Food perception promotes phosphorylation of MFFS131 and mitochondrial fragmentation in liver.

Liver mitochondria play a central role in metabolic adaptations to changing nutritional states, yet their dynamic regulation upon anticipated changes in nutrient availability has remained unaddressed. Here, we found that sensory food perception rapidly induced mitochondrial fragmentation in the liver through protein kinase B/AKT (AKT)-dependent phosphorylation of serine 131 of the mitochondrial fission factor (MFFS131). This response was mediated by activation of hypothalamic pro-opiomelanocortin (POMC)-expressing neurons. A nonphosphorylatable MFFS131G knock-in mutation abrogated AKT-induced mitochondrial fragmentation in vitro. In vivo, MFFS131G knock-in mice displayed altered liver mitochondrial dynamics and impaired insulin-stimulated suppression of hepatic glucose production. Thus, rapid activation of a hypothalamus-liver axis can adapt mitochondrial function to anticipated changes of nutritional state in control of hepatic glucose metabolism.

The Art of Dosing for Subcutaneous Immunotherapy in North America.

Subcutaneous immunotherapy (SCIT) is a long-established treatment option for allergic rhinoconjunctivitis. Proper dosing of the allergens is critical for the efficacy and safety of SCIT. Of the hundreds of liquid allergen extracts in the United States, effective and well-tolerated SCIT dosing has only been established for a small number. Thus, SCIT dosing remains largely empiric and continues to be, by necessity, an art. To highlight the complexity of SCIT dosing, this review summarizes the historical and current landscape of U.S. allergen extracts, differences among U.S. and European allergen extracts, allergen selection for SCIT, considerations for compounding of allergen extract mixtures, and recommended dosing. As of 2021, 18 standardized allergen extracts are available in the United States; all other extracts remain unstandardized without characterization of allergen content or potency. U.S. allergen extracts differ from European extracts in formulation and potency characterization. There is no standardized methodology for SCIT allergen selection, and interpretation of allergen sensitization is not straightforward. Compounding of SCIT mixtures requires consideration of potential dilution effects, allergen cross-reactivity, proteolytic activity, and additives. Probable effective dose ranges for SCIT are recommended in U.S. allergy immunotherapy practice parameters, although there are few studies using U.S. extracts supporting these doses as therapeutic. In contrast, optimized doses of sublingual immunotherapy tablets have been confirmed in North American phase 3 trials. The SCIT dosing for each patient remains an art that requires clinical experience and consideration of polysensitization, tolerability, compounding of allergen extract mixtures, and the range of recommended doses within the context of extract potency variability.

Nutrient-sensing AgRP neurons relay control of liver autophagy during energy deprivation.

Autophagy represents a key regulator of aging and metabolism in sensing energy deprivation. We find that fasting in mice activates autophagy in the liver paralleled by activation of hypothalamic AgRP neurons. Optogenetic and chemogenetic activation of AgRP neurons induces autophagy, alters phosphorylation of autophagy regulators, and promotes ketogenesis. AgRP neuron-dependent induction of liver autophagy relies on NPY release in the paraventricular nucleus of the hypothalamus (PVH) via presynaptic inhibition of NPY1R-expressing neurons to activate PVHCRH neurons. Conversely, inhibiting AgRP neurons during energy deprivation abrogates induction of hepatic autophagy and rewiring of metabolism. AgRP neuron activation increases circulating corticosterone concentrations, and reduction of hepatic glucocorticoid receptor expression attenuates AgRP neuron-dependent activation of hepatic autophagy. Collectively, our study reveals a fundamental regulatory principle of liver autophagy in control of metabolic adaptation during nutrient deprivation.

Technical standards in allergen exposure chambers worldwide - an EAACI Task Force Report.

