METABOLISM-CLINICAL AND EXPERIMENTAL

Advances in body composition and gender differences in susceptibility to frailty syndrome: Role of osteosarcopenic obesity
Conforto R, Rizzo V, Russo R, Mazza E, Maurotti S, Pujia C, Succurro E, Arturi F, Ferro Y, Sciacqua A, Pujia A and Montalcini T
There is general consensus that an improper diet negatively impacts health and that nutrition is a primary tool for the prevention of non-communicable diseases. Unfortunately, the importance of studying body composition, which can reveal early predictors of gender-related diseases, is still not well understood in this context. Currently, individuals are still classified as obese based solely on their body mass index, without considering the amount of fat, its distribution, and the quantity of muscle and bone mass. In this regard, the body composition phenotype defined as "osteosarcopenic obesity" affects approximately 6-41 % of postmenopausal women, with prevalence increasing with age due to the hormonal and metabolic changes that occur during this period. This particular phenotype arises from the strong relationship between visceral fat, muscle, bone, and gut microbiota and predispose postmenopausal women to frailty. Frailty is a complex clinical phenomenon with significant care and economic implications for our society. Recent studies suggest that women have a higher prevalence of frailty syndrome and its individual components, such as osteoporosis, fractures and sarcopenia, compared to men. Here, we provide a comprehensive overview of recent advances regarding the impact of gender on body composition and frailty. Furthermore, we reflect on the crucial importance of personalized nutritional interventions, with a focus on reducing visceral fat, increasing protein intake and optimizing vitamin D levels. A review of the scientific literature on this topic highlights the importance of studying body composition for a personalized and gender-specific approach to nutrition and dietetics, in order to identify frailty syndrome early and establish personalized treatments. This new method of researching disease predictors could likely help clarify the controversial results of studies on vitamin D, calcium and proteins, translate into practical wellness promotion across diverse elderly populations.
Evidence from clinical studies of leptin: current and future clinical applications in humans
Perakakis N and Mantzoros CS
Leptin has been established as the prototype adipose tissue secreted hormone and as a major regulator of several human physiology functions. Here, we are primarily reviewing the findings from studies in humans involving leptin administration. We are describing the metabolic, endocrine and immunologic effects of leptin replacement in conditions of leptin deficiency, such as short-term fasting in healthy individuals, relative energy deficiency in sports (REDS), congenital leptin deficiency (CLD), generalized (GL) and partial lipodystrophy (PL), HIV-associated lipodystrophy (HIV-L) and of leptin treatment in conditions of leptin excess (common obesity, type 2 diabetes, steatotic liver disease). We are comparing the results with the findings from preclinical models and present the main conclusions regarding the role of leptin in human physiology, pathophysiology and therapeutics. We conclude that, in conditions of energy deficiency, leptin substitution effectively reduces body weight and fat mass through reduction of appetite, it improves hypertriglyceridemia, insulin resistance and hepatic steatosis (especially in GL and PL), it restores neuroendocrine function (especially the gonadotropic axis), it regulates adaptive immune system cell populations and it improves bone health. On the contrary, leptin treatment in conditions of leptin excess, such as common obesity and type 2 diabetes, does not improve any metabolic abnormalities. Strategies to overcome leptin tolerance/resistance in obesity and type 2 diabetes have provided promising results in animal studies, which should though be tested in humans in randomized clinical trials.
Wars1 downregulation in hepatocytes induces mitochondrial stress and disrupts metabolic homeostasis
Pontanari F, Demagny H, Faure A, Li X, Benegiamo G, Jalil A, Perino A, Auwerx J and Schoonjans K
Several laboratories, including ours, have employed the Slc25a47 mouse model to investigate the role of SLC25A47, a hepatocyte-specific mitochondrial carrier, in regulating hepatic metabolism and systemic physiology. In this study, we reveal that the hepatic and systemic phenotypes observed following recombination of the Slc25a47-Wars1 locus in hepatocytes are primarily driven by the unexpected downregulation of Wars1, the cytosolic tryptophan aminoacyl-tRNA synthetase located adjacent to Slc25a47. While the downregulation of Wars1 predictably affects cytosolic translation, we also observed a significant impairment in mitochondrial protein synthesis within hepatocytes. This disturbance in mitochondrial function leads to an activation of the mitochondrial unfolded protein response (UPR), a critical component of the mitochondrial stress response (MSR). Our findings clarify the distinct roles of Slc25a47 and Wars1 in maintaining both systemic and hepatic metabolic homeostasis. This study sheds new light on the broader implications of aminoacyl-tRNA synthetases in mitochondrial physiology and stress responses.
