KATP channel activity and slow oscillations in pancreatic beta cells are regulated by mitochondrial ATP production.

Pancreatic beta cells secrete insulin in response to plasma glucose. The ATP-sensitive potassium channel (KATP ) links glucose metabolism to islet electrical activity in these cells by responding to increased cytosolic [ATP]/[ADP]. It was recently proposed that pyruvate kinase (PK) in close proximity to beta cell KATP locally produces the ATP that inhibits KATP activity. This proposal was largely based on the observation that applying phosphoenolpyruvate (PEP) and ADP to the cytoplasmic side of excised inside-out patches inhibited KATP . To test the relative contributions of local vs. mitochondrial ATP production, we recorded KATP activity using mouse beta cells and INS-1 832/13 cells. In contrast to prior reports, we could not replicate inhibition of KATP activity by PEP + ADP. However, when the pH of the PEP solutions was not corrected for the addition of PEP, strong channel inhibition was observed as a result of the well-known action of protons to inhibit KATP . In cell-attached recordings, perifusing either a PK activator or an inhibitor had little or no effect on KATP channel closure by glucose, further suggesting that PK is not an important regulator of KATP . In contrast, addition of mitochondrial inhibitors robustly increased KATP activity. Finally, by measuring the [ATP]/[ADP] responses to imposed calcium oscillations in mouse beta cells, we found that oxidative phosphorylation could raise [ATP]/[ADP] even when ADP was at its nadir during the burst silent phase, in agreement with our mathematical model. These results indicate that ATP produced by mitochondrial oxidative phosphorylation is the primary controller of KATP in pancreatic beta cells. KEY POINTS: Phosphoenolpyruvate (PEP) plus adenosine diphosphate does not inhibit KATP activity in excised patches. PEP solutions only inhibit KATP activity if the pH is unbalanced. Modulating pyruvate kinase has minimal effects on KATP activity. Mitochondrial inhibition, in contrast, robustly potentiates KATP activity in cell-attached patches. Although the ADP level falls during the silent phase of calcium oscillations, mitochondria can still produce enough ATP via oxidative phosphorylation to close KATP . Mitochondrial oxidative phosphorylation is therefore the main source of the ATP that inhibits the KATP activity of pancreatic beta cells.

Formation of a conceptual framework during the development of a patient-reported outcome measure for early gastrointestinal recovery: phase I of the PRO-diGi study.

AIM: Patients admitted to hospital for abdominal surgery often experience gastrointestinal dysfunction. Many studies have reported outcomes following gastrointestinal dysfunction, yet there is no unified definition of recovery or a validated patient-reported outcome measure (PROM). The first stage of PROM development requires formation of a conceptual framework to identify key themes to patients. The aim of this study was to utilize semistructured interviews to identify core themes and concepts relevant to patients to facilitate development of a conceptual framework. METHOD: Adult patients admitted to hospital for major gastrointestinal, urological or gynaecological surgery, in an emergency or elective setting, were eligible to participate. Patients treated nonoperatively for small bowel obstruction were also eligible. Interviews were conducted by telephone, audio-recorded, transcribed, coded and analysed using NVivo software by two researchers and reviewed by lay members of the steering group. Interviews continued until data saturation was reached. Ethical approval was gained prior to interviews (21/WA/0231). RESULTS: Twenty nine interviews were completed (17 men, median age 64 years) across three specialties (20 gastrointestinal, six gynaecological, three urological). Two overarching themes of 'general recovery' and 'gastrointestinal symptoms' were identified. General recovery included three themes: 'life impact', 'mental impact', including anxiety, and 'physical impact', including fatigue. Gastrointestinal symptoms included three themes: 'abdominal symptoms' such as pain, 'diet and appetite' and 'expulsory function', such as stool frequency. A total of 18 gastrointestinal symptoms were identified during patient recovery-many of which lasted several weeks following discharge. CONCLUSION: This study reports a range of gastrointestinal and nongastrointestinal symptoms experienced by patients during early gastrointestinal recovery. Identified symptoms have been synthesized into a conceptual framework to enable development of a definitive PROM for early gastrointestinal recovery.

Oscillations in K(ATP) conductance drive slow calcium oscillations in pancreatic ß-cells.

