Coisa de Homem | Colesterol

O colesterol é essencial para o organismo, mas quando seus níveis estão em desequilíbrio oferece riscos à saúde. Saiba mais no episódio do Coisa de Homem desta quarta-feira (19).

Colesterol

No dia 8 de agosto foi celebrado o Dia Mundial de Combate ao Colesterol!

Laboratory Monitoring in Isotretinoin Therapy for Acne: How Long and How Often Must We Test Our Patients?

The optimal frequency and timing of laboratory monitoring during isotretinoin treatment remains controversial. We aimed to investigate the frequency, timing, and severity of abnormal results during isotretinoin for acne. We conducted a retrospective cohort study comprising 444 acne patients prescribed isotretinoin at Boston Medical Center from 2004 to 2017; these patients had at least one available baseline laboratory result. We categorized patients into two groups: group A (normal values at baseline and during the first 2 months of isotretinoin therapy) and group B (abnormal values at baseline or during the first 2 months of isotretinoin therapy) and assessed the laboratory values after 2 months. The frequency of abnormal results for triglycerides, cholesterol, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) after 2 months for patients in group A was 21.1%, 13.6%, 8.8%, and 6.0%, respectively, with very rare grade 2 (moderate) or higher abnormalities. In contrast, the frequency of abnormal results for patients in group B for triglycerides, cholesterol, AST, and ALT was higher at 67.9%, 88.0%, 40.0%, and 25.0%, respectively (P < 0.05, except for ALT). No patient developed higher than grade 1 (mild) complete blood count (CBC) abnormality. This study proposed that healthy patients with normal results at baseline and during the first 2 months of isotretinoin therapy might not need routine monitoring after month 2 of medication. Routine monitoring of CBC is not necessary.

Genome-wide association study and meta-analysis of phytosterols identifies a novel locus for serum levels of campesterol.

Sitosterolemia is a rare inherited disorder caused by mutations in the ABCG5/ABCG8 genes. These genes encode proteins involved in the transport of plant sterols. Mutations in these genes lead to decreased excretion of phytosterols, which can accumulate in the body and lead to a variety of health problems, including premature coronary artery disease. We conducted the first genome-wide association study (GWAS) in the Middle East/North Africa population to identify genetic determinants of plant sterol levels in Qatari people. GWAS was performed on serum levels of ß-sitosterol and campesterol using the Metabolon platform from Qatar Biobank (QBB) and genome sequence data provided by Qatar Genome Program. A trans-ancestry meta-analysis of data from our Qatari cohort with summary statistics from a previously published large cohort (9758 subjects) of European ancestry was conducted. Using conditional analysis, we identified two independent single nucleotide polymorphisms associated with ß-sitosterol (rs145164937 and rs4299376), and two others with campesterol (rs7598542 and rs75901165) in the Qatari population in addition to previously reported variants. All of them map to the ABCG5/8 locus except rs75901165 which is located within the Intraflagellar Transport 43 (IFT43) gene. The meta-analysis replicated most of the reported variants, and our study provided significant support for the association of variants in SCARB1 and ABO with sitosterolemia. Evaluation of a polygenic risk score devised from European GWAS data showed moderate performance when applied to QBB (adjusted-R2 = 0.082). These findings provide new insights into the genetic architecture of phytosterol metabolism while showing the importance including under-represented populations in future GWAS studies.

Aberrant lipid accumulation and retinal pigment epithelium dysfunction in PRCD-deficient mice.

