MASLD vs. NAFLD: A better definition for children with obesity at higher risk of kidney damage

Role of metabolic dysfunction-associated steatotic liver disease and of its genetics on kidney function in childhood obesity

OBJECTIVES

Evidence linked metabolic associated steatotic liver disease (MASLD) to kidney damage with the potential contribution of the I148M variant of the Patatin-like phospholipase containing domain 3 (PNPLA3) gene. We aimed at investigating the relationship of MASLD and of its genetics with kidney function in children with obesity.

METHODS

A comprehensive evaluation including genotyping for the I148M PNPLA3 polymorphism was performed in 1037 children with obesity. Fatty liver (FL) was assessed by liver ultrasound. According to MASLD criteria, subjects with obesity but without FL were included in group 1, while patients with obesity and FL (encompassing one MASLD criterion) were clustered into group 2. Group 3 included patients with obesity, FL, and metabolic dysregulation (encompassing >1 MASLD criterion).

RESULTS

Alanine transaminase levels significantly increased while estimated glomerular filtration rate (eGFR) significantly reduced from group 1 to 3. Group 3 showed a higher percentage of carriers of the I148M allele of the PNPLA3 gene compared to other groups (p < 0.0001). Carriers of group 2 and of group 3 showed reduced eGFR levels than noncarriers of group 2 (p = 0.04) and of group 3 (p = 0.02), respectively. A general linear model for eGFR variance in the study population showed an inverse association of eGFR with both MASLD and PNPLA3 genotypes (p = 0.011 and p = 0.02, respectively). An inverse association of eGFR with MASLD was also confirmed only in carriers (p = 0.006).

CONCLUSIONS

The coexistence of more than 1 MASLD criterion in children with obesity seems to adversely affect kidney function. The PNPLA3 I148M allele further impacts on this association.

Association of healthy lifestyles with risk of all-cause and cause-specific mortality among individuals with metabolic dysfunction-associated steatotic liver disease: results from the DFTJ cohort

AIM

To examine the associations of healthy lifestyles with risk of all-cause and cause-specific mortality among adults with metabolic dysfunction-associated steatotic liver disease (MASLD), and whether the association was mediated by systemic immune-inflammatory biomarkers (SIIBs).

METHODS

The study included 10,347 subjects with MASLD, who were enrolled in the Dongfeng-Tongji cohort study. The healthy lifestyles referred to non-smoking, being physically active (≥7.5 metabolic equivalents-hours/week), low-risk alcohol consumption (1-14 g/day for women and 1-28 g/day for men), and optimal sleep duration (≥6 to ≤8 h/day). Cox proportional hazard models were used to examine the relationship between each lifestyle and SIIBs with the risk of all-cause and cause-specific mortality. A mediation analysis was conducted to investigate the role of SIIBs on the association between healthy lifestyles and mortality.

RESULTS

There were 418 MASLD subjects dead till the follow-up of 2018, including 259 deaths from cardiovascular disease (CVD). Compared to MASLD participants with 0-1 healthy lifestyle score (HLS), those with 3-4 HLS had the lowest risk of all-cause mortality [hazard ratio (HR), 0.46; 95% CI, (0.36-0.60)], and CVD mortality [HR (95%CI), 0.41 (0.29-0.58)]. Mediation analyses indicated that SIIBs mediated the association between healthy lifestyles and mortality, with proportions ranging from 2.5% to 6.1%.

CONCLUSIONS

These findings suggest that adherence to healthy lifestyles can significantly reduce mortality for MASLD patients, and the decreased SIIBs may partially explain the protection mechanism of healthy lifestyles.

Kidney Damage in Pediatric Obesity: Insights from an Emerging Perspective

The role of obesity as a risk factor for chronic kidney disease (CKD) in adulthood has been well established. Over the last years, kidney damage (KD) has emerged as a significant consequence of obesity since childhood. Indeed, a complex interplay of metabolic factors, including insulin resistance (IR), hypertension, oxidative stress, adipose tissue dysfunction, and systemic inflammation, might affect renal hemodynamics, contributing to CKD development over time in at-risk young patients. As the prevalence of pediatric obesity continues to rise globally, understanding the implications for kidney health in terms of early intervention is of paramount importance. Careful monitoring of kidney function within a multidisciplinary approach in children with obesity is crucial for detecting early KD, allowing for timely lifestyle modifications and treatment. In this framework, continued research is essential to further elucidate mechanisms linking obesity and KD and to explore not only effective preventive strategies but also the long-term impact of obesity on kidney health in children with obesity. Given the intimate link of KD with the metabolic milieu in children with obesity, we aimed to provide a comprehensive and insightful overview on KD and its implications in pediatric obesity by reviewing the most recent literature in the field.

