Diagnostic findings in sinonasal aspergillosis in dogs in the United Kingdom: 475 cases (2011-2021)

OBJECTIVES

To describe the diagnostic tests used and their comparative performance in dogs diagnosed with sinonasal aspergillosis in the United Kingdom. A secondary objective was to describe the signalment, clinical findings and common clinicopathologic abnormalities in sinonasal aspergillosis.

MATERIALS AND METHODS

A multi-centre retrospective survey was performed involving 23 referral centres in the United Kingdom to identify dogs diagnosed with sinonasal aspergillosis from January 2011 to December 2021. Dogs were included if fungal plaques were seen during rhinoscopy or if ancillary testing (via histopathology, culture, cytology, serology or PCR) was positive and other differential diagnoses were excluded.

RESULTS

A total of 662 cases were entered into the database across the 23 referral centres. Four hundred and seventy-five cases met the study inclusion criteria. Of these, 419 dogs had fungal plaques and compatible clinical signs. Fungal plaques were not seen in 56 dogs with turbinate destruction that had compatible clinical signs and a positive ancillary test result. Ancillary diagnostics were performed in 312 of 419 (74%) dogs with observed fungal plaques permitting calculation of sensitivity of cytology as 67%, fungal culture 59%, histopathology 47% and PCR 71%.

CLINICAL SIGNIFICANCE

The sensitivities of ancillary diagnostics in this study were lower than previously reported challenging the clinical utility of such tests in sinonasal aspergillosis. Treatment and management decisions should be based on a combination of diagnostics including imaging findings, visual inspection, and ancillary testing, rather than ancillary tests alone.

On the interdependence of ketone body oxidation, glycogen content, glycolysis and energy metabolism in the heart

In heart, glucose and glycolysis are important for anaplerosis and potentially therefore for d-β-hydroxybutyrate (βHB) oxidation. As a glucose store, glycogen may also furnish anaplerosis. We determined the effects of glycogen content on βHB oxidation and glycolytic rates, and their downstream effects on energetics, in the isolated rat heart. High glycogen (HG) and low glycogen (LG) containing hearts were perfused with 11 mM [5-3 H]glucose and/or 4 mM [14 C]βHB to measure glycolytic rates or βHB oxidation, respectively, then freeze-clamped for glycogen and metabolomic analyses. Free cytosolic [NAD+ ]/[NADH] and mitochondrial [Q+ ]/[QH2 ] ratios were estimated using the lactate dehydrogenase and succinate dehydrogenase reaction, respectively. Phosphocreatine (PCr) and inorganic phosphate (Pi ) concentrations were measured using 31 P-nuclear magnetic resonance spectroscopy. Rates of βHB oxidation in LG hearts were half that in HG hearts, with βHB oxidation directly proportional to glycogen content. βHB oxidation decreased glycolysis in all hearts. Glycogenolysis in glycogen-replete hearts perfused with βHB alone was twice that of hearts perfused with βHB and glucose, which had significantly higher levels of the glycolytic intermediates fructose 1,6-bisphosphate and 3-phosphoglycerate, and higher free cytosolic [NAD+ ]/[NADH]. βHB oxidation increased the Krebs cycle intermediates citrate, 2-oxoglutarate and succinate, the total NADP/H pool, reduced mitochondrial [Q+ ]/[QH2 ], and increased the calculated free energy of ATP hydrolysis (∆GATP ). Although βHB oxidation inhibited glycolysis, glycolytic intermediates were not depleted, and cytosolic free NAD remained oxidised. βHB oxidation alone increased Krebs cycle intermediates, reduced mitochondrial Q and increased ∆GATP . We conclude that glycogen facilitates cardiac βHB oxidation by anaplerosis. KEY POINTS: Ketone bodies (d-β-hydroxybutyrate, acetoacetate) are increasingly recognised as important cardiac energetic substrates, in both healthy and diseased hearts. As 2-carbon equivalents they are cataplerotic, causing depletion of Krebs cycle intermediates; therefore their utilisation requires anaplerotic supplementation, and intra-myocardial glycogen has been suggested as a potential anaplerotic source during ketone oxidation. It is demonstrated here that cardiac glycogen does indeed provide anaplerotic substrate to facilitate β-hydroxybutyrate oxidation in isolated perfused rat heart, and this contribution was quantified using a novel pulse-chase metabolic approach. Further, using metabolomics and 31 P-MR, it was shown that glycolytic flux from myocardial glycogen increased the heart's ability to oxidise βHB, and βHB oxidation increased the mitochondrial redox potential, ultimately increasing the free energy of ATP hydrolysis.

Primary school mobile dental program in New South Wales, Australia: protocol for the evaluation of a state government oral health initiative

BACKGROUND

Socioeconomically disadvantaged children are disproportionately affected by oral disease. Mobile dental services help underserved communities overcome barriers to accessing health care, including time, geography, and trust. The NSW Health Primary School Mobile Dental Program (PSMDP) is designed to provide diagnostic and preventive dental services to children at their schools. The PSMDP is mainly targeted toward high-risk children and priority populations. This study aims to evaluate the program's performance across five local health districts (LHDs) where the program is being implemented.

METHODS

The evaluation will use routinely collected administrative data, along with other program-specific data sources, from the district public oral health services to conduct a statistical analysis that determines the reach and uptake of the program, its effectiveness, and the associated costs and cost-consequences. The PSMDP evaluation program utilises data from Electronic Dental Records (EDRs) and other data sources, including patient demographics, service mix, general health, oral health clinical data and risk factor information. The overall design includes cross-sectional and longitudinal components. The design combines comprehensive output monitoring across the five participating LHDs and investigates the associations between socio-demographic factors, service patterns and health outcomes. Time series analysis using difference-in-difference estimation will be conducted across the four years of the program, involving services, risk factors, and health outcomes. Comparison groups will be identified via propensity matching across the five participating LHDs. An economic analysis will estimate the costs and cost-consequences for children who participate in the program versus the comparison group.

DISCUSSION

The use of EDRs for oral health services evaluation research is a relatively new approach, and the evaluation works within the limitations and strengths of utilising administrative datasets. The study will also provide avenues to improve the quality of data collected and system-level improvements to better enable future services to be aligned with disease prevalence and population needs.

The effects of endogenously- and exogenously-induced hyperketonemia on exercise performance and adaptation

Elevating blood ketones may enhance exercise capacity and modulate adaptations to exercise training; however, these effects may depend on whether hyperketonemia is induced endogenously through dietary carbohydrate restriction, or exogenously through ketone supplementation. To determine this, we compared the effects of endogenously- and exogenously-induced hyperketonemia on exercise capacity and adaptation. Trained endurance athletes undertook 6 days of laboratory based cycling ("race") whilst following either: a carbohydrate-rich control diet (n = 7; CHO); a carbohydrate-rich diet + ketone drink four-times daily (n = 7; Ex Ket); or a ketogenic diet (n = 7; End Ket). Exercise capacity was measured daily, and adaptations in exercise metabolism, exercise physiology and postprandial insulin sensitivity (via an oral glucose tolerance test) were measured before and after dietary interventions. Urinary β-hydroxybutyrate increased by ⁓150-fold and ⁓650-fold versus CHO with Ex Ket and End Ket, respectively. Exercise capacity was increased versus pre-intervention by ~5% on race day 1 with CHO (p < 0.05), by 6%-8% on days 1, 4, and 6 (all p < 0.05) with Ex Ket and decreased by 48%-57% on all race days (all p > 0.05) with End Ket. There was an ⁓3-fold increase in fat oxidation from pre- to post-intervention (p < 0.05) with End Ket and increased perceived exercise exertion (p < 0.05). No changes in exercise substrate metabolism occurred with Ex Ket, but participants had blunted postprandial insulin sensitivity (p < 0.05). Dietary carbohydrate restriction and ketone supplementation both induce hyperketonemia; however, these are distinct physiological conditions with contrasting effects on exercise capacity and adaptation to exercise training.