Progressive Rod-Cone Degeneration (PRCD) is an integral membrane protein found in photoreceptor outer segment (OS) disc membranes and its function remains unknown. Mutations in Prcd are implicated in Retinitis pigmentosa (RP) in humans and multiple dog breeds. PRCD-deficient models exhibit decreased levels of cholesterol in the plasma. However, potential changes in the retinal cholesterol remain unexplored. In addition, impaired phagocytosis observed in these animal models points to potential deficits in the retinal pigment epithelium (RPE). Here, using a Prcd-/- murine model we investigated the alterations in the retinal cholesterol levels and impairments in the structural and functional integrity of the RPE. Lipidomic and immunohistochemical analyses show a 5-fold increase in the levels of cholesteryl esters (C.Es) and lipid deposits in the PRCD-deficient retina, respectively, indicating alterations in total retinal cholesterol. Furthermore, the RPE of Prcd-/- mice exhibit a 1.7-fold increase in the expression of lipid transporter gene ATP-binding cassette transporter A1 (Abca1). Longitudinal fundus and spectral domain optical coherence tomography (SD-OCT) examinations showed focal lesions and RPE hyperreflectivity. Strikingly, the RPE of Prcd-/- mice exhibited age-related pathological features such as lipofuscin accumulation, Bruch's membrane (BrM) deposits and drusenoid focal deposits, mirroring an Age-related Macular Degeneration (AMD)-like phenotype. We propose that the extensive lipofuscin accumulation likely impairs lysosomal function, leading to the defective phagocytosis observed in Prcd-/- mice. Our findings support the dysregulation of retinal cholesterol homeostasis in the absence of PRCD. Further, we demonstrate that progressive photoreceptor degeneration in Prcd-/- mice is accompanied by progressive structural and functional deficits in the RPE, which likely exacerbates vision loss over time.

Link between remnant cholesterol and the reversion to normoglycemia in Chinese adults with prediabetes: a 5-year cohort study.

Despite the clear association between remnant cholesterol (RC)and diabetes risk, no study to date has examined the relationship between RC and reversal of prediabetes to normoglycemia. This retrospective cohort study included a total of 15,023 patients with prediabetes who underwent a physical examination between 2010 and 2016. The link between initial RC levels and the reversion from prediabetes to normoglycemia was analyzed using the Cox proportional-hazards regression model. Additionally, the study explored the possible relationship between RC and the probability of returning normoglycemia by applying Cox proportional hazards regression models with cubic spline functions. To address competing risks, a multivariate Cox regression analysis was undertaken, treating the onset of diabetes as a competing risk event for reversing prediabetes to normoglycemia. Additionally, the study incorporated extensive subgroup analyses alongside multiple sensitivity analyses, enhancing the reliability and robustness of the results. After adjusting for covariates, the findings indicated that RC was inversely associated with the likelihood of reverting to normoglycemia (per 5 mg/dL increase, HR = 0.918, 95% CI 0.909-0.927). The analysis also revealed a nonlinear relationship between RC and normoglycemia reversion, with an inflection point at 51.08 mg/dL. For RC values below this inflection point (RC < 50.08 mg/dL), the HR for the probability of returning to normoglycemia was 0.907 (95% CI 0.897-0.917 per 5 mg/dL). Additionally, the competing risks model demonstrated a negative relationship between RC and the reversal of prediabetes to normoglycemia (SHR = 0.92, 95% CI 0.91-0.93). Sensitivity analyses confirmed the robustness and stability of these results. This study demonstrated a negative and non-linear association between RC and the probability of reversion to normoglycemia in Chinese adults with prediabetes. By actively intervening to reduce RC levels, at least to below 51.08 mg/dL, further reduction of RC may significantly increase the probability of returning to normoglycemia from prediabetes.

The Regulation of Frontal Cortex Cholesterol Metabolism Abnormalities by NR3C1/NRIP1/NR1H2 Is Involved in the Occurrence of Stress-Induced Depression.

Stress-induced alterations in central neuron metabolism and function are crucial contributors to depression onset. However, the metabolic dysfunctions of the neurons associated with depression and specific molecular mechanisms remain unclear. This study initially analyzed the relationship between cholesterol and depression using the NHANES database. We then induced depressive-like behaviors in mice via restraint stress. Applying bioinformatics, pathology, and molecular biology, we observed the pathological characteristics of brain cholesterol homeostasis and investigated the regulatory mechanisms of brain cholesterol metabolism disorders. Through the NHANES database, we initially confirmed a significant correlation between cholesterol metabolism abnormalities and depression. Furthermore, based on successful stress mouse model establishment, we discovered the number of cholesterol-related DEGs significantly increased in the brain due to stress, and exhibited regional heterogeneity. Further investigation of the frontal cortex, a brain region closely related to depression, revealed stress caused significant disruption to key genes related to cholesterol metabolism, including HMGCR, CYP46A1, ACAT1, APOE, ABCA1, and LDLR, leading to an increase in total cholesterol content and a significant decrease in synaptic proteins PSD-95 and SYN. This indicates cholesterol metabolism affects neuronal synaptic plasticity and is associated with stress-induced depressive-like behavior in mice. Adeno-associated virus interference with NR3C1 in the prefrontal cortex of mice subjected to short-term stress resulted in reduced protein levels of NRIP1, NR1H2, ABCA1, and total cholesterol content. At the same time, it increased synaptic proteins PSD95 and SYN, effectively alleviating depressive-like behavior. Therefore, these results suggest that short-term stress may induce cholesterol metabolism disorders by activating the NR3C1/NRIP1/NR1H2 signaling pathway. This impairs neuronal synaptic plasticity and consequently participates in depressive-like behavior in mice. These findings suggest that abnormal cholesterol metabolism in the brain induced by stress is a significant contributor to depression onset.