ATP-sensitive K+ (K(ATP)) channels were first reported in the ß-cells of pancreatic islets in 1984, and it was soon established that they are the primary means by which the blood glucose level is transduced to cellular electrical activity and consequently insulin secretion. However, the role that the K(ATP) channels play in driving the bursting electrical activity of islet ß-cells, which drives pulsatile insulin secretion, remains unclear. One difficulty is that bursting is abolished when several different ion channel types are blocked pharmacologically or genetically, making it challenging to distinguish causation from correlation. Here, we demonstrate a means for determining whether activity-dependent oscillations in K(ATP) conductance play the primary role in driving electrical bursting in ß-cells. We use mathematical models to predict that if K(ATP) is the driver, then contrary to intuition, the mean, peak, and nadir levels of ATP/ADP should be invariant to changes in glucose within the concentration range that supports bursting. We test this in islets using Perceval-HR to image oscillations in ATP/ADP. We find that mean, peak, and nadir levels are indeed approximately invariant, supporting the hypothesis that oscillations in K(ATP) conductance are the main drivers of the slow bursting oscillations typically seen at stimulatory glucose levels in mouse islets. In conclusion, we provide, for the first time to our knowledge, causal evidence for the role of K(ATP) channels not only as the primary target for glucose regulation but also for their role in driving bursting electrical activity and pulsatile insulin secretion.

Prophylactic Oral Dextrose Gel and Neurosensory Impairment at 2-Year Follow-up of Participants in the hPOD Randomized Trial.

Importance: Prophylactic oral dextrose gel reduces neonatal hypoglycemia, but later benefits or harms remain unclear. Objective: To assess the effects on later development of prophylactic dextrose gel for infants born at risk of neonatal hypoglycemia. Design, Setting, and Participants: Prospective follow-up of a multicenter randomized clinical trial conducted in 18 Australian and New Zealand hospitals from January 2015 to May 2019. Participants were late preterm or term at-risk infants; those randomized in 9 New Zealand centers (n = 1359) were included and followed up between January 2017 and July 2021. Interventions: Infants were randomized to prophylactic 40% dextrose (n = 681) or placebo (n = 678) gel, 0.5 mL/kg, massaged into the buccal mucosa 1 hour after birth. Main Outcomes and Measures: The primary outcome of this follow-up study was neurosensory impairment at 2 years' corrected age. There were 44 secondary outcomes, including cognitive, language, and motor composite Bayley-III scores (mean [SD], 100 [15]; higher scores indicate better performance). Results: Of eligible infants, 1197 (91%) were assessed (581 females [49%]). Neurosensory impairment was not significantly different between the dextrose and placebo gel groups (20.8% vs 18.7%; unadjusted risk difference [RD], 2.09% [95% CI, -2.43% to 6.60%]; adjusted risk ratio [aRR], 1.13 [95% CI, 0.90 to 1.41]). The risk of cognitive and language delay was not significantly different between the dextrose and placebo groups (cognitive: 7.6% vs 5.3%; RD, 2.32% [95% CI, -0.46% to 5.11%]; aRR, 1.40 [95% CI, 0.91 to 2.17]; language: 17.0% vs 14.7%; RD, 2.35% [95% CI, -1.80% to 6.50%]; aRR, 1.19 [95% CI, 0.92 to 1.54]). However, the dextrose gel group had a significantly higher risk of motor delay (2.5% vs 0.7%; RD, 1.81% [95% CI, 0.40% to 3.23%]; aRR, 3.79 [95% CI, 1.27 to 11.32]) and significantly lower composite scores for cognitive (adjusted mean difference [aMD], -1.30 [95% CI, -2.55 to -0.05]), language (aMD, -2.16 [95% CI, -3.86 to -0.46]), and motor (aMD, -1.40 [95% CI, -2.60 to -0.20]) performance. There were no significant differences between groups in the other 27 secondary outcomes. Conclusions and Relevance: Among late preterm and term infants born at risk of neonatal hypoglycemia, prophylactic oral 40% dextrose gel at 1 hour of age, compared with placebo, resulted in no significant difference in the risk of neurosensory impairment at 2 years' corrected age. However, the study may have been underpowered to detect a small but potentially clinically important increase in risk, and further research including longer-term follow-up is required. Trial Registration: anzctr.org.au Identifier: ACTRN12614001263684.

Delayed induction of type I and III interferons mediates nasal epithelial cell permissiveness to SARS-CoV-2.