A seafood risk tool for assessing and mitigating chemical and pathogen hazards in the aquaculture supply chain

Intricate links between aquatic animals and their environment expose them to chemical and pathogenic hazards, which can disrupt seafood supply. Here we outline a risk schema for assessing potential impacts of chemical and microbial hazards on discrete subsectors of aquaculture-and control measures that may protect supply. As national governments develop strategies to achieve volumetric expansion in seafood production from aquaculture to meet increasing demand, we propose an urgent need for simultaneous focus on controlling those hazards that limit its production, harvesting, processing, trade and safe consumption. Policies aligning national and international water quality control measures for minimizing interaction with, and impact of, hazards on seafood supply will be critical as consumers increasingly rely on the aquaculture sector to supply safe, nutritious and healthy diets.

Evaluation of Acute Supplementation With the Ketone Ester (R)-3-Hydroxybutyl-(R)-3-Hydroxybutyrate (deltaG) in Healthy Volunteers by Cardiac and Skeletal Muscle 31P Magnetic Resonance Spectroscopy

In this acute intervention study, we investigated the potential benefit of ketone supplementation in humans by studying cardiac phosphocreatine to adenosine-triphosphate ratios (PCr/ATP) and skeletal muscle PCr recovery using phosphorus magnetic resonance spectroscopy (³¹P-MRS) before and after ingestion of a ketone ester drink. We recruited 28 healthy individuals: 12 aged 23–70 years for cardiac ³¹P-MRS, and 16 aged 60–75 years for skeletal muscle ³¹P-MRS. Baseline and post-intervention resting cardiac and dynamic skeletal muscle ³¹P-MRS scans were performed in one visit, where 25 g of the ketone monoester, deltaG^®, was administered after the baseline scan. Administration was timed so that post-intervention ³¹P-MRS would take place 30 min after deltaG^® ingestion. The deltaG^® ketone drink was well-tolerated by all participants. In participants who provided blood samples, post-intervention blood glucose, lactate and non-esterified fatty acid concentrations decreased significantly (−28.8%, p ≪ 0.001; −28.2%, p = 0.02; and −49.1%, p ≪ 0.001, respectively), while levels of the ketone body D-beta-hydroxybutyrate significantly increased from mean (standard deviation) 0.7 (0.3) to 4.0 (1.1) mmol/L after 30 min (p ≪ 0.001). There were no significant changes in cardiac PCr/ATP or skeletal muscle metabolic parameters between baseline and post-intervention. Acute ketone supplementation caused mild ketosis in blood, with drops in glucose, lactate, and free fatty acids; however, such changes were not associated with changes in ³¹P-MRS measures in the heart or in skeletal muscle. Future work may focus on the effect of longer-term ketone supplementation on tissue energetics in groups with compromised mitochondrial function.

Abnormal whole-body energy metabolism in iron-deficient humans despite preserved skeletal muscle oxidative phosphorylation

Iron deficiency impairs skeletal muscle metabolism. The underlying mechanisms are incompletely characterised, but animal and human experiments suggest the involvement of signalling pathways co-dependent upon oxygen and iron availability, including the pathway associated with hypoxia-inducible factor (HIF). We performed a prospective, case-control, clinical physiology study to explore the effects of iron deficiency on human metabolism, using exercise as a stressor. Thirteen iron-deficient (ID) individuals and thirteen iron-replete (IR) control participants each underwent 31P-magnetic resonance spectroscopy of exercising calf muscle to investigate differences in oxidative phosphorylation, followed by whole-body cardiopulmonary exercise testing. Thereafter, individuals were given an intravenous (IV) infusion, randomised to either iron or saline, and the assessments repeated ~ 1 week later. Neither baseline iron status nor IV iron significantly influenced high-energy phosphate metabolism. During submaximal cardiopulmonary exercise, the rate of decline in blood lactate concentration was diminished in the ID group (P = 0.005). Intravenous iron corrected this abnormality. Furthermore, IV iron increased lactate threshold during maximal cardiopulmonary exercise by ~ 10%, regardless of baseline iron status. These findings demonstrate abnormal whole-body energy metabolism in iron-deficient but otherwise healthy humans. Iron deficiency promotes a more glycolytic phenotype without having a detectable effect on mitochondrial bioenergetics.

Exogenous d ‐β‐hydroxybutyrate lowers blood glucose in part by decreasing the availability of L‐alanine for gluconeogenesis

Background

Interventions that induce ketosis simultaneously lower blood glucose and the explanation for this phenomenon is unknown. Additionally, the glucose‐lowering effect of acute ketosis is greater in people with type 2 diabetes (T2D). On the contrary, L‐alanine is a gluconeogenic substrate secreted by skeletal muscle at higher levels in people with T2D and infusing of ketones lower circulating L‐alanine blood levels. In this study, we sought to determine whether supplementation with L‐alanine would attenuate the glucose‐lowering effect of exogenous ketosis using a ketone ester (KE).

Methods

This crossover study involved 10 healthy human volunteers who fasted for 24 h prior to the ingestion of 25 g of d‐β‐hydroxybutyrate (βHB) in the form of a KE drink (ΔG^®) on two separate visits. During one of the visits, participants additionally ingested 2 g of L‐alanine to see whether L‐alanine supplementation would attenuate the glucose‐lowering effect of the KE drink. Blood L‐alanine, L‐glutamine, glucose, βHB, free fatty acids (FFA), lactate and C‐peptide were measured for 120 min after ingestion of the KE, with or without L‐alanine.

Findings

The KE drinks elevated blood βHB concentrations from negligible levels to 4.52 ± 1.23 mmol/L, lowered glucose from 4.97 ± SD 0.39 to 3.77 ± SD 0.40 mmol/L, and lowered and L‐alanine from 0.56 ± SD 0.88 to 0.41 ± SD 0.91 mmol/L. L‐alanine in the KE drink elevated blood L‐Alanine by 0.68 ± SD 0.15 mmol/L, but had no significant effect on blood βHB, L‐glutamine, FFA, lactate, nor C‐peptide concentrations. By contrast, L‐alanine supplementation significantly attenuated the ketosis‐induced drop in glucose from 28% ± SD 8% to 16% ± SD 7% (p < .01).

Conclusions

The glucose‐lowering effect of acutely elevated βHB is partially due to βHB decreasing L‐alanine availability as a substrate for gluconeogenesis.