Lipid homeostasis in diabetic kidney disease.

Lipid homeostasis is crucial for proper cellular and systemic functions. A growing number of studies confirm the importance of lipid homeostasis in diabetic kidney disease (DKD). Lipotoxicity caused by imbalance in renal lipid homeostasis can further exasperate renal injury. Large lipid deposits and lipid droplet accumulation are present in the kidneys of DKD patients. Autophagy plays a critical role in DKD lipid homeostasis and is involved in the regulation of lipid content. Inhibition or reduction of autophagy can lead to lipid accumulation, which in turn further affects autophagy. Lipophagy selectively recognizes and degrades lipids and helps to regulate cellular lipid metabolism and maintain intracellular lipid homeostasis. Therefore, we provide a systematic review of fatty acid, cholesterol, and sphingolipid metabolism, and discuss the responses of different renal intrinsic cells to imbalances in lipid homeostasis. Finally, we discuss the mechanism by which autophagy, especially lipophagy, maintains lipid homeostasis to support the development of new DKD drugs targeting lipid homeostasis.

Machine learning analysis of serum cholesterol's impact on knee osteoarthritis progression.

The controversy surrounding whether serum total cholesterol is a risk factor for the graded progression of knee osteoarthritis (KOA) has prompted this study to develop an authentic prediction model using a machine learning (ML) algorithm. The objective was to investigate whether serum total cholesterol plays a significant role in the progression of KOA. This cross-sectional study utilized data from the public database DRYAD. LASSO regression was employed to identify risk factors associated with the graded progression of KOA. Additionally, six ML algorithms were utilized in conjunction with clinical features and relevant variables to construct a prediction model. The significance and ranking of variables were carefully analyzed. The variables incorporated in the model include JBS3, Diabetes, Hypertension, HDL, TC, BMI, SES, and AGE. Serum total cholesterol emerged as a significant risk factor for the graded progression of KOA in all six ML algorithms used for importance ranking. XGBoost algorithm was based on the combined best performance of the training and validation sets. The ML algorithm enables predictive modeling of risk factors for the progression of the KOA K-L classification and confirms that serum total cholesterol is an important risk factor for the progression of KOA.

N-SREBP2 Provides a Mechanism for Dynamic Control of Cellular Cholesterol Homeostasis.

Cholesterol is required to maintain the functional integrity of cellular membrane systems and signalling pathways, but its supply must be closely and dynamically regulated because excess cholesterol is toxic. Sterol regulatory element-binding protein 2 (SREBP2) and the ER-resident protein HMG-CoA reductase (HMGCR) are key regulators of cholesterol biosynthesis. Here, we assessed the mechanistic aspects of their regulation in hepatic cells. Unexpectedly, we found that the transcriptionally active fragment of SREBP2 (N-SREBP2) was produced constitutively. Moreover, in the absence of an exogenous cholesterol supply, nuclear N-SREBP2 became resistant to proteasome-mediated degradation. This resistance was paired with increased occupancy at the HMGCR promoter and HMGCR expression. Inhibiting nuclear N-SREBP2 degradation did not increase HMGCR RNA levels; this increase required cholesterol depletion. Our findings, combined with previous physiological and biophysical investigations, suggest a new model of SREBP2-mediated regulation of cholesterol biosynthesis in the organ that handles large and rapid fluctuations in the dietary supply of this key lipid. Specifically, in the nucleus, cholesterol and the ubiquitin-proteasome system provide a short-loop system that modulates the rate of cholesterol biosynthesis via regulation of nuclear N-SREBP2 turnover and HMGCR expression. Our findings have important implications for maintaining cellular cholesterol homeostasis and lowering blood cholesterol via the SREBP2-HMGCR axis.

