Regional Brazilian diet-induced pre-natal malnutrition in rats is correlated with the proliferation of cultured vascular smooth muscle cells

Consumption of a multi-deficient diet causes dynamic changes in the intestinal morphofunctional barrier, body composition and impaired physical development in post-weaning mice

Few studies have focused on nutrient-deficient diets and associated pathobiological dynamics of body composition and intestinal barrier function. This study evaluated the impact of a nutrient-deficient diet on physical development and intestinal morphofunctional barrier in mice. C57BL/6 (21 days of age) mice were fed a Northeastern Brazil regional basic diet (RBD) or a control diet for 21 d. The animals were subjected to bioimpedance analysis, lactulose test, morphometric analysis and quantitative reverse transcription-PCR to evaluate tight junctions and intestinal transporters. RBD feeding significantly reduced weight (P < 0·05) from day 5, weight gain from day 3 and tail length from day 14. The intake of RBD reduced total body water, extracellular fluid, fat mass and fat-free mass from day 7 (P < 0·05). RBD induced changes in the jejunum, with an increase in the villus:crypt ratio on day 7, followed by reduction on days 14 and 21 (P < 0·05). Lactulose:mannitol ratio increased on day 14 (P < 0·05). Changes in intestinal barrier function on day 14 were associated with reductions in claudin-1 and occludin, and on day 21, there was a reduction in the levels of claudin-2 and occludin. SGLT-1 levels decreased on day 21. RBD compromises body composition and physical development with dynamic changes in intestinal barrier morphofunctional. RBD is associated with damage to intestinal permeability, reduced levels of claudin-1 and occludin transcripts and return of bowel function in a chronic period.

Undernutrition - thirty years of the Regional Basic Diet: the legacy of Naíde Teodósio in different fields of knowledge

Undernutrition is characterized by an imbalance of essential nutrients with an insufficient nutritional intake, a disorder in which the clinical manifestations in most cases are the result of the economic and social context in which the individual lives. In 1990, the study by the medical and humanitarian Naíde Teodósio (1915-2005) and coworkers, which formulated the Regional Basic Diet (RBD) model for inducing undernutrition, was published. This diet model took its origin from the observation of the dietary habits of families that inhabited impoverished areas from the Pernambuco State. RBD mimics an undernutrition framework that extends not only to the Brazilian population, but to populations in different regions worldwide. The studies based on RBD-induced deficiencies provide a better understanding of the impact of undernutrition on the pathophysiological mechanisms underlying the most diverse prevalent diseases. Indexed papers that are analyzed in this review focus on the importance of using RBD in different areas of knowledge. These papers reflect a new paradigm in translational medicine: they show how the study of pathology using the RBD model in animals over the past 30 years has and still can help scientists today, shedding light on the mechanisms of prevalent diseases that affect impoverished populations.

Post-weaning protein malnutrition induces myocardial dysfunction associated with oxidative stress and altered calcium handling proteins in adult rats

Hypercaloric low-protein diet may lead to a state of malnutrition found in the low-income population of Northeastern Brazil. Although malnutrition during critical periods in the early life is associated with cardiovascular diseases in adulthood, the mechanisms of cardiac dysfunction are still unclear. Here we studied the effects of post-weaning malnutrition due to low protein intake induced by a regional basic diet on the cardiac contractility of young adult rats. In vivo arterial hemodynamic and in vitro myocardial contractility were evaluated in 3-month-old rats. Additionally, protein content of the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA), total phospholamban (PLB) and phosphorylated at serine 16 (p-Ser(16)-PLB), α2-subunit of the Na(+)/K(+)-ATPase (α2-NKA), and Na(+)/Ca(2+) exchanger (NXC) and in situ production of superoxide anion (O2(-)) were measured in the heart. Blood pressure and heart rate increased in the post-weaning malnourished (PWM) rats. Moreover, malnutrition decreased twitch force and inotropic responses of the isolated cardiac muscle. Protein expression of SERCA, PLB/SERCA, and p-Ser(16)-PLB/PLB ratios and α2-NKA were decreased without changing NCX. The contraction dependent on transsarcolemmal calcium influx was unchanged but responsiveness to Ca(2+) and tetanic peak contractions were impaired in the PWM group. Myocardial O2(-) production was significantly increased by PWM. Our data demonstrated that this hypercaloric low-protein diet in rats is associated with myocardial dysfunction, altered expression of major calcium handling proteins, and increased local oxidative stress. These findings reinforce the attention needed for pediatric care, since chronic malnutrition in early life is related to increased cardiovascular risk in adulthood. Graphical Abstract.

