Circulating ALT Levels in Healthy Volunteers Over Life-Span: Assessing Aging Paradox and Nutritional Implications

Metabolic dysfunction-associated steatotic liver disease: The question of long-term high-normal alanine aminotransferase as a screening test

The growing prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is being driven by the obesity epidemic. The quest for solutions continues particularly with regard to early detection. This editorial comments on the utility of long-term high-normal alanine aminotransferase (ALT) in screening for MASLD. Chen et al found that new onset MASLD can be detected by repetitively high normal ALT. Implicit in this concept is the question of what should be the accepted upper limit of normal (ULN) for ALT. It was previously set at 40 IU/L based on studies that included people with subclinical liver disease but the new consensus is 30/19 U/L in healthy males/females. Thus, when Chen et al defines the ULN as 40 U/L, others may view it as excessively high. It is important to recognize the variables affecting ULN e.g. instrumentation, diurnal variations, exercise and ageing. These variables matter when the distinctions are subtle e.g. normal vs high-normal. In this regard, the utility of long-term high normal ALT as a disease marker could be enhanced by combining it with other biomarkers, imaging and MASLD genetics to create machine learning classifiers. All in all, Chen et al's work on long-term high normal ALT as a marker of new-onset MASLD deserves merit.

Nomogram based on pretreatment hepatic and renal function indicators for survival prediction of locally advanced esophageal squamous cell carcinoma with treatment of neoadjuvant chemoradiotherapy plus surgery

The parameters for survival prediction of esophageal squamous cell carcinoma (ESCC) patients treated with neoadjuvant chemoradiotherapy (NCRT) combined with surgery are unclear. Here, we aimed to construct a nomogram for survival prediction of ESCC patients treated with NCRT combined with surgery based on pretreatment serological hepatic and renal function tests. A total of 174 patients diagnosed as ESCC were enrolled as a training cohort from July 2007 to June 2019, and approximately 50% of the cases (n = 88) were randomly selected as an internal validation cohort. Univariate and multivariate Cox survival analyses were performed to identify independent prognostic factors to establish a nomogram. Predictive accuracy of the nomogram was evaluated by Harrell's concordance index (C-index) and calibration curve. ALT, ALP, TBA, TP, AST, TBIL and CREA were identified as independent prognostic factors and incorporated into the construction of the hepatic and renal function test nomogram (HRFTNomogram). The C-index of the HRFTNomogram for overall survival (OS) was 0.764 (95% CI 0.701-0.827) in the training cohort, which was higher than that of the TNM staging system (0.507 (95% CI 0.429-0.585), P < 0.001). The 5-year OS calibration curve of the training cohort demonstrated that the predictive accuracy of the HRFTNomogram was satisfactory. Moreover, patients in the high-risk group stratified by the HRFTNomogram had poorer 5-year OS than those in the low-risk group in the training cohort (27.4% vs. 80.3%, P < 0.001). Similar results were observed in the internal validation cohort. A novel HRFTNomogram might help predict the survival of locally advanced ESCC patients treated with NCRT followed by esophagectomy.

Non-linear association between aspartate aminotransferase to alanine aminotransferase ratio and mortality in critically ill older patients: A retrospective cohort study

BACKGROUND

The aspartate aminotransferase to alanine aminotransferase (AST/ALT) ratio has been shown to be associated with poor clinical outcomes across various patient groups. However, little is unclear about the association between the two in critically ill older patients. Therefore, we aim to investigate the association of the AST/ALT ratio with hospital mortality in this special population.

METHODS

In this retrospective cohort study, we extracted elderly patients (age ≥ 65 years) from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The primary outcome was in-hospital mortality. The association between the AST/ALT ratio and hospital mortality was studied using univariable and multivariable Cox regression analysis, as well as restricted cubic splines (RCS). Survival analysis was performed using the Kaplan-Meier (KM) method according to the AST/ALT ratio.

RESULTS

Among the 13,358 eligible patients, the mean age was 77.6 years, 7,077 patients (52.9%) were male, and 2,511 patients (18.8%) died in hospital. The AST/ALT ratio was found to be independently associated with in-hospital mortality (HR = 1.05, 95% CI: 1.01-1.09, P = 0.022) after adjusting for potential confounders. Furthermore, a non-linear relationship and saturation effect were observed between them, with the inflection point being 1.80. When the AST/ALT ratio was less than 1.80, we found that every 1 unit increase in the AST/ALT ratio resulted in a 39% increased risk of in-hospital mortality (HR = 1.39, 95% CI: 1.18-1.64, P < 0.001). However, when the AST/ALT ratio was greater than 1.80, the association became saturated (HR = 1.01, 95% CI: 0.96-1.07, P = 0.609). Sensitivity and subgroup analyses showed the results were robust.

