Is it possible to identify underlying cardiovascular risk in young trained military?

BACKGROUND

Exercise is an important tool in the prevention of cardiovascular risk. Counter-intuitively, elite athletes and military have been found to have high cardiovascular risk. This study aimed to identify underlying cardiovascular risk in young trained military using different parameters including the leptin: adiponectin (L:A) ratio.

METHODS

Healthy military males (N.=54) participated in this study. Anthropometric and body composition were measured. After overnight fasting, the following parameters were determined: plasma lipid profile, electronegative-LDL, leptin and adiponectin concentrations. Data were expressed as median (25th and 75th percentiles). The relationship between variables was tested using the Spearman correlation test, with statistical significance set at P<0.05.

RESULTS

Total cholesterol (143 [130-157] mg/dL), triglycerides (TG; 88.5 [63-116] mg/dL) and LDL cholesterol (77.6 [68.8-94.5] mg/dL) plasma levels were adequate. However, all participants were found to have HDL cholesterol below 60 mg/dL (43 [40-49] mg/dL) and 44% (N.=24) had a TG:HDL ratio (2.0 [1.4-2.9]) above 2.0. The L:A ratio was higher than 0.32 for 29% (N.=16) of the participants. The main correlations observed were between waist circumference (WC) and WC:height ratio, with TG (r=0.37; r=0.56), TG:HDL ratio (r=0.41; r=0.36), HDL (r= -0.344; r= -0.26), and L:A ratio (r=0.25; r=0.46).

CONCLUSIONS

Trained military men could be classified as at borderline cardiovascular risk when considering only their lipid profiles. However, this observation may be misleading, since lipid profiles are altered by very intense and long exercise. The L:A ratio be should be monitored more closely to establish whether a relationship exists between WC and WC:height and the L:A ratio has potential diagnostic.

Resveratrol prevents hyperleptinemia and central leptin resistance in adult rats programmed by early weaning

We have previously shown that early weaning in rats increases the risk of obesity and insulin resistance at adulthood, and leptin resistance can be a prime factor leading to these changes. Resveratrol is reported to decrease oxidative stress, insulin resistance, and cardiovascular risk. However, there is no report about its effect on leptin resistance. Thus, in this study we have evaluated resveratrol-preventing effect on the development of visceral obesity, insulin, and leptin resistance in rats programmed by early weaning. To induce early weaning, lactating dams were separated into 2 groups: early weaning (EW)--dams were wrapped with a bandage to interrupt lactation in the last 3 days of lactation and control (C)--dams whose pups had free access to milk during throughout lactation period (21 days). At 150 days-old, EW offspring were subdivided into 2 groups: EW+res--treated with resveratrol solution (30 mg/kg BW/day) or EW--receiving equal volume of vehicle solution, both given by gavage during 30 days. Control group received vehicle solution. Resveratrol prevented the higher body weight, hyperphagia, visceral obesity, hyperleptinemia, hyperglycemia, insulin resistance, and hypoadiponectinemia at adulthood in animals that were early weaned. Leptin resistance, associated with lower JAK2 and pSTAT3 and higher NPY in hypothalamus of EW rats were also normalized by resveratrol. The present results suggest that resveratrol is useful as therapeutic tool in treating obesity, mainly because it prevents the development of central leptin resistance.

Regulation of insulin sensitivity by adiponectin and its receptors in response to physical exercise

Adiponectin is an adipocyte-derived abundant plasma protein, also called Acrp30 (adipocyte complement-related protein), adipoQ, ApM1 (AdiPose Most abundant Gene transcript 1), or GBP28 (gelatin-binding protein-28). Insulin resistance is a primary contributing factor in the pathogenesis of type 2 diabetes. Adiponectin binds to adiponectin receptors AdipoR1 and AdipoR2, and exerts antidiabetic effects via activation of AMPK and PPAR-α pathways, respectively. In the same sense chronic exercise has been showed to induce numerous metabolic factors that can improve insulin resistance. It has been reported that physical exercise training increases adiponectin receptors, which may mediate the improvement of insulin resistance in response to exercise, which is the focus of the present review.

Physical exercise is associated with better fat mass distribution and lower insulin resistance in spinal cord injured individuals

OBJECTIVES

The aim of the study was to compare total and regional body composition and their relationship with glucose homeostasis in physically active and non-active individuals with cervical spinal cord injury (c-SCI).

METHODS

Individuals with lesion level between C5-C7 were divided into two groups: physically active (PA; n = 14; who practiced physical exercise for at least 3 months, three times per week or more, minimum of 150 minutes/week): and non-physically active (N-PA n = 8). Total fat mass (t-FM) and regional fat mass (r-FM) were assessed by dual energy X-ray absorptiometry. Fasting plasma insulin (FPI) was determined by enzyme-linked immunosorbent assay.

RESULTS

PA group present lower (P < 0.01) total fat mass (t-FM), % and kg, regional fat mass (r-FM), % and kg, FPI levels and HOMA index, while they had higher (P < 0.001) total free fat mass (t-FFM), %, and regional free fat mass (r-FFM), %, compared to the N-PA group. In the N-PA group, FPI and HOMA index were negatively (P < 0.05) correlated with FFM% (r = -0.71, -0.69, respectively) and positively correlated to trunk-FM (r = 0.71, 0.69, respectively) and trunk-FM:t-FM (kg) ratio (r = 0.83, 0.79, respectively).

CONCLUSION

Physical exercise is associated with lower t-FM, r-FM, and insulin resistance, which could contribute to the decrease of the risk of cardiovascular and metabolic conditions in individuals with c-SCI.

Developmental plasticity in thyroid function primed by maternal hyperleptinemia in early lactation: a time-course study in rats

Pups whose mothers were leptin-treated during the last 3 days of lactation have thyroid dysfunction at adulthood. However, there was no report about leptin treatment in the first days of life or about its action on thyroid function during development. Here, we evaluated the effects of maternal leptin treatment on the first 10 days of lactation upon thyroid function of the offspring at 21, 30, and 180 days old. At birth, lactating Wistar rats were divided into: Leptin (Lep) - leptin-treated (8 μg/100 g of body weight, s.c.) for the first 10 days of lactation and Control (C, saline-treated). Mothers were killed at the end of lactation and their offspring at 21, 30, and 180 days old. Triiodothyronine (T3), thyroxine (T4), thyrotropin (TSH), and leptin levels in serum and milk were measured. Liver mitochondrial glycerolphosphate dehydrogenase (mGPD) activity was determined. Significant differences had p<0.05. At the end of lactation, Lep mothers had higher milk T3 (+ 30%), while their offspring had higher serum T3 (+ 20%) and TSH (+ 84%). At 30 days-old, Lep offspring showed lower TSH ( - 48%), T3 ( - 20%), and mGPDm ( - 42%). At 180 days-old, Lep group presented hyperleptinemia (1.4-fold increase), higher serum T3 (+ 22%), and lower mGPD activity ( - 57%). Maternal hyperleptinemia on lactation causes hypothyroidism in the pups at 30 days, which may program for higher serum T3 at adulthood. In conclusion, maternal hyperleptinemia during lactation, that is common in obese mothers, may have an impact in future disease development, such as thyroid dysfunction.

Maternal prolactin inhibition during lactation affects physical performance evaluated by acute exhaustive swimming exercise in adult rat offspring

Maternal prolactin inhibition at the end of lactation programs for metabolic syndrome and hypothyroidism in adult offspring, which could negatively affect exercise performance. We evaluated the effects of maternal hypoprolactinemia in late lactation on physical performance in adult progeny. Lactating Wistar rats were treated with bromocriptine (BRO, 1 mg per day) or saline on days 19, 20, and 21 of lactation and offspring were followed until 180 days old. Physical performance was recorded in untrained rats at 90 and 180 days by an acute exhaustive swimming test (exercise group-Ex). At day 90, BRO offspring showed higher visceral fat mass, higher plasma thiobarbituric acid reactive substances, lower total antioxidant capacity, higher liver glycogen, lower glycemia, and normal insulinemia. Although thyroid hormones (TH) levels were unchanged, mitochondrial glycerol phosphate dehydrogenase (mGPD) activity was lower in muscle and in brown adipose tissue (BAT). At this age, BRO-Ex offspring showed higher exercise capacity, lower blood lactate, higher serum T3, and higher muscle and BAT mGPD activities. At day 180, BRO offspring showed central obesity, hypothyroidism, insulin resistance, and lower EDL (extensor digitorum longus) muscle glycogen with unaltered plasma oxidative stress markers. This group showed no alteration of exercise capacity or blood lactate. After exercise, EDL and liver glycogen were lower, while T3 levels, BAT and muscle mGPD activities were normalized. Liver glycogen seem to be related with higher exercise capacity in younger BRO offspring, while the loss of this temporary advantage maybe related to the hypothyroidism and insulin resistance developed with age.