Maternal protein restriction compromises myocardial contractility in the young adult rat by changing proteins involved in calcium handling

Maternal protein restriction (MPR) during pregnancy is associated with increased cardiovascular risk in the offspring in adulthood. In this study we evaluated the cardiac function of young male rats born from mothers subjected to MPR during pregnancy, focusing on the myocardial mechanics and calcium-handling proteins. After weaning, rats received normal diet until 3 mo old, when the following parameters were assessed: arterial and left ventricular hemodynamics and in vitro cardiac contractility in isolated papillary muscles. The body weight was lower and arterial pressure higher in the MPR group compared with young adult offspring of female rats that received standard diet (controls); and left ventricle time derivatives increased in the MPR group. The force developed by the cardiac muscle was similar; but time to peak and relaxation time were longer, and the derivatives of force were depressed in the MPR. In addition, MPR group exhibited decreased post-pause potentiation of force, suggesting reduced reuptake function of the sarcoplasmic reticulum. Corroborating, the myocardial content of SERCA-2a and phosphorylated PLB-Ser16/total PLB ratio was decreased and sodium-calcium exchanger was increased in the MPR group. The contraction dependent on transsarcolemmal influx of calcium was higher in MPR if compared with the control group. In summary, young rats born from mothers subjected to protein restriction during pregnancy exhibit changes in the myocardial mechanics with altered expression of calcium-handling proteins, reinforcing the hypothesis that maternal malnutrition is related to increased cardiovascular risk in the offspring, not only for hypertension, but also cardiac dysfunction.

Rats undernourished in utero have altered Ca2+ signaling and reduced fertility in adulthood

Epidemiological and animal studies have shown that placental undernutrition impairs reproduction in adult offspring, but the underlying molecular mechanisms within the male genital tract remain unknown. Due to its special physiological characteristics in transport and the modulation of the environment to which its luminal content is exposed, we hypothesized that the vas deferens would be a highly sensitive target. The goals were to investigate whether intrauterine malnutrition affects molecular mechanisms related to Ca(2+)- and oxidative stress-modulated processes and causes structural alterations in the adult rat vas deferens that could attenuate fecundity and fertility. Male adult rats malnourished in utero had increased vas deferens weight associated with thickening of the muscular coat, a decrease in the total and haploid germ cells, a marked increase in the immature cells, and a decline in the numbers of pregnant females and total offspring per male rat. The ex vivo response of vas deferens from malnourished rats demonstrated an accentuated decrease in the contractile response to phenylephrine. The vas deferens had a marked decrease in Ca(2+) transport due to the uncoupling of Ca(2+)-stimulated ATP hydrolysis and ATP-driven Ca(2+) flux, and the downregulation of both sarco-endoplasmic reticulum Ca(2+)-ATPase 2 and the coupling factor 12-kDa FK506-binding protein. An increase in protein carbonylation (a marker of oxidative damage) and an imbalance between protein kinases C and A were observed as a legacy of undernutrition in early life. These results provide the structural and molecular basis to explain at least in part how maternal undernutrition affects fecundity and fertility in adult male rats.

Faria T, Siman FDM, Silveira EA, Meira EF, da Costa CP, Vassallo DV, Padilha AS. Post-weaning protein malnutrition increases blood pressure and induces endothelial dysfunctions in rats

Malnutrition during critical periods in early life may increase the subsequent risk of hypertension and metabolic diseases in adulthood, but the underlying mechanisms are still unclear. We aimed to evaluate the effects of post-weaning protein malnutrition on blood pressure and vascular reactivity in aortic rings (conductance artery) and isolated-perfused tail arteries (resistance artery) from control (fed with Labina®) and post-weaning protein malnutrition rats (offspring that received a diet with low protein content for three months). Systolic and diastolic blood pressure and heart rate increased in the post-weaning protein malnutrition rats. In the aortic rings, reactivity to phenylephrine (10(-10)-3.10(-4) M) was similar in both groups. Endothelium removal or L-NAME (10(-4) M) incubation increased the response to phenylephrine, but the L-NAME effect was greater in the aortic rings from the post-weaning protein malnutrition rats. The protein expression of the endothelial nitric oxide isoform increased in the aortic rings from the post-weaning protein malnutrition rats. Incubation with apocynin (0.3 mM) reduced the response to phenylephrine in both groups, but this effect was higher in the post-weaning protein malnutrition rats, suggesting an increase of superoxide anion release. In the tail artery of the post-weaning protein malnutrition rats, the vascular reactivity to phenylephrine (0.001-300 µg) and the relaxation to acetylcholine (10(-10)-10(-3) M) were increased. Post-weaning protein malnutrition increases blood pressure and induces vascular dysfunction. Although the vascular reactivity in the aortic rings did not change, an increase in superoxide anion and nitric oxide was observed in the post-weaning protein malnutrition rats. However, in the resistance arteries, the increased vascular reactivity may be a potential mechanism underlying the increased blood pressure observed in this model.

