PHYOX2: a pivotal randomized study of nedosiran in primary hyperoxaluria type 1 or 2.

Nedosiran is an investigational RNA interference agent designed to inhibit expression of hepatic lactate dehydrogenase, the enzyme thought responsible for the terminal step of oxalate synthesis. Oxalate overproduction is the hallmark of all genetic subtypes of primary hyperoxaluria (PH). In this double-blind, placebo-controlled study, we randomly assigned (2:1) 35 participants with PH1 (n = 29) or PH2 (n = 6) with eGFR ≥30 mL/min/1.73 m2 to subcutaneous nedosiran or placebo once monthly for 6 months. The area under the curve (AUC) of percent reduction from baseline in 24-hour urinary oxalate (Uox) excretion (primary endpoint), between day 90-180, was significantly greater with nedosiran vs placebo (least squares mean [SE], +3507 [788] vs -1664 [1190], respectively; difference, 5172; 95% CI 2929-7414; P < 0.001). A greater proportion of participants receiving nedosiran vs placebo achieved normal or near-normal (<0.60 mmol/24 hours; <1.3 × ULN) Uox excretion on ≥2 consecutive visits starting at day 90 (50% vs 0; P = 0.002); this effect was mirrored in the nedosiran-treated PH1 subgroup (64.7% vs 0; P < 0.001). The PH1 subgroup maintained a sustained Uox reduction while on nedosiran, whereas no consistent effect was seen in the PH2 subgroup. Nedosiran-treated participants with PH1 also showed a significant reduction in plasma oxalate versus placebo (P = 0.017). Nedosiran was generally safe and well tolerated. In the nedosiran arm, the incidence of injection-site reactions was 9% (all mild and self-limiting). In conclusion, participants with PH1 receiving nedosiran had clinically meaningful reductions in Uox, the mediator of kidney damage in PH.

PD-L1 Prevents the Development of Autoimmune Heart Disease in Graft-versus-Host Disease.

Effector memory T cells (TEM) are less capable of inducing graft-versus-host disease (GVHD) compared with naive T cells (TN). Previously, in the TS1 TCR transgenic model of GVHD, wherein TS1 CD4 cells specific for a model minor histocompatibility Ag (miHA) induce GVHD in miHA-positive recipients, we found that cell-intrinsic properties of TS1 TEM reduced their GVHD potency relative to TS1 TN Posttransplant, TS1 TEM progeny expressed higher levels of PD-1 than did TS1 TN progeny, leading us to test the hypothesis that TEM induce less GVHD because of increased sensitivity to PD-ligands. In this study, we tested this hypothesis and found that indeed TS1 TEM induced more severe skin and liver GVHD in the absence of PD-ligands. However, lack of PD-ligands did not result in early weight loss and colon GVHD comparable to that induced by TS1 TN, indicating that additional pathways restrain alloreactive TEM TS1 TN also caused more severe GVHD without PD-ligands. The absence of PD-ligands on donor bone marrow was sufficient to augment GVHD caused by either TEM or TN, indicating that donor PD-ligand-expressing APCs critically regulate GVHD. In the absence of PD-ligands, both TS1 TEM and TN induced late-onset myocarditis. Surprisingly, this was an autoimmune manifestation, because its development required non-TS1 polyclonal CD8+ T cells. Myocarditis development also required donor bone marrow to be PD-ligand deficient, demonstrating the importance of donor APC regulatory function. In summary, PD-ligands suppress both miHA-directed GVHD and the development of alloimmunity-induced autoimmunity after allogeneic hematopoietic transplantation.

A randomized, placebo-controlled trial of canakinumab in patients with peripheral artery disease.