Diabetic mitochondria are resistant to palmitoyl CoA inhibition of respiration, which is detrimental during ischemia

The bioactive lipid intermediate palmitoyl CoA (PCoA) can inhibit mitochondrial ADP/ATP transport, though the physiological relevance of this regulation remains unclear. We questioned whether myocardial ischemia provides a pathological setting in which PCoA regulation of ADP/ATP transport would be beneficial, and secondly, whether the chronically elevated lipid content within the diabetic heart could make mitochondria less sensitive to the effects of PCoA. PCoA acutely decreased ADP‐stimulated state 3 respiration and increased the apparent K_m for ADP twofold. The half maximal inhibitory concentration (IC₅₀) of PCoA in control mitochondria was 22 µM. This inhibitory effect of PCoA on respiration was blunted in diabetic mitochondria, with no significant difference in the K_m for ADP in the presence of PCoA, and an increase in the IC₅₀ to 32 µM PCoA. The competitive inhibition by PCoA was localised to the phosphorylation apparatus, particularly the ADP/ATP carrier (AAC). During ischemia, the AAC imports ATP into the mitochondria, where it is hydrolysed by reversal of the ATP synthase, regenerating the membrane potential. Addition of PCoA dose‐dependently prevented this wasteful ATP hydrolysis for membrane repolarisation during ischemia, however, this beneficial effect was blunted in diabetic mitochondria. Finally, using ³¹P‐magnetic resonance spectroscopy we demonstrated that diabetic hearts lose ATP more rapidly during ischemia, with a threefold higher ATP decay rate compared with control hearts. In conclusion, PCoA plays a role in protecting mitochondrial energetics during ischemia, by preventing wasteful ATP hydrolysis. However, this beneficial effect is blunted in diabetes, contributing to the impaired energy metabolism seen during myocardial ischemia in the diabetic heart.

Metabolic maturation of differentiating cardiosphere-derived cells

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Collagen IV promotes proliferation of cardiosphere-derived cells.

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Fibronectin supports differentiation of cardiosphere-derived cells.

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Oxidative metabolism increases as cardiac progenitors mature.

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Stimulating fatty acid oxidation promotes cardiac progenitor cell maturation.

Cardiosphere-derived cells (CDCs) can be expanded in vitro and induced to differentiate along the cardiac lineage. To recapitulate the phenotype of an adult cardiomyocyte, differentiating progenitors need to upregulate mitochondrial glucose and fatty acid oxidation. Here we cultured and differentiated CDCs using protocols aimed to maintain stemness or to promote differentiation, including triggering fatty acid oxidation using an agonist of peroxisome proliferator-activated receptor alpha (PPARα). Metabolic changes were characterised in undifferentiated CDCs and during differentiation towards a cardiac phenotype. CDCs from rat atria were expanded on fibronectin or collagen IV via cardiosphere formation. Differentiation was assessed using flow cytometry and qPCR and substrate metabolism was quantified using radiolabelled substrates. Collagen IV promoted proliferation of CDCs whereas fibronectin primed cells for differentiation towards a cardiac phenotype. In both populations, treatment with 5-Azacytidine induced a switch towards oxidative metabolism, as shown by changes in gene expression, decreased glycolytic flux and increased oxidation of glucose and palmitate. Addition of a PPARα agonist during differentiation increased both glucose and fatty acid oxidation and expression of cardiac genes. We conclude that oxidative metabolism and cell differentiation act in partnership with increases in one driving an increase in the other.

Exogenous ketosis in patients with type 2 diabetes: Safety, tolerability and effect on glycaemic control

Introduction

Ketogenic diets have shown to improve glycaemic control in patients with type 2 diabetes. This study investigated the safety, tolerability, and effects on glycaemic control in patients with type 2 diabetes of an exogenous ketone monoester (KE) capable of inducing fasting‐like elevations in serum β‐hydroxybutyrate (βHB) without the need for caloric or carbohydrate restriction.

Methods

Twenty one participants (14 men and 7 women, aged 45 ± 11 years) with insulin‐independent type 2 diabetes, and unchanged hypoglycaemic medication for the previous 6 months, were recruited for this non‐randomised interventional study. Participants wore intermittent scanning glucose monitors (IS‐GM) for a total of 6 weeks and were given 25 ml of KE 3 times daily for 4 weeks. Serum electrolytes, acid‐base status, and βHB concentrations were measured weekly and cardiovascular risk markers were measured before and after the intervention. The primary endpoints were safety and tolerability, with the secondary endpoint being glycaemic control.

Results

The 21 participants consumed a total of 1,588 drinks (39.7 litres) of KE over the course of the intervention. Adverse reactions were mild and infrequent, including mild nausea, headache, and gastric discomfort following fewer than 0.5% of the drinks. Serum electrolyte concentrations, acid‐base status, and renal function remained normal throughout the study. Compared to baseline, exogenous ketosis induced a significant decrease in all glycaemic control markers, including fructosamine (335 ± 60 μmol/L to 290 ± 49 μmol/L, p < .01), HbA1c (61 ± 10 mmol/mol to 55 ± 9 mmol/mol [7.7 ± 0.9% to 7.2 ± 0.9%], p < .01), mean daily glucose (7.8 ± 1.4 mM to 7.4 ± 1.3 mM [140 ± 23 mg/dl to 133 ± 25 mg/dl], p < .01) and time in range (67 ± 11% to 69 ± 10%, p < .01).

Conclusions

Constant ketone monoester consumption over 1 month was safe, well tolerated, and improved glycaemic control in patients with type 2 diabetes.

This study involved a month of closely supervised exogenous ketosis using a ketone monoester. Additionally, it involved six weeks of continuous glucose monitorization to compare glucose control before, during and after exogenous ketosis. Exogenous ketosis was safe, well‐tolerated and improved glucose control.

β-Hydroxybutyrate Oxidation in Exercise Is Impaired by Low-Carbohydrate and High-Fat Availability

Purpose: In this study, we determined ketone oxidation rates in athletes under metabolic conditions of high and low carbohydrate (CHO) and fat availability. Methods: Six healthy male athletes completed 1 h of bicycle ergometer exercise at 75% maximal power (WMax) on three occasions. Prior to exercise, participants consumed 573 mg·kg bw^-1 of a ketone ester (KE) containing a ¹³C label. To manipulate CHO availability, athletes undertook glycogen depleting exercise followed by isocaloric high-CHO or very-low-CHO diets. To manipulate fat availability, participants were given a continuous infusion of lipid during two visits. Using stable isotope methodology, β-hydroxybutyrate (βHB) oxidation rates were therefore investigated under the following metabolic conditions: (i) high CHO + normal fat (KE+CHO); (ii) high CHO + high fat KE+CHO+FAT); and (iii) low CHO + high fat (KE+FAT). Results: Pre-exercise intramuscular glycogen (IMGLY) was approximately halved in the KE+FAT vs. KE+CHO and KE+CHO+FAT conditions (both p < 0.05). Blood free fatty acids (FFA) and intramuscular long-chain acylcarnitines were significantly greater in the KE+FAT vs. other conditions and in the KE+CHO+FAT vs. KE+CHO conditions before exercise. Following ingestion of the ¹³C labeled KE, blood βHB levels increased to ≈4.5 mM before exercise in all conditions. βHB oxidation was modestly greater in the KE+CHO vs. KE+FAT conditions (mean diff. = 0.09 g·min^-1, p = 0.03; d = 0.3), tended to be greater in the KE+CHO+FAT vs. KE+FAT conditions (mean diff. = 0.07 g·min^-1; p = 0.1; d = 0.3) and were the same in the KE+CHO vs. KE+CHO+FAT conditions (p < 0.05; d < 0.1). A moderate positive correlation between pre-exercise IMGLY and βHB oxidation rates during exercise was present (p = 0.04; r = 0.5). Post-exercise intramuscular βHB abundance was markedly elevated in the KE+FAT vs. KE+CHO and KE+CHO+FAT conditions (both, p < 0.001; d = 2.3). Conclusion: βHB oxidation rates during exercise are modestly impaired by low CHO availability, independent of circulating βHB levels.

