" program conducted in the Western United States. RESULTS: Child self-esteem and parental vegetable intake were moderately associated with physical activity, while parental vegetable intake and child fruit intake were strongly associated with physical activity among males. Physical activity was not significantly associated with body mass index percentile, sedentary screen time behaviors, or body esteem. Only decreased body esteem in males was correlated with sedentary screen time behaviors. CONCLUSIONS AND PRACTICE IMPLICATIONS: Understanding the correlates of physical activity and sedentary screen time behaviors in this underrepresented population allows nurses to better understand the connections between physical activity and other aspects of well-being in children. Further investigation is needed to determine how these relationships can be incorporated into physical activity interventions that improve the health of overweight Hispanic school-aged children.

Renal ischemia-reperfusion injury amplifies the humoral immune response.

Renal transplant recipients who experience delayed graft function have increased risks of rejection and long-term graft failure. Ischemic damage is the most common cause of delayed graft function, and although it is known that tissue inflammation accompanies renal ischemia, it is unknown whether renal ischemia affects the production of antibodies by B lymphocytes, which may lead to chronic humoral rejection and allograft failure. Here, mice immunized with a foreign antigen 24-96 hours after renal ischemia-reperfusion injury developed increased levels of antigen-specific IgG1 compared with sham-treated controls. This amplified IgG1 response did not follow unilateral ischemia, and it did not occur in response to a T-independent antigen. To test whether innate immune activation in the kidney after ischemia affects the systemic immune response to antigen, we repeated the immunization experiment using mice deficient in factor B that lack a functional alternative pathway of complement. Renal ischemia-reperfusion injury did not cause amplification of the antigen-specific antibodies in these mice, suggesting that the increased immune response requires a functional alternative pathway of complement. Taken together, these data suggest that ischemic renal injury leads to a rise in antibody production, which may be harmful to renal allografts, possibly explaining a mechanism underlying the link between delayed graft function and long-term allograft failure.

Complement activation and toll-like receptor-2 signaling contribute to cytokine production after renal ischemia/reperfusion.

The innate immune system causes tissue inflammation and injury after renal ischemia/reperfusion (I/R). The complement system is activated on ischemic tubular epithelial cells (TECs) and induces the cells to produce pro-inflammatory chemokines. TECs also express toll-like receptors (TLRs)-2 and -4. Signaling through the TLRs induces TECs to produce a variety of chemokines, some of which can also be induced by complement activation fragments. We sought to determine whether the effects of complement activation and TLR signaling in TECs are redundant, or whether additive protection can be achieved by blocking both of these innate immune systems. To confirm that the complement system, TLR-2 signaling, and TLR-4 signaling induce production of a similar repertoire of inflammatory chemokines, we stimulated TECs with complement sufficient serum or with TLR-2 and TLR-4 ligands in vitro. We found that all three of these stimuli induce TECs to produce KC, MIP-2, IL-6, and TNF-α, and that there was a trend toward greater production of KC in cells exposed to two stimuli. Based upon these results, we hypothesized that mice deficient in both complement activation and TLR-2 signaling would demonstrate greater protection from I/R than mice deficient only in the complement system. To test this hypothesis we induced ischemic acute kidney injury (AKI) in wild-type mice, mice with targeted deletion of complement factor B (fB(-/-) mice), or mice with targeted deletion of factor B and TLR-2 (fB(-/-)TLR2(-/-) mice). Surprisingly, we found that fB(-/-)TLR2(-/-) mice developed more severe injury than those with single deficiency of factor B. Our results indicate that blockade of the complement system may be more protective than simultaneous blockade of both the complement system and TLR-2 in ischemic AKI.

B cell subsets contribute to renal injury and renal protection after ischemia/reperfusion.

Ischemia/reperfusion (I/R) triggers a robust inflammatory response within the kidney. Numerous components of the immune system contribute to the resultant renal injury, including the complement system. We sought to identify whether natural Abs bind to the postischemic kidney and contribute to complement activation after I/R. We depleted peritoneal B cells in mice by hypotonic shock. Depletion of the peritoneal B cells prevented the deposition of IgM within the glomeruli after renal I/R and attenuated renal injury after I/R. We found that glomerular IgM activates the classical pathway of complement, but it does not cause substantial deposition of C3 within the kidney. Furthermore, mice deficient in classical pathway proteins were not protected from injury, indicating that glomerular IgM does not cause injury through activation of the classical pathway. We also subjected mice deficient in all mature B cells (µMT mice) to renal I/R and found that they sustained worse renal injury than wild-type controls. Serum IL-10 levels were lower in the µMT mice. Taken together, these results indicate that natural Ab produced by peritoneal B cells binds within the glomerulus after renal I/R and contributes to functional renal injury. However, nonperitoneal B cells attenuate renal injury after I/R, possibly through the production of IL-10.