CONCLUSION

In critically ill older patients, the association between the AST/ALT ratio and in-hospital mortality was non-linear and showed a saturation effect. An elevated AST/ALT ratio was significantly associated with increased in-hospital mortality when the AST/ALT ratio was less than 1.80.

Multi-omics reveals aging-related pathway in natural aging mouse liver

Aging is associated with gradual changes in liver structure, altered metabolites and other physiological/pathological functions in hepatic cells. However, its characterized phenotypes based on altered metabolites and the underlying biological mechanism are unclear. Advancements in high-throughput omics technology provide new opportunities to understand the pathological process of aging. Here, in our present study, both metabolomics and phosphoproteomics were applied to identify the altered metabolites and phosphorylated proteins in liver of young (the WTY group) and naturally aged (the WTA group) mice, to find novel biomarkers and pathways, and uncover the biological mechanism. Analysis showed that the body weights, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) increased in the WTA group. The grips decreased with age, while the triglyceride (TG) and cholesterol (TC) did not change significantly. The increase of fibrosis, accumulation of inflammatory cells, hepatocytes degeneration, the deposition of lipid droplets and glycogen, the damaged mitochondria, and deduction of endoplasmic reticulum were observed in the aging liver under optical and electron microscopes. In addition, a network of metabolites and phosphorylated proteomes of the aging liver was established. Metabolomics detected 970 metabolites in the positive ion mode and 778 metabolites in the negative ion mode. A total of 150 pathways were pooled. Phosphoproteomics identified 2618 proteins which contained 16621 phosphosites. A total of 164 pathways were detected. 65 common pathways were detected in two omics. Phosphorylated protein heat shock protein HSP 90-alpha (HSP90A) and v-raf murine viral oncogene homolog B1(BRAF), related to cancer pathway, were significantly upregulated in aged mice liver. Western blot verified that protein expression of MEK and ERK, downstream of BRAF pathway were elevated in the liver of aging mice. However, the protein expression of BRAF was not a significant difference. Overall, these findings revealed a close link between aging and cancer and contributed to our understanding of the multi-omics changes in natural aging.

Lower alanine aminotransferase levels are associated with increased all-cause and cardiovascular mortality in nonalcoholic fatty liver patients

BACKGROUND

Serum alanine aminotransferase (ALT) levels are often considered a marker to evaluate liver disease and its severity.

AIM

To investigate the association between ALT levels and all-cause and cause-specific mortality in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

The Third National Health and Nutrition Examination Survey (NHANES-III) from 1988 to 1994 and NHANES-III-related mortality data from 2019 onward were used to obtain the necessary data for the study. NAFLD was defined as hepatic steatosis, as diagnosed by ultrasound, with no other liver diseases. ALT levels were categorized into four groups according to the different recommended upper limits of normal (ULN) in men and women: < 0.5 ULN, 0.5-1 ULN, 1-2 ULN, and ≥ 2 ULN. The hazard ratios for all-cause mortality and cause-specific mortality were analyzed using the Cox proportional hazard model.

RESULTS

Multivariate logistic regression analysis demonstrated that the odds ratio of NAFLD correlated positively with increased serum ALT levels. In patients with NAFLD, all-cause mortality and cardiovascular mortality were the highest when ALT was < 0.5 ULN, yet cancer-related mortality was the highest when ALT was ≥ 2 ULN. The same results could be found in both men and women. Univariate analysis showed that severe NAFLD with normal ALT levels had the highest all-cause and cause-specific mortality, but the difference was not statistically significant after adjustment for age and multivariate factors.

CONCLUSION

The risk of NAFLD was positively correlated with ALT level, but all-cause and cardiovascular mortality were the highest when ALT was < 0.5 ULN. Regardless of the severity of NAFLD, normal or lower ALT levels were associated with higher mortality than elevated ALT levels. Clinicians should be aware that high ALT levels indicate liver injury, but low ALT levels are associated with a higher risk of death.

Probing the Relationship Between Declining Renal Glomerular Filtration Over the Life Span and General Biological Aging: Does the Former Provide Means to Estimate the Latter?