The ketone ester, 3-hydroxybutyl-3-hydroxybutyrate, attenuates neurobehavioral deficits and improves neuropathology following controlled cortical impact in male rats

Traumatic brain injury (TBI) is a leading cause of human death and disability with no effective therapy to fully prevent long-term neurological deficits in surviving patients. Ketone ester supplementation is protective in animal models of neurodegeneration, but its efficacy against TBI pathophysiology is unknown. Here, we assessed the neuroprotective effect of the ketone monoester, 3-hydroxybutyl-3-hydroxybutyrate, (KE) in male Sprague Dawley rats (n=32). TBI was induced using the controlled cortical impact (CCI) with Sham animals not receiving the brain impact. KE was administered daily by oral gavage (0.5 ml/kg/day) and provided ad libitum at 0.3% (v/v) in the drinking water. KE supplementation started immediately after TBI and lasted for the duration of the study. Motor and sensory deficits were assessed using the Neurobehavioral Severity Scale-Revised (NSS-R) at four weeks post-injury. The NSS-R total score in CCI + KE (1.2 ± 0.4) was significantly lower than in CCI + water (4.4 ± 0.5). Similarly, the NSS-R motor scores in CCI + KE (0.6 ± 0.7) were significantly lower than CCI + water (2.9 ± 1.5). Although the NSS-R sensory score in the CCI + KE group (0.5 ± 0.2) was significantly lower compared to CCI + water (1.8 ± 0.4), no difference was observed between CCI + water and Sham + water (1.0 ± 0.2) groups. The lesion volume was smaller in the CCI + KE (10 ± 3 mm³) compared to CCI + water (47 ± 11 mm³; p < 0.001). KE significantly decreased Iba1⁺ stained areas in the cortex and hippocampus, and GFAP⁺ stained areas in all brain regions analyzed - prefrontal cortex, hippocampus, cortex, amygdala (p < 0.01). In summary, our results indicate that KE can protect against TBI-induced morphological and functional deficits when administered immediately after an insult.

Nicotinic acid receptor agonists impair myocardial contractility by energy starvation

Nicotinic acid receptor agonists have previously been shown to cause acute reductions in cardiac contractility. We sought to uncover the changes in cardiac metabolism underlying these alterations in function. In nine humans, we recorded cardiac energetics and function before and after a single oral dose of nicotinic acid using cardiac MRI to demonstrate contractile function and Phosphorus-31 (31 P) magnetic resonance spectroscopy to demonstrate myocardial energetics. Nicotinic Acid 400 mg lowered ejection fraction by 4% (64 ± 8% to 60 ± 7%, P = .03), and was accompanied by a fall in phosphocreatine/ATP ratio by 0.4 (2.2 ± 0.4 to 1.8 ± 0.1, P = .04). In four groups of eight Wistar rats, we used pyruvate dehydrogenase (PDH) flux studies to demonstrate changes in carbohydrate metabolism induced by the nicotinic acid receptor agonist, Acipimox, using hyperpolarized Carbon-13 (13 C) magnetic resonance spectroscopy. In rats which had been starved overnight, Acipimox caused a fall in ejection fraction by 7.8% (67.5 ± 8.9 to 60 ± 3.1, P = .03) and a nearly threefold rise in flux through PDH (from 0.182 ± 0.114 to 0.486 ± 0.139, P = .002), though this rise did not match pyruvate dehydrogenase flux observed in rats fed carbohydrate rich chow (0.726 ± 0.201). In fed rats, Acipimox decreased pyruvate dehydrogenase flux (to 0.512 ± 0.13, P = .04). Concentration of plasma insulin fell by two-thirds in fed rats administered Acipimox (from 1695 ± 891 ng/L to 550 ± 222 ng/L, P = .005) in spite of glucose concentrations remaining the same. In conclusion, we demonstrate that nicotinic acid receptor agonists impair cardiac contractility associated with a decline in cardiac energetics and show that the mechanism is likely a combination of reduced fatty acid availability and a failure to upregulate carbohydrate metabolism, essentially starving the heart of fuel.

A Ketone Ester Drink Enhances Endurance Exercise Performance in Parkinson's Disease

Objectives

Routine exercise is thought to be among the only disease-modifying treatments for Parkinson's disease; however, patients' progressive loss of physical ability limits its application. Therefore, we sought to investigate whether a ketone ester drink, which has previously been shown to enhance endurance exercise performance in elite athletes, could also improve performance in persons with Parkinson's disease.

Participants

14 patients, aged 40-80 years, with Hoehn and Yahr stage 1-2 Parkinson's disease.

Intervention

A randomized, placebo-controlled, crossover study in which each participant was administered a ketone ester drink or an isocaloric carbohydrate-based control drink on separate occasions prior to engaging in a steady state cycling test at 80 rpm to assess endurance exercise performance.

Outcomes Measures

The primary outcome variable was length of time participants could sustain a therapeutic 80 rpm cadence. Secondary, metabolic outcomes measures included cardiorespiratory parameters as well as serum β-hydroxybutyrate, glucose, and lactate.

Results

The ketone ester increased the time that participants were able to sustain an 80 rpm cycling cadence by 24 ± 9% (p = 0.027). Correspondingly, the ketone ester increased β-hydroxybutyrate levels to >3 mmol/L and decreased respiratory exchange ratio, consistent with a shift away from carbohydrate-dependent metabolism.

Conclusion

Ketone ester supplementation improved endurance exercise performance in persons with Parkinson's disease and may, therefore, be useful as an adjunctive therapy to enhance the effectiveness of exercise treatment for Parkinson's disease.

Opioid Analgesics Do Not Improve Abdominal Pain or Quality of Life in Crohn's Disease

BACKGROUND

Abdominal pain and opioid analgesic use are common in Crohn's disease (CD).

AIMS

We sought to identify factors associated with abdominal pain in CD and evaluate the impact of opioid analgesics on pain and quality-of-life scores in this setting.