Impacto da desnutrição e do treinamento aeróbico moderado sobre a estrutura da parede arterial de ratos em processo de envelhecimento

Foram avaliadas as repercussões tardias da desnutrição multicarencial imposta no período de aleitamento e os possíveis efeitos e/ou alterações tanto do processo de envelhecimento como do treinamento físico aeróbio moderado sobre o diâmetro luminal e a área da túnica média da parede das artérias carótida comum esquerda, aorta horizontal e aorta torácica de ratos em processo de envelhecimento. Vinte e quatro ratos machos, Wistar, foram separados de acordo com a dieta e o treinamento físico em: GNS - nutrido sedentário, GNT - nutrido treinado, GDS - desnutrido sedentário e GDT - desnutrido treinado. Aos 10 meses, o GNT e o GDT foram submetidos ao treinamento, em meio aquático, durante oito semanas. Em seguida, os ratos foram anestesiados, sacrificados e, posteriormente, foram coletados fragmentos arteriais para o processamento histológico. A área da túnica média foi mensurada através da diferença entre as áreas externa e interna da parede arterial e o diâmetro luminal foi mensurado a partir da média de dois diâmetros medidos a partir de quatro pontos marcados na camada interna do vaso. A área da túnica média apresentou redução na aorta horizontal quando comparamos os grupos GNS x GDS (p = 0,015) e um aumento da artéria carótida comum esquerda entre os grupos GNT e GNS (p < 0,001). A aorta torácica apresentou um aumento do diâmetro luminal ao compararmos o GDS com o GDT (p= 0,041). Tanto a desnutrição multicarencial induziu alterações parciais na parede aorta horizontal, como também o treinamento físico foi capaz de promover mudanças na área da túnica média da artéria carótida comum esquerda e no diâmetro luminal da aorta torácica.

Effects of birth weight on spontaneous baroreflex sensitivity in adult life

BACKGROUND AND AIM

Several epidemiological studies have suggested a link between low birth weight and coronary heart disease; this may be partly due to the association between low birth weight and conventional risk factors. Among the factors involved in the regulation of cardiovascular homeostasis, baroreflexes play a crucial role. The objective of the present study was to investigate if baroreflex sensitivity (BRS) in adulthood is associated with birth weight.

METHODS AND RESULTS

Two hundred and eleven adults from Turin, Italy, aged 22-24 years, were examined in a cross sectional survey. Birth weight, blood pressure, pulse rate, family history of hypertension, anthropometric and environmental parameters and spontaneous baroreflex sensitivity were evaluated. In this study we observed a significant increase in baroreflex sensitivity across the tertiles of birth weight, even after correction for gender, blood pressure and heart rate; in a regression model, birth weight was positively and independently associated with BRS; moreover, BRS showed a significant negative correlation with adult pulse rate.

CONCLUSION

This finding may be helpful in understanding the association between low birth weight and cardiovascular disease outcome in later life, since baroreflex failure is associated with an increased cardiovascular morbidity and mortality.

Renal function in juvenile rats subjected to prenatal malnutrition and chronic salt overload

Dietary sodium may contribute to hypertension and to cardiovascular and renal disease if a primary deficiency of the kidney to excrete sodium exists. In order to investigate whether chronic 1% NaCl in the drinking water changes blood pressure and renal haemodynamics in juvenile Wistar rats subjected to prenatal malnutrition, an evaluation of plasma volume, oxidative stress in the kidney, proteinuria and renal haemodynamics was carried out. Malnutrition was induced by a multideficient diet. Mean arterial pressure, renal blood flow and glomerular filtration rate (GFR) were measured using a blood pressure transducer, a flow probe and inulin clearance, respectively. Plasma volume and oxidative stress were measured by means of the Evans Blue method and by monitoring thiobarbituric acid reactive substances (TBARS) in the kidneys, respectively. Urinary protein was measured by precipitation with 3% sulphosalicylic acid. It was observed that prenatally malnourished rats presented higher values of plasma volume (26%, P < 0.05), kidney TBARS (43%, P < 0.01) and blood pressure (10%, P < 0.01) when compared with the control group. However, they showed no change in renal haemodynamics or proteinuria. Neither prenatally malnourished nor control rats treated with sodium overload presented plasma volume or blood pressure values different from their respective control groups, but both groups presented elevated proteinuria (P < 0.01). The prenatally malnourished group treated with sodium overload presented higher values of kidney TBARS, GFR and filtration fraction (58, 87 and 72% higher, respectively, P < 0.01) than its respective control group. In summary, sodium overload did not exacerbate the hypertension in juvenile prenatally malnourished rats, but induced renal haemodynamic adjustments compatible with the development of renal disease.