Impact of early malnourishment on the chronic inflammatory response and its implications for the effect of indomethacin on Wistar rats

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.

Furosemide Pharmacokinetics in Adult Rats become Abnormal with an Adverse Intrauterine Environment and Modulated by a Post-Weaning High-Fat Diet

Adult individuals born with intrauterine growth restriction (IUGR) have physiological maladaptations that significantly increase risk of chronic disease. We suggested that such abnormalities in organ function would alter pharmacokinetics throughout life, exacerbated by environmental mismatch. Pregnant and lactating rats were fed either a purified control diet (18% protein) or low-protein diet (9% protein) to produce IUGR offspring. Offspring were weaned onto either laboratory chow (11% fat) or high-fat diet (45% fat). Adult offspring (5 months old) were dosed with furosemide (10 mg/kg i.p.) and serum and urine collected. The overall exposure profile in IUGR males was significantly reduced due to a ~35% increase in both clearance and volume of distribution. Females appeared resistant to the IUGR phenotype. The effects of the high-fat diet trended in the opposite direction to that of IUGR, with increased drug exposure due to decreases in both clearance (31% males, 46% females) and volume of distribution (24% males, 44% females), with a 10% longer half-life in both genders. The alterations in furosemide pharmacokinetics and pharmacodynamics were explained by changes in the expression of renal organic anion transporters 1 and 3, and sodium-potassium-chloride cotransporter-2. In summary, this study suggests that IUGR and diet interact to produce subpopulations with similar body-weights but dissimilar pharmacokinetic profiles; this underlines the limitation of one-size-fits-all dosing which does not account for physiological differences in body composition resulting from IUGR and diet.

Zinc treatment ameliorates diarrhea and intestinal inflammation in undernourished rats

BACKGROUND

WHO guidelines recommend zinc supplementation as a key adjunct therapy for childhood diarrhea in developing countries, however zinc's anti-diarrheal effects remain only partially understood. Recently, it has been recognized that low-grade inflammation may influence stunting. In this study, we examined whether oral zinc supplementation could improve weight, intestinal inflammation, and diarrhea in undernourished weanling rats.

METHODS

Rats were undernourished using a northeastern Brazil regional diet (RBD) for two weeks, followed by oral gavage with a saturated lactose solution (30 g/kg) in the last 7 days to induce osmotic diarrhea. Animals were checked for diarrhea daily after lactose intake. Blood was drawn in order to measure serum zinc levels by atomic absorption spectroscopy. Rats were euthanized to harvest jejunal tissue for histology and cytokine profiles by ELISA. In a subset of animals, spleen samples were harvested under aseptic conditions to quantify bacterial translocation.

RESULTS

Oral zinc supplementation increased serum zinc levels following lactose-induced osmotic diarrhea. In undernourished rats, zinc improved weight gain following osmotic diarrhea and significantly reduced diarrheal scores by the third day of lactose intake (p < 0.05), with improved jejunum histology (p < 0.0001). Zinc supplementation diminished bacterial translocation only in lactose-challenged undernourished rats (p = 0.03) compared with the untreated challenged controls and reduced intestinal IL-1β and TNF-α cytokines to control levels.

CONCLUSION

Altogether our findings provide novel mechanisms of zinc action in the setting of diarrhea and undernutrition and support the use of zinc to prevent the vicious cycle of malnutrition and diarrhea.

The effect of indomethacin, myeloperoxidase, and certain steroid hormones on bactericidal activity: an ex vivo and in vivo experimental study

BACKGROUND

The role of myeloperoxidase (MPO) is essential in the killing of phagocytosed bacteria. Certain steroid hormones increase MPO plasma concentration. Our aim was to test the effect of MPO, its inhibitor indomethacin, and certain steroid hormones on bactericidal activity.

METHODS

Human polymorphonuclear leukocytes (PMN) were incubated with opsonised Escherichia coli and either MPO, indomethacin, estradiol, or hydrocortisone. Intracellular killing capacity was evaluated with UV microscopy after treatment with fluorescent dye. Next, an in vivo experiment was performed with nine groups of rats: in the first phase of the study indomethacin treatment and Pasteurella multocida infection (Ii), indomethacin treatment without infection (I0), untreated control with infection (Mi) and untreated control without infection (M0); in the second phase of the study rats with infection and testosterone treatment (NT), castration, infection and testosterone treatment (CT), castration, infection and estradiol treatment (CE), non-castrated infected control (N0), and castrated infected control (C0). After treatment bacteria were reisolated from the liver and heart blood on agar plates, and laboratory parameters were analyzed. For the comparison of laboratory results ANOVA or Kruskal-Wallis test and LSD post hoc test was used.

RESULTS

Indomethacin did not have a remarkable effect on the bacterial killing of PMNs, while the other compounds increased bacterial killing to various degrees. In the animal model indomethacin and infection caused a poor clinical state, a great number of reisolated bacteria, elevated white blood cell (WBC) count, decreased C-reactive protein (CRP) and serum albumin levels. Testosterone treatment resulted in less bacterial colony numbers in group NT, but not in group CT compared to respective controls (N0, C0). Estradiol treatment (CE) decreased colony numbers compared to control (C0). Hormone administration resulted in lower WBC counts, and in group CE, a decreased CRP.

CONCLUSIONS

MPO, estradiol, and hydrocortisone improve bacterial killing activity of PMNs. Indomethacin treatment and castration weaken immune responses and clinical state of infected rats, while testosterone and estradiol have a beneficial effect.