Extensive atherosclerotic plaque burden in the lower extremities often leads to symptomatic peripheral artery disease (PAD) including impaired walking performance and claudication. Interleukin-1ß (IL-1ß) may play an important pro-inflammatory role in the pathogenesis of this disease. Interruption of IL-1ß signaling was hypothesized to decrease plaque progression in the leg macrovasculature and improve the mobility of patients with PAD with intermittent claudication. Thirty-eight patients (mean age 65 years; 71% male) with symptomatic PAD (confirmed by ankle-brachial index) were randomized 1:1 to receive canakinumab (150 mg subcutaneously) or placebo monthly for up to 12 months. The mean vessel wall area (by 3.0 T black-blood magnetic resonance imaging (MRI)) of the superficial femoral artery (SFA) was used to measure plaque volume. Mobility was assessed using the 6-minute walk test. Canakinumab was safe and well tolerated. Markers of systemic inflammation (interleukin-6 and high-sensitivity C-reactive protein) fell as early as 1 month after treatment. MRI (32 patients at 3 months; 21 patients at 12 months) showed no evidence of plaque progression in the SFA in either placebo-treated or canakinumab-treated patients. Although an exploratory endpoint, placebo-adjusted maximum and pain-free walking distance (58 m) improved as early as 3 months after treatment with canakinumab when compared with placebo. Although canakinumab did not alter plaque progression in the SFA, there is an early signal that it may improve maximum and pain-free walking distance in patients with symptomatic PAD. Larger studies aimed at this endpoint will be required to definitively demonstrate this. ClinicalTrials.gov Identifier: NCT01731990.

Decreased polycystin 2 expression alters calcium-contraction coupling and changes ß-adrenergic signaling pathways.

Cardiac disorders are the main cause of mortality in autosomal-dominant polycystic kidney disease (ADPKD). However, how mutated polycystins predispose patients with ADPKD to cardiac pathologies before development of renal dysfunction is unknown. We investigate the effect of decreased levels of polycystin 2 (PC2), a calcium channel that interacts with the ryanodine receptor, on myocardial function. We hypothesize that heterozygous PC2 mice (Pkd2(+/-)) undergo cardiac remodeling as a result of changes in calcium handling, separate from renal complications. We found that Pkd2(+/-) cardiomyocytes have altered calcium handling, independent of desensitized calcium-contraction coupling. Paradoxically, in Pkd2(+/-) mice, protein kinase A (PKA) phosphorylation of phospholamban (PLB) was decreased, whereas PKA phosphorylation of troponin I was increased, explaining the decoupling between calcium signaling and contractility. In silico modeling supported this relationship. Echocardiography measurements showed that Pkd2(+/-) mice have increased left ventricular ejection fraction after stimulation with isoproterenol (ISO), a ß-adrenergic receptor (ßAR) agonist. Blockers of ßAR-1 and ßAR-2 inhibited the ISO response in Pkd2(+/-) mice, suggesting that the dephosphorylated state of PLB is primarily by ßAR-2 signaling. Importantly, the Pkd2(+/-) mice were normotensive and had no evidence of renal cysts. Our results showed that decreased PC2 levels shifted the ßAR pathway balance and changed expression of calcium handling proteins, which resulted in altered cardiac contractility. We propose that PC2 levels in the heart may directly contribute to cardiac remodeling in patients with ADPKD in the absence of renal dysfunction.

Endothelial uncoupling protein 2 regulates mitophagy and pulmonary hypertension during intermittent hypoxia.