Postnatal low protein diet programs leptin signaling in the hypothalamic-pituitary-thyroid axis and pituitary TSH response to leptin in adult male rats

Maternal protein restriction (PR) during lactation programs a lower body weight, hyperthyroidism, leptin resistance, and over-expression of leptin receptor in the pituitary gland at adulthood. Because leptin regulates energy homeo-stasis and the hypothalamus-pituitary-thyroid (HPT) axis, we evaluated adipocyte morphology, the leptin signaling pathway in the HPT axis and the in vitro thyrotropin (TSH) response to leptin in adult progeny in this model. At birth, dams were separated in control diet with 23% protein or PR diet with 8% protein. After weaning, offspring received a normal diet. Adult PR offspring showed lower adipocytes area, higher leptin:visceral fat ratio, lower hypothalamic signal transducer and activator of transcription 3 (STAT3), higher pituitary leptin receptor (Ob-R) and lower thyroid janus tyrosine kinase 2 (JAK2) contents. Regarding the in vitro study, 10(-7)  M leptin stimulated TSH secretion in C offspring at 30 min, but had no effect in PR offspring. At 120 min, 10(-7)  M leptin decreased TSH secretion in C offspring and increased in PR offspring. Maternal nutritional status during lactation programs for adipocyte atrophy, higher relative leptin secretion and changes in the downstream leptin signaling in the HPT axis and the TSH response to leptin, suggesting a role for leptin in the development of the HPT axis and helping to explain thyroid dysfunction and leptin resistance in this programming model. Because leptin stimulates thyroid function, it is unlikely that these alterations were responsible for the increased in serum T4 and T3. Therefore, neonatal PR programs a hyperthyroidism, lower adipogenesis, and impairment of leptin action.

Maternal prolactin inhibition during lactation is associated to renal dysfunction in their adult rat offspring

The renal function of rats whose mothers had hypoprolactinemia at the end of lactation was evaluated during development. Lactating Wistar rats were treated with bromocriptine (BRO, 1 mg twice a day, s.c.) or saline on days 19, 20, and 21 of lactation, and their male offspring were followed from weaning until 180 days old. 1 rat from each of the 12 litters/group was evaluated at 2 time points (90 and 180 days). Body and kidney weights, sodium, potassium, and creatinine were measured. Values were considered significant when p<0.05. Adult BRO-treated offspring presented higher body weight (+10%), lower relative renal weight at 90 and 180 days (-9.2% and -15.7%, respectively), glomerulosclerosis, and peritubular fibrosis. At 90 and 180 days, creatinine clearance was lower (-32% and -30%, respectively), whereas serum potassium was higher (+19% and +29%, respectively), but there were no changes in serum sodium. At 180 days, higher proteinuria (+36%) and serum creatinine levels (+20%) were detected. Our data suggest that prolactin inhibition during late lactation programs renal function damage in adult offspring that develops gradually, first affecting the creatinine clearance and potassium serum levels with further development of hyperproteinuria and higher serum creatinine, without affecting sodium. Thus, precocious weaning programs some components of the metabolic syndrome, which can be a risk factor for further development of kidney disease.

Leptin-programmed rats respond to cold exposure changing hypothalamic leptin receptor and thyroid function differently from cold-exposed controls

We showed that neonatal leptin treatment programmes for hyperleptinemia and central leptin resistance both at 30days-old and adulthood, while programmes for lower serum T3 at 30days-old, but higher thyroid hormones (TH) at adulthood. As in these animals, acute cold at 30days-old normalized leptinemia and restored the expression of hypothalamic leptin receptor (OBR), here we evaluate the effect of cold exposure on the thyroid function and OBR in adult rats programmed by neonatal hyperleptinemia. Pups were divided into 2 groups: Lep-injected with leptin (8μg/100g/BW, sc) for the first 10days of lactation, and C-injected with saline. At 150days, both groups were subdivided into: LepC and CC, which were exposed to 8°C for 12h. Serum leptin, TH, TSH, liver type I and brown adipose tissue (BAT) type II deiodinases (D1 and D2) activities, liver mitochondrial alpha-glycerol-3-phosphate dehydrogenase (mGPD) activity and adrenal catecholamine content were measured. Hypothalamic and thyroid OBR protein contents were evaluated. Differences were significant when p<0.05. Lep group had hyperleptinemia (+19%), higher T4 (+20%) and T3 (+30%) with lower TSH (-55%), higher liver D1 (1.4 fold-increase), lower BAT D2 (-44%) and liver mGPD activities (-55%), higher adrenal catecholamines (+44%), lower hypothalamic OBR (-51%) and normal thyroid OBR. Cold exposure normalized leptinemia, D1, mGPD, catecholamine and hypothalamic OBR. However, cold exposure further increased TH and decreased D2. Thus, cold exposure normalizes most of the changes programmed by neonatal hyperleptinemia, at the expense of worsening the hyperthyroidism and BAT thermogenesis.

Blocking leptin action one week after weaning reverts most of the programming caused by neonatal hyperleptinemia in the adult rat

Hyperleptinemia during lactation programs for higher serum leptin in 30-day-old and adult rats, associated with metabolic changes. Here we evaluated the inhibition of serum leptin at 29 and 30 days on the metabolic phenotype of rats programmed with leptin during lactation. Pups from Wistar rats were saline-injected or leptin-injected from postnatal day 1 to day 10. At 29 and 30 days old, animals were injected with anti-leptin antibody (LA and CA) or saline (LS and CS). In adult animals, higher visceral (+53%) and total fat mass (+33%), hyperleptinemia (+67%), hypertriglyceridemia (+47%), and hypoadiponectinemia (-44%) observed in LS group compared to CS were prevented by immunoneutralization of leptin, since LA group had those parameters values similar to CS group. However, immunoblockade of leptin in normal animals led to the same metabolic changes seen in leptin-treated animals, in addition to lower serum adiponectin (-77% vs. CS) and higher insulin resistance index (+37%). Liver sirtuin1 (SIRT1) was higher (+41%) only in LA group, suggesting a role for SIRT1 in the prevention of leptin programming. Hypothalamic OBR was lower and SOCS3 higher in LS group and these changes were normalized in LA group. In conclusion, blocking leptin action one week after weaning seems to revert most of the alterations observed in rats programmed by neonatal hyperleptinemia. Higher liver SIRT1 expression may be one of the mechanisms involved, leading to a better glucose and lipid metabolism. Our data suggest that the lack or the excess of leptin programs an adverse metabolic phenotype in adulthood.

Resveratrol reduces lipid peroxidation and increases sirtuin 1 expression in adult animals programmed by neonatal protein restriction

Resveratrol (Res) has been associated with protective effects against oxidative stress. This study evaluated the effect of Res over lipid peroxidation, antioxidant defense, hepatic sirtuin 1 (SIRT1), which up-regulates antioxidant enzymes, and copper/zinc superoxide dismutase (Cu/Zn SOD) in adult offspring whose mothers were protein restricted during lactation. Lactating Wistar rats were divided into control (C) group, which were fed a normal diet (23% protein), and low-protein and high-carbohydrate (LPHC) group, which were fed a diet containing 8% protein. After weaning (21 days), C and LPHC offspring were fed a normal diet until they were 180 days old. At the 160th day, animals were separated into four groups as follows: control, control+Res, LPHC, and LPHC+Res. Resveratrol was given for 20 days (30  mg/kg per day by gavage). LPHC animals showed a higher total antioxidant capacity (TAC) without change in lipid peroxidation and SIRT1 expression. The treatment with Res increased TAC only in the control group without effect on lipid peroxidation and SIRT1. LPHC animals treated with Res had lower lipid peroxidation and higher protein and mRNA expression of SIRT1 without any further increase in TAC. No significant difference in liver Cu/Zn SOD expression was observed among the groups. In conclusion, maternal protein restriction during lactation programs the offspring for a higher antioxidant capacity, and these animals seem to respond to Res treatment with a lower lipid peroxidation and higher hepatic SIRT1 expression that we did not observe in the Res-treated controls. It is probable that the protective effect can be attributed to Res activating SIRT1, only in the LPHC-programmed group.

