1. Investigación

H2S, a gasotransmitter that can be produced both via the transsulfuration pathway and non-enzymatically, plays a key role in vasodilation and angiogenesis during pregnancy. In fact, the involvement of H2S production on plasma levels of sFLT1, PGF, and other molecules related to preeclampsia has been demonstrated. Interestingly, we have found that maternal fructose intake (a common component of the Western diet) affects tissular H2S production. However, its consumption is allowed during pregnancy. Thus, (1) to study whether maternal fructose intake affects placental production of H2S in the offspring, when pregnant; and (2) to study if fructose consumption during pregnancy can increase the risk of preeclampsia, pregnant rats from fructose-fed mothers (10% w/v) subjected (FF) or not (FC) to a fructose supplementation were studied and compared to pregnant control rats (CC). Placental gene expression, H2S production, plasma sFLT1, and PGF were determined. Descendants of fructose-fed mothers (FC) presented an increase in H2S production. However, if they consumed fructose during their own gestation (FF), this effect was reversed so that the increase disappeared. Curiously, placental synthesis of H2S was mainly non-enzymatic. Related to this, placental expression of Cys dioxygenase, an enzyme involved in Cys catabolism (a molecule required for non-enzymatic H2S synthesis), was significantly decreased in FC rats. Related to preeclampsia, gene expression of sFLT1 (a molecule with antiangiogenic properties) was augmented in both FF and FC dams, although these differences were not reflected in their plasma levels. Furthermore, placental expression of PGF (a molecule with angiogenic properties) was decreased in both FC and FF dams, becoming significantly diminished in plasma of FC versus control dams. Both fructose consumption and maternal fructose intake induce changes in molecules that contribute to increasing the risk of preeclampsia, and these effects are not always mediated by changes in H2S production.

Fructose-rich beverages and foods consumption correlates with the epidemic rise in cardiovascular disease, diabetes and obesity. Severity of COVID-19 has been related to these metabolic diseases. Fructose-rich foods could place people at an increased risk for severe COVID-19. We investigated whether maternal fructose intake in offspring affects hepatic and ileal gene expression of proteins that permit SARS-CoV2 entry to the cell. Carbohydrates were supplied to pregnant rats in drinking water. Adult and young male descendants subjected to water, liquid fructose alone or as a part of a Western diet, were studied. Maternal fructose reduced hepatic SARS-CoV2 entry factors expression in older offspring. On the contrary, maternal fructose boosted the Western diet-induced increase in viral entry factors expression in ileum of young descendants. Maternal fructose intake produced a fetal programming that increases hepatic viral protection and, in contrast, exacerbates fructose plus cholesterolinduced diminution in SARS-CoV2 protection in small intestine of progeny.

Endoplasmic reticulum (ER) homeostasis is crucial to appropriate cell functioning, and when disturbed, a safeguard system called unfolded protein response (UPR) is activated. Fructose consumption modifies ER homeostasis and has been related to metabolic syndrome. However, fructose sweetened beverages intake is allowed during gestation. Therefore, we investigate whether maternal fructose intake affects the ER status and induces UPR. Thus, administrating liquid fructose (10% w/v) to pregnant rats partially activated the ER-stress in maternal and fetal liver and placenta. In fact, a fructose-induced increase in the levels of pIRE1 (phosphorylated inositol requiring enzyme-1) and its downstream effector, X-box binding protein-1 spliced form (XBP1s), was observed. XBP1s is a key transcription factor, however, XBP1s nuclear translocation and the expression of its target genes were reduced in the liver of the carbohydrate-fed mothers, and specifically diminished in the fetal liver and placenta in the fructose-fed mothers. These XBP1s target genes belong to the ER-associated protein degradation (ERAD) system, used to buffer ER-stress and to restore ER-homeostasis. It is known that XBP1s needs to form a complex with diverse proteins to migrate into the nucleus. Since methylglyoxal (MGO) content, a precursor of advanced glycation endproducts (AGE), was augmented in the three tissues in the fructose-fed mothers and has been related to interfere with the functioning of many proteins, the role of MGO in XBP1s migration should not be discarded. In conclusion, maternal fructose intake produces ER-stress, but without XBP1s nuclear migration. Therefore, a complete activation of UPR that would resolve ER-stress is lacking. A state of fructose-induced oxidative stress is probably involved.

