Non-alcoholic fatty liver disease is characterised by a reduced polyunsaturated fatty acid transport via free fatty acids and high-density lipoproteins (HDL)

Diverting hepatic lipid fluxes with lifestyles revision and pharmacological interventions as a strategy to tackle steatotic liver disease (SLD) and hepatocellular carcinoma (HCC)

Steatotic liver disease (SLD) and Hepatocellular Carcinoma (HCC) are characterised by a substantial rewiring of lipid fluxes caused by systemic metabolic unbalances and/or disrupted intracellular metabolic pathways. SLD is a direct consequence of the interaction between genetic predisposition and a chronic positive energy balance affecting whole-body energy homeostasis and the function of metabolically-competent organs. In this review, we discuss how the impairment of the cross-talk between peripheral organs and the liver stalls glucose and lipid metabolism, leading to unbalances in hepatic lipid fluxes that promote hepatic fat accumulation. We also describe how prolonged metabolic stress builds up toxic lipid species in the liver, and how lipotoxicity and metabolic disturbances drive disease progression by promoting a chronic activation of wound healing, leading to fibrosis and HCC. Last, we provide a critical overview of current state of the art (pre-clinical and clinical evidence) regarding mechanisms of action and therapeutic efficacy of candidate SLD treatment options, and their potential to interfere with SLD/HCC pathophysiology by diverting lipids away from the liver therefore improving metabolic health.

Phosphatidylcholine ameliorates lipid accumulation and liver injury in high-fat diet mice by modulating bile acid metabolism and gut microbiota

Phosphatidylcholine (PC) has garnered considerable attention due to its involvement in a wide array of crucial biological functions. However, there is still much to active explore regarding the precise mechanisms that underlie PC's actions in the context of high-fat diet. In this study, we found that both PC intervention and treatment significantly mitigated lipid accumulation, liver damage, and body weight gaining triggered by the high-fat diet. Untargeted and targeted metabolomic analyses uncovered substantial effects of PC on bile acid metabolism, especially led to a substantial reduction in elevated levels of free bile acids. 16S rRNA gene sequencing revealed that PC modulated the gut microbiota structures and compositions in high-fat diet mice, particularly exhibiting a positive association with Pseudoflavonifractor abundance, and a negative correlation with Olsenella, Parasutterella, and Allobaculum abundance. Our study suggested that PC held promise as a potential candidate for alleviating lipid metabolism injury, liver disease or obesity.

Lipid metabolism in MASLD and MASH: From mechanism to the clinic

Metabolic dysfunction-associated steatotic liver disease/steatohepatitis (MASLD/MASH) is recognised as a metabolic disease characterised by excess intrahepatic lipid accumulation due to lipid overflow and synthesis, alongside impaired oxidation and/or export of these lipids. But where do these lipids come from? The main pathways related to hepatic lipid accumulation are de novo lipogenesis and excess fatty acid transport to the liver (due to increased lipolysis, adipose tissue insulin resistance, as well as excess dietary fatty acid intake, in particular of saturated fatty acids). Not only triglycerides but also other lipids are secreted by the liver and are associated with a worse histological profile in MASH, as shown by lipidomics. Herein, we review the role of lipid metabolism in MASLD/MASH and discuss the impact of weight loss (diet, bariatric surgery, GLP-1RAs) or other pharmacological treatments (PPAR or THRβ agonists) on hepatic lipid metabolism, lipidomics, and the resolution of MASH.

A Mediterranean Diet-Oriented Intervention Rescues Impaired Blood Cell Bioenergetics in Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease

Background: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD), a novel term for Non-Alcoholic Fatty Liver Disease (NAFLD), is associated with liver mitochondrial dysfunction. We previously demonstrated that mitochondrial respiratory capacity in peripheral blood mononuclear cells (PBMCs) was significantly reduced in patients with MASLD compared to non-MASLD controls. For MASLD treatment, guidelines recommend behavioral and dietary changes to reduce body weight. A recent 12-month clinical trial demonstrated that ameliorating patients' lifestyles through improved adherence to the Mediterranean diet and encouraged physical activity results in MASLD remission or regression. Methods: As a sub-study of the 12-month clinical trial, we evaluated the effects of the Mediterranean diet-oriented intervention on PBMC mitochondrial DNA content and respiratory parameters and on various biomarkers associated with MASLD. Results: Contrary to what was found at the baseline, after twelve months of intervention, systemic inflammatory and bioenergetics parameters did not differ between MASLD patients (N = 15) and control subjects (N = 17). PBMCs from MASLD subjects showed rescued basal respiration, ATP-linked respiration, maximal respiration, and spare respiratory capacity. The observed recovery coincided with a significant increase in the patients' adherence to the Mediterranean diet (Medscore). Conclusions: Our findings indicate that a Mediterranean diet-oriented intervention, without calorie reduction, preserves blood cell mitochondrial function in MASLD subjects. Thus, PBMC bioenergetics-based assays might be taken into account not only for diagnosing but also for monitoring therapeutic responses in MASLD.