Allergen exposure chambers (AECs) can be used for controlled exposure to allergenic and non-allergenic airborne particles in an enclosed environment, in order to (i) characterize the pathological features of respiratory diseases and (ii) contribute to and accelerate the clinical development of pharmacological treatments and allergen immunotherapy for allergic disease of the respiratory tract (such as allergic rhinitis, allergic rhinoconjunctivitis, and allergic asthma). In the guidelines of the European Medicines Agency for the clinical development of products for allergen immunotherapy (AIT), the role of AECs in determining primary endpoints in dose-finding Phase II trials is emphasized. Although methodologically insulated from the variability of natural pollen exposure, chamber models remain confined to supporting secondary, rather than primary, endpoints in Phase III registration trials. The need for further validation in comparison with field exposure is clearly mandated. On this basis, the European Academy of Allergy and Clinical Immunology (EAACI) initiated a Task Force in 2015 charged to gain a better understanding of how AECs can generate knowledge about respiratory allergies and can contribute to the clinical development of treatments. Researchers working with AECs worldwide were asked to provide technical information in eight sections: (i) dimensions and structure of the AEC, (ii) AEC staff, (iii) airflow, air processing, and operating conditions, (iv) particle dispersal, (v) pollen/particle counting, (vi) safety and non-contamination measures, (vii) procedures for symptom assessments, (viii) tested allergens/substances and validation procedures. On this basis, a minimal set of technical requirements for AECs applied to the field of allergology is proposed.

Treatment Effect of the Tree Pollen SLIT-Tablet on Allergic Rhinoconjunctivitis During Oak Pollen Season.

BACKGROUND: Birch, alder, hazel, and oak are members of the birch homologous group based on cross-reactivity toward the birch pollen allergen Betula verrucosa 1. Theoretically, allergy to these tree pollens may be treated by immunotherapy with one representative allergen extract. OBJECTIVE: To evaluate post hoc whether treatment of birch pollen-induced allergic rhinoconjunctivitis with a standardized tree sublingual immunotherapy (SLIT)-tablet containing birch pollen extract reduces symptoms and symptom-relieving medication use during the oak pollen season (OPS). METHODS: In a randomized, multinational, double-blind trial (EudraCT-2015-004821-15), 634 participants (ages 12-65 years) received daily tree SLIT-tablet (12 SQ-Bet) or placebo before and during tree pollen season (alder/hazel plus birch pollen season [BPS]). Symptom-relieving medication was allowed. The primary end point was the average total combined score (sum of rhinoconjunctivitis daily symptom score and daily medication score) during BPS. Outcomes during the OPS (excluding overlapping BPS days) were analyzed post hoc. RESULTS: Relative improvements in average total combined score, daily symptom score, and daily medication score with the tree SLIT-tablet versus placebo during the OPS were 25%, 22%, and 32%, respectively (all P < .001). Significant correlations were observed between birch and oak serum immunoglobulin E (sIgE) at baseline (r = 0.86) and between birch and oak IgG4 after treatment (r = 0.72). Oak sIgE and IgG4 kinetics in response to tree SLIT-tablet treatment were similar to birch. CONCLUSIONS: The tree SLIT-tablet leads to significant improvement of rhinoconjunctivitis outcomes during the OPS, supporting the clinical relevance of immunological cross-reactivity toward birch and oak allergens.

Allergy to oak pollen in North America.

Background: Oak pollen is an important allergen in North America. The genus Quercus (oak) belongs to the family Fagaceae under the order Fagales. Objective: The objective of this article was to narratively review the oak pollen season, clinical and epidemiologic aspects of allergy to oak pollen, oak taxonomy, and oak allergen cross-reactivity, with a focus on the North American perspective. Methods: A PubMed literature review (no limits) was conducted. Publications related to oak pollen, oak-related allergic rhinitis with or without conjunctivitis, and oak-related allergic asthma were selected for review. Results: Oak species are common throughout the United States and contribute up to 50% to overall atmospheric pollen loads. Mean peak oak pollen counts can reach >2000 grains/m³. The start of the oak pollen season generally corresponds to the seasonal shift from winter to spring based on latitude and elevation, and may begin as early as mid February. The duration of the season can last > 100 days and, in general, is longer at lower latitudes. In the United States, ∼30% of individuals with allergy are sensitized to oak. The oak pollen season correlates with increased allergic rhinitis symptom-relieving medication use and asthma-related emergency department visits or hospitalizations. Oak falls within the birch homologous group. Extensive immunologic cross-reactivity has been demonstrated between oak pollen and birch pollen allergens, and, more specifically, their major allergens Que a 1 and Bet v 1. The cross-reactivity between oak and birch has implications for allergy immunotherapy (AIT) because guidelines suggest selecting one representative allergen within a homologous group for AIT, a principle that would apply to oak. Conclusion: Allergy to oak pollen is common in North America and has a substantial clinical impact. Oak pollen allergens are cross-reactive with birch pollen allergens, which may have implications for AIT.

