An altered microbiota pattern precedes Type 2 diabetes mellitus development: From the CORDIOPREV study

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Type 2 diabetes (T2DM) increases the risk of recurrence in myocardial infarction patients.

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A gut microbiota profile is associated to the further T2DM development.

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Microbiome data improved the prediction of T2DM development when added to clinical parameters.

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A risk score including the most predictive genera was associated with the probability of T2DM.

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A high risk score was associated with a higher hepatic insulin resistance and β-cell dysfunction.

Introduction

A distinctive gut microbiome have been linked to type 2 diabetes mellitus (T2DM).

Objectives

We aimed to evaluate whether gut microbiota composition, in addition to clinical biomarkers, could improve the prediction of new incident cases of diabetes in patients with coronary heart disease.

Methods

All the patients from the CORDIOPREV (Clinical Trials.gov.Identifier: NCT00924937) study without T2DM at baseline were included (n = 462). Overall, 107 patients developed it after a median of 60 months. The gut microbiota composition was determined by 16S rRNA gene sequencing and predictive models were created using hold-out method.

Results

A gut microbiota profile associated with T2DM development was determined through a microbiome-based predictive model. The addition of microbiome data to clinical parameters (variables included in FINDRISC risk score and the diabetes risk score of the American Diabetes Association, HDL, triglycerides and HbA1c) improved the prediction increasing the area under the curve from 0.632 to 0.946. Furthermore, a microbiome-based risk score including the ten most discriminant genera, was associated with the probability of develop T2DM.

Conclusion

These results suggest that a microbiota profile is associated to the T2DM development. An integrate predictive model of microbiome and clinical data that can improve the prediction of T2DM is also proposed, if is validated in independent populations to prevent this disease.

Beta cell functionality and hepatic insulin resistance are major contributors to type 2 diabetes remission and starting pharmacological therapy: from CORDIOPREV randomized controlled trial

In order to assess whether previous hepatic IR (Hepatic-IR_fasting) and beta-cell functionality could modulate type 2 diabetes remission and the need for starting glucose-lowering treatment, newly-diagnosed type 2 diabetes participants who had never received glucose-lowering treatment (190 out of 1002) from the CORonary Diet Intervention with Olive oil and cardiovascular PREVention study (a prospective, randomized and controlled clinical trial), were randomized to consume a Mediterranean or a low-fat diet. Type 2 diabetes remission was defined according to the American Diabetes Association recommendation for levels of HbA1c, fasting plasma glucose and 2h plasma glucose after oral glucose tolerance test, and having maintained them for at least 2 consecutive years. Patients were classified according to the median of Hepatic-IR_fasting and beta-cell functionality, measured as the disposition index (DI) at baseline. Cox proportional hazards regression determined the potential for Hepatic-IR_fasting and DI indexes as predictors of diabetes remission and the probability of starting pharmacological treatment after a 5-year follow-up. Low-Hepatic-IR_fasting or high-DI patients had a higher probability of diabetes remission than high-Hepatic-IR_fasting or low-DI subjects (HR:1.79; 95% CI 1.06-3.05; and HR:2.66; 95% CI 1.60-4.43, respectively) after a dietary intervention with no pharmacological treatment and no weight loss. The combination of low-Hepatic-IR_fasting and high-DI presented the highest probability of remission (HR:4.63; 95% CI 2.00-10.70). Among patients maintaining diabetes, those with high- Hepatic-IR_fasting and low-DI showed the highest risk of starting glucose-lowering therapy (HR:3.24;95% CI 1.50-7.02). Newly-diagnosed type 2 diabetes patients with better beta-cell functionality and lower Hepatic-IR_fasting had a higher probability of type 2 diabetes remission in a dietary intervention without pharmacological treatment or weight loss, whereas among patients not achieving remission, those with worse beta-cell functionality and higher Hepatic-IR_fasting index had the highest risk of starting glucose-lowering treatment after 5 years of follow-up.

