Impact on Diabetic Ketoacidosis Resolution After Implementation of a 2-Bag Fluid Order Set.

BACKGROUND: Diabetic ketoacidosis (DKA) is a serious acute complication of both type 1 and type 2 diabetes that requires prompt management. Limited data exist supporting the use of a 2-bag DKA protocol in adult patients across all levels of care. OBJECTIVE: To evaluate the efficacy and safety of a 2-bag DKA protocol in comparison with a traditional DKA management strategy. METHODS: Retrospective review of patients admitted with DKA between January 1, 2021, and February 28, 2022, at a single center. Patients were separated into 2 cohorts, traditional or 2-bag. The primary outcome was time to anion gap closure and/or beta-hydroxybutyrate normalization. Secondary outcomes include length of hospitalization, insulin infusion time, and hypoglycemic events. RESULTS: One hundred forty-three patients had a DKA order set initiated during their admission, 59 in the traditional cohort and 84 in the 2-bag cohort. Mean time to anion gap closure was shorter in the 2-bag cohort (12.7 vs 16.9 hours; P = 0.005) and beta-hydroxybutyrate normalization (15.6 vs 25.6 hours; P = 0.026). No difference in hospital length of stay (4 vs 6 days; P = 0.113), duration of insulin infusion (41.6 vs 40.6 hours; P = 0.455), or rates of hypoglycemia (6 vs 4; P = 0.872) was seen. CONCLUSION AND RELEVANCE: Implementation of a 2-bag DKA protocol in the inpatient setting was associated with a shorter time to anion gap closure and beta-hydroxybutyrate normalization. These findings support the option of expansion of a 2-bag DKA protocol to adult patients across all levels of care irrespective of the admission diagnosis.

The emergency department evaluation and management of massive hemoptysis.

INTRODUCTION: Massive hemoptysis is a life-threatening emergency that requires rapid evaluation and management. Recognition of this deadly condition, knowledge of the initial resuscitation and diagnostic evaluation, and communication with consultants capable of definitive management are key to successful treatment. OBJECTIVE: The objective of this narrative review is to provide an evidence-based review on the management of massive hemoptysis for the emergency clinician. DISCUSSION: Rapid diagnosis and management of life-threatening hemoptysis is key to patient survival. The majority of cases arise from the bronchial arterial system, which is under systemic blood pressure. Initial management includes patient and airway stabilization, reversal of coagulopathy, and identification of the source of bleeding using computed tomography angiogram. Bronchial artery embolization with interventional radiology has become the mainstay of treatment; however, unstable patients may require advanced bronchoscopic procedures to treat or temporize while additional information and treatment can be directed at the underlying pathology. CONCLUSION: Massive hemoptysis is a life-threatening condition that emergency clinicians must be prepared to manage. Emergency clinicians should focus their management on immediate resuscitation, airway preservation often including intubation and isolation of the non-bleeding lung, and coordination of definitive management with available consultants including interventional radiology, interventional pulmonology, and thoracic surgery.

Retinal lipid and glucose metabolism dictates angiogenesis through the lipid sensor Ffar1.

Tissues with high metabolic rates often use lipids, as well as glucose, for energy, conferring a survival advantage during feast and famine. Current dogma suggests that high-energy-consuming photoreceptors depend on glucose. Here we show that the retina also uses fatty acid ß-oxidation for energy. Moreover, we identify a lipid sensor, free fatty acid receptor 1 (Ffar1), that curbs glucose uptake when fatty acids are available. Very-low-density lipoprotein receptor (Vldlr), which is present in photoreceptors and is expressed in other tissues with a high metabolic rate, facilitates the uptake of triglyceride-derived fatty acid. In the retinas of Vldlr(-/-) mice with low fatty acid uptake but high circulating lipid levels, we found that Ffar1 suppresses expression of the glucose transporter Glut1. Impaired glucose entry into photoreceptors results in a dual (lipid and glucose) fuel shortage and a reduction in the levels of the Krebs cycle intermediate α-ketoglutarate (α-KG). Low α-KG levels promotes stabilization of hypoxia-induced factor 1a (Hif1a) and secretion of vascular endothelial growth factor A (Vegfa) by starved Vldlr(-/-) photoreceptors, leading to neovascularization. The aberrant vessels in the Vldlr(-/-) retinas, which invade normally avascular photoreceptors, are reminiscent of the vascular defects in retinal angiomatous proliferation, a subset of neovascular age-related macular degeneration (AMD), which is associated with high vitreous VEGFA levels in humans. Dysregulated lipid and glucose photoreceptor energy metabolism may therefore be a driving force in macular telangiectasia, neovascular AMD and other retinal diseases.