The nasal epithelium is a plausible entry point for SARS-CoV-2, a site of pathogenesis and transmission, and may initiate the host response to SARS-CoV-2. Antiviral interferon (IFN) responses are critical to outcome of SARS-CoV-2. Yet little is known about the interaction between SARS-CoV-2 and innate immunity in this tissue. Here we apply single-cell RNA sequencing and proteomics to a primary cell model of human nasal epithelium differentiated at air-liquid interface. SARS-CoV-2 demonstrates widespread tropism for nasal epithelial cell types. The host response is dominated by type I and III IFNs and interferon-stimulated gene products. This response is notably delayed in onset relative to viral gene expression and compared to other respiratory viruses. Nevertheless, once established, the paracrine IFN response begins to impact on SARS-CoV-2 replication. When provided prior to infection, recombinant IFNß or IFNλ1 induces an efficient antiviral state that potently restricts SARS-CoV-2 viral replication, preserving epithelial barrier integrity. These data imply that the IFN-I/III response to SARS-CoV-2 initiates in the nasal airway and suggest nasal delivery of recombinant IFNs to be a potential chemoprophylactic strategy.

Visitation policies at NCI-designated comprehensive cancer centers during the COVID-19 pandemic.

PURPOSE: Family/caregiver visitation provides critical support for patients confronting cancer and is associated with positive outcomes. However, the COVID-19 pandemic brought historic disruptions including widespread visitation restrictions. Here, we characterize in-depth the visitor policies of NCI-designated comprehensive cancer centers (CCCs) and analyze geographic/temporal patterns across CCCs. METHODS: The public-facing CCC websites, including archived webpages, were reviewed to abstract initial visitation policies and revisions, including end-of-life (EoL) exceptions and timing of visitation restrictions relative to regional lockdowns. Chi-squared and Fisher's exact tests were employed to analyze associations between geographic region, timing, and severity of restrictions. RESULTS: Most CCCs (n=43, 86%) enacted visitation restrictions between March 15 and April 15, 2020. About half barred all visitors for COVID-negative inpatients (n=24, 48%) or outpatients (n=26, 52%). Most (n=36, 72%) prohibited visitors for patients with confirmed/suspected COVID-19. Most (n=40, 80%) published EoL exceptions but the specifics were highly variable. The median time from initial restrictions to government-mandated lockdowns was 1 day, with a wide range (25 days before to 26 days after). There was no association between timing of initial restrictions and geographic location (p=0.14) or severity of inpatient policies (p=1.0), even among centers in the same city. Outpatient policies published reactively (after lockdown) were more restrictive than those published proactively (p=0.04). CONCLUSION: CCCs enacted strict but strikingly variable COVID-19 visitation restrictions, with important implications for patients/families seeking cancer care. A unified, evidence-based approach to visitation policies is needed to balance proven infection control measures with the needs of patients and families.

Healthcare Disparities and the COVID-19 Pandemic: Analysis of Primary Language and Translations of Visitor Policies at NCI-Designated Comprehensive Cancer Centers.

CONTEXT: Coronavirus Disease 2019 (COVID-19) has caused unprecedented disruptions to cancer care, including through strict hospital visitation policies. Since a substantial proportion of the U.S. population report a non-English language as their primary language, it is critical that information is disseminated in multiple languages. OBJECTIVES: To examine the availability of language translations of visitation restrictions on adult National Cancer Institute-designated comprehensive cancer centers (CCCs) Web sites. METHODS: Cross-sectional analysis of visitation policies abstracted from public-facing Web sites of CCCs in June 2020. Using U.S. Census data, CCC's city and state proportions of self-identifying Hispanic/Latinx population were categorized into three cohorts: low (<10%), moderate (10%-20%), and high (>20%). RESULTS: As of June 2020, all 50 CCCs published a COVID-19 visitation policy on their Web site. Of these, 33 (66%) posted policies only in English, whereas 17 (34%) included one or more non-English translations. A minority of CCCs published Spanish language resources, which did not differ based on state or city demographics: for example, only 42% (8 of 19), 10% (1 of 10), and 38% (8 of 21) of CCCs published Spanish language resources in cities with low, moderate, and high Hispanic/Latinx populations, respectively. CONCLUSION: `Most CCC's did not publish non-English language translations of their visitor policies. Even in cities and states with larger Hispanic/Latinx populations, most CCCs did not publish resources in Spanish. This study highlights a key opportunity to mitigate communication barriers and deliver culturally competent, patient-centered care.