METHODS

We performed a longitudinal cohort study using a prospective, consented IBD natural history registry from a single academic center between 2009 and 2013. Consecutive CD patients were followed for at least 1 year after an index visit. Data were abstracted regarding pain experience (from validated surveys), inflammatory activity (using endoscopic/histologic findings), laboratory studies, coexistent psychiatric disorders, medical therapy, opioid analgesic, and tobacco use.

RESULTS

Of 542 CD patients (56.6% women), 232 (42.8%) described abdominal pain. Individuals with pain were more likely to undergo surgery and were more frequently prescribed analgesics and/or antidepressants/anxiolytics. Elevated ESR (OR 1.79; 95%CI 1.11-2.87), coexistent anxiety/depression (OR 1.87; 95%CI 1.13-3.09), smoking (OR 2.08; 95%CI 1.27-3.40), and opioid use (OR 2.46; 95%CI 1.33-4.57) were independently associated with abdominal pain. Eighty patients (14.8%) were prescribed opioids, while 31 began taking them at or after the index visit. Patients started on opioids demonstrated no improvement in abdominal pain or quality-of-life scores on follow-up compared to patients not taking opioids.

CONCLUSIONS

Abdominal pain is common in CD and is associated with significant opioid analgesic utilization and increased incidence of anxiety/depression, smoking, and elevated inflammatory markers. Importantly, opioid use in CD was not associated with improvement in pain or quality-of-life scores. These findings reinforce the limitations of currently available analgesics in IBD and support exploration of alternative therapies.

Nutritional ketosis improves exercise metabolism in patients with very long-chain acyl-CoA dehydrogenase deficiency

A maladaptive shift from fat to carbohydrate (CHO) oxidation during exercise is thought to underlie myopathy and exercise-induced rhabdomyolysis in patients with fatty acid oxidation (FAO) disorders. We hypothesised that ingestion of a ketone ester (KE) drink prior to exercise could serve as an alternative oxidative substrate supply to boost muscular ATP homeostasis. To establish a rational basis for therapeutic use of KE supplementation in FAO, we tested this hypothesis in patients deficient in Very Long-Chain acyl-CoA Dehydrogenase (VLCAD). Five patients (range 17-45 y; 4 M/1F) patients were included in an investigator-initiated, randomised, blinded, placebo-controlled, 2-way cross-over study. Patients drank either a KE + CHO mix or an isocaloric CHO equivalent and performed 35 minutes upright cycling followed by 10 minutes supine cycling inside a Magnetic Resonance scanner at individual maximal FAO work rate (fatmax; approximately 40% VO₂ max). The protocol was repeated after a 1-week interval with the alternate drink. Primary outcome measures were quadriceps phosphocreatine (PCr), Pi and pH dynamics during exercise and recovery assayed by in vivo ³¹ P-MR spectroscopy. Secondary outcomes included plasma and muscle metabolites and respiratory gas exchange recordings. Ingestion of KE rapidly induced mild ketosis and increased muscle BHB content. During exercise at FATMAX, VLCADD-specific plasma acylcarnitine levels, quadriceps glycolytic intermediate levels and in vivo Pi/PCr ratio were all lower in KE + CHO than CHO. These results provide a rational basis for future clinical trials of synthetic ketone ester supplementation therapy in patients with FAO disorders. Trial registration: ClinicalTrials.gov. Protocol ID: NCT03531554; METC2014.492; ABR51222.042.14.

Male sex adversely affects the phenotypic expression of diabetic heart disease

BACKGROUND

Type 2 diabetes (T2D) is associated with an increased risk of heart failure (HF) and cardiovascular mortality. A large-scale meta-analysis on HF found that diabetes was more frequent in women than men, and diabetes appeared to have attenuated the otherwise protective effect of female sex on progression of cardiomyopathy. The exact underlying mechanisms for this remain unclear. Here, we aimed to determine the effect of sex on the phenotypic expression of diabetic heart disease in patients with T2D.

METHODS

A total of 62 male [mean age 44 ± 8 years, body mass index (BMI) 33 ± 5 kg/m², mean HBA1c of 7.8 ± 1.8%] and 67 female (44 ± 10 years, BMI 35 ± 6 kg/m², HBA1c 7.6 ± 1.2%) T2D patients on oral glucose-lowering treatment, and 16 male (48 ± 17 years, BMI 25 ± 3 kg/m²) and 14 female (50 ± 10 years, BMI 25 ± 4 kg/m²) controls were recruited. Left ventricular (LV) volumes, mass, function and deformation, and left atrial (LA) volumes and function were assessed using cardiac magnetic resonance imaging (CMR).

RESULTS

Participants in all groups were of similar age, and there were no significant differences in blood pressure (BP), diabetes duration or metabolic profile between the two diabetes groups. Concentric remodeling was present in both sexes (p < 0.0001), with greater degree of concentric hypertrophy in males (12%, p = 0.0015). Biplane LA ejection fraction (LAEF) (p = 0.038), peak systolic circumferential strain (p < 0.0001) and diastolic strain rates (p = 0.001) were significantly reduced in men compared with women with T2D. There were no significant differences in biplane LAEF, peak systolic circumferential strain and diastolic strain rates in women with T2D compared with female controls. Whereas in women with T2D, glycaemic control was linked to LV contractile function, there was no such relationship in men with T2D.

CONCLUSION

Male sex adversely affects the phenotypic expression of diabetic heart disease. The striking differences in the cardiac phenotype between male and female patients with T2D promote awareness of gender-specific risk factors in search of treatment and prevention of diabetes-associated HF.

CONDENSED ABSTRACT

We aimed to determine the effect of sex on the phenotypic expression of diabetic heart disease in patients with T2D. While our findings support the notion that in T2D, male sex adversely affects the phenotypic expression of diabetic heart disease, this is in apparent conflict with the previous large-scale study showing diabetes attenuates the otherwise protective effect of female sex on progression of cardiomyopathy. Further longitudinal studies looking at gender differences in clinical outcomes in T2D patients are needed. These sex-related differences promote awareness of sex-specific risk factors in search of treatment and prevention of diabetes-associated HF.

A ketone monoester drink reduces the glycemic response to an oral glucose challenge in individuals with obesity: a randomized trial

BACKGROUND

Exogenous ketones make it possible to reach a state of ketosis that may improve metabolic control in humans.

OBJECTIVES

The main objective of this study was to determine whether the ingestion of a ketone monoester (KE) drink before a 2-h oral-glucose-tolerance test (OGTT) would lower blood glucose concentrations. Secondary objectives were to determine the impact of KE on nonesterified fatty acid (NEFA) concentration and glucoregulatory hormones.

METHODS

We conducted a randomized controlled crossover experiment in 15 individuals with obesity (mean ± SD age: 47 ± 10 y; BMI: 34 ± 5 kg/m2). After an overnight fast, participants consumed a KE drink [(R)-3-hydroxybutyl (R)-3-hydroxybutyrate; 0.45 mL/kg body weight] or taste-matched control drink 30 min before completing a 75-g OGTT. Participants and study personnel performing laboratory analyses were blinded to each condition.