Sirtuin1 over-expression does not impact retinal vascular and neuronal degeneration in a mouse model of oxygen-induced retinopathy.

Proliferative retinopathy is a leading cause of blindness, including retinopathy of prematurity (ROP) in children and diabetic retinopathy in adults. Retinopathy is characterized by an initial phase of vessel loss, leading to tissue ischemia and hypoxia, followed by sight threatening pathologic neovascularization in the second phase. Previously we found that Sirtuin1 (Sirt1), a metabolically dependent protein deacetylase, regulates vascular regeneration in a mouse model of oxygen-induced proliferative retinopathy (OIR), as neuronal depletion of Sirt1 in retina worsens retinopathy. In this study we assessed whether over-expression of Sirtuin1 in retinal neurons and vessels achieved by crossing Sirt1 over-expressing flox mice with Nestin-Cre mice or Tie2-Cre mice, respectively, may protect against retinopathy. We found that over-expression of Sirt1 in Nestin expressing retinal neurons does not impact vaso-obliteration or pathologic neovascularization in OIR, nor does it influence neuronal degeneration in OIR. Similarly, increased expression of Sirt1 in Tie2 expressing vascular endothelial cells and monocytes/macrophages does not protect retinal vessels in OIR. In addition to the genetic approaches, dietary supplement with Sirt1 activators, resveratrol or SRT1720, were fed to wild type mice with OIR. Neither treatment showed significant vaso-protective effects in retinopathy. Together these results indicate that although endogenous Sirt1 is important as a stress-induced protector in retinopathy, over-expression of Sirt1 or treatment with small molecule activators at the examined doses do not provide additional protection against retinopathy in mice. Further studies are needed to examine in depth whether increasing levels of Sirt1 may serve as a potential therapeutic approach to treat or prevent retinopathy.

Neuronal sirtuin1 mediates retinal vascular regeneration in oxygen-induced ischemic retinopathy.

Regeneration of blood vessels in ischemic neuronal tissue is critical to reduce tissue damage in diseases. In proliferative retinopathy, initial vessel loss leads to retinal ischemia, which can induce either regrowth of vessels to restore normal metabolism and minimize damage, or progress to hypoxia-induced sight-threatening pathologic vaso-proliferation. It is not well understood how retinal neurons mediate regeneration of vascular growth in response to ischemic insults. In this study we aim to investigate the potential role of Sirtuin 1 (Sirt1), a metabolically-regulated protein deacetylase, in mediating the response of ischemic neurons to regulate vascular regrowth in a mouse model of oxygen-induced ischemic retinopathy (OIR). We found that Sirt1 is highly induced in the avascular ischemic retina in OIR. Conditional depletion of neuronal Sirt1 leads to significantly decreased retinal vascular regeneration into the avascular zone and increased hypoxia-induced pathologic vascular growth. This effect is likely independent of PGC-1α, a known Sirt1 target, as absence of PGC-1α in knockout mice does not impact vascular growth in retinopathy. We found that neuronal Sirt1 controls vascular regrowth in part through modulating deacetylation and stability of hypoxia-induced factor 1α and 2α, and thereby modulating expression of angiogenic factors. These results indicate that ischemic neurons induce Sirt1 to promote revascularization into ischemic neuronal areas, suggesting a novel role of neuronal Sirt1 in mediating vascular regeneration in ischemic conditions, with potential implications beyond retinopathy.

SOCS3 is an endogenous inhibitor of pathologic angiogenesis.

