Hyperketonemia and ketosis increase the risk of complications in type 1 diabetes

Acetoacetate promotes muscle cell proliferation via the miR-133b/SRF axis through the Mek-Erk-MEF2 pathway

Acetoacetate (AA) is an important ketone body that is used as an oxidative fuel to supply energy for the cellular activities of various tissues, including the brain and skeletal muscle. We recently revealed a new signaling role for AA by showing that it promotes muscle cell proliferation in vitro, enhances muscle regeneration in vivo, and ameliorates the dystrophic muscle phenotype of Mdx mice. In this study, we provide new molecular insight into this function of AA. We show that AA promotes C2C12 cell proliferation by transcriptionally upregulating the expression of muscle-specific miR-133b, which in turn stimulates muscle cell proliferation by targeting serum response factor. Furthermore, we show that the AA-induced upregulation of miR-133b is transcriptionally mediated by MEF2 via the Mek-Erk1/2 signaling pathway. Mechanistically, our findings provide further convincing evidence that AA acts as signaling metabolite to actively regulate various cellular activities in mammalian cells.

Engineered acetoacetate-inducible whole-cell biosensors based on the AtoSC two-component system

Whole-cell biosensors hold potential in a variety of industrial, medical, and environmental applications. These biosensors can be constructed through the repurposing of bacterial sensing mechanisms, including the common two-component system (TCS). Here we report on the construction of a range of novel biosensors that are sensitive to acetoacetate, a molecule that plays a number of roles in human health and biology. These biosensors are based on the AtoSC TCS. An ordinary differential equation model to describe the action of the AtoSC TCS was developed and sensitivity analysis of this model used to help inform biosensor design. The final collection of biosensors constructed displayed a range of switching behaviours at physiologically relevant acetoacetate concentrations and can operate in several Escherichia coli host strains. It is envisaged that these biosensor strains will offer an alternative to currently available commercial strip tests and, in future, may be adopted for more complex in vivo or industrial monitoring applications.

Towards Understanding COVID-19: Molecular Insights, Co-infections, Associated Disorders, and Aging

BACKGROUND

COVID-19 can be related to any diseases caused by microbial infection(s) because 1) co-infection with COVID-19-related virus and other microorganism(s) and 2) because metabolites produced by microorganisms such as bacteria, fungi, and protozoan can be involved in necrotizing pneumonia and other necrotizing medical conditions observed in COVID-19.

OBJECTIVE

By way of illustration, the microbial metabolite of aromatic amino acid tryptophan, a biogenic amine tryptamine inducing neurodegeneration in cell and animal models, also induces necrosis.

METHODS

This report includes analysis of COVID-19 positivity by zip codes in Florida and relation of the positivity to population density, possible effect of ecological and social factors on spread of COVID-19, autopsy analysis of COVID-19 cases from around the world, serum metabolomics analysis, and evaluation of autoantigenome related to COVID-19.

RESULTS

In the present estimations, COVID-19 positivity percent per zip code population varied in Florida from 4.65% to 44.3% (February 2021 data). COVID-19 analysis is partially included in my book Microbial Metabolism and Disease (2021). The autoantigenome related to COVID-19 is characterized by alterations in protein biosynthesis proteins including aminoacyl-tRNA synthetases. Protein biosynthesis alteration is a feature of Alzheimer's disease. Serum metabolomics of COVID-19 positive patients show alteration in shikimate pathway metabolism, which is associated with the presence of Alzheimer's disease-associated human gut bacteria.

CONCLUSION

Such alterations in microbial metabolism and protein biosynthesis can lead to toxicity and neurodegeneration as described earlier in my book Protein Biosynthesis Interference in Disease (2020).

Ketogenic Diets and Chronic Disease: Weighing the Benefits Against the Risks

Very-low-carbohydrate ketogenic diets have been long been used to reduce seizure frequency and more recently have been promoted for a variety of health conditions, including obesity, diabetes, and liver disease. Ketogenic diets may provide short-term improvement and aid in symptom management for some chronic diseases. Such diets affect diet quality, typically increasing intake of foods linked to chronic disease risk and decreasing intake of foods found to be protective in epidemiological studies. This review examines the effects of ketogenic diets on common chronic diseases, as well as their impact on diet quality and possible risks associated with their use. Given often-temporary improvements, unfavorable effects on dietary intake, and inadequate data demonstrating long-term safety, for most individuals, the risks of ketogenic diets may outweigh the benefits.

Starvation Ketoacidosis Induced by Ketogenic Diet and Consumption of Ketone Supplement

The ever-changing landscape of dieting and its correlation with health outcomes have continued to evolve with time. New diets appear and disappear just as quickly as they gain notoriety. This is a rare case of a 67-year-old female with a history of type II diabetes who presented with generalized weakness, nausea, and vomiting, and was found to have severe anion gap metabolic acidosis. In an effort to lose weight, she was combining a ketogenic diet with prolonged fasting and exogenous ketone supplement use that she purchased online. The patient reported drinking an exogenous ketone ester supplement that contained 30 g of D-beta hydroxybutyrate (BHB) per serving, three times per day. This case is unique in that the patient was initially thought to be in diabetic ketoacidosis upon arrival, but after further investigation into her initial labs, medication, and social history, the underlying factor for hospitalization became evident; that is, a combination of a ketogenic diet with prolonged fasting and exogenous BHB-induced ketoacidosis in the setting of type II diabetes. Thus, this case highlights the importance of thorough history taking, the dangers of over-the-counter supplement consumption, and the risks consumers inherit with trend dieting.

Characteristics of post-mortem beta-hydroxybutyrate-positivet cases - A retrospective study on age, sex and BMI in 1407 forensic autopsies

BACKGROUND

Post-mortem biochemistry, including the analysis of beta-hydroxybutyrate (BHB), is increasingly employed in forensic medicine, especially in conditions such as diabetes and chronic alcoholism. However, not much is known about the associations between age, body mass index (BMI), and sex and BHB concentrations in ketoacidotic conditions.

AIM

To retrospectively study the association between age, BMI and sex in several conditions, such as diabetic ketoacidosis (DKA), alcoholic ketoacidosis (AKA), and elevated post-mortem BHB concentrations.

METHODS

1407 forensic autopsy cases analysed for BHB were grouped by diagnosis: DKA, AKA, HHS [hyperosmolar hyperglycaemic state], acidosis NOS [not otherwise specified], or hypothermia. Age, sex, BMI and the concentrations of blood alcohol, vitreous glucose and blood BHB were recorded.

RESULTS

Cases of AKA and DKA were most numerous (184 and 156, respectively). In DKA and in its male subgroup, cases with severe ketosis (BHB>1000 µg/g) were younger and had a lower BMI than those with moderate ketosis (BHB 250-1000 µg/g) and controls (P<0.001). In DKA and in its female subgroup, cases with moderate ketosis cases were older (P = 0.0218 and P = 0.0083) than controls. In AKA and in its male subgroup, cases with severe ketosis had a lower BMI than those with moderate ketosis (P = 0.0391 and P = 0.0469) and controls (P<0.001). Cases with moderate ketosis had a lower BMI than controls (P<0.001).

CONCLUSIONS

BHB concentration is associated with BMI in DKA and AKA, and with both BMI and age in DKA. Constitutional factors should, therefore, be considered in potential AKA and DKA cases.

The Perfect Storm: Rapid Progression of Diabetic Ketoacidosis in Pediatric Diabetes in the Setting of COVID-19

Objective

The coronavirus disease 2019 (COVID-19) pandemic has introduced countless challenges to the medical field. Although pediatric patients have been reported to have lower rates of COVID-19 mortality, the presence of pre-existing conditions can heighten the severity of their clinical presentation. This report discusses the potential influence COVID-19 might have on diabetic ketoacidosis.

Methods

Our patient, a 6-year-old girl with known type 1 diabetes, presented with acute onset of abnormal breathing and altered mental status. The day prior, she had 1 episode of emesis, diarrhea, and abdominal pain but no fever. She presented to an outside hospital and was reported to have agonal breathing with a Glasgow Coma Scale score of 8 (eyes open to pain, no verbal response to stimuli, and localized pain). She was promptly intubated, and the initial laboratory tests revealed severe diabetic ketoacidosis (DKA). A family member had COVID-19, and she also tested positive for COVID-19.

Results

Our patient’s rapid progression and severity of illness require a discussion of how COVID-19 might affect diabetes and indicate opportunities for improving clinical practice in children with pre-existing diabetes. We discussed how COVID-19 might change the underlying pathophysiology of DKA and cause metabolic complications. Possible mechanisms include binding to angiotensin-converting enzyme 2 receptors and enabling a proinflammatory “cytokine storm.” Additionally, ketoacidosis and altered mental status have been present in patients with COVID-19 without diabetes, which might potentiate the symptoms in developing DKA.