High-density lipoprotein cholesterol trajectory and new-onset metabolic dysfunction-associated fatty liver disease incidence: a longitudinal study

BACKGROUND

Although high-density lipoprotein cholesterol (HDL-C) exerts a significant influence on the development of metabolic dysfunction-associated fatty liver disease (MAFLD), the association of dynamic changes in HDL-C levels with the risk of MAFLD remains unclear. Thus, the aim of the current study was to explore the association between the changing trajectories of HDL-C and new-onset MAFLD. The findings of this study may provide a theoretical basis for future personalized intervention and prevention targeting MAFLD.

METHODS

A total of 1507 participants who met the inclusion criteria were recruited from a community-based physical examination population in Nanjing, China from 2017 to 2021. Group-based trajectory models were constructed to determine the heterogeneous HDL-C trajectories. The incidence of MAFLD in each group in 2022 was followed up, and the Cox proportional hazards regression model was applied to investigate the associations between different HDL-C trajectories and the risk of new-onset MAFLD.

RESULTS

The incidences of MAFLD in the low-stable, moderate-stable, moderate-high-stable, and high-stable groups of HDL-C trajectory were 26.5%, 13.8%, 7.2% and 2.6%, respectively. The incidence rate of MAFLD in the order of the above trajectory groups exhibited a decreasing trend (χ2 = 72.55, Ptrend<0.001). After adjusting for confounders, the risk of MAFLD onset in HDL-C low-stable group was still 5.421 times (95%CI: 1.303-22.554, P = 0.020) higher than that in the high-stable group. Subgroup analyses of the combined (moderate high-stable and high-stable groups combined), moderate-stable and low-stable groups showed that sex, age, and overweight/obesity did not affect the association between HDL-C trajectory and MAFLD risk.

CONCLUSIONS

Persistently low HDL-C level is a risk factor for the onset of MAFLD. Long-term monitoring of HDL-C levels and timely intervention for those experiencing persistent declines are crucial for early prevention of MAFLD.

Nomogram for predicting 5-year metabolic dysfunction-associated steatotic liver disease risk: retrospective cohort study

Objective

To create a nomogram-based model to estimate the Chinese population's 5-year risk of metabolic dysfunction-associated steatotic liver disease (MASLD).

Methods

We randomly divided 7582 participants into two groups in a 7:3 ratio: one group was assigned to work with the training set, which consisted of 5307 cases, and the other group was assigned to validate the model using 2275 cases. The least absolute shrinkage and selection operator model was employed to ascertain the variables with the highest correlation among all potential variables. A logistic model was constructed by incorporating these selected variables, which were subsequently visualized using a nomogram. The discriminatory ability, calibration, and clinical utility of the model were assessed using the receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA).

Results

During the 5-year follow-up, 1034 (13.64%) total participants were newly diagnosed with MASLD. Using eight variables (gender, body mass index, waist, hemoglobin, alanine aminotransferase, uric acid, triglycerides, and high-density lipoprotein), we built a 5-year MASLD risk prediction model. The nomogram showed an area under the ROC of 0.795 (95% CI: 0.779-0.811) in the training set and 0.785 (95% CI: 0.760-0.810) in the validation set. The calibration curves revealed a 5-year period of agreement between the observed and predicted MASLD risks. DCA curves illustrated the practicality of this nomogram over threshold probability profiles ranging from 5% to 50%.

Conclusion

We created and tested a nomogram to forecast the risk of MASLD prevalence over the next 5 years.

