A novel pH-sensitive liposome formulation containing oleyl alcohol

AbstractpH-sensitive liposomes are designed to undergo acid-triggered destabilization. First generation pH-sensitive liposomes, based on the cone-shaped lipid dioleoylphosphatidylethanolamine (DOPE), have been shown to lose fusogenicity in the presence of serum. Here, we report the design and evaluation of novel serum-resistant pH-sensitive liposome formulations that are based on the composition of egg phosphatidylcholine (PC), cholesteryl hemisuccinate (CHEMS), oleyl alcohol (OAlc), and Tween-80 (T-80). When loaded with the fluorescent probe calcein, these liposomes exhibited excellent stability at pH 7.4 and underwent rapid destabilization upon acidification as shown by calcein dequenching and particle size increase. Adjusting the mole percentages of T-80 and OAlc in the formulation could regulate the stability and pH-sensitive properties of these liposomes. Liposomes with a higher T-80 content exhibited greater stability but were less sensitive to acid-induced destabilization. Meanwhile, formulations with a higher OAlc content exhibited greater content release in response to low pH. The pH-triggered liposomal destabilization did not produce membrane fusion according to an octadecylrhodamine B chloride (R18) lipid-mixing assay. Compared to DOPE-based pH-sensitive liposomes, the above formulations showed much better retention of their pH-sensitive properties in the presence of 10% serum. These liposomes were then evaluated for intracellular delivery of entrapped cytosine-β-d-arabinofuranoside (araC) in KB human oral cancer cells, which have elevated folate receptor (FR) expression. The FR, which is amplified in many types of human tumors, has been shown to mediate the internalization of folate-derivatized liposomes into an acidic intracellular compartment. FR-targeted OAlc-based pH-sensitive liposomes, entrapping 200 mM araC, showed ∼17-times greater FR-dependent cytotoxicity in KB cells compared to araC delivered via FR-targeted non-pH-sensitive liposomes. These data indicated that pH-sensitive liposomes based on OAlc, combined with FR-mediated targeting, are promising delivery vehicles for membrane impermeable therapeutic agents

The COVID-19 Pandemic Identifies Significant Global Inequities in Hemodialysis Care in Low and Lower-Middle Income Countries-An ISN/DOPPS Survey

INTRODUCTION It is unknown how the COVID-19 pandemic has affected the care of vulnerable chronic hemodialysis (HD) patients across regions, particularly in low and lower-middle income countries (LLMICs). We aimed to identify global inequities in HD care delivery during the COVID-19 pandemic. METHODS The ISN and the Dialysis Outcomes and Practice Patterns Study (DOPPS) conducted a global online survey of HD units between March and November, 2020, to ascertain practice patterns and access to resources relevant to HD care during the COVID-19 pandemic. Responses were categorized according to World Bank income classification for comparisons. RESULTS Surveys were returned from 412 facilities in 78 countries: 15 (4%) in low-income countries (LICs), 111 (27%) in lower-middle income countries (LMICs), 145 (35%) in upper-middle income countries (UMICs), and 141 (34%) in high-income countries (HICs). Respondents reported that diagnostic tests for SARS-CoV-2 were unavailable or of limited availability in LICs (72%) and LMICs (68%) as compared with UMICs (33%) and HICs (20%). The number of patients who missed HD treatments was reported to have increased during the COVID-19 pandemic in LICs (64%) and LMICs (67%) as compared with UMICs (31%) and HICs (6%). Limited access to HD, intensive care unit (ICU) care, and mechanical ventilation among hospitalized patients on chronic dialysis with COVID-19 were also reportedly higher in LICs and LMICs as compared with UMICs and HICs. Staff in LLMICs reported less routine testing for SARS-CoV-2 when asymptomatic as compared with UMICs and HICs-14% in LICs and 11% in LMICs, compared with 26% and 28% in UMICs and HICs, respectively. Severe shortages of personal protective equipment (PPE) were reported by the respondents from LICs and LMICs compared with UMICs and HICs, especially with respect to the use of the N95 particulate-air respirator masks. CONCLUSION Striking global inequities were identified in the care of chronic HD patients during the pandemic. Urgent action is required to address these inequities which disproportionately affect LLMIC settings thereby exacerbating pre-existing vulnerabilities that may contribute to poorer outcomes

Prescription of reninâ angiotensinâ aldosterone system inhibitors (RAASi) and its determinants in patients with advanced CKD under nephrologist care

Reninâ angiotensinâ aldosterone system inhibitors (RAASi) are recommended for chronic kidney disease (CKD) patients. In this study, we describe RAASi prescription patterns in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) in Brazil, Germany, France, and the United States (US). 5870 patients (mean age 66â 72 years; congestive heart failure [CHF] in 11%â 19%; diabetes in 43%â 54%; serum potassium â ¥5 in 20%â 35%) were included. RAASi prescription was more common in Germany (80%) and France (77%) than Brazil (66%) and the United States (52%), where the prevalence of prescription decreases particularly in patients with CKD stage 5. In the multivariable regression model, RAASi prescription was least common in the United States and more common in patients who were younger, had diabetes, hypertension, or less advanced CKD. In conclusion, RAASi prescription patterns vary by country, and by demographic and clinical characteristics. RAASi appear to be underused, even among patients with strong classâ specific recommendations. Although the reasons for this variation could not be fully identified in this crossâ sectional observation, our data indicate that the risk of hyperkalemia may contribute to the underuse of this class of agents in moderate to advanced CKD.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150590/1/jch13563.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150590/2/jch13563_am.pd