While a consistent, gradual decline in the renal glomerular filtration rate (GFR) is a characteristic occurrence over the human life span, the exact pathophysiology behind this event remains unresolved. Evidence to date suggests that the endogenous glucose-insulin system could be involved at some level. Diabetic-induced nephropathy, one of the most prevalent chronic renal diseases, is closely linked to a severe form of insulin resistance (IR). Nevertheless, it is less certain that the ubiquitous milder forms of IR in nondiabetics ascribed customarily to routine, poor choices in diet and exercise management can over time diminish GFR and adversely influence other renal functions to any perceptible extent.

Baseline data for cross-sectional analyses were obtained from a cohort of healthy, nondiabetic volunteers (fasting blood glucose [FBG] ≤ 125 mg/dL) involved in prior clinical studies. Slope-based rather than threshold analyses were mainly employed. These measurements were applied for the most part to correlate age, FBG levels used as an estimate of IR activity, and systolic blood pressure (SBP) to a variety of metabolic parameters during aging with a primary focus on GFR.

Considering cause and effect, FBG and SBP correlate positively with the diminishing GFR over a major part of the life span. The decline in GFR begins somewhere around the mid-20s and coincides with key temporal increases in FBG and SBP levels.

A close time-based setting suggests that IR plays a prominent role in the declining GFR that occurs over the life span. This is perhaps due in part through deleterious effects of rising levels of insulin, glucose, and SBP individually or combined that are also popular proposed causative factors for human aging in general. On the philosophical side, the latter fact suggests that the declining GFR might provide a practical way to estimate the rate of overall human biological aging.

Analysis of time-dependent changes in the FIB4 index in patients with obesity receiving weight reduction therapy

Weight reduction therapy represents a fundamental strategy to prevent nonalcoholic fatty liver disease (NAFLD) in patients with obesity, which may result in liver fibrosis. Histological findings previously demonstrated that weight reduction therapy attenuated NAFLD. The FIB4 index is widely used to assess the status of NAFLD. The present study investigated whether the FIB4 index improved during weight reduction therapy. We used cohort data of the Japan Obesity and Metabolic syndrome Study and examined the correlation between body weight (BW) loss (BW loss) and changes in the FIB4 index (ΔFIB4 index) in patients who successfully reduced their BW by more than 5% from baseline BW after 3, 6, and 12 months (M) of weight reduction therapy. A negative correlation (r = −0.342, p = 0.029) was observed between BW loss and FIB4 index after 3 M, but not after 6 M, whereas a positive correlation (r = 0.298, p = 0.03) was noted after 12 M. These results revealed changes in the correlation between ΔBW loss and ΔFIB4 index during the therapy, mainly due to time-dependent changes in components of the FIB4 index formula. Thus, we concluded that the FIB4 index is useful and reliable to assess liver fibrosis until 3 M during weight reduction therapy. However, after 3 M, we should recognize that the FIB4 index may not reflect liver status. Therefore, it is important to consider this characteristic of the FIB4 index as a limitation when assessing liver fibrosis in obese patients receiving weight reduction therapy.

Assessing Genders Separately in Nondiabetic Persons Regarding Links Between Insulin Resistance and Fat Mass With Elements Related to the Metabolic Syndrome

OBJECTIVE

Initial results gathered from previously published observations dealing with nondiabetic volunteers reveal that both the fasting blood glucose (FBG) level employed as a surrogate for insulin resistance (IR) and the amount of body fat mass (FM) correlate significantly with the strength and pathological direction of many harmful elements making up the metabolic syndrome (MS). These initial results were obtained using combined data from both females and males. How the two markers correlate with specific metabolic parameters in each gender separately was not established.

METHOD

Baseline data from more than 700 volunteers were examined mainly using correlations to compare whether the breadth of IR estimated by FBG levels and/or the accumulation of body FM on the early development and progression of many chronic metabolic derangements differ to any meaningful extent between nondiabetic females and males.

RESULTS

The following significant positive correlations were found in the data on females employing either FBG or FM as independent variables regarding development of elements associated with MS: in body composition (scale weight, fat free mass [FFM]); in blood chemistries (triglycerides, high-sensitivity C-reactive protein [hsCRP], alanine aminotransferase [ALT]); and in blood counts (white blood cells [WBC], neutrophils). Also consistent with MS, high-density lipoprotein cholesterol levels declined significantly. In males, findings with FBG as the independent variable differ from females in some respects. These major exceptions are lack of significant correlations with FFM and high-density lipoprotein cholesterol as well as a weaker link with ALT. Despite a positive hsCRP linkage, a poorer response of WBC and neutrophils appeared in males when correlations were made. The latter disassociations disappeared when FM replaced FBG as the independent variable.