Prolactin inhibition at mid-lactation influences adiposity and thyroid function in adult rats

Maternal hypoprolactinemia at the end of lactation (a precocious weaning model) increases milk leptin transfer and results in overweight, leptin resistance, and secondary hypothyroidism at adulthood. We studied the effects of prolactin (PRL) inhibition during mid-lactation (a partial malnutrition model) on milk leptin transfer, leptinemia, body composition, and thyroid function. Lactating rats were treated with bromocryptine (BRO, 1 mg/twice daily) or saline on days 7, 8, and 9 of lactation. Offspring were sacrificed 10, 21, and 90 days after birth. After treatment, BRO-treated dams showed hypoprolactinemia and hyperleptinemia, and produced less milk with lower levels of lactose and higher milk triglycerides. Milk leptin levels were lower at weaning. Offspring of BRO-treated dams had lower body weight and length as well as less visceral fat during lactation and adulthood. Total fat was also lower at weaning and adult life, whereas total protein was higher at 90 days-old. BRO offspring presented lower serum T4 and TSH at 10 days-old and weaning, respectively. When adults, these rats exhibited hypoleptinemia, lower levels of thyroid hormones, and higher TSH. Early inhibition of PRL therefore leads to offspring malnutrition and affects subsequent growth. Also, inhibition of PRL during lactation predisposes offspring to hypothyroidism; however, when the inhibition occurs during late lactation, the hypothyroidism is secondary, whereas when it is restricted to mid-lactation, the thyroid hypofunction is primary. The programming effect of milk suppression thus depends on the developmental stage of offspring.

Neonatal nicotine exposure alters leptin signaling in the hypothalamus-pituitary-thyroid axis in the late postnatal period and adulthood in rats

AIMS

Postnatal nicotine exposure causes precocious primary hypothyroidism and programs for overweight, hyperleptinemia and secondary hypothyroidism in adulthood. As leptin and thyroid hormones share the ability to increase energy expenditure, we studied the effects of maternal nicotine exposure during lactation on the leptin signaling in the hypothalamus-pituitary-thyroid axis of suckling and adult offspring.

MAIN METHODS

Two days after delivery, osmotic minipumps were implanted in lactating rats, and nicotine (NIC, 6 mg/kg/day s.c.) or saline (C) was administered for 14days. Offspring were killed at 15 and 180 days-old. Proteins belonging to leptin signaling were analyzed by Western blot. Significant differences had p<0.05.

KEY FINDINGS

In the hypothalamus, NIC offspring showed higher OB-R and pSTAT-3 content (+58%,+1.34x) at 15 days, and lower OB-R, JAK-2 and pSTAT-3 (-61%, -42%, -56%) at 180 days. In the pituitary gland, NIC offspring showed lower JAK-2 content (-52%) at 15 days, but no differences in adulthood. In the thyroid gland, the NIC group presented lower OB-R, JAK-2 and STAT-3 (-44%, -50%, -47%) and higher pSTAT-3 expression (+80%) at 15 days. At 180 days-old, NIC offspring presented higher thyroid OB-R (+1.54x) and lower pSTAT-3 content (-34%).

SIGNIFICANCE

Neonatal primary hypothyroidism induced by maternal nicotine exposure during lactation may be partially explained by decreased leptin signaling in the thyroid, though the early stimulation of the central leptin pathway did not prevent the thyroid dysfunction. Long-term effects of postnatal nicotine exposure on leptin signaling in the hypothalamus and thyroid appear to involve central and peripheral leptin resistance in adulthood.

Leptin treatment during lactation programs leptin synthesis, intermediate metabolism, and liver microsteatosis in adult rats

Epidemiological and experimental studies have associated development of metabolic syndrome with stressful events (nutritional, hormonal, or environmental) in early life. This phenomenon is known as programing and changes in adipokines levels in early life, especially leptin, seem to be involved with its development. We have shown that neonatal hyperleptinemia on lactation programs for leptin resistance, hyperthyroidism, and higher corticosterone and catecholamines levels with cardiovascular consequences. In the present study, we evaluated the effect of hyperleptinemia during lactation on the glucose and lipid metabolism and liver morphology of adult rats, which were saline or leptin-treated (8 microg/100 g of body weight) daily, for the first 10 days of life. Leptin group had lower body mass during treatment, but higher body mass and hyperleptinemia at adulthood, without difference in fat mass. We showed that the probable source of hyperleptinemia is the higher leptin content in the subcutaneous adipose tissue. The programed rats showed hyperinsulinemia and hypoadiponectinemia with higher expression of the hypothalamic Suppressor of Cytokine Signaling 3 (SOCS3), suggesting insulin resistance. Besides, they presented higher liver glycogen and hypertriglyceridemia. We also observed liver microsteatosis in the leptin-programed adult rats. Our data show that neonatal hyperleptinemia alters glucose metabolism, which seems to be partially compensated by the hyperinsulinemia. However, changes in the lipid metabolism are not compensated. It is probable that these changes induced by neonatal hyperleptinemia result from a selective tissue specific resistance both to insulin and leptin at adulthood, and the increase of SOCS3 may play an important role in this process.

Programming of rat adrenal medulla by neonatal hyperleptinemia: adrenal morphology, catecholamine secretion, and leptin signaling pathway

Leptin serum concentration in early life is an important factor for adequate future development of the offspring. Previously, we demonstrated that hyperleptinemia on lactation programmed for hyperleptinemia, central leptin resistance with lower expression of the long form of leptin receptor at hypothalamus, and higher medullary catecholamine levels with cardiovascular consequences at adulthood. The central objective of this study was to determine the direct effect of leptin on adrenal medullary function of adult rats that were leptin treated during lactation. Adrenal morphology was also accessed. Recombinant murine leptin was injected in the pups during the first 10 days of life (group L, leptin-programmed) or at adulthood during 6 days (group LC). The controls of both experiments received saline (groups C and CC). Both treatments resulted in hyperleptinemia at 150 days old (+78% and 2-fold increase, respectively; P < 0.05). Programmed animals showed hypertrophy of adrenal and higher adrenal catecholamine content at 150 days old (3-fold increase, P < 0.05), and no changes were observed in the LC group. However, LC rats had lower adrenal content of tyrosine hydroxylase (-17%, P < 0.05). Leptin-programmed rats had a lower response to leptin in vitro stimulation (-22%, P < 0.05) and lower expression of key proteins of the leptin signaling pathway, leptin receptor and janus tyrosine kinase 2 in the medullas (-61% and -29%, respectively, P < 0.05). However, they presented higher expression of phosphorylated signal transducer and activator of transcription 3 (+2-fold, P < 0.05). Leptin treatment at adulthood did not affect these parameters. The higher catecholamine synthesis and secretion in the leptin-programmed rats observed in our previous study does not seem to be a consequence of the direct effect of leptin on the medullas. We suggest that the hyperleptinemia of the programmed animals increases adrenal medullary function through sympathetic nervous system activation. In conclusion, high leptin levels on lactation program the activity of the sympathoadrenal system at adulthood that may contribute to the development of adult chronic diseases such as hypertension.

Nicotine exposure affects mother's and pup's nutritional, biochemical, and hormonal profiles during lactation in rats

We have shown that maternal nicotine exposure during lactation has long-lasting effects on body adiposity and hormonal status of rat offspring. Here, we studied the nutritional and hormonal profiles in this experimental model. Two days after birth, osmotic minipumps were implanted in lactating rats divided into two groups: NIC - continuous s.c. infusions of nicotine (6 mg/kg per day) for 14 days and C - saline. Dams and pups were killed at 15 and 21 days of lactation. Body weight and food intake were evaluated. Milk, blood, visceral fat, carcass, and adrenal gland were collected. All the significant data were P<0.05. At the end of nicotine exposure (15 days), dams presented higher milk production, hyperprolactinemia, and higher serum high-density lipoprotein cholesterol (HDL-C). Milk from NIC dams had higher lactose concentration and energy content. After nicotine withdrawal (21 days), dams showed lower food intake and hyperleptinemia. The 15-day-old NIC pups presented higher total body fat, higher HDL-C, serum leptin, serum corticosterone, and adrenal catecholamine content, but lower tyrosine hydroxylase protein levels. The 21-day-old NIC pups had higher body protein content and serum globulin. Thus, maternal nicotine exposure during lactation results in important changes in nutritional, biochemical, and hormonal parameters in dams and offspring. The pattern of these effects is clearly distinct when comparing the nicotine-exposed group to the withdrawal group, which could be important for the programming effects observed previously.