The global impact of the Coronavirus 2019 pandemic on in-centre haemodialysis services: an International Society of Nephrology -Dialysis Outcomes Practice Patterns Study survey

Introduction To assess the impact of the COVID-19 pandemic impact on haemodialysis centres, The Dialysis Outcomes and Practice Patterns Study and International Society of Nephrology (ISN) collaborated on a web-survey of centres. Methods A combined approach of random sampling and open invitation was used between March 2020 and March 2021. Responses were obtained from 412 centres in 78 countries and all 10 ISN regions. Results In 8 regions, rates of SARS-CoV-2 infection were <20% in most centres, but in North East Asia and Newly Independent States and Russia rates were ≥20% and ≥30%, respectively. Mortality was ≥10% in most centres in 8 regions, though lower in North America and Caribbean and North East Asia. Diagnostic testing was not available in 33%, 37%, and 61% of centres in Latin America, Africa, and East and Central Europe, respectively. Surgical masks were widely available, but severe shortages of particulate-air filter masks were reported in Latin America (18%) and Africa (30%). Rates of infection in staff ranged from 0% in 90% of centres in North East Asia to ≥50% in 63% of centres in the Middle East and 68% of centres in Newly Independent States and Russia. In most centres <10% of staff died, but in Africa and South Asia 2% and 6% of centres reported ≥50% mortality, respectively. Conclusion There has been wide global variation in SARS-CoV-2 infection rates amongst haemodialysis patients and staff, PPE availability, and testing, and the ways in which services have been redesigned in response to the pandemic

An ISN-DOPPS Survey of the Global Impact of the COVID-19 Pandemic on Peritoneal Dialysis Services

INTRODUCTION Home dialysis may minimize SARS-CoV2 exposure risks compared to center-based dialysis. We explored how the pandemic may have introduced challenges related to peritoneal dialysis (PD) supply availability, routine patient care, and how facility practices changed during this time. METHODS The PD/Dialysis Outcomes and Practice Patterns Study (PDOPPS/DOPPS) and International Society of Nephrology (ISN) administered a web-based survey from November 2020 to March 2021. Medical director responses were compared across 10 ISN regions. RESULTS One hundered sixy-five PD facilities in 51 countries returned surveys. During the initial COVID-19 wave, the reported frequency of in-person patient visits decreased in 9 of 10 ISN regions. Before the pandemic, most facilities required a mask during PD exchanges which continued over the course of the pandemic. Although most facilities in different regions did not report PD supply disruptions, sites in Africa and South Asia reported major disruptions. Reductions in laparoscopic surgical procedures for PD catheters were reported by facilities in 9 of 10 regions whereas nonsurgical percutaneous procedures increased in facilities in 6 regions. Training of new PD patients declined in facilities in each region. Increased use of remote technology by patients to communicate with clinics was observed in all regions compared to prepandemic levels. CONCLUSION Marked within-region and across-region variability was noted in PD facility burden, clinical practice, and adaptation to the COVID-19 pandemic. This study highlights opportunities to improve routine PD care, adapt to the ongoing pandemic, and increase preparedness for potential future interruptions in PD care

The association of functional status with mortality and dialysis modality change : results from the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS)

BACKGROUND: Little is known about the prevalence of functional impairment in peritoneal dialysis (PD) patients, its variation by country, and its association with mortality or transfer to hemodialysis. METHODS: A prospective cohort study was conducted in PD patients from 7 countries in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) (2014 - 2017). Functional status (FS) was assessed by combining self-reports of 8 instrumental and 5 basic activities of daily living, using the Lawton-Brody and the Katz questionnaires. Summary FS scores, ranging from 1.25 (most dependent) to 13 (independent), were based on the patient's ability to perform each activity with or without assistance. Logistic regression was used to estimate the odds ratio (OR; 95% confidence interval [CI]) of a FS score < 11 comparing each country with the United States (US). Cox regression was used to estimate the hazard ratio (HR; 95% CI) for the effect of a low FS score on mortality and transfer to hemodialysis, adjusting for case mix. RESULTS: Of 2,593 patients with complete data on FS, 48% were fully independent (FS = 13), 32% had a FS score 11 to < 13, 14% had a FS score 8 to < 11, and 6% had a FS score < 8. Relative to the US, low FS scores (< 11; more dependent) were more frequent in Thailand (OR = 10.48, 5.90 - 18.60) and the United Kingdom (UK) (OR = 3.29, 1.77 - 6.08), but similar in other PDOPPS countries. The FS score was inversely and monotonically associated with mortality but not with transfer to hemodialysis; the HR, comparing a FS score < 8 vs 13, was 4.01 (2.44 - 6.61) for mortality and 0.91 (0.58 - 1.43) for transfer to hemodialysis. CONCLUSION: Regional differences in FS scores observed across PDOPPS countries may have been partly due to differences in regional patient selection for PD. Functional impairment was associated with mortality but not with permanent transfer to hemodialysis