Mild Impairment of Mitochondrial OXPHOS Promotes Fatty Acid Utilization in POMC Neurons and Improves Glucose Homeostasis in Obesity.

Mitochondrial oxidative phosphorylation (OXPHOS) and substrate utilization critically regulate the function of hypothalamic proopiomelanocortin (POMC)-expressing neurons. Here, we demonstrate that inactivation of apoptosis-inducing factor (AIF) in POMC neurons mildly impairs mitochondrial respiration and decreases firing of POMC neurons in lean mice. In contrast, under diet-induced obese conditions, POMC-Cre-specific inactivation of AIF prevents obesity-induced silencing of POMC neurons, translating into improved glucose metabolism, improved leptin, and insulin sensitivity, as well as increased energy expenditure in AIFΔPOMC mice. On a cellular level, AIF deficiency improves mitochondrial morphology, facilitates the utilization of fatty acids for mitochondrial respiration, and increases reactive oxygen species (ROS) formation in POMC neurons from obese mice, ultimately leading to restored POMC firing upon HFD feeding. Collectively, partial impairment of mitochondrial function shifts substrate utilization of POMC neurons from glucose to fatty acid metabolism and restores their firing properties, resulting in improved systemic glucose and energy metabolism in obesity.

Lack of effect of Timothy grass pollen sublingual immunotherapy tablet on birch pollen-induced allergic rhinoconjunctivitis in an environmental exposure unit.

BACKGROUND: Timothy grass pollen allergen extract tablets (Grastek) are standardized sublingual immunotherapy tablets (SLIT-T) approved for the treatment of grass pollen-induced allergic rhinitis (AR) and conjunctivitis. Many grass allergic patients are also cosensitized to birch pollen. Whether Timothy grass SLIT-T can confer symptomatic benefits for birch pollen-induced AR symptoms is unknown. OBJECTIVE: To evaluate the treatment effect of Timothy grass SLIT-T for birch pollen-induced AR in participants sensitized to both grass and birch pollen using an environmental exposure unit (EEU). METHODS: This study was a phase 4, randomized, double-blind, placebo-controlled, parallel-group study that enrolled participants aged 18 to 65 years allergic to both timothy grass and birch pollen. After a baseline EEU birch pollen challenge, in which a minimum total nasal symptom score (TNSS) of 6 of 12 was required for enrollment, participants were randomized to receive Timothy grass SLIT-T or placebo taken once daily for 4 months. No confirmatory grass pollen challenge was performed. The primary end point was the change in TNSS averaged from assessments from hours 2 to 5 during the posttreatment birch pollen challenge compared with baseline. The secondary and exploratory end points included temporally identical changes in total ocular symptom score (TOSS), total rhinoconjunctivitis symptom score (TRSS), and individual symptom scores. RESULTS: The difference in TNSS reduction after 4 months of therapy between the Timothy grass SLIT-T and placebo group was not significant (P = .83). Reductions in TOSS (P = .19) and TRSS (P = .67) were also comparable between groups. Findings between groups for individual symptom scores were similar (all P > .40), except for watery eyes, in which symptom reduction was slightly better in the placebo arm (P = .01). Timothy grass SLIT-T was well tolerated, and no serious adverse effects occurred. CONCLUSION: A bystander effect of grass SLIT-T on birch pollen-induced AR symptoms was not detected. Symptomatic benefits of grass SLIT-T are likely allergen specific. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02394600.

SQ grass sublingual allergy immunotherapy tablet for disease-modifying treatment of grass pollen allergic rhinoconjunctivitis.