CONCLUSIONS

Progression of many chronic metabolic derangements differ only slightly in females and males.

NAFLD mark: an accurate model based on microRNA-34 for diagnosis of non-alcoholic fatty liver disease patients

BACKGROUND

It remains essential for non-alcoholic fatty liver (NAFLD) patients, to develop a sensitive and specific diagnostic model. Data regarding the use of micro (mi)RNA-34 for NAFLD diagnosis are few. Routine clinical assessment, laboratory tests were done for Egyptian individuals (n = 314) were included (100 healthy individuals and 214 NAFLD patients). Quantification of miRNA-34 was done using real-time PCR. Extremely significant variables were entered into stepwise logistic regression. The diagnostic power of variables was estimated by the area under the ROC (AUC).

RESULTS

MiRNA-34 levels were higher in NAFLD patients than healthy individuals with a significant difference (P< 0.0001). The multivariate analysis was used to evaluate the NAFLD-associated variables (CRP, cholesterol, body mass index (BMI), ALT had p< 0.0001 while mRNA-34 had (p=0.0004). The AUCs (CI) of candidate NAFLD markers were in the order of miRNA-34 0.72 (0.66-0.77) < ALT 0.73 (0.67-0.79) < BMI 0.81 (0.76-0.86) < cholesterol < 0.85 (0.79-0.90) < CRP 0.88 (0.84-0.92). We developed a novel index for discriminating patients with NAFLD named NAFLD Mark. AUC was jumped to 0.98 (0.93-0.99) when five markers were combined. The AUC of NAFLD mark for NAFLD detection was higher than the AUCs of seven common NAFLD indexes (0.44-0.86).

CONCLUSIONS

The NAFLD mark is a non-invasive and highly sensitive and specific model for NAFLD diagnosis.

Analyzing Blood Pressure Ascent during Aging in Non-Diabetics: Focusing on Links to Insulin Resistance and Body Fat Mass

BACKGROUND

A gradual upward progression of blood pressure (BP) occurs regularly in most humans during aging. This is unfortunate, because it is generally recognized that elevation of BP, even when relatively mild, is eventually detrimental to human health. Accordingly, considerably more understanding of the pathophysiology behind such a phenomenon is important in order to institute the correct remedies. Two components of the ubiquitous metabolic syndrome (MS) with nutritional implications, elevated insulin resistance (IR) and excess body fat mass (FM), are often postulated to be critical driving forces behind the elevated BP that is common with aging. The current study, therefore, focuses on the presence and importance of IR and/or body FM in BP regulation of non-diabetics over the lifespan.

METHODOLOGY

In cross sectional analyses, baseline data obtained from healthy, non-diabetic volunteers involved in prior clinical studies were analyzed by examining links between FBG measurements used as a surrogate for IR and body FM through their individual and combined effects on BP.

RESULTS

A significant positive correlation was found between FBG and FM and also between each employed individually as independent variables to the dependent BP and heart rate (HR) variables. In volunteers with higher body FM compared to lower, average systolic BP (SBP) values are increased to some extent at the same FBG measurement suggesting that other factors related to FM in addition to IR are the basis for slight pressure differences. Considering quartiles based upon levels of FM and FBG, low FM-low FBG display significantly reduced average SBP, diastolic blood pressure (DBP), and HR compared to the upper FM-FBG quartiles. While readings of FBG and FM display a decline in elderly subjects after age 70 years (aging paradox), such does not occur with SBP.

CONCLUSIONS

IR is a major driving force behind BP regulation even in non-diabetics. FM influences BP substantially through its relationship with IR and also via other mechanisms directly linked to FM.