Lipoprotein Lipidomics as a Frontier in Non-Alcoholic Fatty Liver Disease Biomarker Discovery

Non-alcoholic fatty liver disease (NAFLD) is a progressive liver disease characterized by the build-up of fat in the liver of individuals in the absence of alcohol consumption. This condition has become a burden in modern societies aggravated by the lack of appropriate predictive biomarkers (other than liver biopsy). To better understand this disease and to find appropriate biomarkers, a new technology has emerged in the last two decades with the ability to explore the unmapped role of lipids in this disease: lipidomics. This technology, based on the combination of chromatography and mass spectrometry, has been extensively used to explore the lipid metabolism of NAFLD. In this review, we aim to summarize the knowledge gained through lipidomics assays exploring tissues, plasma, and lipoproteins from individuals with NAFLD. Our goal is to identify common features and active pathways that could facilitate the finding of a reliable biomarker from this field. The most frequent observation was a variable decrease (1-9%) in polyunsaturated fatty acids in phospholipids and non-esterified fatty acids in NAFLD patients, both in plasma and liver. Additionally, a reduction in phosphatidylcholines is a common feature in the liver. Due to the scarcity of studies, further research is needed to properly detect lipoprotein, plasma, and tissue lipid signatures of NAFLD etiologies, and NAFLD subtypes, and to define the relevance of this technology in disease management strategies in the push toward personalized medicine.

Increased Odds of Metabolic Dysfunction-Associated Steatotic Liver Disease Are Linked to Reduced n-6, but Not n-3 Polyunsaturated Fatty Acids in Plasma

The increasing prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) underscores the need for better understanding of its complex pathogenesis. Lipid accumulation in hepatocytes is among principal mechanisms contributing to MASLD development. While routine lipid parameters are well studied, the profile of circulating fatty acids in MASLD patients remains less explored. This study aimed to assess relative proportions of individual fatty acids in plasma of MASLD patients and to explore their associations with other biochemical markers of MASLD. Ninety-one patients and 48 healthy individuals were enrolled. The relative proportions of fatty acids in plasma were determined using gas chromatography with FID detection. Proportions of total n-6 polyunsaturated fatty acids (PUFAs) and linoleic acid (LA) in plasma were lower in MASLD patients (p = 0.001 and p = 0.004, respectively), with no differences observed in n-3 PUFAs. Total plasma n-6 PUFAs correlated negatively with body mass index, hepatic steatosis indices, triglyceride concentration and coronary risk index. Decreased prevalence of n-6 PUFAs in plasma was independently associated with higher odds of MASLD (OR = 0.769; CI: 0.611-0.968; p = 0.025). Our findings indicate an altered circulatory fatty acid distribution in MASLD, characterized by a reduced amount of n-6 PUFAs, particularly LA, which may have significant implications for the prevention and treatment of MASLD.

Ketogenesis supports hepatic polyunsaturated fatty acid homeostasis via fatty acid elongation

Therapeutic interventions targeting hepatic lipid metabolism in metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (MASH) remain elusive. Using mass spectrometry-based stable isotope tracing and shotgun lipidomics, we established a novel link between ketogenesis and MASLD pathophysiology. Our findings show that mouse liver and primary hepatocytes consume ketone bodies to support fatty acid (FA) biosynthesis via both de novo lipogenesis (DNL) and FA elongation. Analysis of 13 C-labeled FAs in hepatocytes lacking mitochondrial D-β-hydroxybutyrate dehydrogenase (BDH1) revealed a partial reliance on mitochondrial conversion of D-βOHB to acetoacetate (AcAc) for cytoplasmic DNL contribution, whereas FA elongation from ketone bodies was fully dependent on cytosolic acetoacetyl-CoA synthetase (AACS). Ketone bodies were essential for polyunsaturated FA (PUFA) homeostasis in hepatocytes, as loss of AACS diminished both free and esterified PUFAs. Ketogenic insufficiency depleted liver PUFAs and increased triacylglycerols, mimicking human MASLD, suggesting that ketogenesis supports PUFA homeostasis, and may mitigate MASLD-MASH progression in humans.