Temporal evaluation of body composition, glucose homeostasis and lipid profile of male rats programmed by maternal protein restriction during lactation

Neonatal protein restriction causes lower body weight and hormonal dysfunctions in 6 months-old rats. In this model, we studied the body composition, glycogen content, serum lipid, serum protein, and hormones related to glucose homeostasis in the offspring during development. At birth, lactating rats were divided into: control dams - fed a normal diet (23% protein) and protein restricted dams - fed a diet with 8% protein. After weaning, pups received normal diet. Offspring were killed at 21, 90, and 180 days-old. Protein restricted offspring showed lower visceral fat (90th day: 14%; 180th day: 19%) and lower total fat (90th day: 16%; 180th day: 14%) that explain their lower body weight. They presented lower glycemia (180th day: 17%), lower insulinemia (21st day: 63%; 180th day: 24%), higher adiponectinemia (21st day: 169%), higher liver glycogen (21st day: 104%), and higher muscle glycogen (180th day: 106%), suggesting a higher insulin sensitivity. The higher serum corticosterone (50%), higher adrenal total catecholamines content (98%) as well as in vitro catecholamine secretion (26%) of adult protein restricted offspring, suggest a programming stimulatory effect upon adrenal gland. They also presented several biochemical changes, such as lower serum total protein, albumin and globulin (21st day: 17, 21, 12%, respectively), higher LDL-c (21st day: 69%), lower triglycerides (21st day: 42%; 90th day: 39%), and lower total cholesterol (180th day: 16%). Thus, maternal protein restriction during lactation induces an energy-protein malnutrition, characterized by an impairment of the pup's protein anabolism and, after weaning, the lower adiposity suggests lower lipogenesis and higher lipolytic activity, probably caused by catecholamine and glucocorticoid action.

Early maternal hyperleptinemia programs adipogenic phenotype in rats

We have previously reported on the treatment of maternal rats with leptin during the three last days of lactation program for overweight and leptin hypothalamic resistance in the offspring. Here we have investigated whether treatment of maternal rats with leptin in the first ten days of lactation can program metabolic dysfunctions on the adult offspring. Lactating rats were divided into 2 groups: rats (LEP) injected with recombinant mouse leptin (8 microg/100 g/body weight, daily during the first 10 days of lactation) and control group (C) that received the same volume of saline. After weaning, all pups had free access to normal diet, their body weight and food intake were monitored at 4 days interval until 180 days, when they were tested for food intake and response to either leptin (0.5 mg/kg body weight, ip) or saline. The offspring from leptin-treated mothers gained more weight from day 69 onward and had higher food intake from day 145 onward, higher amount of visceral adipose tissue (57%), higher serum glucose (10%), and higher serum leptin (135%) at 180 days compared to control group. The food intake was not reduced as expected after acute injection of leptin in these animals, suggesting resistance to the anorexigenic effect of leptin. We conclude that maternal hyperleptinemia in early lactation programed higher food intake, body weight gain due to higher total and visceral fat mass, and resistance to anorexigenic effect of leptin in the adult offspring even when this hyperleptinemia occurred at the beginning of lactation.

Maternal prolactin inhibition during lactation programs for metabolic syndrome in adult progeny

Neonatal malnutrition is associated with metabolic syndrome in adulthood. Maternal hypoprolactinaemia at the end of lactation (a precocious weaning model) caused obesity, leptin resistance and hypothyroidism in adult offspring, suggesting an association of prolactin (PRL) and programming of metabolic dysfunctions. Metabolic syndrome pathogenesis is still unclear, but abdominal obesity, higher triglycerides, lower high-density lipoprotein (HDL-c) and insulin resistance have been proposed to be important factors involved. We studied the consequences of maternal hypoprolactinaemia during lactation on parameters associated with metabolic syndrome. Lactating Wistar rats were treated with bromocriptine (BRO, 1 mg twice a day) or saline on days 19, 20 and 21 of lactation and their offspring were followed from weaning until 180 days old. Adult BRO offspring had higher body weight (+10%, P < 0.05), total body fat (+41%, P < 0.05), visceral fat (+20%, P < 0.05), subcutaneous fat (+3 times, P < 0.05) and total body protein (+24%, P < 0.05). BRO group presented hyperglycaemia (+16%, P < 0.05), lower muscle glycogen (51%, P < 0.05), higher cholesterol (+30%, P < 0.05), higher low-density lipoprotein (LDL-c) (+1.5 times, P < 0.05), higher triglycerides (+49%, P < 0.05), lower HDL-c (28%, P < 0.05), hyperleptinaemia (+2.9 times, P < 0.05), hypoadiponectinaemia (16%, P < 0.05) and hypoprolactinaemia (54%, P < 0.05) as well as higher insulin resistance index (+24%, P < 0.05). Regarding adrenal function, BRO rats showed hypercorticosteronaemia (+46%, P < 0.05) and higher total catecholamine (+37%, P < 0.05). In the hypothalamus, no change was observed in protein expression of the leptin signalling pathway. Thus, neonatal malnutrition induced by maternal PRL inhibition during late lactation programs for obesity, dyslipidaemia and insulin resistance in adult offspring increasing the risk for metabolic syndrome development.

Short- and long-term effects of maternal nicotine exposure during lactation on body adiposity, lipid profile, and thyroid function of rat offspring

Epidemiological studies show a higher prevalence of obesity in children from smoking mothers and smoking may affect human thyroid function. To evaluate the mechanism of smoking as an imprinting factor for these dysfunctions, we evaluated the programming effects of maternal nicotine (NIC) exposure during lactation. Two days after birth, osmotic minipumps were implanted in lactating rats, divided into: NIC (6 mg/kg per day s.c.) for 14 days; Control - saline. All the significant data were P<0.05 or less. Body weight was increased from 165 days old onwards in NIC offspring. Both during exposure (at 15 days old) and in adulthood (180 days old), NIC group showed higher total fat (27 and 33%). In addition, NIC offspring presented increased visceral fat and total body protein. Lipid profile was not changed in adulthood. Leptinemia was higher at 15 and 180 days old (36 and 113%), with no changes in food intake. Concerning the thyroid status, the 15-days-old NIC offspring showed lower serum-free tri-iodothyronine (FT(3)) and thyroxine (FT(4)) with higher TSH. The 180-days-old NIC offspring exhibited lower TSH, FT(3), and FT(4)). In both periods, liver type 1 deiodinase was lower (26 and 55%). We evidenced that NIC imprints a neonatal thyroid dysfunction and programs for a higher adiposity, hyperleptinemia, and secondary hypothyroidism in adulthood. Our study identifies lactation as a critical period to NIC programming for obesity, with hypothyroidism being a possible contributing factor.

Postnatal early overnutrition changes the leptin signalling pathway in the hypothalamic-pituitary-thyroid axis of young and adult rats

Postnatal early overnutrition (EO) is a risk factor for obesity in adult life. Rats raised in a small litter can develop hyperinsulinaemia, hyperphagia, hyperleptinaemia and hypertension as adults. Since leptin regulates the hypothalamic-pituitary-thyroid axis and the metabolism of thyroid hormones, we studied the leptin signalling pathway in pituitary and thyroid glands of the postnatal EO model. To induce EO, at the third day of lactation the litter size was reduced to three pups per litter (SL group). In control litters (NL group), the litter size was adjusted to 10 pups per litter. Body weight and food intake were monitored. Rat offspring were killed at 21 (weaning) and 180 days old (adulthood). Plasma thyroid hormones, thyroid-stimulating hormone (TSH) and leptin were measured by radioimmunoassay. Proteins of the leptin signalling pathway were analysed by Western blotting. Body weight of offspring in the SL group was higher from the seventh day of lactation (+33%, P < 0.05) until 180 days old (+18%, P < 0.05). Offspring in the SL group showed higher visceral fat mass at 21 and 180 days old (+176 and +52%, respectively, P < 0.05), but plasma leptin was higher only at 21 days (+88%, P < 0.05). The SL offspring showed higher plasma TSH, 3,5,3'-triiodothronine (T(3)) and thyroxine (T(4)) at 21 days (+60, +91 and +68%, respectively, P < 0.05), while the opposite was observed at 180 days regarding thyroid hormones (T(3), -10%; and T(4), -30%, P < 0.05), with no difference in TSH levels. In hypothalamus, no change was observed in the leptin signalling pathway at 21 days. However, lower janus thyrosine kinase 2 (JAK2) and phosphorilated-signal transducer and activator of transcription-3 (p-STAT3) content were detected in adulthood. In pituitary, the SL group presented higher leptin receptors (Ob-R), JAK2 and p-STAT3 content at 21 days and lower JAK2 and STAT3 content at 180 days old. In contrast, in thyroid, the Ob-R expression was lower in young SL rats, while the adult SL group presented higher Ob-R and JAK2 content. We showed that postnatal EO induces short- and long-term effects upon the hypothalamic-pituitary-thyroid axis. These changes may help to explain future development of metabolic and endocrine dysfunctions, such as metabolic syndrome and hypothyroidism.