Conclusion

Prompt recognition of DKA is warranted, as caregivers may attribute the symptoms to COVID-19 rather than to DKA, resulting in an increased severity of illness on presentation with acute symptom onset, as described in this report.

Metabolomic Analysis in Inflammatory Bowel Disease: A Systematic Review

BACKGROUND AND AIMS

The inflammatory bowel diseases [IBD], Crohn's disease and ulcerative colitis, are chronic, idiopathic gastrointestinal diseases. Although their precise aetiology is unknown, it is thought to involve a complex interaction between genetic predisposition and an abnormal host immune response to environmental exposures, probably microbial. Microbial dysbiosis has frequently been documented in IBD. Metabolomics [the study of small molecular intermediates and end products of metabolism in biological samples] provides a unique opportunity to characterize disease-associated metabolic changes and may be of particular use in quantifying gut microbial metabolism. Numerous metabolomic studies have been undertaken in IBD populations, identifying consistent alterations in a range of molecules across several biological matrices. This systematic review aims to summarize these findings.

METHODS

A comprehensive, systematic search was carried out using Medline and Embase. All studies were reviewed by two authors independently using predefined exclusion criteria. Sixty-four relevant papers were assessed for quality and included in the review.

RESULTS

Consistent metabolic perturbations were identified, including increases in levels of branched chain amino acids and lipid classes across stool, serum, plasma and tissue biopsy samples, and reduced levels of microbially modified metabolites in both urine [such as hippurate] and stool [such as secondary bile acids] samples.

CONCLUSIONS

This review provides a summary of metabolomic research in IBD to date, highlighting underlying themes of perturbed gut microbial metabolism and mammalian-microbial co-metabolism associated with disease status.

Medical management of children with type 1 diabetes on low-carbohydrate or ketogenic diets

OBJECTIVES

Low-carbohydrate and ketogenic diets are becoming increasingly popular choices for people with type 1 diabetes (T1D) aiming to achieve optimal glycemic control. A carbohydrate-restricted diet in children has been associated with negative health effects including poor linear growth and inadequate bone mineralization. Guidelines for monitoring children and adolescents choosing to follow a carbohydrate-restricted diet do not exist. We aimed to create a clinical protocol outlining how to clinically and biochemically follow patients choosing a carbohydrate-restricted diet with the goal of medical safety.

METHODS

An interdisciplinary committee was formed and reviewed current consensus guidelines for pediatric patients on carbohydrate-restricted diets for epilepsy and metabolic disorders. A literature search was done to determine management strategies for children with T1D on a low-carbohydrate or ketogenic diet. Key health parameters that require monitoring were identified: growth, glycemic control, bone health, cardiometabolic health, and nutritional status. These health outcomes were used to develop a protocol for monitoring children on carbohydrate-restricted diets.

RESULTS

A one-page protocol for medical providers and educational materials for families interested in following a low-carbohydrate or ketogenic diet were developed and successfully implemented into clinical care.

CONCLUSION

Implementing a protocol for children on carbohydrate-restricted diets in clinic allows medical providers to ensure medical safety while being open to discussing a family's dietary preferences. Following children in the protocol over time will lead to informed clinical guidelines for patients with T1D who choose to follow a carbohydrate-restricted diet.

Effect of short-term ketogenic diet on end-tidal carbon dioxide

BACKGROUND & AIMS

Previous studies have shown that end-tidal carbon dioxide (EtCO₂) is lower with the presence of supraphysiological ketones as in the case of chronic ketogenic diet (KD) and diabetic ketoacidosis (DKA). This study aimed to determine changes in EtCO₂ upon short term KD.

METHODS

Healthy subjects were screened not to have conditions that exerts abnormal EtCO₂ nor contraindicated for KD. Subjects underwent seven days of KD while the EtCO2 and blood ketone (beta-hydroxybutyrate; β-OHB) parameters were sampled at day zero (t0) and seven (t7) of ketosis respectively. Statistically, the t-test and Pearson's coefficient were conducted to determine the changes and correlation of both parameters.

RESULTS

12 subjects completed the study. The mean score ± standard deviation (SD) for EtCO₂ were 35.08 ± 3.53 and 35.67 ± 3.31 mm Hg for t0 and t7 respectively. The mean score ±SD for β-OHB were 0.07 ± 0.08 and 0.87 ± 0.84 mmol/L for t0 and t7 respectively. There was no significant difference of EtCO₂ between the period of study (p > 0.05) but the β-OHB increased during t7 (p < 0.05). There was also no correlation between the parameters.

CONCLUSIONS

These findings suggest that EtCO₂ may not be utilized to determine short term nutritional ketosis.

Effects of insulin treatment on hepatic CYP1A1 and CYP2E1 activities and lipid peroxidation levels in streptozotocin-induced diabetic rats

Reactive oxygen species (ROS) and lipid peroxidation (LPO) levels may increase in diabetic state and lead to oxidative stress, which plays a critical role in the progression of diabetes. There are various sources of ROS, including cytochrome P450 monooxygenases (CYP450s), which may be modulated in terms of their activities and expressions under diabetic conditions. This study is aimed to investigate the effects of streptozotocin-induced diabetes and insulin treatment on hepatic cytochrome P450 1A1 (CYP1A1) and cytochrome P450 2E1 (CYP2E1) activities and LPO levels. Methods: CYP1A1 and CYP2E1 activities were measured with ethoxyresorufin O-deethylase and p-nitrophenol hydroxylase activities, respectively. LPO levels were then corroborated via thiobarbituric acid reactive substances. Results: In diabetic rats, a marked 2.1- and 2.4-fold increase in hepatic CYP1A1 activity and 1.8- and 1.6-fold increase in hepatic CYP2E1 activity were observed compared to controls and insulin-treated diabetic rats, respectively. Hepatic LPO levels in diabetic rats did not significantly change compared to controls. However, in insulin-treated diabetic rats, LPO levels are 0.92- and 0.89-fold remarkably decrease compared to controls and diabetics, respectively. Conclusion: The present study suggests that insulin might have a useful role in the modulation of CYP1A1 and CYP2E1 activities as well as LPO levels in the liver of diabetic rats.

From Maternal Diet to Neurodevelopmental Disorders: A Story of Neuroinflammation

Providing the appropriate quantity and quality of food needed for both the mother's well-being and the healthy development of the offspring is crucial during pregnancy. However, the macro- and micronutrient intake also impacts the body's regulatory supersystems of the mother, such as the immune, endocrine, and nervous systems, which ultimately influence the overall development of the offspring. Of particular importance is the association between unhealthy maternal diet and neurodevelopmental disorders in the offspring. Epidemiological studies have linked neurodevelopmental disorders like autism spectrum disorders, attention-deficit-hyperactivity disorder, and schizophrenia, to maternal immune activation (MIA) during gestation. While the deleterious consequences of diet-induced MIA on offspring neurodevelopment are increasingly revealed, neuroinflammation is emerging as a key underlying mechanism. In this review, we compile the evidence available on how the mother and offspring are both impacted by maternal dietary imbalance. We specifically explore the various inflammatory and anti-inflammatory effects of dietary components and discuss how changes in inflammatory status can prime the offspring brain development toward neurodevelopmental disorders. Lastly, we discuss research evidence on the mechanisms that sustain the relationship between maternal dietary imbalance and offspring brain development, involving altered neuroinflammatory status in the offspring, as well as genetic to cellular programming notably of microglia, and the evidence that the gut microbiome may act as a key mediator.

The Value of Ketone Bodies in the Evaluation of Kidney Function in Patients with Type 2 Diabetes Mellitus

OBJECTIVES

Recent studies have shown that the slightly elevated circulating levels of ketone bodies (KBs) played a significant role in the treatment of various diseases. This study is aimed at investigating the association between different levels of KBs and kidney function in patients with type 2 diabetes mellitus (T2DM).

METHODS

A retrospective study of 955 patients with T2DM (426 women and 529 men) admitted to our hospital from December 2017 to September 2019 was conducted. Patients were divided into different groups in line with the levels of KBs (low-normal group: 0.02-0.04 mmol/L, middle-normal group: 0.05-0.08 mmol/L, high-normal group: 0.09-0.27 mmol/L, and slightly elevated group: >0.27 and <3.0 mmol/L).