OBJECTIVES: Pulmonary hypertension (PH) is a process of lung vascular remodeling, which can lead to right heart dysfunction and significant morbidity. The underlying mechanisms leading to PH are not well understood, and therapies are limited. Using intermittent hypoxia (IH) as a model of oxidant-induced PH, we identified an important role for endothelial cell mitophagy via mitochondrial uncoupling protein 2 (Ucp2) in the development of IH-induced PH. APPROACH AND RESULTS: Ucp2 endothelial knockout (VE-KO) and Ucp2 Flox (Flox) mice were subjected to 5 weeks of IH. Ucp2 VE-KO mice exhibited higher right ventricular systolic pressure and worse right heart hypertrophy, as measured by increased right ventricle weight/left ventricle plus septal weight (RV/LV+S) ratio, at baseline and after IH. These changes were accompanied by increased mitophagy. Primary mouse lung endothelial cells transfected with Ucp2 siRNA and subjected to cyclic exposures to CoCl2 (chemical hypoxia) showed increased mitophagy, as measured by PTEN-induced putative kinase 1 and LC3BII/I ratios, decreased mitochondrial biogenesis, and increased apoptosis. Similar results were obtained in primary lung endothelial cells isolated from VE-KO mice. Moreover, silencing PTEN-induced putative kinase 1 in the endothelium of Ucp2 knockout mice, using endothelial-targeted lentiviral silencing RNA in vivo, prevented IH-induced PH. Human pulmonary artery endothelial cells from people with PH demonstrated changes similar to Ucp2-silenced mouse lung endothelial cells. CONCLUSIONS: The loss of endothelial Ucp2 leads to excessive PTEN-induced putative kinase 1-induced mitophagy, inadequate mitochondrial biosynthesis, and increased apoptosis in endothelium. An endothelial Ucp2-PTEN-induced putative kinase 1 axis may be effective therapeutic targets in PH.

Use of arsenic trioxide in a hemodialysis-dependent patient with relapsed acute promyelocytic leukemia.

Arsenic trioxide has been established for use in both relapsed and front-line treatment of acute promyelocytic leukemia. Dose adjustments are recommended to be considered in severe renal impairment although dosage reduction guidelines are not provided. In addition, toxicities of arsenic are significant. The use of arsenic trioxide has not been well studied in dialysis patients and there is a paucity of data in the literature to support the use in such a situation. We describe an 81-year-old relapsed acute promyelocytic leukemia hemodialysis-dependent patient with a pre-existing cardiac condition who was treated with 10 mg arsenic trioxide three times weekly after dialysis. These findings provide support along with the marginal amount of currently published data for an arsenic trioxide dosing regimen in hemodialysis patients.

Urocortin 2 autocrine/paracrine and pharmacologic effects to activate AMP-activated protein kinase in the heart.

Urocortin 2 (Ucn2), a peptide of the corticotropin-releasing factor (CRF) family, binds with high affinity to type 2 CRF receptors (CRFR2) on cardiomyocytes and confers protection against ischemia/reperfusion. The mechanisms by which the Ucn2-CRFR2 axis mitigates against ischemia/reperfusion injury remain incompletely delineated. Activation of AMP-activated protein kinase (AMPK) also limits cardiac damage during ischemia/reperfusion. AMPK is classically activated by alterations in cellular energetics; however, hormones, cytokines, and additional autocrine/paracrine factors also modulate its activity. We examined the effects of both the endogenous cardiac Ucn2 autocrine/paracrine pathway and Ucn2 treatment on AMPK regulation. Ucn2 treatment increased AMPK activation and downstream acetyl-CoA carboxylase phosphorylation and glucose uptake in isolated heart muscles. These actions were blocked by the CRFR2 antagonist anti-sauvagine-30 and by a PKCε translocation-inhibitor peptide (εV1-2). Hypoxia-induced AMPK activation was also blunted in heart muscles by preincubation with either anti-sauvagine-30, a neutralizing anti-Ucn2 antibody, or εV1-2. Treatment with Ucn2 in vivo augmented ischemic AMPK activation and reduced myocardial injury and cardiac contractile dysfunction after regional ischemia/reperfusion in mice. Ucn2 also directly activated AMPK in ex vivo-perfused mouse hearts and diminished injury and contractile dysfunction during ischemia/reperfusion. Thus, both Ucn2 treatment and the endogenous cardiac Ucn2 autocrine/paracrine pathway activate AMPK signaling pathway, via a PKCε-dependent mechanism, defining a Ucn2-CRFR2-PKCε-AMPK pathway that mitigates against ischemia/reperfusion injury.

Association between right ventricular dysfunction and restrictive lung disease in childhood cancer survivors as measured by quantitative echocardiography.