Prolactin inhibition at the end of lactation programs for a central hypothyroidism in adult rat

Malnutrition during lactation is associated with hypoprolactinemia and failure in milk production. Adult rats whose mothers were malnourished presented higher body weight and serum tri-iodothyronine (T(3)). Maternal hypoprolactinemia at the end of lactation caused higher body weight in adult life, suggesting an association between maternal prolactin (PRL) level and programming of the offspring's adult body weight. Here, we studied the consequences of the maternal PRL inhibition at the end of lactation by bromocriptine (BRO) injection, a dopaminergic agonist, upon serum TSH and thyroid hormones, thyroid iodide uptake, liver mitochondrial alpha-glycerophosphate dehydrogenase (mGPD), liver and pituitary de-iodinase activities (D1 and/or D2), and in vitro post-TRH TSH release in the adult offspring. Wistar lactating rats were divided into BRO - injected with 1 mg/twice a day, daily for the last 3 days of lactation, and C - control, saline-injected with the same frequency. At 180 days of age, the offspring were injected with (125)I i.p. and after 2 h, they were killed. Adult animals whose mothers were treated with BRO at the end of lactation presented lower serum TSH (-51%), T(3) (-23%), and thyroxine (-21%), lower thyroid (125)I uptake (-41%), liver mGPD (-55%), and pituitary D2 (-51%) activities, without changes in the in vitro post-TRH TSH release. We show that maternal PRL suppression at the end of lactation programs a hypometabolic state in adulthood, in part due to a thyroid hypofunction, caused by a central hypothyroidism, probably due to decreased TRH secretion. We suggest that PRL during lactation can regulate the hypothalamus-pituitary-thyroid axis and programs its function.

Maximum acute exercise tolerance in hyperthyroid and hypothyroid rats subjected to forced swimming

Thyroid dysfunction can compromise physical capacity. Here, we analyze the effects of hyperthyroidism and hypothyroidism on maximum swim time in rats subjected to acute forced swimming, as an indicator of anaerobic capacity. Animals were forced to swim against a load (5% of body weight) attached to the tail and were killed 48 hours after the last test. Hyperthyroid rats were treated with thyroxine (50 mug/100 g body weight, i. p. for 7 days). The hypothyroid group received 0.03% methimazole in the drinking water for 4 weeks. Thyroid state was confirmed by alterations in serum thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and liver mitochondrial glycerol phosphate dehydrogenase (mGPD) activity. Hyperthyroid rats presented significantly lower visceral fat mass (VFM) and higher food intake (p<0.05) with unchanged body weight. Maximum swim time (MST), glycogen content (skeletal muscle and liver), and leptin levels were lower while corticosterone was higher (p<0.05). In hypothyroid rats body weight was lower (p<0.05), without changes in VFM. Tested at 7-day intervals, MST was lower for tests 2, 3, and 4 (p<0.05). Muscle glycogen was higher in extensor digitorum longus (EDL) and soleus (p<0.05), without changes in liver. Serum corticosterone was lower, while leptin was higher (p<0.05). These results suggest that in hyperthyroid and hypothyroid rats, thyroid hormones together with corticosterone and/or leptin may impair exercise capacity differently through its known effects on glycogen metabolism.

Thyroid function and body weight programming by neonatal hyperthyroidism in rats - the role of leptin and deiodinase activities

Several authors have shown that secondary hypothyroidism was programed by neonatal thyroxine (T4) treatment. However, the associated changes of body weight (BW) were less studied, especially those related to the body fat proportion. Here, we have evaluated the effect of neonatal thyroxine treatment on BW, fat proportion, serum leptin, and thyroid function of 60-day-old rats. Wistar rats were treated with thyroxine (50 microg/100 g BW, ip) (T) or saline (S), during the first 10 days of life. BW, nose-rump length (NRL), and food consumption were monitored for 60 days, when the animals were sacrificed. Thyroid function was evaluated by thyroid radioiodine uptake (RAIU), serum T3, T4, TSH, and liver mitochondrial alpha-glycerophosphate dehydrogenase (mGPD) and type 1 and 2 deiodinases (D1 and D2) activities, which are thyroid hormone-dependent enzymes. T animals showed lower food intake, BW and NRL, but higher total fat mass (+33%) and serum leptin (+46%). They also showed lower serum T3 (-23%), T4 (-32%), TSH (-36%), RAIU (-29%) and mGPD activity (-22%). Hypothalamic and pituitary D2 activities were higher (+24% and 1.4 fold, respectively), while brown adipose tissue (BAT) D2 and skeletal muscle D1 activities were lower (-30% and -62%, respectively). Thus, neonatal hyperthyroidism programs for a higher fat proportion and hyperleptinemia, which can explain the lower food intake. The TH-dependent enzymes activities changed accordingly, except for the decrease in BAT D2, which may be due the role played by the hyperleptinemia. Finally, the decrease in peripheral deiodination may contribute to a lower me-tabolic rate that may increase the adiposity.

Neonatal programming of neuroimmunomodulation--role of adipocytokines and neuropeptides

Programming is an epigenetic phenomenon by which nutrition, environment and stress acting in a critical period earlier in life change the organism's development. This process was evolutionarily selected as an adaptive tool for the survival of organisms living in nutritionally deficient areas and submitted to stressful conditions. Thus, perinatal malnutrition turns on different genes that provide the organism with a thrifty phenotype. In conditions of abundant supply of nutrients, those programmed organisms can be at risk of developing metabolic diseases (obesity, dyslipidemia, diabetes and hypertension). How nutrition or neonatal stress can program the immune system is less well known. Here, we discuss some of the hormonal and metabolic changes that occur in mothers and neonates and how those factors can imprint hormonal or metabolic changes that program neuroimmunomodulatory effects. Some of these changes involve thyroid hormones, leptin, insulin, glucocorticoids and prolactin as potential imprinting factors. Most of them can be transferred through the milk and may change with malnutrition or stress. We discuss the programming effects of these hormones upon body weight, body composition, insulin action, thyroid, adrenal and immune and inflammatory responses, with special emphasis on leptin, a cytokine that seems to play a central role in these events.

Chronic leptin treatment inhibits liver mitochondrial alpha-glycerol-beta-phosphate dehydrogenase in euthyroid rats

Leptin modulates the hypothalamus-pituitary-thyroid axis and peripheral metabolism of thyroid hormones (THs). We have studied the effect of acute and chronic leptin treatment upon liver mitochondrial glycerol phosphate dehydrogenase activity (mGPD), whose expression and activity are TH dependent. We performed 2 experiments: 1) acute leptin treatment - LepA: adult rats received a single leptin injection (8 microg/100 g BW); 2) chronic leptin treatment - LepC: adult rats received leptin (8 microg/100 g BW) daily, for 6 days. In both experiments, control groups were saline-treated. All rats were sacrificed 2 hours after the last dose. Liver mGPD activity was determined by colorimetric method. Liver D1 activity was measured by the release of (125)I from (125)I-rT3. Serum hormones were measured by RIA. LepA rats showed higher serum thyroid stimulating hormone (TSH) (+ 64%, p<0.05), free T4 (+ 34%, p<0.05), free T3 (+ 64%, p<0.05), and liver D1 activity (+ 85%, p<0.05), but no change in mGPD activity. Since THs increase mGPD activity, the unchanged level in the acute experiment is suggestive of an inhibitory role of leptin. LepC rats presented lower mGPD activity (-1.7-fold, p<0.05) and higher liver D1 activity (+ 32%, p<0.05), but no alteration in serum TSH and free THs. Our results show that leptin downregulates mGPD activity, mainly when hyperleptinemia is chronic.