RESULTS

In the present study, individuals with high-normal levels of KBs had the lowest risk of diabetic kidney disease (DKD) and increased peak systolic velocity (PSV); those with middle-normal levels of KBs had the lowest risk of increased renal arterial resistive index (RI), with a positive correlation between increased α1-microglobulin and KB concentration. In addition, the indicators of glomerulus, renal tubules, and renal arteries were all poor with slightly elevated circulating levels of KBs, and KB concentration lower than 0.09 mmol/L can be applied as the threshold for low risk of renal function damage.

CONCLUSIONS

In summary, slightly elevated circulating levels of ketone bodies are not of benefit for renal function in patients with type 2 diabetes mellitus.

Comprehensive Analyses of Type 1 Diabetes Ketosis- or Ketoacidosis-Related Genes in Activated CD56+CD16+ NK Cells

OBJECTIVES

Alterations in natural killer (NK) cells activity cause damage to pancreatic islets in type 1 diabetes mellitus (T1DM). The aim of this study is to identify T1DM ketosis- or ketoacidosis-related genes in activated CD56⁺CD16⁺ NK cells.

METHODS

Microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were analyzed using the GEO2R tool. Enrichment analyses were performed using Metascape online database and GSEA software. Cell-specific gene co-expression network was built using NetworkAnalyst tools. Cytoscape software was used to identify hub genes and construct co-expressed networks. Target miRNAs were predicted based on the DIANA-micro T, miRDB, and miRWalk online databases.

RESULTS

A total of 70 DEGs were identified between T1DM patients recovered from ketosis or ketoacidosis and healthy control blood samples in GSE44314. Among the DEGs, 10 hub genes were screened out. The mature NK cell-specific gene co-expression network for DEGs in T1DM was built using NetworkAnalyst tools. DEGs between activated CD56⁺CD16⁺ NK cells and CD56^brightCD16^- NK cells were identified from GSE1511. After intersection, 13 overlapping genes between GSE44314 and GSE1511 microarray datasets were screened out, in which 7 hub genes were identified. Additionally, 59 target miRNAs were predicted according to the 7 hub genes. After validating with the exosome miRNA expression profile dataset of GSE97123, seven differentially expressed miRNAs (DEmiRNAs) in plasma-derived exosome were selected. Finally, a mRNA-miRNA network was constructed, which was involved in the T1DM ketosis or ketoacidosis process.

CONCLUSION

This work identified seven hub genes in activated CD56⁺CD16⁺ NK cells and seven miRNAs in plasma-derived exosome as potential predictors of T1DM ketoacidosis, which provided a novel insight for the pathogenesis at the transcriptome level.

From Obesity to Hippocampal Neurodegeneration: Pathogenesis and Non-Pharmacological Interventions

High-caloric diet and physical inactivity predispose individuals to obesity and diabetes, which are risk factors of hippocampal neurodegeneration and cognitive deficits. Along with the adipose-hippocampus crosstalk, chronically inflamed adipose tissue secretes inflammatory cytokine could trigger neuroinflammatory responses in the hippocampus, and in turn, impairs hippocampal neuroplasticity under obese and diabetic conditions. Hence, caloric restriction and physical exercise are critical non-pharmacological interventions to halt the pathogenesis from obesity to hippocampal neurodegeneration. In response to physical exercise, peripheral organs, including the adipose tissue, skeletal muscles, and liver, can secret numerous exerkines, which bring beneficial effects to metabolic and brain health. In this review, we summarized how chronic inflammation in adipose tissue could trigger neuroinflammation and hippocampal impairment, which potentially contribute to cognitive deficits in obese and diabetic conditions. We also discussed the potential mechanisms underlying the neurotrophic and neuroprotective effects of caloric restriction and physical exercise by counteracting neuroinflammation, plasticity deficits, and cognitive impairments. This review provides timely insights into how chronic metabolic disorders, like obesity, could impair brain health and cognitive functions in later life.

Non-diabetic ketoacidosis: a case series and literature review

The genesis of ketone bodies by organisms is a protective mechanism. This metabolic process helps organisms to survive acute metabolic derangements in times of nutrient deficiency. When prolonged, ketogenesis leads to ketoacidosis, which is a potentially life-threatening metabolic disorder due to the accumulation of keto-acids in the body. The most common cause is diabetic ketoacidosis, though starvation ketoacidosis and alcoholic ketoacidosis are not uncommon. The presentation of all ketoacidotic states is similar—being generally unwell, abdominal pain, rapid and shallow breathing, vomiting and dehydration. Non-diabetic ketoacidotic states are very commonly overlooked due to relative unawareness among the clinicians, leading to misdiagnosis and thereby inappropriate management culminating in added mortality and morbidity. We describe here six cases of alcoholic and starvation ketoacidosis, review the literature currently available and discuss the common pitfalls in managing such cases.

Predisposing factors for the development of diabetic ketoacidosis with lower than anticipated glucose levels in type 2 diabetes patients on SGLT2-inhibitors: a review

PURPOSE

SGLT2-inhibitors (SGLT-2i) have been linked to the risk of potential life-threatening diabetic ketoacidosis (DKA). The U.S. Food and Drug Administration and the European Medicines Agency issued warnings in 2015 and 2016 respectively on the predisposing factors to the development of DKA in individuals on an SGLT2i. New predisposing factors to DKA are still being discovered with the use of SGLT-2i. The list by FDA and EMA is yet to be updated. This article aims to provide a holistic list that includes the newer factors that have been implicated in the development of DKA. The overall aim is to guide physicians in prescribing this class of drugs for type 2 diabetes mellitus (T2D).

METHOD

A search was done using PUBMED, Google Scholar, and Directory of Open Access Journals with the following words: SGLT-2 Inhibitors AND Ketoacidosis were entered. We included articles from 2000 to 2020, those in English, those involving any of the approved SGLT2i medications in T2D patients, and studies that focused on DKA linked to SGLT-2i. These articles were reviewed, and relevant data extracted and compiled.

RESULTS AND CONCLUSION

The review has revealed that predisposing factors include (excess) alcohol consumption, female gender, starvation due to illness or fasting, withholding the use of SGLT2i for less than 48 h peri-operatively, and the existence of a variations in the expression of SGLT2 receptors. Patients should be advised on "sick day rules," and if a patient becomes unwell while on an SGLT2i, they should be advised to withhold the medication for the duration of the intercurrent illness.

Benefit/risk profile of dapagliflozin 5 mg in the DEPICT-1 and -2 trials in individuals with type 1 diabetes and body mass index ≥27 kg/m2

AIM

The DEPICT-1 and -2 studies (NCT02268214, NCT02460978) evaluated the efficacy and safety of dapagliflozin in individuals with type 1 diabetes who were receiving intensive insulin therapy. The DEPICT-1 and -2 studies (NCT02268214, NCT02460978) evaluated the efficacy and safety of dapagliflozin in individuals with type 1 diabetes. This post-hoc study investigated the safety and efficacy of dapagliflozin in individuals with BMI ≥27 kg/m² to assess if the benefit/risk ratio associated with dapagliflozin treatment can be further improved than that observed in the overall DEPICT population.

METHODS

Changes in glycated haemoglobin (HbA1c) and body weight, percentage change in daily insulin dose and proportion of participants achieving HbA1c reduction ≥0.5% without severe hypoglycaemia were evaluated at weeks 24 and 52. Changes in mean interstitial glucose, mean amplitude of glycaemic excursions and time in target glycaemic range were evaluated at week 24. Safety was assessed until week 56.

RESULTS

Week-52 adjusted mean (SE) change from baseline for HbA1c was -0.26% (0.05) with dapagliflozin versus +0.08% (0.05) with placebo and for body weight was -2.74 kg (0.25) with dapagliflozin versus +0.81 kg (0.26) with placebo. Mean (SE) percentage change in daily insulin dose was -10.5% (1.23) with dapagliflozin versus -1.4% (1.36) with placebo. Time spent in target glycaemic range increased by 2.2 h/day versus placebo. Dapagliflozin was well tolerated, with fewer participants experiencing diabetic ketoacidosis (dapagliflozin, 1.7%; placebo, 1.0%) than dapagliflozin 5 mg receiving participants in the pooled DEPICT populations.

CONCLUSIONS

Compared with the pooled DEPICT population, the benefit/risk profile of adjunct dapagliflozin therapy was more favourable in individuals with type 1 diabetes with body mass index ≥27 kg/m² because of the reduced risk of diabetic ketoacidosis in this population.