BACKGROUND: Restrictive lung disease is a complication in childhood cancer survivors who received lung-toxic chemotherapy and/or thoracic radiation. Left ventricular dysfunction is documented in these survivors, but less is known about right ventricular (RV) function. Quantitative echocardiography may help detect subclinical RV dysfunction. The aim of this study was to assess RV function quantitatively in childhood cancer survivors after lung-toxic therapy. PROCEDURES: We identified records of 33 childhood cancer survivors who (1) were treated with lung-toxic therapy and/or radiation, (2) were cancer-free for ≥ one year after therapy, and (3) had pulmonary function tests and echocardiograms from their most recent follow-up visit. RESULTS: Participants' mean age was 11.6 ± 4.5 years at cancer diagnosis and 23 ± 8.6 years at evaluation. The most common diagnosis was lymphoma/leukemia (n = 27). Twenty-nine subjects had anthracycline exposure. Eleven of the 33 subjects demonstrated restrictive pulmonary impairment (total lung capacity 3.69 ± 1.5 L [69.3 ± 22.4% predicted]). Among quantitative measures of RV function, isovolumetric acceleration (IVA), a measure of contractility, was significantly lower in the group with restrictive lung disease (2.42 ± 0.56 vs. 1.83 ± 0.78 m/sec(2); P < 0.05). There was a trend towards lower tissue Doppler derived S' and tricuspid annular plane systolic excursion in the group with restrictive lung disease. Subjects with restrictive lung disease were found to have ≥ 2 abnormal parameters (P < 0.01). CONCLUSION: IVA may detect early RV dysfunction in childhood cancer survivors with restrictive lung disease. Our findings require confirmation in a larger study population and validation by cardiac MRI.

Role of uncoupling protein 3 in ischemia-reperfusion injury, arrhythmias, and preconditioning.

Overexpression of mitochondrial uncoupling proteins (UCPs) attenuates ischemia-reperfusion (I/R) injury in cultured cardiomyocytes. However, it is not known whether UCPs play an essential role in cardioprotection in the intact heart. This study evaluated the cardioprotective efficacy of UCPs against I/R injury and characterized the mechanism of UCP-mediated protection in addition to the role of UCPs in ischemic preconditioning (IPC). Cardiac UCP3 knockout (UCP3(-/-)) and wild-type (WT) mice hearts were subjected to ex vivo and in vivo models of I/R injury and IPC. Isolated UCP3(-/-) mouse hearts were retrogradely perfused and found to have poorer recovery of left ventricular function compared with WT hearts under I/R conditions. In vivo occlusion of the left coronary artery resulted in twofold larger infarcts in UCP3(-/-) mice compared with WT mice. Moreover, the incidence of in vivo I/R arrhythmias was higher in UCP3(-/-) mice. Myocardial energetics were significantly impaired with I/R, as reflected by a decreased ATP content and an increase in the AMP-to-ATP ratio. UCP3(-/-) hearts generated more reactive oxygen species (ROS) than WT hearts during I/R. Pretreatment of UCP3(-/-) hearts with the pharmacological uncoupling agent carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone improved postischemic functional recovery. Also the protective efficacy of IPC was abolished in UCP3(-/-) mice. We conclude that UCP3 plays a critical role in cardioprotection against I/R injury and the IPC phenomenon. There is increased myocardial vulnerability to I/R injury in hearts lacking UCP3. The mechanisms of UCP3-mediated cardioprotection include regulation of myocardial energetics and ROS generation by UCP3 during I/R.

Nedosiran in primary hyperoxaluria subtype 3: results from a phase I, single-dose study (PHYOX4).