Relation of Aspartate Aminotransferase to Alanine Aminotransferase Ratio to Nutritional Status and Prognosis in Patients With Acute Heart Failure

Elevated liver fibrosis markers are associated with worse prognosis in acute heart failure (AHF). The aspartate aminotransferase to alanine aminotransferase ratio (AAR) is one such fibrosis marker, and low ALT is a surrogate marker of malnutrition. Here, we evaluated the association between AAR and nutritional status and prognosis in patients with AHF. Consecutive 774 patients who were admitted due to AHF were divided into 3 groups according to AAR at discharge: first tertile, AAR<1.16 (n = 262); second tertile, 1.16≤AAR<1.70 (n = 257); and third tertile, AAR≥1.70 (n = 255). Nutritional indices and a composite of all-cause death or HF rehospitalization were compared in the 3 tertiles. Patients in the third AAR tertile were older and had lower body mass index than patients in other AAR tertiles. A higher AAR was associated with worse nutritional indices (i.e., controlling nutritional status score, geriatric nutritional risk index, and prognostic nutritional index). Clinical outcome rates significantly increased along AAR tertiles (first tertile, 28%; second tertile, 43%; third tertile, 58%, p < 0.001). Cox proportional hazards models including potential prognostic factors revealed high AAR was an independent prognostic factor of AHF. In conclusion, AAR at discharge may be associated with nutritional status and worse clinical outcomes in patients with AHF.

Serum alanine aminotransferase activity and risk factors for cardiovascular disease in a Caucasian population: the Tromsø study

Background

High and low levels of serum alanine aminotransferase (ALT) are both associated with cardiovascular diseases (CVD) risks especially in elderly, but the mechanisms are less known. This study investigated associations between ALT and CVD risk factors including effects of sex and age in a Caucasian population.

Methods

Cross-sectional data were analysed sex-stratified in 2555 men (mean age 60.4 years) and 2858 women (mean age 60.0 years) from the population study Tromsø 6. Associations were assessed by variance analysis and multivariable logistic regression of odds to have abnormal ALT. Risk factors included body mass index (BMI), waist-to-hip-ratio, blood pressure, lipids, glucose, glycated haemoglobin and high-sensitive C-reactive protein (CRP).

Results

Abnormal elevated ALT was detected in 113 men (4.4%) and 188 women (6.6%). Most CVD risk factors associated positively with ALT in both sexes except systolic blood pressure and CRP (women only), while ALT was positively associated with age in men when adjusted for CVD risk factors, P < 0.001. BMI predicted ALT in men (OR 0.94; 95% CI 0.88–1.00, P = 0.047) and women (OR 0.90; 95% CI 0.86–0.95, P < 0.001). A linear inversed association between age and ALT in men and a non-linear inversed U-trend in women with maximum level between 60 and 64 years were found.

Conclusion

This study confirms a positive relationship between ALT and CVD risk factors, particularly BMI. Age is not a major confounder in the ALT-CVD relationship, but separate sex-analyses is recommended in such studies.

Correlating Circulating Vitamin D3 with Aspects of the Metabolic Syndrome and Nonalcoholic Fatty Liver Disease in Healthy Female Volunteers

Background: Significant inverse correlations between circulating vitamin D3 and the presence and strength of common clinical entities influenced by insulin resistance (IR) have been reported. Among these entities are common maladies such as the metabolic syndrome (MS) and nonalcoholic fatty liver disease (NAFLD). Since hypovitaminosis D3 is considered a common worldwide health disturbance, the consequences emanating from such relationships once soundly established might reasonably be ameliorated by vitamin replacement. Accordingly, a need exists for definitive confirmatory support for the existence of these linkages particularly in ordinary, relatively healthy individuals.Methodology: Many aspects of MS and NAFLD were examined in healthy females via linear regression analyses to determine significant correlations mainly using vitamin D3 and fasting blood glucose (FBG), the latter a surrogate for IR, as independent variables.Results: A descending linear regression between vitamin D3 and FBG did not reach full statistical significance, but a negative correlation of vitamin D3 with HbA1C was statistically significant and that with circulating insulin concentrations showed a downward statistical trend. These findings are consistent with previous ones by others suggesting an ameliorating effect of vitamin D3 on IR. Body weight, body mass index (BMI), and body fat correlated statistically significantly with vitamin D3 levels, as did systolic blood pressure. Again, these correlations were negative instead of positive unlike the case when FBG was the independent variable. The significant negative correlation of ALT with vitamin D3 was also consistent with previous reports that higher circulating vitamin D3 favorably influences the extent and intensity of NAFLD.Conclusions: Employing FBG as a surrogate for IR and ALT for status of NAFLD, linear correlations reasonably suggest that increasing circulating vitamin D3 can favorably influence the initial development of and/or strength of risk factors for MS including NAFLD in relatively fit females.