Cold exposure restores the decrease in leptin receptors (OB-Rb) caused by neonatal leptin treatment in 30-day-old rats

We had previously shown that neonatal leptin treatment programs thyroid function in adulthood. As both thyroid hormones (TH) and leptin increased thermogenesis, it was interesting to evaluate the effect of cold exposure on the thyroid function of neonate rats treated with leptin. Pups were divided into two groups: Lep, injected with leptin (8 mug/100 g/BW, s.c.) for the first 10 days of lactation and control (C), injected with saline. When they were 30 days old, the groups were subdivided into two subgroups: LepC and CC, which were exposed to 8 degrees C for 12 h and compared with C and Lep groups, maintained at 25 +/- 1 degrees C. Serum leptin, TH, and TSH were measured by RIA. Type I liver deiodinase (D1) and mitochondrial alpha-glycerol-3-phosphate dehydrogenase (mGPD) activities were assayed by the release of (125)I from (125)I-reverse and colorimetric method respectively. Leptin receptor (OB-Rb) was evaluated by western blot. Lep group had hyperleptinemia (+22%) and lower free tri-iodothyronine (FT(3); -33%). Cold exposure increased TH both in LepC and CC groups compared with respective controls free thyroxine (FT(4):+63 and +39%; FT(3):+75 and +40%). Liver D1 activity was lower in Lep (-22%) and increased with cold exposure (LepC +51% and CC +22%). The mGPD activity was lower in Lep (-34%) and increased (fourfold) when this group is cold exposed. Hypothalamic and thyroidal OB-Rb receptors were lower in Lep group (-47 and -36% respectively) and they were restored to normal levels after cold exposure. Leptin-programmed rats had higher TH response after cold exposure. OB-Rb had a fast response to cold exposure normalizing the lower levels observed in the leptin-programmed animals and may contribute to the higher TH cold responses.

Maternal low-protein diet during lactation programmes body composition and glucose homeostasis in the adult rat offspring

Previously we have reported that maternal malnutrition during lactation programmes body weight and thyroid function in the adult offspring. In the present study we evaluated the effect of maternal protein restriction during lactation upon body composition and hormones related to glucose homeostasis in adult rats. During lactation, Wistar lactating rats and their pups were divided into two experimental groups: control (fed a normal diet; 23 % protein) and protein-restricted (PR; fed a diet containing 8 % protein). At weaning, offspring received a normal diet until they were 180 d old. Body weight (BW) and food intake were monitored. Serum, adrenal glands, visceral fat mass (VFM) and carcasses were collected. PR rats showed lower BW ( − 13 %;P < 0·05), VFM ( − 33 %;P < 0·05), total body fat ( − 33 %;P < 0·05), serum glucose ( − 7 %;P < 0·05), serum insulin ( − 26 %,P < 0·05), homeostasis model assessment index ( − 20 %), but higher total adrenal catecholamine content (+90 %;P < 0·05) and serum corticosterone concentration (+51 %;P < 0·05). No change was observed in food intake, protein mass or total body water. The lower BW of PR rats is due to a reduction of white fat tissue, probably caused by an increase in lipolysis or impairment of lipogenesis; both effects could be related to higher catecholaminergic status, as well as to hypoinsulinaemia. To conclude, changes in key hormones which control intermediary metabolism are programmed by maternal protein restriction during lactation, resulting in BW alterations in adult rats.

Acute and chronic leptin effect upon in vivo and in vitro rat thyroid iodide uptake

Leptin has stimulatory effects on the hypothalamic-pituitary-thyroid axis and on deiodinases activities. Here, we evaluated the effect of leptin injection upon in vivo and in vitro thyroid 125I uptake (RAIU). We designed two experiments: acute leptin (LepA) with a single dose of leptin (8 microg/100 g BW/sc), and chronic leptin (LepC), injected with the same dose of LepA, once a day, for 6 days. In parallel, control groups were saline-injected. For in vivo study, part of the animals were injected with 125I (3700 Bq) and killed after 15 or 120 min. In vivo thyroid RAIU was not changed in LepA animals. However, LepC animals showed higher in vivo thyroid RAIU (15 min:+130% and 120 min:+72%; p<0.05). For in vitro study, the other animals were killed and their thyroids were incubated with 125I. Thyroids explants from LepA and LepC groups presented lower thyroid 125I content (-32% and -29% p<0.05, respectively). The amount of our data suggest that, in vitro, leptin causes a direct inhibition of the rat thyroid RAIU, but in vivo, the effect of leptin was different according to the treatment period, which indicates that other indirect mechanisms are involved in the in vivo leptin chronic stimulation of the thyroid gland.

Maternal leptin treatment during lactation programs the thyroid function of adult rats

Recently, we showed that both maternal malnutrition during lactation and leptin treatment during the neonatal period program thyroid function. In this study we evaluate whether maternal leptin treatment during lactation programs thyroid function of the offspring in the adulthood. The dams were divided into 2 groups: Lep-daily sc single injected with 8 microg/100 g of body weight with recombinant rat leptin during the last 3 days of lactation and control group (C) that received the same volume of saline. The 180 day-old animals received a single i.p. injection of (125)I (2.22x10(4) Bq) and they were killed 2 h after the injection. Triiodothyronine (T3), thyroxine (T4), thyrotropin (TSH) and leptin concentrations were measured by radioimmunoassay. The milk of leptin-treated mothers on the last day of treatment had higher leptin (p<0.05) concentration. The pups of the leptin-treated mothers had at 21 days an unchanged T3, T4 and leptin serum concentrations with higher TSH (p<0.05). The offspring of Lep mothers had at 180 days a higher T3 (p<0.05) with normal thyroid (125)I uptake, T4 and TSH serum concentrations compared to the controls. So, the mother's hyperleptinaemia during lactation programs to a higher T3 serum concentration on the offspring, probably by a higher leptin transfer through the milk.

Neonatal leptin treatment programmes leptin hypothalamic resistance and intermediary metabolic parameters in adult rat

We previously showed that neonatal leptin treatment programmes higher body weight and food intake in adult rats. Here we investigate whether leptin treatment during lactation affects the anorectic effect of leptin on adult rats and their hypothalamic leptin receptors (OB-Rb) and whether those changes could have consequences on intermediary metabolism. When the offspring were born, pups were divided into two groups: the Lep group, injected daily with leptin (8μg/100g body weight, subcutaneously) for the first 10d of lactation, and the control group, injected daily with saline. After weaning (day 21), body weight and food intake were monitored until the rats were 150d old. Food intake was higher in the Lep group (approximately 14%,p<0·05) from day 133 onwards, and body weight was higher (approximately 10%,p<0·05) from day 69 onwards, compared with the control group. At 150d of age, the rats were tested for food intake in response to either leptin (05mg/kg body weight intraperitoneally; groups CL and LepL) or saline (groups CSal and LepSal). The CL group showed a decrease in food intake, but no response was observed in the LepL group, suggesting leptin resistance. The Lep group demonstrated a decrease in OB-Rb expression (−40%p<0·05), hyperleptinaemia (+78%,p<0·05), hyperinsulinaemia (+100%,p<0·02), hypertriacylglycerolaemia (+17%,p<0·05) and a higher protein content in the body (+16%,p<0·05) without changes in fat mass and glycaemia. We conclude that neonatal leptin treatment programmes both hyperleptinaemia and hyperinsulinaemia in adulthood, which leads to leptin resistance by reducing the expression of the hypothalamic leptin receptor.

Prolactin inhibition in dams during lactation programs for overweight and leptin resistance in adult offspring

Maternal malnutrition during lactation reduces prolactin (PRL) and milk production, alters milk composition, and programs the body weight of the offspring. Our study aimed to evaluate the long-term effects of maternal hypoprolactinemia at the end of lactation on food ingestion, body weight, amount of retroperitoneal white adipose tissue (RPWAT), leptinemia, and anorectic leptin effect in the adult offspring. Lactating rats were treated with bromocriptine (BRO), a PRL inhibitor, 1 mg twice a day, or saline (C - control) for the last 3 days of lactation. The body weight and food intake were monitored, and after sacrifice at 180 days, the RPWAT was weighted. In a second experiment, the anorectic leptin effect was tested on 180-day-old animals. Adult offspring whose mothers were BRO-treated showed higher body weight (10%), higher amount of RPWAT (2 x 3 times), higher total body fat (+39%), and hyperleptinemia (2 x 9 times) when compared with C, although food intake did not alter. After injection of leptin, the food ingestion at 2, 4 and 6 h was unaffected in BRO animals, confirming a resistance to the anorectic effect of leptin. Since the maternal PRL inhibition during lactation programs, a higher body weight with no alteration of food ingestion, we suggest a hypometabolic state. The leptin anorectic resistance can be due to the hyperleptinemia. We suggest that PRL changes during lactation can regulate body weight during adulthood.