In vitro dissolution of encapsulated or dispersed Vitamin e and cholesterol is correlated with preservation of refrigerated ovine sperm.

BACKGROUND: Vitamin E ( -tocopherol) and cholesterol are crucial components in cellular protection and physiological processes. Their uses in biological media face challenges due to their poor solubility and stability. OBJECTIVE: The study investigated the complex interactions of these bioactive compounds in various encapsulation systems of cyclodextrin and liposome, as well as dispersion in PEG-6000, in an attempt to improve the viability, motility, and preservation of ovine sperm cells. MATERIALS AND METHODS: The work explored the in vitro dissolution kinetics of vitamin E (d-tocopherol) and cholesterol using semi-empirical models. RESULTS: The release profiles of VitE and Chl varied considerably, depending on the specific carrier systems. For liposome-loaded VitE and Chl, the Korsmeyer-Peppas model gave the best fit; for CD/VitE and CD/Chl, the Higuchi model provided the best fit, whereas for PEG-6000 dispersions (VitE and Chl) both the Higuchi and Korsmeyer-Peppas models demonstrated the excellent fit. All systems indicated a Fickian diffusion mechanism dictated by the concentration gradient. The delivery of VitE and Chl with CD, liposome and PEG dispersion significantly increased sperm mobility and motility. The effect on the VCL parameter was the greatest by liposome-loaded VitE and Chl, followed by CD encapsulation and PEG-6000 dispersion. CONCLUSION: The dynamics of vitamin E and cholesterol within innovative delivery systems offers valuable insights into the development of advanced solutions in reproductive health, particularly on improving the viability, motility of refrigerated ovine sperm cells. Doi.org/10.54680/fr24510110712.

Metabolic Profile in Rats during Long-Term Restriction of Motor Activity.

We performed a comprehensive study of protein (total protein, medium-molecular-weight peptides, creatinine, and urea), purine (uric acid), and lipid (cholesterol, triglycerides) metabolism, activity of AST, ALT, and acid phosphatase in blood plasma of white male rats under conditions of restriction of motor activity up to 28 days. Patterns of changes in metabolic profile during hypokinesia were established: prevalence of catabolic processes and atherogenic shifts in the lipid spectrum with maximum manifestation on 14-21 days of the experiment.

Remnant cholesterol and all-cause mortality risk: findings from the National Health and Nutrition Examination Survey, 2003-2015.

Aims: Cholesterol carried in triglyceride-rich lipoproteins, also called remnant cholesterol, is increasingly acknowledged as an important causal risk factor for atherosclerosis. Elevated remnant cholesterol, marked by elevated plasma triglycerides, is associated causally with an increased risk of atherosclerotic cardiovascular disease. However, the association with all-cause mortality and cause-specific mortality is inconclusive. This study aimed to test the hypothesis that remnant cholesterol levels and plasma triglycerides are associated with increased all-cause mortality and mortality from cardiovascular disease, cancer, and other causes. Methods and results: Using a contemporary population-based cohort, 7,962 individuals from the National Health and Nutrition Examination Survey (NHANES) aged over 40 years at baseline in 2003-2015 were included. During up to 109.2 (± 1.44) months of follow-up, 1,323 individuals died: 385 individuals died from cardiovascular disease, 290 from cancer, 80 from cerebrovascular disease, and 568 from other causes. Compared with the middle tertile remnant cholesterol level, multivariable-adjusted mortality hazard ratios were 1.20 (95% confidence interval 1.02-1.40) for all-cause mortality. For the highest tertile remnant cholesterol level, multivariable-adjusted mortality hazard ratios were 1.21 (95% confidence interval 1.05,1.40). Our conclusions remained stable in subgroup analyses. Exploratory analysis of the cause of death subcategories showed corresponding hazard ratios of 1.25 (1.13-1.38) for Non-cardiovascular and Non-cerebrovascular Death for lower remnant cholesterol individuals, 1.47 (1.01-2.15) for cancer death for lower remnant cholesterol (RC) individuals, and 1.80 (1.36-2.38) for cancer death for higher RC individuals. Conclusion: RC levels were associated with U-shaped all-cause mortality. RC was associated with mortality from non-cardiovascular, non-cerebrovascular, and cancer, but not from cardiovascular causes. This novel finding should be confirmed in other cohorts.