BACKGROUND: Allergy immunotherapy is a treatment option for allergic rhinoconjunctivitis (ARC). It is unique compared with pharmacotherapy in that it modifies the immunologic pathways that elicit an allergic response. The SQ Timothy grass sublingual immunotherapy (SLIT) tablet is approved in North America and throughout Europe for the treatment of adults and children (≥5 years old) with grass pollen-induced ARC. OBJECTIVE: The clinical evidence for the use of SQ grass SLIT-tablet as a disease-modifying treatment for grass pollen ARC is discussed in this review. METHODS: The review included the suitability of SQ grass SLIT-tablet for patients with clinically relevant symptoms to multiple Pooideae grass species, single-season efficacy, safety, adherence, coseasonal initiation, and cost-effectiveness. The data from the long-term SQ grass SLIT-tablet clinical trial that evaluated a clinical effect 2 years after a continuous 3-year treatment period were presented in the context of regulatory criteria that define a clinically meaningful effect. RESULTS: This trial demonstrated that the clinical effect of the SQ grass SLIT-tablet is maintained, which is also supported by the immunologic findings. CONCLUSION: Therefore, the SQ grass SLIT-tablet has an indication as a disease-modifying therapy in Europe, and a sustained effect is recognized in the United States.

Safety and tolerability of a short ragweed sublingual immunotherapy tablet.

BACKGROUND: MK-3641 is a short ragweed sublingual tablet under investigation for immunotherapy of ragweed pollen-induced allergic rhinitis. OBJECTIVE: To characterize the safety and tolerability of a ragweed sublingual tablet (Merck/ALK-Abelló) in ragweed-allergic adults with or without conjunctivitis. METHODS: Data from 4 randomized, double-blinded, placebo-controlled trials of MK-3641 (2 28-day and 2 52-week trials) were evaluated. Pooled analyses examined short-term safety over 28 days from all 4 trials and long-term safety from the 52-week trials. RESULTS: Across all studies, 757, 198, 454, and 1,058 subjects were randomized to placebo or 1.5, 6, or 12 Amb a 1-U of MK-3641, respectively. Treatment-related adverse events were more frequent in the 6- and 12-Amb a 1-U MK-3641 groups than in the placebo group and were primarily local application-site reactions occurring in the first few days of treatment. There was no treatment-associated loss of asthma control or worsening of asthma associated with treatment. No swellings led to airway obstruction or respiratory compromise. No treatment-related anaphylactic shock, life-threatening, or serious treatment-related adverse events were reported for any MK-3641 dose. Of the 1,707 MK-3641-treated subjects, 1 systemic (anaphylactic) reaction was reported (0.06%). The 52-week long-term assessment was generally similar to the safety profile based on the 28-day assessment. CONCLUSION: MK-3641 doses up to and including 12 Amb a 1-U were well tolerated, with no unexpected safety findings. Sublingual immunotherapy risks such as worsening asthma or airway swellings that could cause airway obstruction were not observed. Systemic reactions and use of epinephrine were uncommon. In these studies, after the first dose was administered in a health care setting, self-administration was well tolerated. TRIAL REGISTRATION: clinicaltrials.gov Identifiers: NCT01469182, NCT00783198, NCT00770315, and NCT00978029.

Efficacy and safety of grass sublingual immunotherapy tablet, MK-7243: a large randomized controlled trial.

BACKGROUND: In North America, few studies have evaluated sublingual immunotherapy for allergic rhinitis with or without conjunctivitis (AR/C); pediatric data are sparse. The authors report findings from the largest published immunotherapy trial yet conducted in adults and children. OBJECTIVE: To evaluate grass sublingual immunotherapy tablet (MK-7243) treatment in subjects with AR/C. METHODS: North American subjects (5-65 years old) with grass allergy were randomized 1:1 to once-daily MK-7243 (2,800 BAU Phleum pratense) or placebo. The first dose was given at the investigator's office; subsequent doses were self-administered at home. The primary end point was total combined score (TCS; rhinoconjunctivitis daily symptom score [DSS] plus daily medication score [DMS]) over the entire grass pollen season (GPS). Key secondary end points included entire-season DSS, DMS, peak-season TCS, and rhinoconjunctivitis quality-of-life questionnaire scores. Safety outcomes included adverse events (AEs). RESULTS: One thousand five hundred one subjects were randomized (85% polysensitized, 25% had asthma). MK-7243 yielded improvements vs placebo of 23% in entire-season TCS (median difference -0.98, P < .001), 29% in peak-season TCS (median difference -1.33, P < .001), 20% in entire-season DSS (median difference -0.64, P = .001), 35% in entire-season DMS (mean difference -0.48, P < .001), and 12% in peak-season rhinoconjunctivitis quality-of-life questionnaire (median difference -0.13, P = .027). Efficacy between children and adults was similar. Most AEs were transient local application-site reactions, with no serious treatment-related AEs or anaphylactic shock. Three subjects (1 placebo, 2 MK-7243) had moderate systemic allergic reactions. CONCLUSION: MK-7243 was effective in polysensitized grass-allergic North American children and adults with AR/C in this large trial, confirming previous research.