Nedosiran is an N-acetyl-D-galactosamine (GalNAc)-conjugated RNA interference agent targeting hepatic lactate dehydrogenase (encoded by the LDHA gene), the putative enzyme mediating the final step of oxalate production in all three genetic subtypes of primary hyperoxaluria (PH). This phase I study assessed the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of subcutaneous nedosiran in patients with PH subtype 3 (PH3) and an estimated glomerular filtration rate  ≥ 30 mL/min/1.73 m2. Single-dose nedosiran 3 mg/kg or placebo was administered in a randomized (2:1), double-blinded manner. Safety/tolerability, 24-h urinary oxalate (Uox) concentrations, and plasma nedosiran concentrations were assessed. The main PD endpoint was the proportion of participants achieving a > 30% decrease from baseline in 24-h Uox at two consecutive visits. Six participants enrolled in and completed the study (nedosiran, n = 4; placebo, n = 2). Nedosiran was well-tolerated and lacked safety concerns. Although the PD response was not met, 24-h Uox excretion declined 24.5% in the nedosiran group and increased 10.5% in the placebo group at Day 85. Three of four nedosiran recipients had a > 30% reduction in 24-h Uox excretion during at least one visit, and one attained near-normal (i.e., ≥ 0.46 to < 0.60 mmol/24 h; ≥ 1.0 to < 1.3 × upper limit of the normal reference range) 24-h Uox excretion from Day 29 to Day 85. Nedosiran displayed predictable plasma PK. The acceptable safety and trend toward Uox-lowering after single-dose nedosiran treatment enables further clinical development of nedosiran in patients with PH3 who currently have no viable therapeutic options. A plain language summary is available in the supplementary information.

Endothelium-derived neuregulin protects the heart against ischemic injury.

BACKGROUND: Removal of cardiac endothelial cells (EC) has been shown to produce significant detrimental effects on the function of adjacent cardiac myocytes, suggesting that EC play a critical role in autocrine/paracrine regulation of the heart. Despite this important observation, the mediators of the protective function of EC remain obscure. Neuregulin (NRG, a member of the epidermal growth factor family) is produced by EC and cardiac myocytes contain receptors (erbB) for this ligand. We hypothesized that NRG is an essential factor produced by EC, which promotes cardioprotection against ischemic injury. METHODS AND RESULTS: We demonstrate that human cardiac EC express and release NRG in response to hypoxia-reoxygenation. Under conditions where hypoxia--reoxygenation causes significant cardiac myocyte cell death, NRG can significantly decrease apoptosis of isolated adult ventricular myocytes. Coculturing adult murine myocytes with human umbilical vein, murine lung microvascular, or human coronary artery EC can also protect myocytes against hypoxia--reoxygenation--induced apoptosis. These protective effects are abolished by NRG gene deletion or silencing of NRG expression in EC. Finally, endothelium-selective deletion of NRG in vivo leads to significantly decreased tolerance to ischemic insult, as demonstrated by impaired postischemic contractile recovery in a perfused whole-organ preparation and larger infarct sizes after coronary artery ligation. CONCLUSION: Together, these data demonstrate that EC-derived NRG plays an important role in cardiac myocyte protection against ischemic injury in the heart and supports the idea that manipulation of this signaling pathway may be an important clinical target in this setting.

Heliox in children with croup: a strategy to hasten improvement.

OBJECTIVE: Upper airway obstruction is responsive to the reduction in airflow turbulence provided by helium/oxygen (heliox) admixture. Our pediatric critical care transport team (PCCTT) has used heliox for children with upper airway obstruction from croup. We sought to describe our experience with heliox on transport and hypothesized that heliox-treated children with croup would show a more rapid clinical improvement. METHODS: Children with croup transported by our PCCTT and admitted to the PICU were evaluated. We analyzed pretransport care, transport interventions, and outcomes. Croup scores (Modified Taussig) were assigned retrospectively according to respiratory therapy charting. Data were analyzed using appropriate statistical tests, including Pearson's chi-square test, Fisher's exact test, Mann-Whitney U rank comparison, and two-sample t-test. RESULTS: Thirty-five children met inclusion criteria. Demographics were similar between groups. The pretransport medical care was similar between groups. Children receiving heliox had a higher baseline croup score [mean (SD) = 5.7(2.3) vs no heliox 2.9 (2.0), P < 0.001]. The improvement in croup scores over the first 60 minutes of transport was more rapid in the heliox-treated children (P < 0.001). There was no difference in the number of children requiring additional nebulized racemic epinephrine during transport. The PICU length of stay (P = 0.59) and hospital length of stay (P = 0.64) were similar between groups. CONCLUSION: Heliox added to standard transport treatment for critically ill children with croup provides a more rapid improvement in croup scores. Heliox for croup during transport does not prolong intensive care unit stay. A prospective clinical trial is warranted to evaluate heliox in pediatric transport.