Targeting endoplasmic reticulum stress as a potential therapeutic strategy for diabetic cardiomyopathy
Congur I, Mingrone G and Guan K
Endoplasmic reticulum (ER) is an essential organelle involved in vesicular transport, calcium handling, protein synthesis and folding, and lipid biosynthesis and metabolism. ER stress occurs when ER homeostasis is disrupted by the accumulation of unfolded and/or misfolded proteins in the ER lumen. Adaptive pathways of the unfolded protein response (UPR) are activated to maintain ER homeostasis. In obesity and type 2 diabetes mellitus (T2DM), accumulating data indicate that persistent ER stress due to maladaptive UPR interacts with insulin/leptin signaling, which may be the potential and central mechanistic link between obesity-/T2DM-induced metabolic dysregulation (chronic hyperglycemia, dyslipidemia and lipotoxicity in cardiomyocytes), insulin/leptin resistance and the development of diabetic cardiomyopathy (DiabCM). Meanwhile, these pathological conditions further exacerbate ER stress. However, their interrelationships and the underlying molecular mechanisms are not fully understood. A deeper understanding of ER stress-mediated pathways in DiabCM is needed to develop novel therapeutic strategies. The aim of this review is to discuss the crosstalk between ER stress and leptin/insulin signaling and their involvement in the development of DiabCM focusing on mitochondria-associated ER membranes and chronic inflammation. We also present the current direction of drug development and important considerations for translational research into targeting ER stress for the treatment of DiabCM.
Body weight control via protein kinase CK2: diet-induced obesity counteracted by pharmacological targeting
Buchwald LM, Neess D, Hansen D, Doktor TK, Ramesh V, Steffensen LB, Blagoev B, Litchfield DW, Andresen BS, Ravnskjaer K, Færgeman NJ and Guerra B
Protein kinase CK2 is a highly conserved enzyme implicated in the pathogenesis of various human illnesses including obesity. Despite compelling evidence for the involvement of this kinase in the pathophysiology of obesity, the molecular mechanisms by which CK2 might regulate fat metabolism are still poorly understood.
Serum lipidomic signatures in patients with varying histological severity of metabolic-dysfunction associated steatotic liver disease
Muralidharan S, Lee JWJ, Lim YS, Muthiah M, Tan E, Demicioglu D, Shabbir A, Loo WM, Koo CS, Lee YM, Soon G, Wee A, Halisah N, Abbas S, Ji S, Triebl A, Burla B, Koh HWL, Chan YS, Lee MC, Ng HH, Wenk MR, Torta F and Dan YY
Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a spectrum of pathologies ranging from simple steatosis to steatohepatitis, fibrosis and cirrhosis. Patients with metabolic associated steatohepatitis (MASH) with fibrosis are at greatest risk of liver and cardiovascular complications. To identify such at-risk MASLD patients, physicians are still reliant on invasive liver biopsies. This study aimed to identify circulating lipidomic signatures to better identify patients with MASH in a multi-ethnic Asian cohort.
Targeted metabolomics identified novel metabolites, predominantly phosphatidylcholines and docosahexaenoic acid-containing lipids, predictive of incident chronic kidney disease in middle-to-elderly-aged Chinese adults
Liu L, Cai H, Yang H, Wang S, Li Y, Huang Y, Gao M, Zhang X, Zhang X, Wang H and Qiu G
Evidence is limited regarding the association of circulating metabolites with decline of kidney function, letting alone their value in prediction of development of chronic kidney disease (CKD).
PCSK9 in metabolism and diseases
Ajoolabady A, Pratico D, Mazidi M, Davies IG, Lip GYH, Seidah N, Libby P, Kroemer G and Ren J
PCSK9 is a serine protease that regulates plasma levels of low-density lipoprotein (LDL) and cholesterol by mediating the endolysosomal degradation of LDL receptor (LDLR) in the liver. When PCSK9 functions unchecked, it leads to increased degradation of LDLR, resulting in elevated circulatory levels of LDL and cholesterol. This dysregulation contributes to lipid and cholesterol metabolism abnormalities, foam cell formation, and the development of various diseases, including cardiovascular disease (CVD), viral infections, cancer, and sepsis. Emerging clinical and experimental evidence highlights an imperative role for PCSK9 in metabolic anomalies such as hypercholesterolemia and hyperlipidemia, as well as inflammation, and disturbances in mitochondrial homeostasis. Moreover, metabolic hormones - including insulin, glucagon, adipokines, natriuretic peptides, and sex steroids - regulate the expression and circulatory levels of PCSK9, thus influencing cardiovascular and metabolic functions. In this comprehensive review, we aim to elucidate the regulatory role of PCSK9 in lipid and cholesterol metabolism, pathophysiology of diseases such as CVD, infections, cancer, and sepsis, as well as its pharmaceutical and non-pharmaceutical targeting for therapeutic management of these conditions.