Dietary Intervention Modulates the Expression of Splicing Machinery in Cardiovascular Patients at High Risk of Type 2 Diabetes Development: From the CORDIOPREV Study

Type-2 diabetes mellitus (T2DM) has become a major health problem worldwide. T2DM risk can be reduced with healthy dietary interventions, but the precise molecular underpinnings behind this association are still incompletely understood. We recently discovered that the expression profile of the splicing machinery is associated with the risk of T2DM development. Thus, the aim of this work was to evaluate the influence of 3-year dietary intervention in the expression pattern of the splicing machinery components in peripheral blood mononuclear cells (PBMCs) from patients within the CORDIOPREV study. Expression of splicing machinery components was determined in PBMCs, at baseline and after 3 years of follow-up, from all patients who developed T2DM (Incident-T2DM, n = 107) and 108 randomly selected non-T2DM subjects, who were randomly enrolled in two healthy dietary patterns (Mediterranean or low-fat diets). Dietary intervention modulated the expression of key splicing machinery components (i.e., up-regulation of SPFQ/RMB45/RNU6, etc., down-regulation of RNU2/SRSF6) after three years, independently of the type of healthy diet. Some of these changes (SPFQ/RMB45/SRSF6) were associated with key clinical features and were differentially induced in Incident-T2DM patients and non-T2DM subjects. This study reveals that splicing machinery can be modulated by long-term dietary intervention, and could become a valuable tool to screen the progression of T2DM.

MiRNAs profile as biomarkers of nutritional therapy for the prevention of type 2 diabetes mellitus: From the CORDIOPREV study

BACKGROUND AND AIM

The incidence of type 2 diabetes mellitus (T2DM) has increased worldwide. One of the first actions to reduce the risk of this disease is to implement healthy dietary models; however, no universal dietary strategies have so far been established. In addition, MicroRNAs (miRNAs) are emerging as new biomarkers to predict disease. We aimed to study whether miRNAs could be used to select the nutritional therapy to prevent T2DM development in patients with cardiovascular disease.

METHODS

All patients from the CORDIOPREV study without T2DM at baseline according to the American Diabetes Association (ADA) diagnostic criteria (n = 462) were included in the present study. Of them, after a median dietary intervention period of 60 months with two diets (Low fat or Mediterranean diets), 107 developed T2DM and 355 subjects did not develop the disease. The plasma levels of 24 miRNAs were measured at baseline by qRT-PCR. The risk of T2DM was evaluated by Cox regression analysis based on the plasma levels of the miRNAs at baseline and according to the dietary intervention. Finally, pathways analyses were carried out to identify target genes regulated by the miRNAs studied and cellular processes which could be associated with T2DM development.

RESULTS

Cox regression analyses showed that patients with low plasma levels of miR-145 at baseline showed a higher risk of developing T2DM after consumption of an LFHCC diet. In addition, patients with low levels of miR-29a, miR-28-3p and miR-126 and high plasma levels of miR-150 at baseline showed a higher risk of developing T2DM after consumption of the Med diet. Finally, pathways analysis showed an interaction of miR-126 and miR-29a in the modulation of FoxO, TNF-α, PI3K-AKT, p53 and mTOR signaling, associated with T2DM development.

CONCLUSION

Our results suggest that circulating miRNAs could be used in clinical practice as a new tool for selecting the most suitable diet to prevent type 2 diabetes mellitus development in patients with cardiovascular disease.

CLINICAL TRIALS NUMBER

NCT00924937.

Reduction in Circulating Advanced Glycation End Products by Mediterranean Diet Is Associated with Increased Likelihood of Type 2 Diabetes Remission in Patients with Coronary Heart Disease: From the Cordioprev Study

SCOPE

It is hypothesized that decreased advanced glycation end products (AGEs) levels could affect type 2 diabetes mellitus (T2DM) remission in newly diagnosed patients through the consumption of two healthy diets.

METHODS AND RESULTS

Patients from CORDIOPREV study, all with previous cardiovascular events, with T2DM at the beginning of the study are included. Patients are randomized to a Mediterranean or a low-fat diet for five years. No different diabetes remission rates are found among diets. Serum methylglioxal (MG) and carboximethyllysine (CML), levels dietary AGE, as well as gene expression of AGER1 and RAGE are measured. Serum MG decreases only after the consumption of the Mediterranean diet. Moreover, a COX regression analysis shows that each SD decrease in the MG, occurring after the Mediterranean diet, increases the probability of T2DM remission with HR:2.56(1.02-6.25) and p = 0.046 and each SD increase in disposition index at baseline increases the probability of remission with HR:1.94(1.32-2.87) and p = 0.001.