Kidney function evaluation in children and adolescents with obesity: a not-negligible need

The role of obesity as risk factor for chronic kidney disease (CKD) has been well-recognized. As previously demonstrated in adults, emerging data highlighted the relevant impact of obesity on renal function since childhood. As a matter of fact, obesity also affects renal health through a complex pathogenic mechanism in which insulin resistance (IR) plays a pivotal role. Worthy of note, the vicious interplay among obesity, IR, and renal hemodynamics clinically translates into a plethora of kidney function impairments potentially leading to CKD development. Therefore, renal injury needs to be added to the well-known spectrum of cardiometabolic obesity comorbidities (e.g., type 2 diabetes, IR, metabolic syndrome, cardiovascular disease).

CONCLUSION

Taking this into account, a careful and timely monitoring of kidney function should not be neglected in the global assessment of children with obesity. We aimed to provide a comprehensive overview on the relevance of kidney evaluation in children with obesity by shedding lights on the intriguing relationship of obesity with renal health in this at-risk population.

WHAT IS KNOWN

• Obesity has been found to be a risk factor for chronic kidney disease. • Unlike adults, pediatric data supporting the association between obesity and renal function are still limited.

WHAT IS NEW

• As observed in adults, obesity might affect renal function since childhood. • Kidney function should be carefully evaluated in children with obesity.

Interplay between metabolic dysfunction-associated fatty liver disease and renal function: An intriguing pediatric perspective

Over recent years, the nomenclature of non-alcoholic fatty liver disease has undergone significant changes. Indeed, in 2020, an expert consensus panel proposed the term "Metabolic (dysfunction) associated fatty liver disease" (MAFLD) to underscore the close association of fatty liver with metabolic abnormalities, thereby highlighting the cardiometabolic risks (such as metabolic syndrome, type 2 diabetes, insulin resistance, and cardiovascular disease) faced by these patients since childhood. More recently, this term has been further replaced with metabolic associated steatotic liver disease. It is worth noting that emerging evidence not only supports a close and independent association of MAFLD with chronic kidney disease in adults but also indicates its interplay with metabolic impairments. However, comparable pediatric data remain limited. Given the progressive and chronic nature of both diseases and their prognostic cardiometabolic implications, this editorial aims to provide a pediatric perspective on the intriguing relationship between MAFLD and renal function in childhood.

Association of NAFLD/NASH, and MAFLD/MASLD with chronic kidney disease: an updated narrative review

Chronic kidney disease (CKD) and nonalcoholic fatty liver disease (NAFLD), metabolic dysfunction-associated fatty liver disease (MAFLD) and metabolic dysfunction-associated steatotic liver disease (MASLD) account for substantial financial burden worldwide. These alarming features call for enhanced efforts to prevent and manage the development and progression of CKD. Accumulating evidence supporting a causal role of NAFLD/MAFLD/MASLD-in CKD opens new horizons to achieve this aim. Recent epidemiological studies and meta-analyses exploring the association of NAFLD/MAFLD/MASLD with CKD and the characteristics of NAFLD/MAFLD/MASLD associated with the odds of incident CKD are discussed. The involved pathomechanisms, including the common soil hypothesis, genetics, gut dysbiosis, and portal hypertension, are examined in detail. Finally, lifestyle changes (diet and physical exercise), direct manipulation of gut microbiota, and drug approaches involving statins, renin-angiotensin-aldosterone system inhibitors, GLP-1 Receptor Agonists, Sodium-glucose cotransporter-2, pemafibrate, and vonafexor are examined within the context of prevention and management of CKD among those with NAFLD/MAFLD/MASLD. The evolving NAFLD/MAFLD/MASLD nomenclature may generate confusion among practicing clinicians and investigators. However, comparative studies investigating the pros and contra of different nomenclatures may identify the most useful definitions among NAFLD/MAFLD/MASLD and strategies to identify, prevent, and halt the onset and progression of CKD.