Associations of remnant cholesterol in early pregnancy with gestational diabetes mellitus risk: a prospective birth cohort study.

BACKGROUND: Remnant cholesterol (RC) reportedly contributes to the development of diabetes mellitus. However, evidence on the relationship between maternal RC and the risk of developing gestational diabetes mellitus (GDM) during pregnancy is limited. This study aimed to assess the relationship between maternal RC and GDM risk during early pregnancy, and explore the potential pathways involved in the relationship between RC levels and GDM risk. METHODS: From 2018 to 2021, a prospective birth cohort study was designed and carried out in China. The associations of maternal RC and other lipid parameters with GDM risk were estimated using logistic regression models and restricted cubic splines. Subgroup analyses were performed stratified by prepregnancy body mass index (pre-BMI), maternal age and gravidity. Mediation analyses were conducted to explore the mediating effect of some related factors on the relationship between RC levels and the risk of GDM. RESULTS: A total of 33,018 pregnant women were included. The median RC level was 0.47 ± 0.20 mmol/L. The prevalence of GDM was 15.19%. As RC quartiles increased, the incidence of GDM increased substantially, reaching 19.24% for the highest quartile of RC (P < 0.001). Maternal RC in the first trimester was positively correlated with GDM risk (OR: 2.254, 95% CI: 1.943-2.615). Compared to the lowest RC quartile, higher RC quartiles were correlated with an increased risk of GDM, and the ORs (95% CIs) for Q3 and Q4 were 1.208 (1.101-1.325) and 1.489 (1.364-1.626), respectively. Moreover, a linear dose-response relationship was found for this association (P for all < 0.001, P for nonlinearity > 0.05) and was consistent across subgroups with different pre-BMIs, maternal ages and gravidities (all P values for interactions > 0.05). Furthermore, the correlation between RC level and GDM risk was partially mediated by pre-BMI (9.20%) and blood glucose level (-11.1%). CONCLUSIONS: Higher maternal RC levels in the early stage of pregnancy was positively associated with an increased risk of developing GDM. This association was partially mediated by pre- BMI and blood glucose levels.

Effect of Supplementation of a Butyrate-Based Formula in Individuals with Liver Steatosis and Metabolic Syndrome: A Randomized Double-Blind Placebo-Controlled Clinical Trial.

Postbiotics could exert different metabolic activities in animal models of non-alcoholic fatty liver disease (NAFLD) and in humans affected by metabolic syndrome. This is a randomized, double-blind, placebo-controlled, parallel-group clinical trial that enrolled a sample of 50 Caucasian healthy individuals with NAFLD, defined as liver steatosis, and metabolic syndrome. After a 4-week run-in, the enrolled individuals were randomized to take a food for special medical purposes with functional release, one tablet a day, containing calcium butyrate (500 mg/tablet), zinc gluconate (zinc 5 mg/tablet), and vitamin D3 (500 IU/tablet), or an identical placebo for 3 months. Liver and metabolic parameters were measured at baseline and at the end of the study. No subject experienced any adverse events during the trial. In both groups, a significant decrease in total cholesterol (TC) and triglycerides (TG) plasma levels was observed at the randomization visit vs. pre-run-in visit (p < 0.05). Regarding liver parameters, after treatment, the fatty liver index (FLI) improved significantly vs. baseline values (p < 0.05) and vs. placebo group (p < 0.05) in the active treatment group, and the hepatic steatosis index (HSI) improved significantly vs. baseline values (p < 0.05). Moreover, after active treatment, TC, TG, and gamma-glutamyl transferase (gGT) improved significantly vs. baseline values (p < 0.05), and TC and TG improved vs. placebo group (p < 0.05), as well. In the placebo group, liver parameters remained unchanged after treatment; only TG improved significantly vs. baseline values (p < 0.05). In our study, we observed that the butyrate-based formula improved FLI and plasma lipid patterns in individuals affected by liver steatosis and metabolic syndrome.

Influence of Varied Dietary Cholesterol Levels on Lipid Metabolism in Hamsters.