Successful repurposing of empagliflozin to treat neutropenia in a severe congenital neutropenia patient with G6PC3 mutations
Tsaknakis G, Boutakoglou E, Mavroudi I, Mantzoros CS, Cunha MV and Papadaki HA
Accurate non-invasive detection of MASH with fibrosis F2-F3 using a lightweight machine learning model with minimal clinical and metabolomic variables
Stefanakis K, Mingrone G, George J and Mantzoros CS
There are no known non-invasive tests (NITs) designed for accurately detecting metabolic dysfunction-associated steatohepatitis (MASH) with liver fibrosis stages F2-F3, excluding cirrhosis-the FDA-defined range for prescribing Resmetirom and other drugs in clinical trials. We aimed to validate and re-optimize known NITs, and most importantly to develop new machine learning (ML)-based NITs to accurately detect MASH F2-F3.
An updated overview on hepatocellular carcinoma in patients with Metabolic dysfunction-Associated Steatotic Liver Disease: Trends, pathophysiology and risk-based surveillance
Armandi A, Rosso C, Caviglia GP and Bugianesi E
Hepatocellular carcinoma (HCC) is a relevant complication occurring in individuals with advanced Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD). Recent epidemiological data suggest an alarming increase in the HCC burden worldwide, with a relevant proportion attributable to MASLD (up to 38 %), either in cirrhotic or non-cirrhotic livers. In view of the changing landscape of metabolic syndrome as "silent pandemic", this narrative review aims to provide an updated picture of the burden of HCC in individuals with MASLD. In the complex pathophysiological pathways linking insulin resistance to MASLD and cardiometabolic syndrome, metabolic inflammation appears a relevant driver of systemic as well as organ-specific complications. Novel insights from the field of immunology, gut-derived liver damage, and association with extra-hepatic cancers will be discussed. Finally, strategies for risk-based HCC surveillance (circulating biomarkers, prognostic models and polygenic risk scores) will be provided and the potential impact of novel drug targeting fibrosing Metabolic dysfunction-Associated Steatohepatitis (MASH) on incident HCC will be discussed.
Bilirubin bioconversion to urobilin in the gut-liver-kidney axis: A biomarker for insulin resistance in the Cardiovascular-Kidney-Metabolic (CKM) Syndrome
Kipp ZA, Badmus OO, Stec DE, Hall B and Hinds TD
The rising rates of obesity worldwide have increased the incidence of cardiovascular disease (CVD), making it the number one cause of death. Higher plasma bilirubin levels have been shown to prevent metabolic dysfunction and CVD. However, reducing levels leads to deleterious outcomes, possibly due to reduced bilirubin half-life that escalates the production of its catabolized product, urobilinogen, produced by gut bacteria and naturally oxidized to urobilin. Recent findings suggest that the involvement of the microbiome catabolism of bilirubin to urobilin and its absorption via the hepatic portal vein contributes to CVD, suggesting a liver-gut axis involvement. We discuss the studies that demonstrate that urobilin is frequently raised in the urine of persons with CVD and its probable role in acquiring the disease. Urobilin is excreted from the kidneys into the urine and may serve as a biomarker for Cardiovascular-Kidney-Metabolic (CKM) Syndrome. We deliberate on the newly discovered bilirubin reductase (BilR) bacterial enzyme that produces urobilin. We discuss the bacterial species expressing BilR, how they impact CVD, and whether suppressing urobilin production and increasing bilirubin may provide new therapeutic strategies for CKM. Possible therapeutic mechanisms for achieving this goal are discussed.
Reducing the global prevalence of cardiometabolic risk factors: a bet worth winning
Fogacci F, Ray KK, Nicholls SJ and Cicero AFG
The role of IL-1 family cytokines in diabetic cardiomyopathy
Wu Q, Zeng Y, Geng K, Guo M, Teng FY, Yan PJ, Lei Y, Long Y, Jiang ZZ, Law BY and Xu Y
Diabetic cardiomyopathy (DCM) is the primary cause of heart failure in patients with diabetes and is characterised by contractile dysfunction and left ventricular hypertrophy. The complex pathological and physiological mechanisms underlying DCM have contributed to a limited number of available treatment options. A substantial body of evidence has established that DCM is a low-grade inflammatory cardiovascular disorder, with the interleukin-1 (IL-1) family of cytokines playing crucial roles in initiating inflammatory responses and shaping innate and adaptive immunity. In this review, we aim to provide an overview of the underlying mechanisms of the IL-1 family and their relevance in DCM of various aetiologies. Furthermore, we highlighted potential therapeutic targets within the IL-1 family for the management of DCM.