Trimethylamine N-oxide ameliorates hepatic damage including reduction of hepatic bile acids and cholesterol in Fxr-null mice

There are conflicting animal experiments on the effect of trimethylamine N-oxide (TMAO), the dietary metabolite, on non-alcoholic fatty liver disease (NAFLD). This study aims to determine the effect of TMAO on NAFLD. A diet containing 0.3% TMAO was fed to farnesoid X receptor (Fxr)-null mice, a model of NAFLD, for 13 weeks. Fxr-null mice fed TMAO showed significant reductions in liver damage markers but not wild-type mice. Hepatic bile acid and cholesterol levels were significantly decreased, and triacylglycerol levels tended to decrease in TMAO-fed Fxr-null mice. Changes in mRNA levels of hepatic bile acid and cholesterol transporters and synthetic enzymes were observed, which could explain the decreased hepatic bile acid and cholesterol levels in Fxr-null mice given the TMAO diet but not in the wild-type mice. These results suggest that TMAO intake ameliorates liver damage in Fxr-null mice, further altering bile acid/cholesterol metabolism in an FXR-independent manner.

Serum bile acid and unsaturated fatty acid profiles of non-alcoholic fatty liver disease in type 2 diabetic patients

BACKGROUND

The understanding of bile acid (BA) and unsaturated fatty acid (UFA) profiles, as well as their dysregulation, remains elusive in individuals with type 2 diabetes mellitus (T2DM) coexisting with non-alcoholic fatty liver disease (NAFLD). Investigating these metabolites could offer valuable insights into the pathophy-siology of NAFLD in T2DM.

AIM

To identify potential metabolite biomarkers capable of distinguishing between NAFLD and T2DM.

METHODS

A training model was developed involving 399 participants, comprising 113 healthy controls (HCs), 134 individuals with T2DM without NAFLD, and 152 individuals with T2DM and NAFLD. External validation encompassed 172 participants. NAFLD patients were divided based on liver fibrosis scores. The analytical approach employed univariate testing, orthogonal partial least squares-discriminant analysis, logistic regression, receiver operating characteristic curve analysis, and decision curve analysis to pinpoint and assess the diagnostic value of serum biomarkers.

RESULTS

Compared to HCs, both T2DM and NAFLD groups exhibited diminished levels of specific BAs. In UFAs, particular acids exhibited a positive correlation with NAFLD risk in T2DM, while the ω-6:ω-3 UFA ratio demonstrated a negative correlation. Levels of α-linolenic acid and γ-linolenic acid were linked to significant liver fibrosis in NAFLD. The validation cohort substantiated the predictive efficacy of these biomarkers for assessing NAFLD risk in T2DM patients.

CONCLUSION

This study underscores the connection between altered BA and UFA profiles and the presence of NAFLD in individuals with T2DM, proposing their potential as biomarkers in the pathogenesis of NAFLD.

Association of High-Density Lipoprotein Cholesterol with Sarcopenia in Chinese Community-Dwelling Middle-Aged and Older Adults: Evidence from 4-Year Longitudinal Study

INTRODUCTION

There is inconsistent evidence on the associations between high-density lipoprotein cholesterol (HDL-C) and risk of sarcopenia. The aim of the study was to determine the evidence existing between HDL-C and sarcopenia in Chinese middle-aged and older adults.

METHODS

We used a panel study design of the China Health and Retirement Longitudinal Study (CHARLS), with 7,415 participants (mean age 57.5 years) from 2011, 2013, and 2015. HDL-C was measured by colorimetric test of venous serum samples. Sarcopenia was defined as low muscle mass, plus low muscle strength, or low physical performance. Muscle mass was estimated by anthropometric measures. Muscle strength was measured by handgrip strength using dynamometer. Physical performance was measured by 5-time chair stand test, gait speed test, and short physical performance battery.

RESULTS

With 961 (13.0%) sarcopenia cases, each 1-unit increase (1 SD = 15.4 mg/dL) of HDL-C levels was associated with 42% increased odds of incident sarcopenia (OR = 1.42, 95% confidence interval [CI] = 1.28-1.58) at 4-year follow-up. Females with high HDL-C levels (HDL-C >60 mg/dL) had a higher risk of sarcopenia (OR = 2.49, 95% CI = 1.76-3.52). The restricted cubic spline curves showed a J-shaped association between HDL-C and risk of sarcopenia in females. HDL-C was negatively associated with muscle mass (β = -0.23, 95% CI = -0.27 to -0.20) and hand grip strength (β = -0.05, 95% CI = -0.19 to 0.09).

CONCLUSION

High HDL-C levels were associated with higher risk of sarcopenia among middle-aged and older Chinese adults, and appropriate control of its high levels informs the management of sarcopenia.