Implicating the effect of ketogenic diet as a preventive measure to obesity and diabetes mellitus

Obesity and diabetes are the two major metabolic complications linked with bad eating habits and the sedentary (lazy) lifestyle. In the worst-case situation, metabolic problems are a causative factor for numerous other conditions. There is also an increased demand to control the emergence of such diseases. Dietary and lifestyle improvements contribute to their leadership at an elevated level. The present review, therefore, recommends the use of the ketogenic diet (KD) in obesity and diabetes treatment. The KD involves a diet that replaces glucose sugar with ketone bodies and is effective in numerous diseases, such as metabolic disorders, epileptic seizures, autosomal dominant polycystic disease of the kidney, cancers, peripheral neuropathy, and skeletal muscle atrophy. A lot of high profile pathways are available for KD action, including sustaining the metabolic actions on glucose sugar, suppressing insulin-like growth factor-1 (IGF1) and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways, altering homeostasis of the systemic ketone bodies, contributing to lowering diabetic hyperketonemia, and others. The KD regulates the level of glucose sugar and insulin and can thus claim to be an effective diabetes approach. Thus, a stopgap between obesity and diabetes treatment can also be evidenced by KD.

Perspective: Ketone Supplementation in Sports-Does It Work?

Oral ketone supplements have gained popularity in recent years. There is biological rationale for a potential ergogenic effect of this type of supplement, as they might not only alter muscle fuel preference during exercise (and promote glycogen sparing, with potential benefits for endurance performance) but also favor cognition performance during exertion or muscle glycogen synthesis after exercise. However, as discussed in this Perspective, evidence to date does not support a benefit of acute ketone supplementation on sports performance, cognition, or muscle recovery [although further research with long-duration exercise (i.e., >60 min), is needed], and the evidence for chronic supplementation is sparse. In addition, acute intake of ketone supplements might be associated with gastrointestinal symptoms, and further research is warranted on the long-term safety of repeated use of ketone supplements. In summary, there is currently insufficient evidence to support the overall effectiveness of ketone supplements in sports.

Management of Diabetic Ketoacidosis in Children and Adolescents with Type 1 Diabetes Mellitus

Diabetic ketoacidosis (DKA) is the end result of insulin deficiency in type 1 diabetes mellitus (T1D). Loss of insulin production leads to profound catabolism with increased gluconeogenesis, glycogenolysis, lipolysis, and muscle proteolysis causing hyperglycemia and osmotic diuresis. High levels of counter-regulatory hormones lead to enhanced ketogenesis and the release of 'ketone bodies' into the circulation, which dissociate to release hydrogen ions and cause an overwhelming acidosis. Dehydration, hyperglycemia, and ketoacidosis are the hallmarks of this condition. Treatment is effective repletion of insulin, fluids and electrolytes. Newer approaches to early diagnosis, treatment, and prevention may diminish the risk of DKA and its childhood complications including cerebral edema. However, the potential for some technical and pharmacologic advances in the management of T1D to increase DKA events must be recognized.

Exploring Metabolic Signature of Protein Energy Wasting in Hemodialysis Patients

End-stage renal disease patients undergoing maintenance hemodialysis (HD) are vulnerable to the protein energy wasting (PEW) syndrome. Identification and diagnosis of PEW relies on clinical processes of judgment dependent on fulfilling multiple criteria drawn from serum biochemistry, weight status, predictive muscle mass, dietary energy and protein intakes. Therefore, we sought to explore the biomarkers’ signature with plasma metabolites of PEW by using ¹H-nuclear magnetic resonance for an untargeted metabolomics approach in the HD population, to understand metabolic alteration of PEW. In this case-controlled study, a total of 53 patients undergoing chronic HD were identified having PEW based on established diagnostic criteria and were age- and sex-matched with non-PEW (n = 53) HD patients. Fasting predialysis plasma samples were analyzed. Partial least square discriminant analysis demonstrated a significant separation between groups for specific metabolic pattern alterations. Further quantitative analysis showed that the level of 3-hydroxybutyrate, acetate, arabinose, maltose, ribose, sucrose and tartrate were significantly increased whilst creatinine was significantly decreased (all p < 0.05) in PEW subjects. Pathway analysis indicated that PEW-related metabolites reflected perturbations in fatty acid mechanism and induction of glyoxylate and dicarboxylate pathway attributed to gluconeogenesis. These results provide preliminary data in understanding metabolic alteration of PEW and corresponding abnormal metabolites that could potentially serve as biomarkers of PEW.

Epigenetic Regulator miRNA Pattern Differences Among SARS-CoV, SARS-CoV-2, and SARS-CoV-2 World-Wide Isolates Delineated the Mystery Behind the Epic Pathogenicity and Distinct Clinical Characteristics of Pandemic COVID-19

A detailed understanding of the molecular mechanism of SARS-CoV-2 pathogenesis is still elusive, and there is a need to address its deadly nature and to design effective therapeutics. Here, we present a study that elucidates the interplay between the SARS-CoV and SARS-CoV-2 viruses' and host's miRNAs, an epigenetic regulator, as a mode of pathogenesis; and we explored how the SARS-CoV and SARS-CoV-2 infections differ in terms of their miRNA-mediated interactions with the host and the implications this has in terms of disease complexity. We have utilized computational approaches to predict potential host and viral miRNAs and their possible roles in different important functional pathways. We have identified several putative host antiviral miRNAs that can target the SARS viruses and also predicted SARS viruses-encoded miRNAs targeting host genes. In silico predicted targets were also integrated with SARS-infected human cell microarray and RNA-seq gene expression data. A comparison between the host miRNA binding profiles on 67 different SARS-CoV-2 genomes from 24 different countries with respective country's normalized death count surprisingly uncovered some miRNA clusters, which are associated with increased death rates. We have found that induced cellular miRNAs can be both a boon and a bane to the host immunity, as they have possible roles in neutralizing the viral threat; conversely, they can also function as proviral factors. On the other hand, from over representation analysis, our study revealed that although both SARS-CoV and SARS-CoV-2 viral miRNAs could target broad immune-signaling pathways; only some of the SARS-CoV-2 miRNAs are found to uniquely target some immune-signaling pathways, such as autophagy, IFN-I signaling, etc., which might suggest their immune-escape mechanisms for prolonged latency inside some hosts without any symptoms of COVID-19. Furthermore, SARS-CoV-2 can modulate several important cellular pathways that might lead to the increased anomalies in patients with comorbidities like cardiovascular diseases, diabetes, breathing complications, etc. This might suggest that miRNAs can be a key epigenetic modulator behind the overcomplications amongst the COVID-19 patients. Our results support that miRNAs of host and SARS-CoV-2 can indeed play a role in the pathogenesis which can be further concluded with more experiments. These results will also be useful in designing RNA therapeutics to alleviate the complications from COVID-19.

Acute Ketone Supplementation and Exercise Performance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

PURPOSE

To determine the acute effects of ketone supplementation on exercise performance (primary outcome) and physiological and perceptual responses to exercise (secondary outcomes).

METHODS

A systematic search was conducted in PubMed, Web of Science, and SPORTDiscus (since inception to July 21, 2019) to find randomized controlled trials assessing the effects of acute ketone supplementation compared with a drink containing no ketones (ie, control intervention). The standardized mean difference (Hedges g) between interventions and 95% confidence interval (CI) were computed using a random-effects model.

RESULTS

Thirteen studies met all inclusion criteria. No significant differences were observed between interventions for overall exercise performance (Hedges g = -0.05; 95% CI, -0.30 to 0.20; P = .68). Subanalyses revealed no differences between interventions when analyzing endurance time-trial performance (g = -0.04; 95% CI, -0.35 to 0.28; P = .82) or when assessing the separate effects of supplements containing ketone esters (g = -0.07; 95% CI, -0.38 to 0.24; P = .66) or salts (g = -0.02; 95% CI, -0.45 to 0.41; P = .93). All studies reported increases in plasma ketone concentration after acute ketone supplementation, but no consistent effects were reported on the metabolic (plasma lactate and glucose levels), respiratory (respiratory exchange ratio, oxygen uptake, and ventilatory rate), cardiovascular (heart rate), or perceptual responses to exercise (rating of perceived exertion).

CONCLUSIONS

The present findings suggest that ketone supplementation exerts no clear influence on exercise performance (from sprints to events lasting up to ∼50 min) or metabolic, respiratory, cardiovascular, or perceptual responses to exercise. More research is needed to elucidate if this strategy could provide ergogenic effects on other exercise types (eg, ultraendurance exercise).