Renalase deficiency aggravates ischemic myocardial damage.

Chronic kidney disease (CKD) leads to an 18-fold increase in cardiovascular complications not fully explained by traditional risk factors. Levels of renalase, a recently discovered oxidase that metabolizes catecholamines, are decreased in CKD. Here we show that renalase deficiency in a mouse knockout model causes increased plasma catecholamine levels and hypertension. Plasma blood urea nitrogen, creatinine, and aldosterone were unaffected. However, knockout mice had normal systolic function and mild ventricular hypertrophy but tolerated cardiac ischemia poorly and developed myocardial necrosis threefold more severe than that found in wild-type mice. Treatment with recombinant renalase completely rescued the cardiac phenotype. To gain insight into the mechanisms mediating this cardioprotective effect, we tested if gene deletion affected nitrate and glutathione metabolism, but found no differences between hearts of knockout and wild-type mice. The ratio of oxidized (NAD) to reduced (NADH) nicotinamide adenine dinucleotide in cardiac tissue, however, was significantly decreased in the hearts of renalase knockout mice, as was plasma NADH oxidase activity. In vitro studies confirmed that renalase metabolizes NADH and catecholamines. Thus, renalase plays an important role in cardiovascular pathology and its replacement may reduce cardiac complications in renalase-deficient states such as CKD.

Metalloproteinase-dependent cleavage of neuregulin and autocrine stimulation of vascular endothelial cells.

Inflammation is often accompanied by robust angiogenesis. Vascular endothelial cells (ECs) express erbB receptors and their ligand, neuregulin-1, and can respond to neuregulin by proliferation and angiogenesis. We hypothesized that some growth factor-like responses of ECs to inflammatory cytokines can be explained by cleavage of transmembrane neuregulin with subsequent release of its extracellular epidermal growth factor-like-containing domain and autocrine activation. Using a model of cultured human ECs, we found that interleukin-6 or interferon-gamma causes rapid cleavage and release of transmembrane neuregulin. Inhibitors of metalloproteinases abolish this effect. The addition of an inhibitor of tumor necrosis factor-alpha converting enzyme (TACE) blocks cytokine-induced neuregulin release. Silencing of TACE expression increases the amount of basal proneuregulin present in ECs but does not block neuregulin release in response to phorbol myristate acetate (PMA), suggesting that other proteinases are responsible for mediating protein kinase C-dependent cleavage. Cytokines capable of inducing neuregulin cleavage stimulated ERK activation and in vitro angiogenesis (Matrigel cord formation). This effect is blocked by inhibitors that block neuregulin cleavage, erbB protein tyrosine kinase inhibitors, or antineuregulin-neutralizing antibodies. Cytokine-activated metalloproteinase cleavage of neuregulin may play an important role in autocrine activation of EC signaling pathways, contributing to key biological effects, perhaps including inflammation-associated angiogenesis.

Targeting the biology of ageing with mTOR inhibitors to improve immune function in older adults: phase 2b and phase 3 randomised trials.