RESULTS

The KE increased d-β-hydroxybutyrate to a maximum of ∼3.4 mM (P < 0.001) during the OGTT. Compared with the control drink, KE reduced glucose (-11%, P = 0.002), NEFA (-21%, P = 0.009), and glucagon-like peptide 1 (-31%, P = 0.001) areas under the curve (AUCs), whereas glucagon AUC increased (+11%, P = 0.030). No differences in triglyceride, C-peptide, and insulin AUCs were observed after the KE drink. Mean arterial blood pressure decreased and heart rate increased after the KE drink (both P < 0.01).

CONCLUSIONS

A KE drink consumed before an OGTT lowered glucose and NEFA AUCs with no increase in circulating insulin. Our results suggest that a single drink of KE may acutely improve metabolic control in individuals with obesity. Future research is warranted to examine whether KE could be used safely to have longer-term effects on metabolic control. This trial was registered at clinicaltrials.gov as NCT03461068.

The potential contribution of impaired brain glucose metabolism to congenital Zika syndrome

The Zika virus (ZIKV) became a major worldwide public concern in 2015 due to the congenital syndrome which presents the highest risk during the first trimester of pregnancy and includes microcephaly and eye malformations. Several cellular, genetic and molecular studies have shown alterations in metabolic pathways, endoplasmic reticulum (ER) stress, immunity and dysregulation of RNA and energy metabolism both in vivo and in vitro. Here we summarise the main metabolic complications, with a particular focus on the possibility that brain energy metabolism is altered following ZIKV infection, contributing to developmental abnormalities. Brain energetic failure has been implicated in neurological conditions such as autism disorder and epilepsy, as well as in metabolic diseases with severe neurodevelopmental complications such as Glut-1 deficiency syndrome. Therefore, these energetic alterations are of wide-ranging interest as they might be directly implicated in congenital ZIKV syndrome. Data showing increased glycolysis during ZIKV infection, presumably required for viral replication, might support the idea that the virus can cause energetic stress in the developing brain cells. Consequences may include neuroinflammation, cell cycle dysregulation and cell death. Ketone bodies are non-glycolytic brain fuels that are produced during neonatal life, starvation or fasting, ingestion of high-fat low-carbohydrate diets, and following supplementation with ketone esters. We propose that dietary ketones might alter the course of the disease and could even provide some degree of prevention of ZIKV-associated abnormalities and potentially related neurological conditions characterised by brain glucose impairment.

Multi-Loop Model of Alzheimer Disease: An Integrated Perspective on the Wnt/GSK3β, α-Synuclein, and Type 3 Diabetes Hypotheses

As the prevalence of Alzheimer disease (AD) continues to rise unabated, new models have been put forth to improve our understanding of this devastating condition. Although individual models may have their merits, integrated models may prove more valuable. Indeed, the reliable failures of monotherapies for AD, and the ensuing surrender of major drug companies, suggests that an integrated perspective may be necessary if we are to invent multifaceted treatments that could ultimately prove more successful. In this review article, we discuss the Wnt/Glycogen Synthase Kinase 3β (GSK3β), α-synuclein, and type 3 diabetes hypotheses of AD, and their deep interconnection, in order to foster the integrative thinking that may be required to reach a solution for the coming neurological epidemic.

Transfusion requirement and length of stay of anaemic surgical patients associated with a patient blood management service: a single-Centre retrospective study

OBJECTIVE

To assess the value of patient blood management (PBM) in the detection and management of preoperative anaemia before elective surgery.

BACKGROUND

PBM is recognised as the standard of care, with diagnosis and management of preoperative anaemia being the key components of PBM. No formal assessment of the value of PBM anaemia screening and correction before scheduled surgery had been made at our hospital.

METHODS

We conducted a retrospective study in a tertiary-care, academic hospital of consecutive records of elective surgery (n = 25 641). We excluded minor surgeries. We identified anaemic patients who had been assessed by PBM or not (non-PBM). We calculated transfusion incidence and hospital length of stay (LOS) across all surgical specialities.

RESULTS

During the 1-year study period, 15 245 patients were eligible for inclusion; 311 patients (2·0%) were transfused, and 83·3% of transfusions were in anaemic patients. Transfusion incidence was 9·2% in anaemic PBM-assessed patients and 17·4% in non-PBM patients. For haemoglobin (Hb) <100 g L^-1 , the transfusion incidence was 22·1% [95% confidence interval (CI) 15·5-30·6%] in PBM and 40·0% (95% CI 35·1-45·0%) in non-PBM patients, and for Hb 100-119 g L^-1 , it was 4·7% (95% CI 2·8-7·5%) and 7·9% (95% CI 6·3-9·8%), respectively. Overall mean LOS was 2·1 days [standard deviation (SD) 6·0]. Mean LOS with Hb <100 g L^-1 was 6·7 days (SD 14·8) in PBM-assessed patients and 12·4 days (SD 19·5) in non-PBM patients and was 3·1 (SD 5·2) and 6·2 (SD 9·5) days, respectively, for Hb 100-119 g L^-1 .

CONCLUSION

Anaemic elective surgery patients assessed by patient blood management (PBM) had a markedly lower transfusion risk and shorter LOS than anaemic patients not assessed by PBM.

The Mechanisms by Which the Ketone Body D-β-Hydroxybutyrate May Improve the Multiple Cellular Pathologies of Parkinson's Disease

Parkinson's disease, a progressive neurodegenerative disorder characterized by motor and non-motor symptoms, is strongly associated with the death of dopaminergic neurons in the brain's substantia nigra. Although dopamine replacement therapy temporarily helps patients manage their motor symptoms, this current standard of care fails to address the underlying network of pathologies that contribute to the persistent death of dopaminergic neurons. Thus, new treatment approaches are needed that address the underlying pathologies and, thereby, slow or halt the progression of the actual disease. D-β-hydroxybutyrate – a ketone body produced by the liver to support brain function during periods of starvation – may provide an option. Lifestyle interventions that induce endogenous D-β-hydroxybutyrate production, such as caloric restriction and ketogenic diets, are known to increase healthspan and lifespan in animal models and are used to treat neurological disorders. The efficacy of these ketosis-inducing interventions, along with the recent development of commercially available D-β-hydroxybutyrate-based nutritional supplements, should inspire interest in the possibility that D-β-hydroxybutyrate itself exerts neuroprotective effects. This review provides a molecular model to justify the further exploration of such a possibility. Herein, we explore the cellular mechanisms by which the ketone body, D-β-hydroxybutyrate, acting both as a metabolite and as a signaling molecule, could help to prevent the development, or slow the progression of, Parkinson's disease. Specifically, the metabolism of D-β-hydroxybutyrate may help neurons replenish their depleted ATP stores and protect neurons against oxidative damage. As a G-protein-coupled receptor ligand and histone deacetylase inhibitor, D-β-hydroxybutyrate may further protect neurons against energy deficit and oxidative stress, while also decreasing damaging neuroinflammation and death by apoptosis. Restricted to the available evidence, our model relies largely upon the interpretation of data from the separate literatures on the cellular effects of D-β-hydroxybutyrate and on the pathogenesis of Parkinson's disease. Future studies are needed to reveal whether D-β-hydroxybutyrate actually has the potential to serve as an adjunctive nutritional therapy for Parkinson's disease.