Malnutrition during lactation changes growth hormone mRNA expression in offspring at weaning and in adulthood

Mothers' nutrition during lactation programs growth in their offspring. We studied the contribution of the growth hormone (GH) for this programming, evaluating GH mRNA expression. Lactating dams were grouped as follows: C, control diet with 23% protein; PR, 8% protein-restricted diet; and ER, energy-restricted diet, receiving the control diet in restricted quantities of the PR group's ingestion. Some pups were killed at weaning; the others received the control diet until they were sacrificed as adults. Pituitary GH mRNA was analyzed by Northern blot analysis. At weaning, the ER and PR animals had lower GH mRNA levels (-29% and -18%, respectively) and lower length as well as body weight. Ninety-day-old PR offspring showed a lower body length (-5%), whereas ER offspring showed a higher one (+5%); however, at 180 days, the lengths were not different. Both 90- and 180-day-old animals showed body weight differences against control animals, with PR offspring showing a lower (-10%) and ER offspring showing a higher (+12%) body weight. GH mRNA was higher in ER offspring at 90 and 180 days (+19% and +22%, respectively); it was lower in PR offspring at 90 and 180 days (-19% and -17%, respectively). Thus, we showed a direct relation between GH mRNA expression and length as well as body weight. We suggest that malnutrition during lactation may program GH mRNA expression patterns in adulthood and that these changes could be responsible for differences in growth patterns.

Neonatal hyperleptinaemia programmes adrenal medullary function in adult rats: effects on cardiovascular parameters

Epidemiological studies have shown a strong correlation between stressful events (nutritional, hormonal or environmental) in early life and development of adult diseases such as obesity, diabetes and cardiovascular failure. It is known that gestation and lactation are crucial periods for healthy growth in mammals and that the sympathoadrenal system is markedly influenced by environmental conditions during these periods. We previously demonstrated that neonatal hyperleptinaemia in rats programmes higher body weight, higher food intake and hypothalamic leptin resistance in adulthood. Using this model of programming, we investigated adrenal medullary function and effects on cardiovascular parameters in male rats in adulthood. Leptin treatment during the first 10 days of lactation (8 microg 100 g(-1) day(-1), s.c.) resulted in lower body weight (6.5%, P < 0.05), hyperleptinaemia (10-fold, P < 0.05) and higher catecholamine content in adrenal glands (18.5%, P < 0.05) on the last day of treatment. In adulthood (150 days), the rats presented higher body weight (5%, P < 0.05), adrenal catecholamine content (3-fold, P < 0.05), tyrosine hydroxylase expression (35%, P < 0.05) and basal and caffeine-stimulated catecholamine release (53% and 100%, respectively, P < 0.05). Systolic blood pressure and heart rate were also higher in adult rats (7% and 6%, respectively, P < 0.05). Our results show that hyperleptinaemia in early life increases adrenal medullary function in adulthood and that this may alter cardiovascular parameters. Thus, we suggest that imprinting factors which increase leptin and catecholamine levels during the neonatal period could be involved in development of adult chronic diseases.

Temporal evaluation of the thyroid function of rats programmed by leptin treatment on the neonatal period

Hormones and malnutrition can imprint several changes in the beginning of life that programs homeostatic changes in the adulthood. We analyzed the thyroid function in 21, 30, 60 and 150 days old animals that were injected with leptin on the first 10 days of life, to determine whether this corresponds to a critical period for the establishment of the hormonal imprinting in the programming of the thyroid function. Pups were divided, within 24 hours of birth, into two groups: Lep group, which was injected once daily with 8 microg/100 g B.W. of recombinant mouse leptin for the first 10 days of lactation, and C-control group that received the same volume of saline. Lep group had higher leptin concentration at days 30 (+6 x , p<0.001) and 150 (+108%, p<0.05) than the controls. These animals had lower serum TT4 (-13%; p<0.05) and TT3 (-17.3%; p<0.002) at 30 days and higher serum TT4 and FT4 concentrations at 150 days (+17.5% and +10%, p<0.05 %, respectively, p<0.05) with lower serum TSH concentrations at 60 (-38.5%, p<0.05) and 150 days (-46%, p<0.05). These animals had also lower hepatic mitochondrial alpha-glycerol-3-phosphate dehydrogenase (mGPDH) activity at 21 (-22.5%; p<0.05), 30 (-50.4%; p<0.05) and 150 days (-40%; p<0.05) than the controls. These data show that the leptin injection in the beginning of lactation cause a hypothyroidism on the offspring as soon as 30 days of age and this alteration may be the imprinted factor for the programming of a higher thyroid function at the adulthood.

Adaptive changes in thyroid function of female rats fed a high-fat and low-protein diet during gestation and lactation

The percent of lipids in the western diet has been continuously increasing in the last decades and is associated with a decrease in the proportion of protein intake. Recently, we demonstrated that protein malnutrition during lactation is associated with lower body weight and thyroid hypofunction in female rats and their offspring. Our objective in the present study was to determine if a high-fat and low-protein diet was associated with similar changes. Three-month-old female Wistar rats were randomly assigned to one of the following groups with 8 animals each: high-fat and low-protein (40% lipid, 5% protein, and 55% carbohydrate of the total energy content) from the 3rd week of gestation to the end of lactation; control group--standard diet (11% lipid, 23% protein, and 66% carbohydrate of the total energy content). Food consumption and body weight were monitored daily. Serum thyrotropin and thyroid hormone concentrations were determined by specific radioimmunoassay at the end of lactation. Animals receiving high-fat and low-protein diet had a significantly lower body weight (13.9% at weaning, P < 0.05) and serum albumin (25%, P < 0.05) and thyrotropin (26.2%, P < 0.01) concentrations, and a higher serum triiodothyronine concentration (74%, P < 0.005) and 131I-thyroid uptake (77%, P < 0.005). These data show that a high-fat and low-protein diet can promote maternal thyroid hyperfunction that differs from the thyroid hypofunction observed in dams fed a low-protein diet, a phenomenon that can be of adaptive importance for pup nurturing.

Prolactin inhibition in lactating rats changes leptin transfer through the milk

Malnutrition during lactation reduces milk production and changes pup's leptin serum levels. To test prolactin role in this nutritional state, we evaluated whether prolactin suppression during lactation changes serum leptin in dams, its transfer through the milk, and pup's serum leptin. Lactating rats were treated with bromocryptine (1 mg/twice a day, s.c.) or saline three days before sacrifice (days 2-4 or days 19-21). Food intake and body weight were measured until sacrifice (4th and 21st day). Serum prolactin and leptin were determined by radioimmunoassay. Bromocryptine injected dams had lower serum prolactin and milk production as expected. The mothers presented lower food ingestion (day 21: -25%), lower body weight (day 4: -12%; day 21: -10%), higher serum leptin (day 4: +68%), lower milk leptin on the 4th day (11 times) and higher (8 times) on the 21st day. The offspring of bromocryptine-treated mothers presented lower body weight in both periods of lactation and lower serum leptin on the 4th day (-40%) and higher on the 21st day (+37%) of lactation. We suggest that prolactin, through its effect on leptin secretion into the milk, may play an important role in signalizing maternal nutritional status to the pups.

Effects of maternal leptin treatment during lactation on the body weight and leptin resistance of adult offspring

We investigate whether leptin treatment to lactating rats affects food intake, body weight and leptin serum concentration and its anorectic effect on their adult offspring. Lactating rats were divided into 2 groups: Lep-single injected with recombinant rat leptin (8 microg/100 g of body weight, daily for the last 3 consecutive days of lactation) and control group (C) that received the same volume of saline. After weaning all pups had free access to the control diet, their body weight and food intake were monitored at each 4 days until 180 days of age, when they were tested for its food intake and response to either leptin (0.5 mg/kg body wt, ip) or saline vehicle. The offspring of the leptin-treated dams gained more weight and had higher food intake from day 37 onward (p<0.05), higher amount of retroperitoneal white adipose tissue (RPWAT) (37%, p<0.05) and higher leptin serum concentration (40%, p<0.05) at 180 days of age compared to control group. The food intake at 2, 4, 6 and 24 h was unaffected after acute injection of leptin in these animals, suggesting resistance to the anorectic effect of leptin. The maternal leptin treatment during lactation makes their adult offspring more susceptible to overweight with resistance to the anorectic effect of leptin.