BACKGROUND: The COVID-19 pandemic highlights the need for therapies that improve immune function in older adults, including interferon (IFN)-induced antiviral immunity that declines with age. In a previous phase 2a trial, RTB101 (previously known as BEZ235), an oral mechanistic target of rapamycin (mTOR) inhibitor, was observed to increase IFN-induced antiviral gene expression and decrease the incidence of respiratory tract infections (RTIs) in older adults. Therefore, we aimed to investigate whether oral RTB101 upregulated IFN-induced antiviral responses and decreased the incidence of viral RTIs when given once daily for 16 weeks during winter cold and flu season. METHODS: We did a phase 2b and a phase 3 double-blind, randomised, placebo-controlled trial in adults aged at least 65 years enrolled in New Zealand, Australia, and the USA at 54 sites. In the phase 2b trial, patients were aged 65-85 years, with asthma, type 2 diabetes, chronic obstructive pulmonary disease (COPD), congestive heart failure, were current smokers, or had an emergency room or hospitalisation for an RTI within the past 12 months. In the phase 3 trial, patients were aged at least 65 years, did not have COPD, and were not current smokers. In the phase 2b trial, patients were randomly assigned to using a validated automated randomisation system to oral RTB101 5 mg, RTB101 10 mg once daily, or placebo in part 1 and RTB101 10 mg once daily, RTB101 10 mg twice daily, RTB101 10 mg plus everolimus once daily, or matching placebo in part 2. In the phase 3 trial, patients were randomly assigned to RTB101 10mg once daily or matching placebo. The phase 2b primary outcome was the incidence of laboratory-confirmed RTIs during 16 weeks of winter cold and influenza season and the phase 3 primary outcome was the incidence of clinically symptomatic respiratory illness defined as symptoms consistent with an RTI, irrespective of whether an infection was laboratory-confirmed. Patients, investigators, and sponsor were masked to treatment assignments. All patients who received at least part of one dose of study drug were included in the primary and safety analyses. The phase 2b trial was registered with ANZCTR, ACTRN12617000468325, ClinicalTrials.gov, NCT03373903, and the phase 3 trial was registered with ANZCTR, ACTRN12619000628145. FINDINGS: In the phase 2b trial, we recruited 652 participants in total between May 16, 2017, and Jan 10, 2018, 179 participants to part 1 of the study (randomly assigned 1:1:1 to RTB101 5 mg once daily [61 participants], RTB101 10 mg once daily [58 participants], or matching placebo [60 participants]) and 473 patients to part 2 (randomly assigned 1:1:1:1 to RTB101 10 mg once daily [118 participants], RTB101 10 mg twice daily [120 participants], RTB101 10 mg in combination with everolimus 0·1 mg daily [115 participants] or matching placebo [120 participants]). In our first prespecified statistical analysis of the primary efficacy endpoint for part 2 of the phase 2b trial efficacy of RTB101 10 mg in combination with everolimus 0·1 mg once daily compared with placebo did not meet statistical significance but, in our second prespecified analysis, which included data from part 1 and part 2, we found a statistically significant reduction in the proportion of patients who had one or more laboratory-confirmed RTIs in the RTB101 10 mg once daily treatment group (34 [19%] of 176) compared with the pooled placebo group (50 [28%] of 180; odds ratio [OR] 0·601 [90% CI 0·391-0·922]; p=0·02). In the phase 3 trial, we enrolled 1024 patients between May 7, 2018, and July 19, 2019. 513 (50·1%) participants were randomly assigned to RTB101 10 mg once daily and 510 (49·9%) to placebo. In the full analysis set of the phase 3 trial, RTB101 did not reduce the proportion of patients with clinically symptomatic respiratory illness (134 [26%] of 511 patients in the RTB101 treatment group vs 125 [25%] 510 patients in the placebo treatment group; OR 1·07 [90% CI 0·80-1·42]; p=0·65). In both trials, significantly more IFN-induced antiviral genes were upregulated in patients treated with RTB101 as compared with placebo. The study drug was found to be safe and well-tolerated across trials and treatment groups. Only one patient in the placebo group in the phase 3 trial had serious adverse events (nausea, fatigue, hyponatraemia, and arthralgia) which were considered related to study drug treatment. Three patients died in the phase 2b trial and one in the phase 3 trial but no deaths were considered related to study treatment. INTERPRETATION: The combined results indicate that low doses of the mTOR inhibitor RTB101 are well tolerated and upregulate IFN-induced antiviral responses in older adults. Further refinement of clinical trial endpoints and patient populations might be required to identify whether upregulation of IFN responses by mTOR inhibitors consistently decreases the incidence or severity of viral infections in older adults. FUNDING: resTORbio and the National Institute on Aging.