Dynamic changes in the mouse hepatic lipidome following warm ischemia reperfusion injury

Liver failure secondary to metabolic dysfunction-associated steatotic liver disease (MASLD) has become the most common cause for liver transplantation in many parts of the world. Moreover, the prevalence of MASLD not only increases the demand for liver transplantation, but also limits the supply of suitable donor organs because steatosis predisposes grafts to ischemia-reperfusion injury (IRI). There are currently no pharmacological interventions to limit hepatic IRI because the mechanisms by which steatosis leads to increased injury are unclear. To identify potential novel mediators of IRI, we used liquid chromatography and mass spectrometry to assess temporal changes in the hepatic lipidome in steatotic and non-steatotic livers after warm IRI in mice. Our untargeted analyses revealed distinct differences between the steatotic and non-steatotic response to IRI and highlighted dynamic changes in lipid composition with marked changes in glycerophospholipids. These findings enhance our knowledge of the lipidomic changes that occur following IRI and provide a foundation for future mechanistic studies. A better understanding of the mechanisms underlying such changes will lead to novel therapeutic strategies to combat IRI.

High maternal adiposity during pregnancy programs an imbalance in the lipidome and predisposes to diet-induced hepatosteatosis in the offspring

BACKGROUND

Exposure to high maternal adiposity in utero is a significant risk factor for the later-life development of metabolic syndrome (MetS), including non-alcoholic fatty liver disease (NAFLD). We have previously shown that high pre-pregnancy adiposity programs adipose tissue dysfunction in the offspring, leading to spillover of fatty acids into the circulation, a key pathogenic event in obesity-associated MetS. Herein, we hypothesized that programming of adipose tissue dysfunction in offspring born to overweight dams increases the risk for developing NAFLD.

RESULTS

Females heterozygous for leptin receptor deficiency (Hetdb) were used as a model of high pre-pregnancy adiposity. Female wild-type (Wt) offspring born to Hetdb pregnancies gained significantly more body fat following high-fat/fructose diet (HFFD) compared with Wt offspring born to Wt dams. HFFD increased circulating free fatty acids (FFA) in male offspring of control dams, while FFA levels were similar in HFFD-fed offspring from Wt dams and CD or HFFD-fed Wt offspring from Hetdb dams. Despite female-specific protection from diet-induced FFA spillover, both male and female offspring from Hetdb dams were more susceptible to diet-induced hepatosteatosis. Lipidomic analysis revealed that CD-offspring of overweight dams had decreased hepatic polyunsaturated FA (PUFA) levels compared with control offspring. Changes to saturated FA (SFA) and the de novo lipogenic (DNL) index were diet driven; however, there was a significant effect of the intrauterine environment on FA elongation and Δ9 desaturase activity.

CONCLUSION

High maternal adiposity during pregnancy programs a susceptibility to diet-induced hepatosteatosis.

Inflammation and Oxidative Stress Induced by Obesity, Gestational Diabetes, and Preeclampsia in Pregnancy: Role of High-Density Lipoproteins as Vectors for Bioactive Compounds

Inflammation and oxidative stress are essential components in a myriad of pathogenic entities that lead to metabolic and chronic diseases. Moreover, inflammation in its different phases is necessary for the initiation and maintenance of a healthy pregnancy. Therefore, an equilibrium between a necessary/pathologic level of inflammation and oxidative stress during pregnancy is needed to avoid disease development. High-density lipoproteins (HDL) are important for a healthy pregnancy and a good neonatal outcome. Their role in fetal development during challenging situations is vital for maintaining the equilibrium. However, in certain conditions, such as obesity, diabetes, and other cardiovascular diseases, it has been observed that HDL loses its protective properties, becoming dysfunctional. Bioactive compounds have been widely studied as mediators of inflammation and oxidative stress in different diseases, but their mechanisms of action are still unknown. Nonetheless, these agents, which are obtained from functional foods, increase the concentration of HDL, TRC, and antioxidant activity. Therefore, this review first summarizes several mechanisms of HDL participation in the equilibrium between inflammation and oxidative stress. Second, it gives an insight into how HDL may act as a vector for bioactive compounds. Third, it describes the relationships between the inflammation process in pregnancy and HDL activity. Consequently, different databases were used, including MEDLINE, PubMed, and Scopus, where scientific articles published in the English language up to 2023 were identified.