Inflammatory cytokines and growth factors drive angiogenesis independently; however, their integrated role in pathologic and physiologic angiogenesis is not fully understood. Suppressor of cytokine signaling-3 (SOCS3) is an inducible negative feedback regulator of inflammation and growth factor signaling. In the present study, we show that SOCS3 curbs pathologic angiogenesis. Using a Cre/Lox system, we deleted SOCS3 in vessels and studied developmental and pathologic angiogenesis in murine models of oxygen-induced retinopathy and cancer. Conditional loss of SOCS3 leads to increased pathologic neovascularization, resulting in pronounced retinopathy and increased tumor size. In contrast, physiologic vascularization is not regulated by SOCS3. In vitro, SOCS3 knockdown increases proliferation and sprouting of endothelial cells costimulated with IGF-1 and TNFα via reduced feedback inhibition of the STAT3 and mTOR pathways. These results identify SOCS3 as a pivotal endogenous feedback inhibitor of pathologic angiogenesis and a potential therapeutic target acting at the converging crossroads of growth factor- and cytokine-induced vessel growth.

Propranolol inhibition of ß-adrenergic receptor does not suppress pathologic neovascularization in oxygen-induced retinopathy.

PURPOSE: Retinopathy of prematurity (ROP) is a leading cause of blindness in children and is, in its most severe form, characterized by uncontrolled growth of vision-threatening pathologic vessels. Propranolol, a nonselective ß-adrenergic receptor blocker, was reported to protect against pathologic retinal neovascularization in a mouse model of oxygen-induced retinopathy (OIR). Based on this single animal study using nonstandard evaluation of retinopathy, clinical trials are currently ongoing to evaluate propranolol treatment in stage 2 ROP patients who tend to experience spontaneous disease regression and are at low risk of blindness. Because these ROP patients are vulnerable premature infants who are still in a fragile state of incomplete development, the efficacy of propranolol treatment in retinopathy needs to be evaluated thoroughly in preclinical animal models of retinopathy and potential benefits weighed against potential adverse effects. METHODS: Retinopathy was induced by exposing neonatal mice to 75% oxygen from postnatal day (P) 7 to P12. Three routes of propranolol treatment were assessed from P12 to P16: oral gavage, intraperitoneal injection, or subcutaneous injection, with doses varying between 2 and 60 mg/kg/day. At P17, retinal flatmounts were stained with isolectin and quantified with a standard protocol to measure vasoobliteration and pathologic neovascularization. Retinal gene expression was analyzed with qRT-PCR using RNA isolated from retinas of control and propranolol-treated pups. RESULTS: None of the treatment approaches at any dose of propranolol (up to 60 mg/kg/day) were effective in preventing the development of retinopathy in a mouse model of OIR, evaluated using standard techniques. Propranolol treatment also did not change retinal expression of angiogenic factors including vascular endothelial growth factor. CONCLUSIONS: Propranolol treatment via three routes and up to 30 times the standard human dose failed to suppress retinopathy development in mice. These data bring into question whether propranolol through inhibition of ß-adrenergic receptors is an appropriate therapeutic approach for treating ROP.

Retinal expression of Wnt-pathway mediated genes in low-density lipoprotein receptor-related protein 5 (Lrp5) knockout mice.

Mutations in low-density lipoprotein receptor-related protein 5 (Lrp5) impair retinal angiogenesis in patients with familial exudative vitreoretinopathy (FEVR), a rare type of blinding vascular eye disease. The defective retinal vasculature phenotype in human FEVR patients is recapitulated in Lrp5 knockout (Lrp5(-/-)) mouse with delayed and incomplete development of retinal vessels. In this study we examined gene expression changes in the developing Lrp5(-/-) mouse retina to gain insight into the molecular mechanisms that underlie the pathology of FEVR in humans. Gene expression levels were assessed with an Illumina microarray on total RNA from Lrp5(-/-) and WT retinas isolated on postnatal day (P) 8. Regulated genes were confirmed using RT-qPCR analysis. Consistent with a role in vascular development, we identified expression changes in genes involved in cell-cell adhesion, blood vessel morphogenesis and membrane transport in Lrp5(-/-) retina compared to WT retina. In particular, tight junction protein claudin5 and amino acid transporter slc38a5 are both highly down-regulated in Lrp5(-/-) retina. Similarly, several Wnt ligands including Wnt7b show decreased expression levels. Plasmalemma vesicle associated protein (plvap), an endothelial permeability marker, in contrast, is up-regulated consistent with increased permeability in Lrp5(-/-) retinas. Together these data suggest that Lrp5 regulates multiple groups of genes that influence retinal angiogenesis and may contribute to the pathogenesis of FEVR.