An overlooked danger of ketogenic diets: Making the case that ketone bodies induce vascular damage by the same mechanisms as glucose

Intense debate surrounds the use of low-carbohydrate, ketogenic diets for the promotion of weight loss and avoidance of cardiovascular disease. The rationale behind these diets is that they promote fat oxidation and minimize the addition of glucose to proteins in the formation of adducts that trigger inflammation. Although nutritional ketosis is widely assumed to be a safe metabolic condition, proper consideration has not been given to the fact that ketones are reactive toward proteins through the same mechanisms as glucose. Here, the case is made that ketone bodies are more potent than glucose in bringing about the protein modifications to which the harmful effects of glucose have been attributed. It is suggested, therefore, that attempts to minimize such protein modifications through nutritional ketosis are futile and may lead to adverse health outcomes.

The incidence, risk factors, and long-term outcomes of acute kidney injury in hospitalized diabetic ketoacidosis patients

Background

Emerging evidence has demonstrated that acute kidney injury (AKI) is an important risk factor associated with increased morbidity and mortality in diabetic ketoacidosis (DKA) patients. The current study aimed to investigate the incidence rate, risk factors, long-term renal outcomes, and mortality in DKA patients with AKI.

Methods

A total of 179 patients diagnosed with DKA at Sun Yat-sen Memorial Hospital from January 2012 to January 2018 were included in the analysis. AKI was diagnosed according to the 2012 KDIGO criteria. Risk factors, long-term renal outcomes, and mortality were analyzed by logistic regression and Cox proportional hazards models.

Results

Among 179 DKA patients, 98 patients (54.75%) were diagnosed as AKI. Aging; increased blood glucose, serum uric acid and white blood cells; decreased serum pH and albumin; coma; and preexisting chronic kidney disease (CKD) were risk factors of AKI in patients with DKA. During follow-up, DKA patients with AKI showed more than a two-fold decline in eGFR within 1 year after discharge from the hospital when compared with non-AKI DKA patients. Furthermore, AKI was also an independent risk factor for poor long-term renal outcomes and mortality in DKA patients.

Conclusions

Multiple risk factors contribute to the development of AKI in DKA patients. AKI and advanced AKI stage are associated with rapid progressive CKD and long-term mortality in patients with DKA.

Ergogenic Properties of Ketogenic Diets in Normal-Weight Individuals: A Systematic Review

Ketogenic diets (KDs) have received increasing attention among athletes and physically active individuals. However, the question as to whether and how the diet could benefit this healthy cohort remains unclear.Purpose: This study was designed to systematically review the existing evidence concerning the effect of KDs on body composition, aerobic and anaerobic capacity, muscle development, and sports performance in normal-weight individuals including athletes.Methods: A systematic search of English literature was conducted through electronic databases including PubMed, EBSCOhost, and Google Scholar. Upon the use of search criteria, 23 full-text original human studies involving non-obese participants were included in this review. For more stratified and focused analysis, these articles were further categorized based on the outcomes being examined including 1) body mass (BM) and %fat, 2) substrate utilization, 3) blood substrate and hormonal responses, 4) aerobic capacity and endurance performance, and 5) strength, power, and anaerobic capacity.Results: Our review indicates that a non-calorie-restricted KD carried out for ≥3 weeks can produce a modest reduction in BM and %fat, while maintaining fat-free mass. This diet leads to augmented use of fat as fuel, but this adaptation doesn't seem to improve endurance performance. Additionally, ad libitum KDs combined with resistance training will pose no harm to developing strength and power, especially when protein intake is increased modestly.Conclusions: It appears that a non-calorie-restricted KD provides minimal ergogenic benefits in normal-weight individuals including athletes, but can be used for optimizing BM and body composition without compromising aerobic and anaerobic performance. Key teaching pointsKetogenic diets have received increasing attention among athletes and physically active individuals.It remains elusive as to whether ketogenic diets could confer ergogenic benefits for those who are normal weight but want to use the diet to improve fitness and performance.An interesting dilemma exists in that ketogenic diets can reduce body mass and %fat and increase fat oxidation, but they can also decrease glycogen stores and limit sports performance.This review concludes that a non-calorie-restricted ketogenic diet provides minimal ergogenic benefits in normal-weight individuals, but can be used to optimize body mass and composition without compromising athletic performance.This finding can be important for esthetic or weight-sensitive athletes because the diet may allow them to reach a target body mass without having to sacrifice athletic performance.The ketogenic diet-induced metabolic adaptations require a state of ketosis, and thus caution should be taken because an excessive increase in ketone bodies can be detrimental to health.

Euglycemic diabetic ketoacidosis due to a strict low-carbohydrate diet during treatment with sodium-glucose cotransporter 2 inhibitors

Background

Euglycemic diabetic ketoacidosis is a critical clinical presentation that can occur during treatment with sodium-glucose cotransporter 2 inhibitors. However, little is known regarding how a low-carbohydrate diet in combination with this treatment can increase the risk for this condition. Here, we report a case of euglycemic diabetic ketoacidosis in a patient treated with sodium-glucose cotransporter 2 inhibitors after initiation of a low-carbohydrate diet.

Case Presentation

A 54-year-old woman who was taking canagliflozin was transferred to our hospital with severe dyspnea. She had been started on a strict low-carbohydrate diet for 6 days before admission. Laboratory evaluation revealed severe ketoacidosis and a blood glucose level of 196 mg/dL. After her symptoms improved, she was diagnosed with type 1 diabetes mellitus.

Conclusion

Although low-carbohydrate diets are recommended for patients with diabetes mellitus, physicians should exercise great caution in recommending low-carbohydrate diets to patients undergoing treatment with sodium-glucose cotransporter 2 inhibitors.

Diagnosis of Bovine Respiratory Disease in feedlot cattle using blood 1H NMR metabolomics

Current diagnosis methods for Bovine Respiratory Disease (BRD) in feedlots have a low diagnostic accuracy. The current study aimed to search for blood biomarkers of BRD using ¹H NMR metabolomics and determine their accuracy in diagnosing BRD. Animals with visual signs of BRD (n = 149) and visually healthy (non-BRD; n = 148) were sampled for blood metabolomics analysis. Lung lesions indicative of BRD were scored at slaughter. Non-targeted ¹H NMR metabolomics was used to develop predictive algorithms for disease classification using classification and regression trees. In the absence of a gold standard for BRD diagnosis, six reference diagnosis methods were used to define an animal as BRD or non-BRD. Sensitivity (Se) and specificity (Sp) were used to estimate diagnostic accuracy (Acc). Blood metabolomics demonstrated a high accuracy at diagnosing BRD when using visual signs of BRD (Acc = 0.85), however was less accurate at diagnosing BRD using rectal temperature (Acc = 0.65), lung auscultation score (Acc = 0.61) and lung lesions at slaughter as reference diagnosis methods (Acc = 0.71). Phenylalanine, lactate, hydroxybutyrate, tyrosine, citrate and leucine were identified as metabolites of importance in classifying animals as BRD or non-BRD. The blood metabolome classified BRD and non-BRD animals with high accuracy and shows potential for use as a BRD diagnosis tool.

Dysregulation of Ketone Body Metabolism Is Associated With Poor Prognosis for Clear Cell Renal Cell Carcinoma Patients

Kidney is an important organ for ketone body metabolism. However, the role of abnormal ketone metabolism and its possible function in tumorigenesis of clear cell renal cell carcinoma (ccRCC) have not yet been elucidated. Three differentially expressed key enzymes involved in ketone body metabolism, ACAT1, BDH2, and HMGCL, were screened out between ccRCC and normal kidney tissues using the GEO and TCGA databases.We confirmed that the transcription and protein expression of ACAT1, BDH2, and HMGCL were significantly lower in ccRCC by real-time RT-PCR and IHC assays. Those patients with lower expression of these three genes have a worse outcome. In addition, we demonstrated that ectopic expression of each of these genes inhibited the proliferation of ccRCC cells. The overexpressed ACAT1 and BDH2 genes remarkably impeded the migratory and invasive capacity of ccRCC cells. Furthermore, exogenous β-hydroxybutyrate suppressed the growth of ccRCC cells in vitro in a dose-dependent manner. Our findings suggest that ACAT1, BDH2, and HMGCL are potential tumor suppressor genes, and constitute effective prognostic biomarkers for ccRCC. Ketone body metabolism might thus be a promising target in a process for developing novel therapeutic approaches to treat ccRCC.