The complement inhibitors Crry and factor H are critical for preventing autologous complement activation on renal tubular epithelial cells.

Congenital and acquired deficiencies of complement regulatory proteins are associated with pathologic complement activation in several renal diseases. To elucidate the mechanisms by which renal tubular epithelial cells (TECs) control the complement system, we examined the expression of complement regulatory proteins by the cells. We found that Crry is the only membrane-bound complement regulator expressed by murine TECs, and its expression is concentrated on the basolateral surface. Consistent with the polarized localization of Crry, less complement activation was observed when the basolateral surface of TECs was exposed to serum than when the apical surface was exposed. Furthermore, greater complement activation occurred when the basolateral surface of TECs from Crry(-/-)fB(-/-) mice was exposed to normal serum compared with TECs from wild-type mice. Complement activation on the apical and basolateral surfaces was also greater when factor H, an alternative pathway regulatory protein found in serum, was blocked from interacting with the cells. Finally, we injected Crry(-/-)fB(-/-) and Crry(+/+)fB(-/-) mice with purified factor B (an essential protein of the alternative pathway). Spontaneous complement activation was seen on the tubules of Crry(-/-)fB(-/-) mice after injection with factor B, and the mice developed acute tubular injury. These studies indicate that factor H and Crry regulate complement activation on the basolateral surface of TECs and that factor H regulates complement activation on the apical surface. However, congenital deficiency of Crry or reduced expression of the protein on the basolateral surface of injured cells permits spontaneous complement activation and tubular injury.

Liver cyst cytokines promote endothelial cell proliferation and development.

Autosomal dominant polycystic kidney (ADPKD) is highly prevalent genetic disease. Liver cyst disease is the most common extrarenal manifestation in ADPKD and accounts for up to 10% of ADPKD morbidity and mortality. The clinical features of ADPKD liver disease arise from dramatic increases in liver cyst volumes. To identify mechanisms that promote liver cyst growth, the present study characterized the degree of vascularization of liver cyst walls and determined that cyst-specific cytokines and growth factors can drive endothelial cell proliferation and development. Microscopic techniques demonstrated liver cyst walls are well vascularized. A comparative analysis found the vascular density in free liver cyst walls was greater in mice than in humans. Treatment of human micro-vascular endothelial cells (HMEC-1) with human liver cyst fluid (huLCF) induced a rapid increase in vascular endothelium growth factor receptor 2 (VEGFR2) phosphorylation that persisted for 45-60 min and was blocked by 20 microM SU5416, a VEGFR tyrosine kinase inhibitor. Similarly, huLCF treatment of HMEC-1 cells induced an increase in the cell proliferation rate (131 +/- 6% of control levels; P > 0.05) and the degree of vascular development ('tube' diameter assay: 92 +/- 14 microm for huLCF vs. 12 +/- 7 microm for vehicle); P > 0.05). Both cell proliferation and vascular development were sensitive to SU5416. These studies indicate that factors secreted by liver cyst epithelia can activate VEGF signaling pathways and induce endothelial cell proliferation and differentiation. The present studies suggest that targeting VEGFR2-dependent angiogenesis may be an effective therapeutic strategy in blocking ADPKD liver cyst vascularization and growth.

CXCR2 agonists in ADPKD liver cyst fluids promote cell proliferation.

Autosomal dominant polycystic kidney disease (ADPKD) is a highly prevalent genetic disease that results in cyst formation in kidney and liver. Cytokines and growth factors secreted by the cyst-lining epithelia are positioned to initiate autocrine/paracrine signaling and promote cyst growth. Comparative analyses of human kidney and liver cyst fluids revealed disparate cytokine/growth factor profiles. CXCR2 agonists, including IL-8, epithelial neutrophil-activating peptide (ENA-78), growth-related oncogene-alpha (GRO-alpha), are potent proliferative agents that were found at high levels in liver but not kidney cyst fluids. Liver cysts are lined by epithelial cells derived from the intrahepatic bile duct (i.e., cholangiocytes). In polarized pkd2(WS25/-) mouse liver cyst epithelial monolayers, CXCR2 agonists were released both apically and basally, indicating that they may act both on the endothelial and epithelial cells within or lining the cyst wall. IL-8 and human liver cyst fluid induced cell proliferation of HMEC-1 cells, a human microvascular endothelial cell line, and Mz-ChA1 cells, a human cholangiocyte cell model. IL-8 expression can be regulated by specific stresses. Hypoxia and mechanical stretch, two likely stressors acting on the liver cyst epithelia, significantly increased IL-8 secretion and promoter activity. AP-1, c/EBP, and NF-kappaB were required but not sufficient to drive the stress-induced increase in IL-8 transcription. An upstream element between -272 and -1,481 bp allowed for the stress-induced increase in IL-8 transcription. These studies support the hypothesis that CXCR2 signaling promotes ADPKD liver cyst growth.