Nutritional Ketoacidosis During Incremental Exercise in Healthy Athletes

Purpose: Ketosis, achieved through ingestion of ketone esters, may influence endurance exercise capacity by altering substrate metabolism. However, the effects of ketone consumption on acid-base status and subsequent metabolic and respiratory compensations are poorly described.

Methods: Twelve athletically trained individuals completed an incremental bicycle ergometer exercise test to exhaustion following the consumption of either a ketone ester [(R)-3-hydroxybutyrate-(R)-1,3-butanediol] or a taste-matched control drink (bitter flavoured water) in a blinded, cross-over study. Respiratory gases and arterialised blood gas samples were taken at rest and at regular intervals during exercise.

Results: Ketone ester consumption increased blood D-β-hydroxybutyrate concentration from 0.2 to 3.7 mM/L (p < 0.01), causing significant falls versus control in blood pH to 7.37 and bicarbonate to 18.5 mM/L before exercise. To compensate for ketoacidosis, minute ventilation was modestly increased (p < 0.05) with non-linearity in the ventilatory response to exercise (ventilatory threshold) occurring at a 22 W lower workload (p < 0.05). Blood pH and bicarbonate concentrations were the same at maximal exercise intensities. There was no difference in exercise performance having consumed the ketone ester or control drink.

Conclusion: Athletes compensated for the greater acid load caused by ketone ester ingestion by elevating minute ventilation and earlier hyperventilation during incremental exercise.

Beyond RPE: The Perception of Exercise Under Normal and Ketotic Conditions

Aim

Subjective perceptions of exercising exertion are integral to maintaining homeostasis. Traditional methods have utilized scores of 'rating of perceived exertion' (RPE) to quantify these subjective perceptions, and here we aimed to test whether RPE may encompass identifiable localized perceptions from the lungs (breathlessness) and legs (leg discomfort), as well as their corresponding measures of anxiety. We utilized the intervention of ketoacidosis (via consumption of an exogenous ketone ester drink) to independently perturb exercise-related metabolites and humoral signals, thus allowing us to additionally identify the possible contributing physiological signals to each of these perceptions.

Methods

Twelve trained volunteers underwent two incremental bicycle ergometer tests to exhaustion, following ingestion of either an exogenous ketone ester or a taste-matched placebo drink. Cardiorespiratory measures, blood samples and perceived exertion scales were taken throughout. Firstly, two-way repeated-measures ANOVAs were employed to identify the overall effects of ketoacidosis, followed by generalized linear mixed model regression to isolate physiological predictors contributing to each perception.

Results

Rating of perceived exertion was found to contain contributions from localized perceptions of breathlessness and leg discomfort, with no measurable effect of ketoacidosis on overall exertion. Leg discomfort, anxiety of breathing and anxiety of leg discomfort were increased during ketoacidosis, and correspondingly contained pH within their prediction models. Anxiety of leg discomfort also encompassed additional humoral signals of blood glucose and ketone concentrations.

Conclusion

These results indicate the presence of localized components of RPE in the form of breathlessness and leg discomfort. Furthermore, subjective perceptions of anxiety appear to result from a complex interplay of humoral signals, which may be evolutionarily important when monitoring exertion under times of metabolic stress, such as during starvation.

Abstract P6-05-02: Identification of microRNAs differentially expressed in brain metastasis secondary to breast cancer

Background: Despite sequential improvements in the adjuvant treatment of breast cancer (BC), recurrence and metastasis remains a major clinical problem and in particular, brain metastasis (BCBM). A number of microRNAs (miRNAs) have been linked to the metastatic process in BC, but to date there is limited work on the microRNAs involved in BCBM. The current study aim to identify differentially expressed miRNAs within primary breast cancer who did not recur (BCNR) versus primary BC cases which did recur (BCR) and their matched BCBM cases.

Methods: Formalin-fixed paraffin-embedded (FFPE) material was collected of 12 primary BCNRs from the Liverpool tissue bank and of 40 paired primary BCR samples and their matched BCBM from the Walton Research Tissue Bank and RCSI National Breast Cancer Bioresource. miRNA was extracted (Qiagen miRNeasy FFPE kit) and profiled using the NanoString™ nCounter™ miRNA Expression Assay (Human v3 miRNA). The differentially expressed miRNAs between BCNR versus BCR and BCR versus their matched BCBM were identified by significance of microarray analysis (SAM) on the MeV4.9 software. Pathway analysis was performed using the DIANA-mirPath v3.0 software and the Ingenuity Pathway Analysis (IPA) to identify a network of genes/pathways regulated by the differentially expressed miRNAs.

Results: 12 BCNR and 30 matched pairs of BCR and BCBM passed the quality control and normalisation processes. Principal component analysis (PCA) performed on 166 miRNAs after QC/normalisation clearly distinguishes the BCNR and the primary BCR from the matched BCBM cases, whereas SAM revealed 58 differentially expressed miRNAs with a 10% FDR (false discovery rate) and an absolute log2 fold-change (FC) &gt;1 between BCNR and BCR and 11 between the matched BCs and BCBMs. Pathway clustering revealed that these differentially expressed miRNAs (10% FDR, log2FC&gt;1) within both BCNR vs BCR and BCR vs BCBM cohorts are highly enriched for genes involved in extracellular matrix (ECM)-receptor interactions, proteoglycans, adherens junctions, TGF-β, p53 and Hippo signalling. IPA identified a network of genes, implicated in the processes of breast cancer invasion and metastasis, regulated by the identified miRNAs, such as, TWIST, MET, TP53, MYC, EZH2, ZEB1, TAGLN and BIRC5. Four of the significantly differentially expressed miRNAs, hsa-miR-132-3p, hsa-miR-199a-5p, hsa-miR-150-5p and hsa-miR-155-5p were present within both cohorts (BCNR vs BCR and BCR vs BCBM) and regulate genes involved in Hippo and TGF-β signalling (DIANA-mirPath v3.0 analysis: p=5.23x10-08 and p=2.67x10-07 respectively).

Conclusion: The current study, utilising a large cohort of paired BCR and BCBM cases, provides novel insight into the molecular mechanisms and role of miRNAs in BCBM. Four miRNAs (hsa-miR-132-3p, hsa-miR-199a-5p, hsa-miR-150-5p and hsa-miR-155-5p) in particular could be potentially used to identify patients with increased risk of developing brain metastasis and help facilitate the development of specific treatments for BCBM, which to date have proved elusive. The miRNAs identified require further exploration as potential biomarkers as well as novel therapeutic targets.

Citation Format: Giannoudis A, Clarke K, Zakaria R, Vareslija D, Farahani M, Rainbow L, Platt-Higgins A, Ruthven S, Brougham K, Rudland PS, Jenkinson MD, Young L, Falciani F, Palmieri C. Identification of microRNAs differentially expressed in brain metastasis secondary to breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-05-02.