Blood Ketone Bodies and Breath Acetone Analysis and Their Correlations in Type 2 Diabetes Mellitus

Analysis of volatile organic compounds in the breath for disease detection and monitoring has gained momentum and clinical significance due to its rapid test results and non-invasiveness, especially for diabetes mellitus (DM). Studies have suggested that breath gases, including acetone, may be related to simultaneous blood glucose (BG) and blood ketone levels in adults with types 2 and 1 diabetes. Detecting altered concentrations of ketones in the breath, blood and urine may be crucial for the diagnosis and monitoring of diabetes mellitus. This study assesses the efficacy of a simple breath test as a non-invasive means of diabetes monitoring in adults with type 2 diabetes mellitus. Human breath samples were collected in Tedlar™ bags and analyzed by headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME/GC-MS). The measurements were compared with capillary BG and blood ketone levels (β-hydroxybutyrate and acetoacetate) taken at the same time on a single visit to a routine hospital clinic in 30 subjects with type 2 diabetes and 28 control volunteers. Ketone bodies of diabetic subjects showed a significant increase when compared to the control subjects; however, the ketone levels were was controlled in both diabetic and non-diabetic volunteers. Worthy of note, a statistically significant relationship was found between breath acetone and blood acetoacetate (R = 0.89) and between breath acetone and β-hydroxybutyrate (R = 0.82).

Impact of Carbohydrate on Glucose Variability in Patients with Type 1 Diabetes Assessed Through Professional Continuous Glucose Monitoring: A Retrospective Study

INTRODUCTION

The aim of this study was to objectively analyze the correlation between dietary components and blood glucose variation by means of continuous glucose monitoring (CGM).

METHODS

Patients with type 1 diabetes mellitus (T1DM) who received CGM to manage their blood glucose levels were enrolled into the study, and the components of their total caloric intake were analyzed. Glycemic variation parameters were calculated, and dietary components, including percentages of carbohydrate, protein and fat in the total dietary intake, were analyzed by a dietitian. The interaction between parameters of glycemic variability and dietary components was analyzed.

RESULTS

Sixty-one patients with T1DM (33 females, 28 males) were enrolled. The mean age of the participants was 34.7 years, and the average duration of diabetes was 14 years. Glycated hemoglobin before CGM was 8.54%. Participants with a carbohydrate intake that accounted for < 50% of their total caloric intake had a longer DM duration and a higher protein and fat intake than did those with a carbohydrate intake that accounted for ≥ 50% of total caloric intake, but there was no between-group difference in total caloric intake per day. The group with a carbohydrate intake that accounted for < 50% of their total caloric intake also had lower nocturnal continuous overlapping net glycemic action (CONGA) 1, - 2 and - 4 values. The percentage of protein intake had a slightly negative correlation with mean amplitude of glycemic excursions (MAGE) (r = - 0.286, p < 0.05) and a moderately negative correlation with coefficient of variation (CV) (r = 0.289, p < 0.05). One additional percentage of protein calories of total calories per day decreased the MAGE to 4.25 mg/dL and CV to 0.012 (p < 0.05). The optimal dietary protein percentage for MAGE < 140 mg/dL was 15.13%. The performance of predictive models revealed the beneficial effect of adequate carbohydrate intake on glucose variation when combined with protein consumption.

CONCLUSIONS

Adequate carbohydrate consumption-but not more than half the daily total calories-combined with protein calories that amount to approximately 15% of the daily caloric intake is important for glucose stability and beneficial for patients with T1DM.

Circulating acetoacetate is associated with poor prognosis in heart failure patients

Background

Acetoacetate is used as an alternative energy source in the heart, and has the potential to improve cardiac function. However, the prognostic impact of acetoacetate has not been investigated in heart failure.

Methods

This study enrolled consecutive 615 hospitalized patients with heart failure. We investigated the associations between circulating acetoacetate and clinical characteristics or prognosis in HF patients.

Results

We divided the patients into two groups based on circulating acetoacetate levels (high group: acetoacetate ≥35 µmoL/L, n = 313; and low group: acetoacetate <35 µmoL/L, n = 302). The high group had an older age (68 vs. 65 years, P = 0.003) and higher log brain natriuretic peptide levels (2.43 vs. 2.23, P < 0.001) compared with the low group. In contrast, there were no significant differences in the prevalence of co-morbidities, including diabetes mellitus, chronic kidney disease, and anemia, between the two groups. During the median follow-up period of 328 days, 66 all-cause deaths occurred. The high group had a worse prognosis compared with the low group (Log rank, P = 0.041). In the Cox proportional hazard analysis, circulating acetoacetate levels (per 10 µmoL/L increase) were associated with all-cause mortality (hazard ratio 1.020, 95% confidence interval 1.010–1.030, P < 0.001).

Conclusions

Circulating acetoacetate is associated with all-cause mortality in patients with heart failure. These results provide new insights into the role of alternative cardiac metabolism in heart failure patients, and raise the possibility of acetoacetate as a novel biomarker to predict the prognosis of heart failure patients.

High Concentration of Ketone Body β-Hydroxybutyrate Modifies Synaptic Vesicle Cycle and Depolarizes Plasma Membrane of Rat Brain Synaptosomes

Ketoacidosis is a dangerous complication of diabetes mellitus in which plasma levels of ketone bodies can reach 20-25 mM. This condition is life-threatening. In contrast, a ketogenic diet, achieving plasma levels of ketone bodies of about 4-5 mM, can be used for treating different brain diseases. However, the factors leading to the conversion of the neuroprotective ketone bodies' action to the neurotoxic action during ketoacidosis are still unknown. We investigated the influence of high concentration (25 mM) of the main ketone body, β-hydroxybutyrate (BHB), on intrasynaptosomal pH (pHi), synaptic vesicle cycle, plasma membrane, and mitochondrial potentials. Using the fluorescent dye BCECF-AM, it was shown that BHB at concentrations of 8 and 25 mM did not influence pHi in synaptosomes. By means of the fluorescent dye acridine orange, it was demonstrated that 25 mM of BHB had no effect on exocytosis but inhibited compensatory endocytosis by 5-fold. Increasing buffer capacity with 25 mM HEPES did not affect endocytosis. Glucose abolished BHB-induced endocytosis inhibition. Using the fluorescent dye DiSC3(5), it was shown that 25 mM of BHB induced a significant plasma membrane depolarization. This effect was not impacted by glucose. Using the fluorescent dye rhodamine-123, it was shown that BHB alone (25 mМ) did not alter the potential of intrasynaptosomal mitochondria.Importantly, the high concentration of BHB (25 mМ) causes the depolarization of the plasma membrane and stronger inhibition of endocytosis compared with the intermediate concentration (8 mM).

Ketogenic Diets and Exercise Performance

The ketogenic diet (KD) has gained a resurgence in popularity due to its purported reputation for fighting obesity. The KD has also acquired attention as an alternative and/or supplemental method for producing energy in the form of ketone bodies. Recent scientific evidence highlights the KD as a promising strategy to treat obesity, diabetes, and cardiac dysfunction. In addition, studies support ketone body supplements as a potential method to induce ketosis and supply sustainable fuel sources to promote exercise performance. Despite the acceptance in the mainstream media, the KD remains controversial in the medical and scientific communities. Research suggests that the KD or ketone body supplementation may result in unexpected side effects, including altered blood lipid profiles, abnormal glucose homeostasis, increased adiposity, fatigue, and gastrointestinal distress. The purpose of this review article is to provide an overview of ketone body metabolism and a background on the KD and ketone body supplements in the context of obesity and exercise performance. The effectiveness of these dietary or supplementation strategies as a therapy for weight loss or as an ergogenic aid will be discussed. In addition, the recent evidence that indicates ketone body metabolism is a potential target for cardiac dysfunction will be reviewed.

Ketogenic diet in endocrine disorders: Current perspectives

Ketogenic diet (KD) is a high-fat, adequate-protein, and low-carbohydrate diet that leads to nutritional ketosis, long known for antiepileptic effects and has been used therapeutically to treat refractory epilepsy. This review attempts to summarize the evidence and clinical application of KD in diabetes, obesity, and other endocrine disorders. KD is usually animal protein based. An empiric vegetarian Indian variant of KD has been provided keeping in mind the Indian food habits. KD has beneficial effects on cardiac ischemic preconditioning, improves oxygenation in patients with respiratory failure, improves glycemic control in diabetics, is associated with significant weight loss, and has a beneficial impact on polycystic ovarian syndrome. Multivitamin supplementations are recommended with KD. Recently, ketones are being proposed as super-metabolic fuel; and KD is currently regarded as apt dietary therapy for "diabesity."

Carbohydrate Restriction in Type 1 Diabetes: A Realistic Therapy for Improved Glycaemic Control and Athletic Performance?