Syrian hamsters are valuable models for studying lipid metabolism due to their sensitivity to dietary cholesterol, yet the precise impact of varying cholesterol levels has not been comprehensively assessed. This study examined the impact of varying dietary cholesterol levels on lipid metabolism in Syrian hamsters. Diets ranging from 0% to 1% cholesterol were administered to assess lipid profiles and oxidative stress markers. Key findings indicate specific cholesterol thresholds for inducing distinct lipid profiles: below 0.13% for normal lipids, 0.97% for elevated LDL-C, 0.43% for increased VLDL-C, and above 0.85% for heightened hepatic lipid accumulation. A cholesterol supplementation of 0.43% induced hypercholesterolemia without adverse liver effects or abnormal lipoprotein expression. Furthermore, cholesterol supplementation significantly increased liver weight, plasma total cholesterol, LDL-C, and VLDL-C levels while reducing the HDL-C/LDL-C ratio. Fecal cholesterol excretion increased, with stable bile acid levels. High cholesterol diets correlated with elevated plasma ALT activities, reduced hepatic lipid peroxidation, and altered leptin and CETP levels. These findings underscore Syrian hamsters as robust models for hyperlipidemia research, offering insights into experimental methodologies. The identified cholesterol thresholds facilitate precise lipid profile manipulation, enhancing the hamster's utility in lipid metabolism studies and potentially informing clinical approaches to managing lipid disorders.

Adherence to a Cholesterol-Lowering Diet and the Risk of Pancreatic Cancer: A Case-Control Study.

BACKGROUND: Pancreatic cancer risk has been associated with increased serum cholesterol level, which is in turn partially influenced by diet. This study aimed at evaluating the association between pancreatic cancer risk and the adherence to a plant-based cholesterol-lowering diet. METHODS: Data were derived from an Italian case-control study including 258 pancreatic cancer patients and 551 controls. The cholesterol-lowering diet score was based on seven components: high intakes of (i) non-cellulosic polysaccharides (a proxy of viscous fibers), (ii) monounsaturated fatty acids, (iii) legumes, and (iv) seeds/corn oils (a proxy of phytosterols); and low intakes of (v) saturated fatty acids, (vi) dietary cholesterol, and (vii) food with a high glycemic index. The score was calculated adding one point for each fulfilled component, thus ranging from zero (no adherence) to seven (complete adherence). The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated through the logistic regression model. RESULTS: Scores 5-7 were associated with reduced cancer risk (OR = 0.30; 95% CI: 0.18-0.52) compared to scores 0-2. CONCLUSIONS: Adherence to a plant-based cholesterol-lowering diet was associated with a reduced risk of pancreatic cancer.

A Mixture of Lactobacillus HY7601 and KY1032 Regulates Energy Metabolism in Adipose Tissue and Improves Cholesterol Disposal in High-Fat-Diet-Fed Mice.

We aimed to characterize the anti-obesity and anti-atherosclerosis effects of Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 using high-fat diet (HFD)-fed obese C57BL/6 mice. We divided the mice into control (CON), HFD, HFD with 108 CFU/kg/day probiotics (HFD + KL, HY7301:KY1032 = 1:1), and HFD with 109 CFU/kg/day probiotics (HFD + KH, HY7301:KY1032 = 1:1) groups and fed/treated them during 7 weeks. The body mass, brown adipose tissue (BAT), inguinal white adipose tissue (iWAT), and epididymal white adipose tissue (eWAT) masses and the total cholesterol and triglyceride concentrations were remarkably lower in probiotic-treated groups than in the HFD group in a dose-dependent manner. In addition, the expression of uncoupling protein 1 in the BAT, iWAT, and eWAT was significantly higher in probiotic-treated HFD mice than in the HFD mice, as demonstrated by immunofluorescence staining and Western blotting. We also measured the expression of cholesterol transport genes in the liver and jejunum and found that the expression of those encoding liver-X-receptor α, ATP-binding cassette transporters G5 and G8, and cholesterol 7α-hydroxylase were significantly higher in the HFD + KH mice than in the HFD mice. Thus, a Lactobacillus HY7601 and KY1032 mixture with 109 CFU/kg/day concentration can assist with body weight regulation through the management of lipid metabolism and thermogenesis.