Data on uncoupling protein-3 levels, hypoxia, low flow ischemia, and insulin stimulation in dystrophin-deficient mdx mouse hearts

The data contain body weights, plasma free fatty acids concentrations and cardiac uncoupling protein-3 protein levels for wild-type and mdx mice. The data provide heart rates, left ventricular contractile functions, coronary flow, phosphocreatine concentrations, and adenosine 5’-triphosphate (ATP) concentrations throughout hypoxia in mdx mouse hearts. This data article also provides left ventricular contractile functions after low flow ischemia with and without glucose, glycogen levels before ischemia or hypoxia, glucose uptake rates during low flow ischemia and insulin stimulation, and insulin-stimulated phospho-Akt protein levels, a protein in insulin signaling, in mdx mouse hearts.

Risk factors for relapse and recurrence of depression in adults and how they operate: A four-phase systematic review and meta-synthesis

PURPOSE

To review and synthesise prognostic indices that predict subsequent risk, prescriptive indices that moderate treatment response, and mechanisms that underlie each with respect to relapse and recurrence of depression in adults.

RESULTS AND CONCLUSIONS

Childhood maltreatment, post-treatment residual symptoms, and a history of recurrence emerged as strong prognostic indicators of risk and each could be used prescriptively to indicate who benefits most from continued or prophylactic treatment. Targeting prognostic indices or their "down-stream" consequences will be particularly beneficial because each is either a cause or a consequence of the causal mechanisms underlying risk of recurrence. The cognitive and neural mechanisms that underlie the prognostic indices are likely addressed by the effects of treatments that are moderated by the prescriptive factors. For example, psychosocial interventions that target the consequences of childhood maltreatment, extending pharmacotherapy or adapting psychological therapies to deal with residual symptoms, or using cognitive or mindfulness-based therapies for those with prior histories of recurrence. Future research that focuses on understanding causal pathways that link childhood maltreatment, or cognitive diatheses, to dysfunction in the neocortical and limbic pathways that process affective information and facilitate cognitive control, might result in more enduring effects of treatments for depression.

Heat Stability of Two Candidate International Reference Preparations for Recombinant Human Tissue Factor

Adequate heat stability of international reference preparations (IRP) for thromboplastin (tissue factor) is an essential requirement. Accelerated degradation testing was performed by three laboratories on two candidate IRP for recombinant human tissue factor.

Heat treatment of these candidates resulted in slight shortening of the PT, contrasting with heat-induced prolongation of the PT observed with a conventional human brain derived IRP.

Heat stability of these candidates was improved when compared with the stability of previous recombinant human tissue factor preparations.

The PT-ratio did not change significantly when the candidates were stored for 28 days at 44° C. It’ can therefore be concluded that both candidates are acceptable with regard to stability.

Prior ingestion of exogenous ketone monoester attenuates the glycaemic response to an oral glucose tolerance test in healthy young individuals

KEY POINTS

The recent development of exogenous ketone supplements allows direct testing of the metabolic effects of elevated blood ketones without the confounding influence of widespread changes experienced with ketogenic diets or prolonged fasting. In the present study, we determined the effect of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate ketone monoester on the glycaemic response and insulin sensitivity index during a 2 h oral glucose tolerance test (OGTT) in humans. The results obtained show that consuming a ketone monoester supplement 30 min prior to an OGTT reduced the glycaemic response and markers of insulin sensitivity without affecting insulin secretion. The findings of the present study provides evidence that ketone supplements could have therapeutic potential for future application as a glucose-lowering nutritional supplement.

ABSTRACT

The main objectives of the present study were: (i) to determine whether acute ingestion of ketone monoester (K_me ); (R)-3-hydroxybutyl (R)-3-hydroxybutyrate impacts plasma glucose levels during a standardized oral glucose tolerance test (OGTT) and (ii) to compare changes in insulin concentrations and estimates of insulin sensitivity after acute K_me supplementation. Twenty healthy participants (n = 10 males/females) aged between 18 and 35 years took part in a randomized cross-over study. After an overnight fast, participants consumed a K_me supplement (ΔG®; TΔS Ltd, UK, Oxford, UK; 0.45 ml kg^-1 body weight) or placebo (water) 30 min before completing a 75 g OGTT. Blood samples were collected every 15-30 min over 2.5 h. The participants and study personnel performing the laboratory analyses were blinded to the study condition. K_me acutely raised blood d-beta-hydroxybutyrate (β-OHB) to 3.2 ± 0.6 mm within 30 min with levels remaining elevated throughout the entire OGTT. Compared to placebo, K_me significantly decreased the glucose area under the curve (AUC; -17%, P = 0.001), non-esterified fatty acid AUC (-44%, P < 0.001) and C-peptide incremental AUC (P = 0.005), at the same time as improving oral glucose insulin sensitivity index by ∼11% (P = 0.001). In conclusion, a K_me supplement that acutely increased β-OHB levels up to ∼3 mm attenuated the glycaemic response to an OGTT in healthy humans. The reduction in glycaemic response did not appear to be driven by an increase in insulin secretion, although it was accompanied by improved markers of insulin sensitivity. These results suggest that ketone monoester supplements could have therapeutic potential in the management and prevention of metabolic diseases.

Inhibition of sarcolemmal FAT/CD36 by sulfo-N-succinimidyl oleate rapidly corrects metabolism and restores function in the diabetic heart following hypoxia/reoxygenation

Aims

The type 2 diabetic heart oxidizes more fat and less glucose, which can impair metabolic flexibility and function. Increased sarcolemmal fatty acid translocase (FAT/CD36) imports more fatty acid into the diabetic myocardium, feeding increased fatty acid oxidation and elevated lipid deposition. Unlike other metabolic modulators that target mitochondrial fatty acid oxidation, we proposed that pharmacologically inhibiting fatty acid uptake, as the primary step in the pathway, would provide an alternative mechanism to rebalance metabolism and prevent lipid accumulation following hypoxic stress.

Methods and results

Hearts from type 2 diabetic and control male Wistar rats were perfused in normoxia, hypoxia and reoxygenation, with the FAT/CD36 inhibitor sulfo-N-succinimidyl oleate (SSO) infused 4 min before hypoxia. SSO infusion into diabetic hearts decreased the fatty acid oxidation rate by 29% and myocardial triglyceride concentration by 48% compared with untreated diabetic hearts, restoring fatty acid metabolism to control levels following hypoxia-reoxygenation. SSO infusion increased the glycolytic rate by 46% in diabetic hearts during hypoxia, increased pyruvate dehydrogenase activity by 53% and decreased lactate efflux rate by 56% compared with untreated diabetic hearts during reoxygenation. In addition, SSO treatment of diabetic hearts increased intermediates within the second span of the Krebs cycle, namely fumarate, oxaloacetate, and the FAD total pool. The cardiac dysfunction in diabetic hearts following decreased oxygen availability was prevented by SSO-infusion prior to the hypoxic stress. Infusing SSO into diabetic hearts increased rate pressure product by 60% during hypoxia and by 32% following reoxygenation, restoring function to control levels.

Conclusions

Diabetic hearts have limited metabolic flexibility and cardiac dysfunction when stressed, which can be rapidly rectified by reducing fatty acid uptake with the FAT/CD36 inhibitor, SSO. This novel therapeutic approach not only reduces fat oxidation but also lipotoxicity, by targeting the primary step in the fatty acid metabolism pathway.