CONCLUSIONS

It is demonstrated that the reduction of serum AGEs levels and the modulation of its metabolism, occurring after the consumption of a Mediterranean diet, might be involved in the molecular mechanism underlying the T2DM remission of newly diagnosed patients with coronary heart disease.

Postprandial Lipemia Modulates Pancreatic Alpha-Cell Function in the Prediction of Type 2 Diabetes Development: The CORDIOPREV Study

Diabetes (T2DM) is a major global health issue, and developing new approaches to its prevention is of paramount importance. We hypothesized that abnormalities in lipid metabolism are involved in alpha-cell deregulation. We therefore studied the metabolic factors underlying alpha-cell dysfunction in T2DM progression after a dietary intervention (Mediterranean and low-fat). Additionally, we evaluated whether postprandial glucagon levels may be considered as a predictive factor of T2DM in cardiovascular patients. Non-T2DM participants from the CORDIOPREV study were categorized by tertiles of the area under the curve (AUC) for triacylglycerols and also by tertiles of AUC for glucagon. Our results showed that patients with higher triacylglycerols levels presented elevated postprandial glucagon (P = 0.009). Moreover, we observed higher risk of T2DM (hazard ratio: 2.65; 95% confidence interval: 1.56-4.53) in subjects with elevated glucagon. In conclusion, high postprandial lipemia may induce alpha-cell dysfunction in cardiovascular patients. Our results also showed that postprandial glucagon levels could be used to predict T2DM development.

Lifestyle factors modulate postprandial hypertriglyceridemia: From the CORDIOPREV study

BACKGROUND AND AIMS

Recent evidence suggests that postprandial hypertriglyceridemia (PPT) is associated with the incidence of CVD. Several non-modifiable factors (genetics, age, gender) and lifestyle factors (physical activity, smoking, regular alcohol) have shown their ability to modulate PPT. We evaluate the influence of regular alcohol intake, physical activity and smoking habit modulating PPT in the CORDIOPREV study (NCT00924937).

METHODS

1002 patients were subject to an oral fat load test meal and serial blood samples were drawn at 0, 1, 2, 3 and 4 h during postprandial state. A PPT concentration above 2.5 mmol/L (220 mg/dL) at any time point has been established as a detrimental response. Alcohol consumption was defined as non-drinkers, moderate and severe intake; regular physical activity exceeding than or lower than 1000 MET/week; smoking habit was classified in current, never, recent ex-smokers and long-term ex-smokers.

RESULTS

The prevalence of undesirable PPT response was 68% in current, 58% in recent ex-smokers, 49% in long-term ex-smokers and 48% in never smokers (p < 0.001). Current and recent ex-smokers displayed higher PPT response as well as a greater area under the curve (AUC) and higher incremental (iAUC) of triglycerides (TG) compared with long-term ex-smokers and never smokers (p < 0.05), without differences among these subgroups. No differences were observed in the magnitude of PPT according to regular physical activity or alcohol intake habits.

CONCLUSIONS

Smoking is an independent risk factor modulating the magnitude of PPT. However, after tobacco cessation, ex-smokers show a progressive decrease on their PPT to reach levels similar to those of never smokers.

Apolipoprotein E genetic variants interact with Mediterranean diet to modulate postprandial hypertriglyceridemia in coronary heart disease patients: CORDIOPREV study

BACKGROUND

We try to explore whether long-term consumption of two healthy dietary patterns (low-fat [LF] diet or Mediterranean diet [MedDiet]) interacts with the apolipoprotein E (APOE) single-nucleotide polymorphisms (SNPs: rs439401, rs440446 and rs7412) modulating postprandial hypertriglyceridemia (ppHTG) in coronary heart disease (CHD) patients.

METHODS AND RESULTS

We selected patients from the CORDIOPREV study with genotyping and who underwent an oral fat load test (FLT) at baseline and after 3 years follow-up (n = 506). After 3 years of follow-up, we found a gene-diet interaction between the APOE rs439401 SNP and MedDiet. Specifically, T-allele carriers in the MedDiet group showed a more significant decrease in postprandial triglycerides (TG: P = 0.03) and large triacylglycerol-rich lipoproteins (TRLs) TG (large TRLs TG; P = 0.01) compared with CC subjects. Consistently, the area under the curve of TG (AUC-TG; P-interaction = 0.03) and AUC-large TRLs TG (P-interaction = 0.02) were significantly lower in T-allele carriers compared with CC subjects.