Role of glycogen in cardiac metabolic stress
Xiang KF, Wan JJ, Wang PY and Liu X
Metabolic stress in the myocardium arises from a diverse array of acute and chronic pathophysiological contexts. Glycogen mishandling is a key feature of metabolic stress, while maladaptation in energy-stress situations confers functional deficits. Cardiac glycogen serves as a pivotal reserve for myocardial energy, which is classically described as an energy source and contributes to glucose homeostasis during hypoxia or ischemia. Despite extensive research activity, how glycogen metabolism affects cardiovascular disease remains unclear. In this review, we focus on its regulation across myocardial energy metabolism in response to stress, and its role in metabolism, immunity, and autophagy. We further summarize the cardiovascular-related drugs regulating glycogen metabolism. In this way, we provide current knowledge for the understanding of glycogen metabolism in the myocardium.
Metabolic dysfunction-associated steatotic liver disease and urinary system cancers: Mere coincidence or reason for concern?
Bril F and Elbert A
Metabolic dysfunction-associated steatotic liver disease (MASLD) is a systemic disease characterized by insulin resistance and lipotoxicity. Its association with type 2 diabetes, cardiovascular disease, liver cirrhosis, and hepatocellular carcinoma are well described. However, the association of MASLD and extra-hepatic cancers has received significantly less attention. This narrative review will summarize the conflicting evidence regarding the association between MASLD and cancers of the urinary system, including renal cell carcinoma, urothelial carcinoma, and prostate adenocarcinoma. It will explore potential mechanisms that could be responsible for a higher risk of urinary system cancers in patients with MASLD. We hope that our comprehensive assessment of the literature will help the readers to better interpret the available evidence.
Engineering organoids-on-chips for drug testing and evaluation
Wang H, Zhu W, Xu C, Su W and Li Z
Organoids-on-chips is an emerging innovative integration of stem cell-derived organoids with advanced organ-on-chip technology, providing a novel platform for the in vitro construction of biomimetic micro-physiological systems. The synergistic merger transcends the limitations of traditional drug screening and safety assessment methodologies, such as 2D cell cultures and animal models. In this review, we examine the prevailing challenges and prerequisites of preclinical models utilized for drug screening and safety evaluations. We highlighted the salient features and merits of organoids-on-chip, elucidating their capability to authentically replicate human physiology, thereby addressing contemporary impediments. We comprehensively overviewed the recent endeavors where organoids-on-chips have been harnessed for drug screening and safety assessment and delved into potential opportunities and challenges for evolving sophisticated, near-physiological organoids-on-chips. Based on current achievements, we further discuss how to enhance the practicality of organoids-on-chips and accelerate the translation from preclinical to clinical stages in healthcare and industry by utilizing multidisciplinary convergent innovation.
Hepatocyte-specific SLC27A4 deletion ameliorates nonalcoholic fatty liver disease in mice via suppression of phosphatidylcholine-mediated PXR activation
Shen C, Pan Z, Xie W, Zhao J, Miao D, Zhao L, Liu M, Zhong Y, Zhong C, Gonzalez FJ, Wang W, Gao Y and Liu C
The protein Solute carrier family 27 member 4 (SLC27A4) is crucial for fatty acid synthesis and β-oxidation, but its role in hepatic steatosis and nonalcoholic fatty liver disease (NAFLD) progression is not fully understood.
Letter to the editor: global burden of metabolic dysfunction-associated steatotic liver disease: results from the global burden of disease study 2021
Li Y and Moshage H
Association between the Life's essential 8 health behaviors score and all-cause mortality in patients with metabolic dysfunction-associated steatotic liver disease
Han Y, Tang J, Wu N, Li Z, Ren H, Hu P and Chen Z
The association between Life's Essential 8 (LE8) score and all-cause mortality in patients with metabolic dysfunction-associated steatotic liver disease (MASLD) remains unknown.
Metabolically unhealthy obesity, sarcopenia and their interactions in obesity pathophysiology and therapeutics: Room for improvement in pharmacotherapy
Katsarou A, Kouvari M, Hill MA and Mantzoros CS