High-density lipoproteins and non-alcoholic fatty liver disease

Background and aims

Non-alcoholic fatty liver disease (NAFLD), a high incidence liver pathology, is associated with a ∼1.5-fold higher cardiovascular disease risk. This phenomenon is generally attributed to the NAFLD-associated increase in circulating levels of pro-atherogenic apolipoprotein B100-containing small dense low-density lipoprotein and plasma hypertriglyceridemia. However, also a significant reduction in cholesterol transported by anti-atherogenic high-density lipoproteins (HDL) is frequently observed in subjects suffering from NAFLD as compared to unaffected people. In this review, we summarize data regarding the relationship between NAFLD and plasma HDL-cholesterol levels, with a special focus on highlighting potential causality between the NAFLD pathology and changes in HDL metabolism.

Methods and results

Publications in PUBMED describing the relationship between HDL levels and NAFLD susceptibility and/or disease severity, either in human clinical settings or genetically-modified mouse models, were critically reviewed for subsequent inclusion in this manuscript. Furthermore, relevant literature describing effects on lipid loading in cultured hepatocytes of models with genetic alterations related to HDL metabolism have been summarized.

Conclusions

Although in vitro observations suggest causality between HDL formation by hepatocytes and protection against NAFLD-like lipid accumulation, current literature remains inconclusive on whether relative HDL deficiency is actually driving the development of fatty liver disease in humans. In light of the current obesity pandemic and the associated marked rise in NAFLD incidence, it is of clear scientific and societal interest to gain further insight into the relationship between HDL-cholesterol levels and fatty liver development to potentially uncover the therapeutic potential of pharmacological HDL level and/or function modulation.

Current Therapeutical Approaches Targeting Lipid Metabolism in NAFLD

Nonalcoholic fatty liver disease (NAFLD, including nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH)) is a high-prevalence disorder, affecting about 1 billion people, which can evolve to more severe conditions like cirrhosis or hepatocellular carcinoma. NAFLD is often concomitant with conditions of the metabolic syndrome, such as central obesity and insulin-resistance, but a specific drug able to revert NAFL and prevent its evolution towards NASH is still lacking. With the liver being a key organ in metabolic processes, the potential therapeutic strategies are many, and range from directly targeting the lipid metabolism to the prevention of tissue inflammation. However, side effects have been reported for the drugs tested up to now. In this review, different approaches to the treatment of NAFLD are presented, including newer therapies and ongoing clinical trials. Particular focus is placed on the reverse cholesterol transport system and on the agonists for nuclear factors like PPAR and FXR, but also drugs initially developed for other conditions such as incretins and thyromimetics along with validated natural compounds that have anti-inflammatory potential. This work provides an overview of the different therapeutic strategies currently being tested for NAFLD, other than, or along with, the recommendation of weight loss.

Mitochondrial Dysfunction in Peripheral Blood Mononuclear Cells as Novel Diagnostic Tools for Non-Alcoholic Fatty Liver Disease: Visualizing Relationships with Known and Potential Disease Biomarkers

Non-alcoholic fatty liver disease (NAFLD) is a health emergency worldwide due to its high prevalence and the lack of specific therapies. Noninvasive biomarkers supporting NAFLD diagnosis are urgently needed. Liver mitochondrial dysfunction is a central NAFLD pathomechanism that changes throughout disease progression. Blood-cell bioenergetics reflecting mitochondrial organ dysfunction is emerging for its potential applications in diagnostics. We measured real-time mitochondrial respirometry in peripheral blood mononuclear cells (PBMCs), anthropometric parameters, routine blood analytes, and circulating cytokines from a cohort of NAFLD patients (N = 19) and non-NAFLD control subjects (N = 18). PBMC basal respiration, ATP-linked respiration, maximal respiration, and spare respiratory capacity were significantly reduced in NAFLD compared to non-NAFLD cases. Correlation plots were applied to visualize relationships between known or potential NAFLD-related biomarkers, while non-parametric methods were applied to identify which biomarkers are NAFLD predictors. Basal and ATP-linked mitochondrial respiration were negatively correlated with triglycerides and fasting insulin levels and HOMA index. Maximal and spare respiratory capacity were negatively correlated with IL-6 levels. All the mitochondrial respiratory parameters were positively correlated with HDL-cholesterol level and negatively correlated with fatty liver index. We propose including blood cell respirometry in panels of NAFLD diagnostic biomarkers to monitor disease progression and the response to current and novel therapies, including mitochondrial-targeted ones.