Wnt signaling mediates pathological vascular growth in proliferative retinopathy.

BACKGROUND: Ischemic proliferative retinopathy, characterized by pathological retinal neovascularization, is a major cause of blindness in working-age adults and children. Defining the molecular pathways distinguishing pathological neovascularization from normal vessels is critical to controlling these blinding diseases with targeted therapy. Because mutations in Wnt signaling cause defective retinal vasculature in humans with some characteristics of the pathological vessels in retinopathy, we investigated the potential role of Wnt signaling in pathological retinal vascular growth in proliferative retinopathy. METHODS AND RESULTS: In this study, we show that Wnt receptors (Frizzled4 and low-density lipoprotein receptor-related protein5 [Lrp5]) and activity are significantly increased in pathological neovascularization in a mouse model of oxygen-induced proliferative retinopathy. Loss of Wnt coreceptor Lrp5 and downstream signaling molecule dishevelled2 significantly decreases the formation of pathological retinal neovascularization in retinopathy. Loss of Lrp5 also affects retinal angiogenesis during development and formation of the blood-retinal barrier, which is linked to significant downregulation of tight junction protein claudin5 in Lrp5(-/-) vessels. Blocking claudin5 significantly suppresses Wnt pathway-driven endothelial cell sprouting in vitro and developmental and pathological vascular growth in retinopathy in vivo. CONCLUSIONS: These results demonstrate an important role of Wnt signaling in pathological vascular development in retinopathy and show a novel function of Cln5 in promoting angiogenesis.

Resveratrol inhibits pathologic retinal neovascularization in Vldlr(-/-) mice.

PURPOSE: Macular telangiectasia (MacTel) is a vision-threatening retinal disease with unknown pathogenesis and no approved treatment. Very low-density lipoprotein receptor mutant mice (Vldlr(-/-)) exhibit critical features of MacTel such as retinal neovascularization and photoreceptor degeneration. In this study, the authors evaluate the therapeutic potential of resveratrol, a plant polyphenol, in Vldlr(-/-) mice as a model for MacTel. METHODS: Vldlr(-/-) and wild-type mice at postnatal day (P) 21 to P60 or P10 to P30 were treated orally with resveratrol. The number of neovascular lesions was evaluated on retinal flatmounts, and resveratrol effects on endothelial cells were assessed by Western blot for phosphorylated ERK1/2, aortic ring, and migration assays. Vegf and Gfap expression was evaluated in laser-capture microdissected retinal layers of angiogenic lesions and nonlesion areas from Vldlr(-/-) and wild-type retinas. RESULTS: From P15 onward, Vldlr(-/-) retinas develop vascular lesions associated with the local upregulation of Vegf in photoreceptors and Gfap in the inner retina. Oral resveratrol reduces lesion formation when administered either before or after disease onset. The reduction of vascular lesions in resveratrol-treated Vldlr(-/-) mice is associated with the suppression of retinal Vegf transcription. Resveratrol also reduces endothelial ERK1/2 signaling as well as the migration and proliferation of endothelial cells. Furthermore, a trend toward increased rhodopsin mRNA in Vldlr(-/-) retinas is observed. CONCLUSIONS: Oral administration of resveratrol is protective against retinal neovascular lesions in Vldlr(-/-) mice by inhibiting Vegf expression and angiogenic activation of retinal endothelial cells. These results suggest that resveratrol might be a safe and effective intervention for treating patients with MacTel.