DYRK1A regulates B cell acute lymphoblastic leukemia through phosphorylation of FOXO1 and STAT3.

DYRK1A is a serine/threonine kinase encoded on human chromosome 21 (HSA21) that has been implicated in several pathologies of Down syndrome (DS), including cognitive deficits and Alzheimer's disease. Although children with DS are predisposed to developing leukemia, especially B cell acute lymphoblastic leukemia (B-ALL), the HSA21 genes that contribute to malignancies remain largely undefined. Here, we report that DYRK1A is overexpressed and required for B-ALL. Genetic and pharmacologic inhibition of DYRK1A decreased leukemic cell expansion and suppressed B-ALL development in vitro and in vivo. Furthermore, we found that FOXO1 and STAT3, transcription factors that are indispensable for B cell development, are critical substrates of DYRK1A. Loss of DYRK1A-mediated FOXO1 and STAT3 signaling disrupted DNA damage and ROS regulation, respectively, leading to preferential cell death in leukemic B cells. Thus, we reveal a DYRK1A/FOXO1/STAT3 axis that facilitates the development and maintenance of B-ALL.

Radiology of anorectal malformations: What does the surgeon need to know?

Imaging is extremely important throughout all phases of care provided to children with anorectal malformations (ARM). A preoperative determination of the patient specific malformation will help establish the operative plan. Moreover, the majority of ARM patients will have an associated anomaly that will require imaging workup for full understanding of those abnormalities prior to addressing the ARM. The complexity of ARM care will mandate continued imaging throughout the post-operative period even in those with straight forward malformations.

The growth of a xenograft breast cancer tumor model with engineered hyaluronan-accumulating stroma is dependent on hyaluronan and independent of CD44.

Hyaluronan accumulation in the tumor microenvironment is associated with poor prognosis in several solid human cancers. To understand the role of stromal hyaluronan in tumor progression, we engineered 3T3HAS3, a hyaluronan-producing fibroblast cell line, by lentiviral transduction of Balb/c 3T3 cells with the human hyaluronan synthase 3 (HAS3) gene. 3T3HAS3 cells significantly enhanced tumor growth when co-grafted with MDA-MB-468 cells in nude mice. Immunohistochemical analysis of the xenograft tumors showed that MDA-MB-468 cells were surrounded by hyaluronan-accumulating stroma, closely resembling the morphology observed in human breast cancer specimens. Tumor growth of MDA-MB-468 + 3T3HAS3 co-grafts was greatly reduced upon hyaluronan degradation by lentiviral transduction of a human hyaluronidase gene in 3T3HAS3 cells, or by systemic administration of pegvorhyaluronidase alfa (PEGPH20). In contrast, the growth of the co-graft tumors was not inhibited when CD44 expression was reduced or ablated by small hairpin RNA-mediated CD44 knockdown in MDA-MB-468 cells, CD44 CRISPR knockout in 3T3HAS3 cells, or by grafting these cells in CD44 knockout nude mice. Collectively, these data demonstrate that tumor growth of an engineered xenograft breast cancer model with hyaluronan-accumulating stroma can be dependent on hyaluronan and independent of CD44.

Phenomenological approach to childhood cataract treatment in New Zealand using semi-structured interviews: how might we improve provision of care.

PURPOSE: To understand how we might improve the provision of medical care for children with cataracts. DESIGN: A phenomenological design was employed. Semi-structured interviews were conducted to capture rich descriptions of the phenomena. Our goal in the interview and the analysis was to understand the sources of distress associated with treatment for cataract and deprivation amblyopia which (1) could be addressed by the medical community and (2) related to treatment adherence. SETTING: Interviews were conducted by a non-clinician researcher in New Zealand (NZ) in a location chosen by informants. In NZ, the red reflex screening test is performed shortly after birth, and surgery to remove paediatric cataracts is publicly funded. PARTICIPANTS: Families of children who had a history of cataract in Auckland, NZ were posted an invitation to participate. Twenty families were interviewed. RESULTS: Our analysis illustrated that informants described a wide range of experiences, from declined cataract surgery to full adherence to medical advice including years of patching for more than 4 hours a day. Across these experiences, we identified three relevant themes; timing of diagnosis, communication between the parent and clinician, and parental social support networks. CONCLUSION: The medical community may be better placed to support families dealing with childhood cataract by improving detection of childhood cataract, building appropriate communication pathways and promoting social support, with an emphasis on empathetic, individualised care.