Around 80% of individuals with Type 1 diabetes (T1D) in the United States do not achieve glycaemic targets and the prevalence of comorbidities suggests that novel therapeutic strategies, including lifestyle modification, are needed. Current nutrition guidelines suggest a flexible approach to carbohydrate intake matched with intensive insulin therapy. These guidelines are designed to facilitate greater freedom around nutritional choices but they may lead to higher caloric intakes and potentially unhealthy eating patterns that are contributing to the high prevalence of obesity and metabolic syndrome in people with T1D. Low carbohydrate diets (LCD; <130 g/day) may represent a means to improve glycaemic control and metabolic health in people with T1D. Regular recreational exercise or achieving a high level of athletic performance is important for many living with T1D. Research conducted on people without T1D suggests that training with reduced carbohydrate availability (often termed "train low") enhances metabolic adaptation compared to training with normal or high carbohydrate availability. However, these "train low" practices have not been tested in athletes with T1D. This review aims to investigate the known pros and cons of LCDs as a potentially effective, achievable, and safe therapy to improve glycaemic control and metabolic health in people with T1D. Secondly, we discuss the potential for low, restricted, or periodised carbohydrate diets in athletes with T1D.

Phenotypic relationships, genetic parameters, genome-wide associations, and identification of potential candidate genes for ketosis and fat-to-protein ratio in German Holstein cows

Energy demand for milk production in early lactation exceeds energy intake, especially in high-yielding Holstein cows. Energy deficiency causes increasing susceptibility to metabolic disorders. In addition to several blood parameters, the fat-to-protein ratio (FPR) is suggested as an indicator for ketosis, because a FPR >1.5 refers to high lipolysis. The aim of this study was to analyze phenotypic, quantitative genetic, and genomic associations between FPR and ketosis. In this regard, 8,912 first-lactation Holstein cows were phenotyped for ketosis according to a veterinarian diagnosis key. Ketosis was diagnosed if the cow showed an abnormal carbohydrate metabolism with increased content of ketone bodies in the blood or urine. At least one entry for ketosis in the first 6 wk after calving implied a score = 1 (diseased); otherwise, a score = 0 (healthy) was assigned. The FPR from the first test-day was defined as a Gaussian distributed trait (FPRgauss), and also as a binary response trait (FPRbin), considering a threshold of FPR = 1.5. After imputation and quality controls, 45,613 SNP markers from the 8,912 genotyped cows were used for genomic studies. Phenotypically, an increasing ketosis incidence was associated with significantly higher FPR, and vice versa. Hence, from a practical trait recording perspective, first test-day FPR is suggested as an indicator for ketosis. The ketosis heritability was slightly larger when modeling the pedigree-based relationship matrix (pedigree-based: 0.17; SNP-based: 0.11). For FPRbin, heritabilities were larger when modeling the genomic relationship matrix (pedigree-based: 0.09; SNP-based: 0.15). For FPRgauss, heritabilities were almost identical for both pedigree and genomic relationship matrices (pedigree-based: 0.14; SNP-based: 0.15). Genetic correlations between ketosis with FPRbin and FPRgauss using either pedigree- or genomic-based relationship matrices were in a moderate range from 0.39 to 0.71. Applying genome-wide association studies, we identified the specific SNP rs109896020 (BTA 5, position: 115,456,438 bp) significantly contributing to ketosis. The identified potential candidate gene PARVB in close chromosomal distance is associated with nonalcoholic fatty liver disease in humans. The most important SNP contributing to FPRbin was located within the DGAT1 gene. Different SNP significantly contributed to ketosis and FPRbin, indicating different mechanisms for both traits genomically.

Role of ketone signaling in the hepatic response to fasting

Ketosis is a metabolic adaptation to fasting, nonalcoholic fatty liver disease (NAFLD), and prolonged exercise. β-OH butyrate acts as a transcriptional regulator and at G protein-coupled receptors to modulate cellular signaling pathways in a hormone-like manner. While physiological ketosis is often adaptive, chronic hyperketonemia may contribute to the metabolic dysfunction of NAFLD. To understand how β-OH butyrate signaling affects hepatic metabolism, we compared the hepatic fasting response in control and 3-hydroxy-3-methylglutaryl-CoA synthase II (HMGCS2) knockdown mice that are unable to elevate β-OH butyrate production. To establish that rescue of ketone metabolic/endocrine signaling would restore the normal hepatic fasting response, we gave intraperitoneal injections of β-OH butyrate (5.7 mmol/kg) to HMGCS2 knockdown and control mice every 2 h for the final 9 h of a 16-h fast. In hypoketonemic, HMGCS2 knockdown mice, fasting more robustly increased mRNA expression of uncoupling protein 2 (UCP2), a protein critical for supporting fatty acid oxidation and ketogenesis. In turn, exogenous β-OH butyrate administration to HMGCS2 knockdown mice decreased fasting UCP2 mRNA expression to that observed in control mice. Also supporting feedback at the transcriptional level, β-OH butyrate lowered the fasting-induced expression of HMGCS2 mRNA in control mice. β-OH butyrate also regulates the glycemic response to fasting. The fast-induced fall in serum glucose was absent in HMGCS2 knockdown mice but was restored by β-OH butyrate administration. These data propose that endogenous β-OH butyrate signaling transcriptionally regulates hepatic fatty acid oxidation and ketogenesis, while modulating glucose tolerance. NEW & NOTEWORTHY Ketogenesis regulates whole body glucose metabolism and β-OH butyrate produced by the liver feeds back to inhibit hepatic β-oxidation and ketogenesis during fasting.

The ups and downs of low-carbohydrate diets in the management of Type 1 diabetes: a review of clinical outcomes

Dietary management has been a mainstay of care in Type 1 diabetes since before the discovery of insulin when severe carbohydrate restriction was advocated. The use of insulin facilitated re-introduction of carbohydrate into the diet. Current management guidelines focus on a healthy and varied diet with consideration of glycaemic load, protein and fat. As a result of frustration with glycaemic outcomes, low-carbohydrate diets have seen a resurgence in popularity. To date, low-carbohydrate diets have not been well studied in the management of Type 1 diabetes. Studies looking at glycaemic outcomes from low-carbohydrate diets have largely been cross-sectional, without validated dietary data and with a lack of control groups. The participants have been highly motivated self-selected individuals who follow intensive insulin management practices, including frequent blood glucose monitoring and additional insulin corrections with tight glycaemic targets. These confounders limit the ability to determine the extent of the impact of dietary carbohydrate restriction on glycaemic outcomes. Carbohydrate-containing foods including grains, fruit and milk are important sources of nutrients. Hence, low-carbohydrate diets require attention to vitamin and energy intake to avoid micronutrient deficiencies and growth issues. Adherence to restricted diets is challenging and can have an impact on social normalcy. In individuals with Type 1 diabetes, adverse health risks such as diabetic ketoacidosis, hypoglycaemia, dyslipidaemia and glycogen depletion remain clinical concerns. In the present paper, we review studies published to date and provide clinical recommendations for ongoing monitoring and support for individuals who choose to adopt a low-carbohydrate diet. Strategies to optimize postprandial glycaemia without carbohydrate restriction are presented.

Ketoacidosis - Where Do the Protons Come From?

In extreme conditions ketosis can progress to ketoacidosis, a dangerous and potentially life-threatening condition. Ketoacidosis is most common in new or poorly treated type 1 diabetes. The acidosis is usually attributed to the 'acidic' nature of the ketone bodies (acetoacetate, 3-hydroxybutyrate, and acetone). However, acetoacetate and 3-hydroxybutyrate are produced not as acids but as their conjugate bases, and acetone is neither an acid nor a base. This raises the question of why severe ketosis is accompanied by acidosis. Here, we analyze steps in ketogenesis and identify four potential sources: adipocyte lipolysis, hydrolysis of inorganic pyrophosphate generated during synthesis of fatty acyl-coenzyme A (CoA), the reaction catalyzed by an enzyme in the β-oxidation pathway (3-hydroxyacyl-CoA dehydrogenase), and increased synthesis of CoA.

The Significance of an Increased Beta-Hydroxybutyrate at Presentation to the Emergency Department in Patients with Diabetes in the Absence of a Hyperglycemic Emergency

The significance of hyperketonemia in adults with diabetes presenting to the emergency department with acute illness, not due to a diabetic hyperglycemic emergency, has not been well characterized. Adult patients with diabetes presenting to the emergency department who had venous blood gas and beta-hydroxybutyrate levels measured whilst in the emergency department were retrospectively evaluated for the relationship between BHB and clinical outcomes. Over 6 months, 404 patients with diabetes had at least one beta-hydroxybutyrate level measured in the emergency department. There were 23 admissions for diabetic ketoacidosis (DKA) or hyperosmolar state. Of the remainder, 58 patients had a beta-hydroxybutyrate ≥ 1 mmol/L; this group had a higher glucose at presentation (19.0 (8.8) versus 10.4 (9.9) mmol/L), higher HbA1c (8.8 (5.4) versus 8.0 (3.3)%), lower bicarbonate (22.6 (6.2) versus 24.8 (4.7) mmol/L), and higher anion gap (14.8 (6.1) versus 12.6 (4.2)) than had those with BHB < 1 mmol/L. There was no association between the presence of ketosis and the length of stay (4.2 (7.3) versus (3.0) (7.2) days). Acute illness in those with diabetes associated with ketosis in the absence of DKA is associated with worse glycaemic control than in those without ketosis. Ketosis may represent an intermediate state of metabolic dysregulation rather than being associated with a more severe acute illness, as suggested by no relationship between BHB and length of stay.