CONCLUSIONS

The long-term consumption of a MedDiet modulates ppHTG through APOE genetic variants in CHD patients. This gene-diet interaction may contribute to a more precise dietary advice in CHD patients.

Agaricus bisporus supplementation reduces high-fat diet-induced body weight gain and fatty liver development

Obesity is a global epidemic characterized not only by excessive fat deposition but also by important complications such as nonalcoholic liver steatosis. Beneficial antiobesogenic effects have been described for some mushrooms. The current study aimed to demonstrate the protective effect of Agaricus bisporus (AB) supplementation against the metabolic alterations induced by high-fat-diet (HFD) feeding. Eight-week-old C57BL/6J mice were fed for 10 weeks with one of the following diets: (1) control diet (n = 7), (2) HFD (n = 7), (3) HFD supplemented with 5% AB (n = 9), and (4) HFD supplemented with 10% AB (n = 9). A pair-fed group was also included for the 10% AB group (n = 6). The impact of AB supplementation on food intake, body weight gain, and liver and fat pad weights was examined. Biochemical, histological, and molecular parameters were also analyzed. Dietary supplementation with 10% AB reduced the HFD-induced increase in body, epididymal, and mesenteric fat weights (p < 0.01, p < 0.05, and p < 0.05, respectively). Supplementation with AB also reduced liver damage in a dose-dependent manner (p < 0.01 and p < 0.001). This effect was confirmed by histological analysis that showed that liver steatosis was markedly reduced in mice fed with AB. The beneficial properties of 10% AB supplementation appear to be mediated through a decrease in food intake and via stimulation of mesenteric and hepatic free-fatty acid beta-oxidation, along with a decrease in epidydimal and hepatic expression of CD36. In conclusion, supplementation with AB prevents excessive body weight gain and liver steatosis induced by HFD consumption.

Mediterranean Diet, Glucose Homeostasis, and Inflammasome Genetic Variants: The CORDIOPREV Study

SCOPE

Insulin resistance (IR) and chronic low-grade inflammation are hallmarks of type 2 diabetes mellitus (T2DM). The "NOD-like receptor pyrin domain containing-3" (NLRP3) inflammasome component of innate immunity is a metabolic stress sensor modulated by dietary and genetics factors. The aim of this study was to evaluate the effects of the consumption of two diets for 3 years, Mediterranean (Med) and low fat, on glucose homeostasis in the 1002 coronary heart disease patients of the CORDIOPREV study, according to a genetic variant of NLRP3 inflammasome.

METHODS AND RESULTS

The study was conducted in the framework of the CORDIOPREV study, a randomized dietary intervention with Med and low-fat diets. Single nucleotide polymorphisms (SNPs) located at inflammasome NLRP3 gene were genotyped by OpenArray platform. Nondiabetic CT+TT carriers of the rs4612666 SNP and AG+AA carriers of the rs10733113 SNP increased insulin sensitivity index (ISI) after 3 years of dietary intervention, whereas no effect was observed in diabetic patients. Further analysis by diet showed that the improvement of the ISI in nondiabetic rs10733113 AG+AA carriers was specific to the consumption of the Med diet.

CONCLUSION

Our results show that the benefits associated with a Med diet regarding glucose homeostasis in non-T2DM patients depend on genetic variation in the inflammasome.

Assessing the effects of model Maillard compound intake on iron, copper and zinc retention and tissue delivery in adult rats