Fructose consumption from added sugars correlates with the epidemic rise in obesity, metabolic syndrome and cardiovascular diseases. However, consumption of beverages containing fructose is allowed during gestation. We have investigated whether maternal fructose intake produces subsequent changes in cholesterol metabolism of progeny. Carbohydrates were supplied to pregnant rats in drinking water (10% w/v solution) throughout gestation. Adult male and female descendants from fructose-fed, control or glucose-fed mothers were studied. Male offspring from fructose-fed mothers had elevated plasma HDL-cholesterol levels, whereas female progeny from fructose-fed mothers presented lower levels of non-HDL cholesterol versus the other two groups. Liver X-receptor (LXR), an important regulator of cholesterol metabolism, and its target genes such as scavenger receptor B1, ATP-binding cassette (ABC)G5 and cholesterol 7-alpha hydroxylase showed decreased gene expression in males from fructose-fed mothers and the opposite in the female progeny. Moreover, the expression of a number of LXR target genes related to lipogenesis paralleled to that for LXR expression. In accordance with this, LXR gene promoter methylation was increased in males from fructose-fed mothers and decreased in the corresponding group of females. Surprisingly, plasma folic acid levels, an important methyl-group donor, were augmented in males from fructose-fed mothers and diminished in female offspring. Maternal fructose intake produces a fetal programming that influences, in a gender-dependent manner, the transcription factor LXR epigenetically, and both hepatic mRNA gene expression and plasma parameters of cholesterol metabolism in adult progeny. Changes in the LXR promoter methylation might be related to the availability of the methyl donor folate.

The aim of the present study was to determine in the BALB/c mice, a model of development of atherosclerosis when both hyperglycemia and hypercholesterolemia are present, whether the atherogenic effects of these parameters could be decreased with the administration of Vitamin E. BALB/c mice were made diabetic and divided in three groups: one fed the standard rodent chow diet (D); the other two fed an atherogenic diet (D + A); one of them supplemented with Vitamin E (D +A+ E). Two groups of non diabetic animals were also performed, one fed the standard diet (C) and the other the atherogenic diet (C + A). After 16 weeks of treatment all the control animals survived, in contrast, a mortality rate of 12, 70 and 37% was observed, respectively, in the D, D + A and D +A+ E groups. Neither fatty deposits nor macrophages were observed in the arterial wall of the animals fed the standard diet (D and C animals). In contrast, this finding was observed in 25% of the C + A, 71% of the D + A and 33% of the D +A+ E. In conclusion, diabetic mice fed an atherogenic diet showed in the aorta a higher number of fatty deposits and macrophages than the control animals. These effects were partially reversed with the administration of Vitamin E, supporting in this model the role of oxidative stress in the development of atherosclerosis.

La arteriosclerosis y las enfermedades cardiovascularcs (ECV) secundarias a la misma constituyen la principal causa de mortalidad en los individuos diabéticos, apareciendo ésta a una edad mucho más temprana que en la población no diabética. Objetivos: estudiar en adolescentes con diabetes mellitus insulinodependiente (DMID) la presencia de factores de riesgo para el desarrollo de ECY. incluyendo: perfil de lipoproteínas, susceptibilidad de las LDL a oxidarse y niveles de vitaminas A y E. Métodos: Se estudiaron adolescentes con DMID (15 varones y 19 mujeres) y controles no diabéticos (15 varones y 17 mujeres). Los valores de colesterol y triglicéridos en plasma y HDL fueron valorados utilizando métodos enzimáticos. El colesterol en LDL fue calculado utilizando la formula de Friedewald. La susceptibilidad de las LDL a oxidarse fue determinada siguiendo la formación de dienos conjugados en LDL incubadas en Cl¡Cu (2 mM). Las vitaminas A y E fueron valoradas utilizando un método de HPLC. Resultados y conclusiones: Los adolescentes con DMID presentaron unos niveles de colesterol y triglicéridos en plasma y de colesterol en LDL y HDL similares a los observados en controles de su mismo sexo. La susceptibilidad de sus LDL a oxidarse fue prácticamente la misma que en individuos controles. Adolescentes con DMID presentaron unos niveles plasmáticos de vitaminas A y E inferiores a los observados en controles de su mismo sexo. Estos menores niveles de vitaminas antioxidantes podrían estar relacionados con el elevado riesgo de desárrollar ECV observada en los individuos con DMID.

The aim of the present study was to determine the direct effect of glucose on LDL oxidation, a key step in the development of atherosclerosis. Purified human LDL were incubated with glucose (500 mg/di) and LDL oxidation was started by adding CuCl2 to the media. Glucose delayed the vitamin E consumption, but accelerated the formation of conjugated dienes and increased both the formation of thiobarbituric acid reacting substances (TBARS) and LDL electrophoretic mobility. When LDL were incubated with increasing concentrations of glucose and submitted to oxidation, the formation of conjugated dienes, TBARS, and the electrophoretic mobility increased in a concentrationdependent manner. When LDL was enriched with vitamin E, it showed a delay in the formation of conjugated dienes, even in the presence of glucose. To determine whether glucose had any effect on LDL oxidation, once the process was started and vitamin E consumed, LDL were submitted to oxidation and, at different times thereafter, glucose was added into the media. Under these conditions glucose also accelerated the LDL oxidation. In summary, present results show that in LDL submitted to oxidation, glucose delays the early phases of the oxidation, slowing the vitamin E consumption, but it accelerates the rate of LDL oxidation once LDL vitamin E has been consumed; the effect being concentration-dependent.