Embryonic caffeine exposure induces adverse effects in adulthood.

The purpose of this study was to determine both the short-term effects on cardiac development and embryo growth and the long-term effects on cardiac function and body composition of in utero caffeine exposure. Pregnant mice (C57BL/6) were exposed to hypoxia (10% O(2)) or room air from embryonic days (E) 8.5-10.5, and treated with caffeine (20 mg/kg, i.p.) or vehicle (normal saline, 0.9% NaCl). This caffeine dose results in a circulating level that is equivalent to 2 cups of coffee in humans. Hypoxic exposure acutely reduced embryonic growth by 30%. Exposure to a single dose of caffeine inhibited cardiac ventricular development by 53% in hypoxia and 37% in room air. Caffeine exposure resulted in inhibition of hypoxia-induced HIF1alpha protein expression in embryos by 40%. When offspring from dams treated with a single dose of caffeine were studied in adulthood, we observed that caffeine treatment alone resulted in a decrease in cardiac function of 38%, as assessed by echocardiography. We also observed a 20% increase in body fat with male mice exposed to caffeine. Caffeine was dissolved in normal saline, so it was used as a control. Room air controls were used to compare to the hypoxic mice. Exposure to a single dose of caffeine during embryogenesis results in both short-term effects on cardiac development and long-term effects on cardiac function.

Cytostatic drugs, neuregulin activation of erbB receptors, and angiogenesis.

Cytostatic drugs were developed to target specific molecular pathways shown to drive tumor growth. Although this approach has been very successful in treating cancers, its use is often hindered by off-target toxic effects. An example of this is trastuzumab, which targets the erbB2 kinase receptor. This drug successfully decreases tumor growth but adversely affects cardiac function. This observation led to important studies elucidating the importance of the erbB pathway in cardioprotection and angiogenesis. This review addresses the problem of off-target effects of cytostatic drugs (specifically trastuzumab) and their effect on cardiac function, summarizes the neuregulin-1 (NRG)/erbB signaling pathway, and discusses its importance in cardiac myocytes. It also highlights important findings showing the role of NRG/erbB signaling in microvascular preservation and angiogenesis, with a brief discussion of preclinical and clinical data regarding treatment of cardiovascular disease with NRG.

PEGylated PLGA nanoparticles for the improved delivery of doxorubicin.

We hypothesize that the efficacy of doxorubicin (DOX) can be maximized and dose-limiting cardiotoxicity minimized by controlled release from PEGylated nanoparticles. To test this hypothesis, a unique surface modification technique was used to create PEGylated poly(lactic-co-glycolic acid) (PLGA) nanoparticles encapsulating DOX. An avidin-biotin coupling system was used to control poly(ethylene glycol) conjugation to the surface of PLGA nanoparticles, of diameter approximately 130 nm, loaded with DOX to 5% (wt/wt). Encapsulation in nanoparticles did not compromise the efficacy of DOX; drug-loaded nanoparticles were found to be at least as potent as free DOX against A20 murine B-cell lymphoma cells in culture and of comparable efficacy against subcutaneously implanted tumors. Cardiotoxicity in mice as measured by echocardiography, serum creatine phosphokinase (CPK), and histopathology was reduced for DOX-loaded nanoparticles as compared with free DOX. Administration of 18 mg/kg of free DOX induced a sevenfold increase in CPK levels and significant decreases in left ventricular fractional shortening over control animals, whereas nanoparticle-encapsulated DOX produced none of these pathological changes. FROM THE CLINICAL EDITOR: The efficacy of doxorubicin (DOX) may be maximized and dose-limiting cardiotoxicity minimized by controlled release from PEGylated nanoparticles. Administration of 18 mg/kg of free DOX induced a sevenfold increase in CPK levels and significant decreases in left ventricular fractional shortening in mice, whereas nanoparticle-encapsulated DOX produced none of these pathological changes.