Ketogenic diet versus ketoacidosis: what determines the influence of ketone bodies on neurons?

Glucose is the main energy substrate for neurons, however, at certain conditions, e.g. in starvation, these cells could also use ketone bodies. This approach is used in clinical conditions as the ketogenic diet. The ketogenic diet is actually a biochemical model of fasting. It includes replacing carbohydrates by fats in daily meal. Synthesis of ketone bodies β-hydroxubutirate, acetoacetate and acetone begins once glycogen stores have depleted in the liver. The ketogenic diet can be used to treat clinical conditions, primarily epilepsy. The mechanism of neuroprotective action of ketogenic diet is not very clear. It is shown that ketone bodies influence neurons at three different levels, namely, metabolic, signaling and epigenetic levels. Ketone bodies are not always neuroprotective. Sometimes they can be toxic for the brain. Ketoacidosis which is a very dangerous complication of diabetes mellitus or alcoholism can be taken as an example. The exact mechanism of how neuroprotective properties of ketone bodies reverse to neurotoxic is yet to be established.

Ketosis-Prone Diabetes (Flatbush Diabetes): an Emerging Worldwide Clinically Important Entity

PURPOSE OF REVIEW

Ketosis-prone diabetes or Flatbush diabetes has been widely recognized as a clinical entity since 1984. Most of the early clinical studies focused on African American or Afro-Caribbean individuals. It is now being recognized as an important clinical entity in sub-Saharan Africans, Asian and Indian populations, and Hispanic populations. Major questions remain as to its pathogenesis and whether it is a unique type of diabetes or a subset of more severe type 2 diabetes with greater loss of insulin action in target tissues. This review summarizes the main clinical and mechanistic studies to improve the understanding of ketosis-prone (Flatbush) diabetes.

RECENT FINDINGS

Little data are available on the magnitude of KPD in the different susceptible populations. It is relatively common in black populations. KPD is defined as a syndrome in which diabetes commences with ketoacidosis in individuals who are GAD and anti-islet cell antibody negative and have no known precipitating causes. The patients present during middle age, are overweight or mildly obese, and in many reports are more likely to be male. After intensive initial insulin therapy, many patients become insulin independent and can be well controlled on diet alone or diet plus oral medications. The clinical course of KPD is like that of patients with type 2 diabetes rather than that of type 1 diabetes. Little differences are found in the clinical characteristics and clinical outcomes between patients presenting with KPD and those presenting with severe hyperglycemia with no ketoacidosis. The mechanisms responsible for the development of ketosis-prone diabetes as well its remission remain unknown.

Leptin concentration and oxidative stress in diabetic ketoacidosis

BACKGROUND

Diabetes is a common metabolic state during ageing, and one in five elderly individuals suffers from diabetes. However, few studies have been performed in elderly diabetic patients, and large randomized clinical trials in this population are rare. The purpose of this study was to investigate changes in serum leptin levels in elderly patients with diabetic ketoacidosis (DKA) before and after treatment and assess its relationship with oxidative stress parameters.

MATERIALS AND METHODS

Serum leptin levels, plasma superoxide dismutase (SOD) activity, plasma malondialdehyde (MDA) levels, plasma total antioxidant capacity (TAC) and plasma 8-iso-prostaglandin F_2α (8-iso-PGF_2α ) levels were measured in elderly patients aged 81.76 ± 9.42 years with DKA before and after treatment.

RESULTS

Plasma SOD activity, TAC and serum leptins before treatment were significantly lower in elderly patients with DKA compared with the control group (P < 0.05), whereas plasma MDA and 8-iso-PGF_2α levels before treatment were significantly higher in elderly patients with DKA (P < 0.05). Plasma SOD activity, TAC and serum leptin levels in elderly patients with DKA were significantly elevated after treatment, whereas their plasma MDA and 8-iso-PGF_2α levels were significantly reduced (P < 0.05). Leptin levels negatively correlated with plasma 8-iso-PGF2α after treatment in elderly DKA patients (r = -0.36, P < 0.05). Stepwise multiple regression analysis showed that 8-iso-PGF_2α was a significant factor affecting serum leptin levels.

CONCLUSIONS

Serum leptin levels in the elderly patients with DKA were significantly reduced after treatment, which was associated with oxidative stress.

Empagliflozin as adjunct to insulin in Japanese participants with type 1 diabetes: Results of a 4-week, double-blind, randomized, placebo-controlled phase 2 trial

AIMS

This phase 2, double-blind, randomized, placebo-controlled trial (ClinicalTrials.gov NCT02702011) with 4 sites in Japan investigated the pharmacodynamics (PD), pharmacokinetics (PK) and safety profile of empagliflozin in Japanese participants with type 1 diabetes mellitus (T1DM) as adjunctive therapy to insulin.

MATERIALS AND METHODS

Participants using multiple daily injections of insulin for ≥12 months, with HbA1c of 7.5%-10.0%, entered a 2-week, open-label, placebo run-in period, followed by a 4-week, double-blind period during which participants were randomized 1:1:1:1 to receive empagliflozin 2.5 mg (n = 13), empagliflozin 10 mg (n = 12), empagliflozin 25 mg (n = 12) or placebo (n = 11). The primary objective was to assess the effect of empagliflozin vs placebo on urinary glucose excretion (UGE) after 7 days of treatment.

RESULTS

PD: Empagliflozin resulted in a dose-dependent significant increase in 24-hour UGE compared with placebo (UGE placebo-corrected mean [95% confidence interval] change from baseline: 2.5 mg, 65.10 [43.29, 86.90] g/24 h; 10 mg, 81.19 [58.80, 103.58] g/24 h; 25 mg, 98.11 [75.91, 120.31] g/24 h). After 4 weeks of treatment, UGE increase was associated with improved glycaemic control, reduced body weight and decreased insulin needs. Empagliflozin treatment also resulted in dose-dependent increases in serum ketone bodies and free fatty acids. PK: Plasma empagliflozin levels increased in a dose-dependent manner and peaked at 1.5 hours. In this short study, empagliflozin was well tolerated, with no increase in rate of hypoglycaemia and no diabetic ketoacidosis events reported.

CONCLUSIONS

Based on this short-duration phase 2 study, the PK/PD profile of empagliflozin in Japanese participants with T1DM is comparable to that of non-Japanese participants.

Management of Type 1 Diabetes With a Very Low-Carbohydrate Diet

OBJECTIVES

To evaluate glycemic control among children and adults with type 1 diabetes mellitus (T1DM) who consume a very low-carbohydrate diet (VLCD).

METHODS

We conducted an online survey of an international social media group for people with T1DM who follow a VLCD. Respondents included adults and parents of children with T1DM. We assessed current hemoglobin A1c (HbA1c) (primary measure), change in HbA1c after the self-reported beginning of the VLCD, total daily insulin dose, and adverse events. We obtained confirmatory data from diabetes care providers and medical records.

RESULTS

Of 316 respondents, 131 (42%) were parents of children with T1DM, and 57% were of female sex. Suggestive evidence of T1DM (based on a 3-tier scoring system in which researchers took into consideration age and weight at diagnosis, pancreatic autoimmunity, insulin requirement, and clinical presentation) was obtained for 273 (86%) respondents. The mean age at diagnosis was 16 ± 14 years, the duration of diabetes was 11 ± 13 years, and the time following a VLCD was 2.2 ± 3.9 years. Participants had a mean daily carbohydrate intake of 36 ± 15 g. Reported mean HbA1c was 5.67% ± 0.66%. Only 7 (2%) respondents reported diabetes-related hospitalizations in the past year, including 4 (1%) for ketoacidosis and 2 (1%) for hypoglycemia.

CONCLUSIONS

Exceptional glycemic control of T1DM with low rates of adverse events was reported by a community of children and adults who consume a VLCD. The generalizability of these findings requires further studies, including high-quality randomized controlled trials.