The behaviour of dietary Maillard reaction compounds (MRP) as metal chelating polymers can alter mineral absorption and/or retention. Our aim in this study was to analyse the long-term effects of the consumption of model MRP from glucose-lysine heated for 90 min at 150 °C (GL) on iron, copper and zinc whole-body retention and tissue delivery. For 88 days, weaning rats were fed a Control diet or one containing 3% GL, until reaching the adult stage. During the experimental period a mineral balance was conducted to investigate the mineral retention. At day 88, the animals were sacrificed, blood was drawn for haemoglobin determination and some organs were removed. Copper and zinc balances were unaffected (Cu: 450 vs. 375 μg; Zn: 6.7 vs. 6.2 mg for Control and GL groups, respectively) and no change was observed in whole-body delivery. Iron retention, too, was unaltered (11.2 mg for Control and GL groups) but due to the tendency toward decreased body weight in the GL group (248 vs. 233 g for the Control and GL groups), whole-body iron concentration was 13% higher in the GL group than in the Control group. Absorbed iron accumulated particularly in the liver (144 vs. 190 μg g(-1) for the Control and GL groups), thus reducing haemoglobin levels. The long-term intake of MRP induced iron accumulation in the body but this did not result in enhanced iron functionality, since the haemoglobin concentration declined. Taking into account the findings of our research group's studies of young and adult rats, we now corroborate the hypothesis that the negative effect of GL MRP consumption on iron functionality takes place regardless of the animals' stage of life.

An advanced glycation end product (AGE)-rich diet promotes Nε-carboxymethyl-lysine accumulation in the cardiac tissue and tendons of rats

The purpose of this study was to investigate the intake, excretion, and tissue accumulation of carboxymethyl-lysine (CML), after feeding rats a diet containing advanced glycation end products (AGEs) from a glucose-lysine (GL) model system. Rats were distributed into two groups and assigned to a control diet or a diet including 3% heated GL (GL diet) for three months. Feces and urine were collected over the last week. After sacrifice, serum was obtained and some organs were removed for CML analysis. The percentage of fecal CML was 2.5-fold higher in the animals fed the GL diet (33.2 vs 76.5% for control and GL group), whereby total recovery was 91.8% compared with a level of 54.6% in the animals fed the control chow, evidencing the importance of the chemical form and the net quantity of dietary CML on its elimination. We suggest that dietary dicarbonyl compounds from GL diet or dietary CML itself are responsible for CML accumulation in hearts and tendons. The most significant result of the present study is that the regular consumption of dietary AGEs in healthy individuals promotes CML accumulation in some organs.

Effects of model Maillard compounds on bone characteristics and functionality

BACKGROUND

Physical and biomechanical properties of bone can be affected by non-enzymatic crosslinks, which are implicated in bone pathologies such as osteoporosis. The purpose of this study was to analyse the effects of the consumption of model Maillard reaction product (MRP) from glucose-lysine heated for 90 min at 150 °C (GL90) on bone composition and features. Rats were fed either a control diet or a diet containing 30 g kg(-1) GL90 for 88 days. Food consumption and the animals' body weights were monitored. After sacrifice, the femur, pelvic bone and tibia were removed for analysis of their composition and physical and biomechanical properties.

RESULTS

The organic matrix of the femur and the density of the pelvic bone decreased after MRP intake, whereas pentosidine content increased greatly with respect to the control group (41.7 ± 9.9 vs 171.4 ± 3.3 mmol mol(-1) collagen). The rising level of C-telopeptide degradation products from type I collagen (β-CTX) suggested a possible situation of increased bone resorption and/or higher turnover.

CONCLUSION

In conjunction, the detrimental effect on the organic matrix, the situation of higher resorption and/or bone turnover indicated by the β-CTX values and the high pentosidine content in bone provoked negative consequences on certain mechanical properties such as the ability to withstand force and absorb energy without failure.

Influence of Maillard products from bread crust on magnesium bioavailability in rats

BACKGROUND

Consumption of Maillard reaction products (MRPs) present in food has been related to deterioration of protein digestibility and changes in mineral bioavailability. We aimed to investigate the effects of MRP intake from bread crust on magnesium balance and tissue distribution, seeking causative factors among its different components.

RESULTS

During the final stage of the trial, magnesium digestibility improved by around 15% in rats fed diets containing bread crust or its derivatives compared with the control diet. Despite certain enhancements in magnesium bioavailability in this stage, for the experimental period as a whole, this parameter remained unchanged. However, specific changes in the content and/or concentration in some organs were observed, particularly in the femur, where magnesium levels were higher due to the smaller size of the bones.

CONCLUSIONS

Consumption of MRPs from bread crust or its different components did not modify the magnesium balance. Nevertheless, the bread crust fractions led to some changes in magnesium tissue distribution which did not match the effects induced by complete bread crust intake, suggesting the importance of designing studies with real-food systems, in order to reinforce the validity of the findings obtained.