Randomized controlled trial of ragweed allergy immunotherapy tablet efficacy and safety in North American adults.

BACKGROUND: Ragweed is an important cause of allergic rhinitis with or without conjunctivitis (AR/C) in North America and elsewhere. Allergen immunotherapy enabling safe patient self-administration is considered an unmet clinical need. Allergy immunotherapy tablet (AIT) treatment has shown promising efficacy and safety for grass allergy but has not been assessed for ragweed allergy. OBJECTIVE: To evaluate efficacy and safety of 2 short ragweed AIT doses in patients with AR/C. METHODS: Adults with ragweed pollen-induced AR/C were randomized 1:1:1 to daily ragweed AIT (6 or 12 Amb a 1 units) or placebo before, throughout, and after ragweed season (approximately 52 weeks). Patients could use predefined allergy rescue medications in season. Efficacy end points included peak and entire season total combined score (TCS) and its components daily symptom score (DSS), and daily medication score (DMS). Safety assessments included adverse events. RESULTS: A total of 565 patients were randomized. During peak season, the 6- and 12-Amb a 1 unit ragweed AIT doses showed 21% (-1.76 score) and 27% (-2.24 score) improvement in TCS vs placebo (P < .05). The 6- and 12-Amb a 1 unit AIT doses significantly improved DSS and DMS vs placebo (P < .05). Peak and entire season efficacy were comparable. The 12-Amb a 1 unit AIT dose reduced peak-season TCS vs placebo by 21% and 25% in subgroups with and without local application-site reactions, respectively. Most treatment-related adverse events were mild, oral reactions; no systemic allergic reactions were reported. One patient in the 6-Amb a 1 unit group received epinephrine at an emergency facility for sensation of localized pharyngeal edema. CONCLUSION: In this trial, ragweed AIT was effective and well tolerated in ragweed-allergic North American adults. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00783198.

Randomized controlled trial of a ragweed allergy immunotherapy tablet in North American and European adults.

BACKGROUND: In North America and Europe, millions of patients experience symptoms of allergic rhinitis with or without conjunctivitis (AR/C) on exposure to ragweed pollen. The disease burden can be significant, with most patients relying on symptomatic medications without disease-modifying potential. However, novel sublingual immunomodulatory treatment options may potentially play an important role if efficacy and side effect profiles allow the convenience of self-administration. OBJECTIVES: This study evaluated an allergy immunotherapy tablet (AIT; SCH 39641/MK-3641) for treatment of ragweed-induced AR/C in the first large randomized, double-blind multinational trial of this therapeutic modality for ragweed allergy. METHODS: Adults (n = 784) with short ragweed-induced AR/C were randomly assigned to approximately 52 weeks of daily self-administered ragweed AIT of 1.5, 6, or 12 units of Ambrosia artemisiifolia major allergen 1 (Amb a 1-U) or placebo. Subjects could use as-needed allergy rescue medication. Symptoms and medications were recorded daily. The primary efficacy end point was total combined daily symptom/medication score (TCS) during peak ragweed season. Safety was monitored through adverse event diaries maintained through study duration. RESULTS: During peak ragweed season, ragweed AIT of 1.5, 6, and 12 Amb a 1-U reduced TCS by 9% (-0.76; P = .22), 19% (-1.58; P = .01), and 24% (-2.04; P = .002) compared with placebo. During the entire season, ragweed AIT of 1.5, 6, and 12 Amb a 1-U reduced TCS by 12% (-0.88; P = .09), 18% (-1.28; P = .01), and 27% (-1.92; P < .001) compared with placebo. Treatment was well tolerated; no systemic allergic reactions occurred. CONCLUSIONS: In this trial, ragweed AIT of 12 Amb a 1-U was effective and tolerable with a safety profile that permitted daily self-administration of ragweed allergen immunotherapy.