Metabolic transit of N(ε)-carboxymethyl-lysine after consumption of AGEs from bread crust

Our aim was to investigate carboxymethyl-lysine (CML) intake and excretion after feeding rats with diets containing advanced glycation end-products (AGEs) from bread crust (BC) or its soluble or insoluble fractions, and to identify the factors responsible for the effects observed. CML in serum and different tissues was measured to detect possible accumulations. For 88 days, weanling rats were fed with either a control diet or one containing BC, or its soluble low molecular weight (LMW), soluble high molecular weight (HMW) or insoluble fractions. In the last week of the assay, faeces and urine were collected daily and stored as a 1 week pool. After sacrifice, blood was drawn to obtain serum and some organs were removed. CML analysis was performed by HPLC/MS/MS in diets, faeces, urines, serum and tissues. Faecal excretion of CML was strongly influenced by dietary CML levels and represents the major route of excretion (i.e. 33.2%). However, the urinary elimination of CML was probably limited or saturated, especially when more complex compounds were present in the diet. BC consumption increased CML in the cardiac tissue (170 ± 18 vs. 97 ± 3 μmol per mol lysine for BC and control groups), which correlated with the CML intake. The levels of this AGE in bone were unaffected by the dietary treatment, but in tail tendons CML was greatly increased in the animals that consumed the BC diet (102 ± 13 vs. 51 ± 8 μmol per mol lysine for BC and control groups, P = 0.006), which was associated with the intake of soluble LMW compounds present in BC. Despite the CML accumulation detected in different tissues, serum levels of protein-bound CML were unchanged, indicating the importance of measuring the free CML in this fluid as a real index of dietary CML.

Effects of diets supplemented with MRPs from bread crust on the food intake and body weights in rats

Traditionally the effects of dietary Maillard reaction products (MRPs) on food intake and body weight have been described in different studies, but few investigations have been conducted to analyse the main contributors responsible. We studied the effects of long-term consumption of MRPs from bread crust (BC) on rat growth, investigating the efficiency of diet and protein utilization. Different soluble and insoluble fractions of BC were studied to analyse the possible contributors. Additionally, the colour of the faecal material and the amount of fluorescent MRPs in the urine were measured in order to demonstrate MRP excretion. Six groups of rats were fed the following diets for 88 days: control (AIN-93G diet); bread dough (BD) and BC (containing 10% of BD or BC, respectively); low and high molecular weight (LMW-HMW) (containing soluble compounds from BC with <5 kDa and >5 kDa, respectively); insoluble (containing insoluble compounds from BC). Dietary MRPs tended to reduce the food intake and body weight significantly after consumption of more complex compounds (HMW and insoluble). The L*-value in the faeces decreased in animals fed BC and its derivatives, providing evidence of the presence of MRPs. The fluorescence associated with MRP excretion in urine was higher when the LMW diet was consumed, suggesting the easier absorption and clearance of the smaller compounds of BC.

Consumption of model maillard reaction products has no significant impact on Ca and Mg retention or on tissue distribution in rats

Our aim was to analyze the influence of the prolonged consumption of Maillard reaction prod-ucts (MRPs) from the glucose-lysine model system, on calcium and magnesium bioavailability and on tissue distribution in female rats. A long-term study (88 days) was conducted, in which two groups of rats (n = 12) were fed either a Control diet or one including 3 % glucose-lysine MRPs (GL90 diet). During the experimental period, the global balance was determined; calcium apparent absorption, retention, and bioavailability were stable after consumption of the assayed MRPs (37 % and 38 % for the Control and GL90 groups, respectively). Consequently, there was no change in calcium tissue distribution. During the final week, an additional balance was performed, following urine and feces collection, which showed calcium bioavailability to be stable. During the same period, magnesium apparent absorption and retention increased, leading to higher digestibility and bioavailability. However, these variations could be isolated events of little significance, since overall there were no variations in magnesium body content or retention (73 mg and 75 mg for the Control and GL90 groups, respectively). This conclusion was supported by the stability of the magnesium content and its concentration in the organs. These findings are in line with those of previous studies, which have reported the low affinity of these metals to form MRP complexes.