New once-daily, highly effective rescue triple therapy after multiple Helicobacter pylori treatment failures: a pilot study

BACKGROUND

Helicobacter pylori treatment failure is a growing problem in daily practice.

AIM

To determine the efficacy of the combination of rabeprazole, levofloxacin and furazolidone as a rescue therapy.

METHODS

Duodenal ulcer patients previously submitted, without success, to at least two H. pylori treatment regimens were included. Gastroscopy (urease test, histological examination and culture) and (13)C-urea breath test were performed. All patients received a combination of rabeprazole 20 mg, levofloxacin 500 mg and furazolidone 200 mg (two tablets) administered in a single dose in the morning for 10 days. Clinical examination and a new (13)C-urea breath test were performed 90 days after therapy.

RESULTS

Twelve patients (eight females and four males), mean age 43 (30-58) years were included. Two patients failed to complete the treatment because of nausea and vomiting. Ten patients completed the study and took all the medications as advised. Culture was obtained in six patients: 100 and 83% of the samples were sensitive to furazolidone and levofloxacin, respectively. Per-protocol and intention-to-treat eradication rates were 100 and 83% (P = 0.019).

CONCLUSIONS

the combination of rabeprazole, levofloxacin and furazolidone in a single daily dose for 10 days constitutes a highly-effective and low-cost alternative as a third-line therapy in patients infected with H. pylori.

Leptin treatment during lactation increases transfer of iodine through the milk

We have previously shown that protein restriction during lactation is associated with changes in iodine secretion into the milk and that a pup's serum leptin concentration was increased at the end of lactation. So, here we evaluate whether leptin treatment during lactation affects iodine transfer through the milk to the pups. Lactating rats were divided into two groups: the leptin (Lep) group, single injected with recombinant rat leptin (8 microg/100g of body weight, daily for 3 consecutive days), and the control (C) group that received the same volume of saline. We studied iodine transfer to the pups through the milk on Days 4, 12 and 21 of lactation. In those days, the dams were separated from their pups for 4 h. Then, the mothers received an injection of 131I (2.22x10(4) Bq ip) and the pups were allowed to nurse for 2 h. The animals were sacrificed 2 h later. Leptin, total serum T3 and total serum T4 concentrations were higher (P<.05) in pups of Lep mothers only on Day 4, suggesting a higher transfer of leptin through the milk at this period, probably with a direct stimulatory effect on thyroid hormone secretion. In other periods, however, even without a detectable increase in a pup's serum leptin concentration, maternal leptin administration increased the pup's thyroid iodine uptake (Day 12, 39%; Day 21, 34%), probably caused by a higher transfer of iodine through the milk, since they had a higher gastric content of 131I on Days 12 (31%) and 21 (128%).

Increased 5'-iodothyronine deiodinase activity is a maternal adaptive mechanism in response to protein restriction during lactation

We have shown that protein restriction during lactation is associated with higher levels of serum and milk tri-iodothyronine (T(3)) with lower serum thyroxine (T(4)), suggesting an increased T(4) to T(3) conversion. To investigate this hypothesis, the activity of type 1 (D1) and/or type 2 (D2) iodothyronine deiodinases was evaluated on days 4, 12 and 21 of lactation in several tIssues of dams fed an 8% protein-restricted (PR) diet and controls fed a 23% protein diet. Serum TSH, T(3) and T(4) were measured by radioimmunoassay. Deiodinase activity was determined by the release of (125)I from (125)I-reverse T(3), under specific conditions for D1 or D2. PR dams had a transitory reduction in liver D1 activity (P<0.05) on day 12, and a small increase in thyroid D1 on day 12 followed by a small decrease on day 21. However, thyroid D2 activity was higher than controls (P<0.05) during the whole of the lactation period. Mammary gland D1 and D2 activities were lower on day 4 of lactation in PR dams (P<0.05), and D2 was higher on day 21 (P<0.05). Potentially, a lower conversion of T(3) to di-iodothyronine in the mammary glands of PR dams at the beginning of lactation may serve to provide more T(3) through the milk. Brown adipose tIssue (BAT) D2 activity was higher (P<0.05) in PR dams during all periods of lactation. PR dams showed higher skeletal muscle D1 activity only at the end of lactation, but no changes in D2 activity. Higher pituitary D1 and D2 activities in the PR group (P<0.05) at the end of lactation could have contributed to the lower serum TSH. These data suggest that the higher thyroid and BAT D2 activity during the whole of lactation and skeletal muscle D1 activity at the end of lactation may contribute to the higher serum T(3) in PR dams.

Once-daily, low-cost, highly effective Helicobacter pylori treatment to family members of gastric cancer patients

BACKGROUND

Helicobacter pylori eradication in family members of gastric cancer patients is now widely accepted, although problems related to costs and compliance persist.

AIM

To compare the efficacy, tolerability and long-term re-infection rates of two once-daily regimens for the eradication of H. pylori in family members of gastric cancer patients.

METHODS

106 first-degree family members of gastric cancer patients were recruited and submitted to the 13C-urea breath test (UBT) to detect H. pylori. If positive, they were randomly allocated to receive a combination of lanzoprazole 30 mg, clarithromycin OD (extended-release formulation) 500 mg and furazolidone 400 mg, once daily, in the morning, for 7 days (Group A) or the same regimen with only 200 mg furazolidone (Group B). Eradication was confirmed by urea breath test performed 6 weeks after treatment. 13C-urea breath test was repeated at 944 (784-1258) days after treatment in successfully treated participants to look for re-infection.

RESULTS

Twenty-five participants were H. pylori negative and two H. pylori-positive individuals refused to sign the informed consent and were excluded. Therefore, 79 participants were studied. Forty participants were allocated to Group A and 39 to Group B. All participants completed treatment. Adverse effects, mostly mild, were observed in 18% of Group A and 18% of Group B (N.S.). The intention-to-treat eradication rate was 87.5% in Group A and 61.5% in Group B (P = 0.006). The mean annual re-infection rate was 3%.

CONCLUSIONS

The combination of lanzoprazole 30 mg, one tablet of clarithromycin OD (extended release formulation) 500 mg and furazolidone 400 mg, once daily for 7 days, constitutes an inexpensive, safe and effective alternative for anti-H. pylori therapy in family members of gastric cancer patients.

Leptin treatment during the neonatal period is associated with higher food intake and adult body weight in rats

For this study, we have determined the effects of neonatal leptin treatment on the evolution of body weight. Experiment 1: pups were divided into two groups: LepF - injected with leptin (8 micro g/100 g of body weight) for the first 10 days of lactation and control (C) - receiving saline. Experiment 2: pups were divided into two groups: LepL - injected with the same leptin concentration of experiment one for the last 10 days of lactation, and C, which received saline. Body weight and food intake were monitored until age 150 days, after which leptin concentrations were measured by ELISA. The LepF group had a significant increase in body weight (p < 0.05) from day 98 onward, in food intake (p < 0.05) from day 74 onward, and higher serum leptin concentration compared to the control (108 %, p < 0.05). The LepL group had a significant increase in body weight (p < 0.05) from day 113 onward, in food intake from day 121 onward (p < 0.001), and higher serum leptin concentration compared to controls (6.9 %, p < 0.05). These results suggest that both periods of lactation constituted a critical window for body weight and food intake programming, but the effects are more marked when the leptin is injected within the first ten days.

Biodistribution of 99mTc-O4Na changes in adult rats whose mothers were malnourished during lactation

99mTc-O4Na biodistribution changes in malnourished adults rats. We evaluated this biodistribution in rats whose mothers were malnourished during lactation.

METHODS

On the first day of lactation the mothers were separated into 3 groups: control (C) group, protein-restricted (PR) group, and energy-restricted (ER) group. After weaning all pups received a control diet until 60 d, when they were injected with 99mTc-O4Na and killed after 30 min. We evaluated the absolute percentage injected dose (%ID) and the %ID per gram (%ID/g) in thyroid, stomach, heart, bone, kidney, lung, liver, brain, and testes.

RESULTS

In the PR group, the %ID and %ID/g were significantly higher in the stomach and lower in the thyroid than in the C group. In the ER pups, the %ID and %ID/g were higher in the liver, stomach, and testes than in the C group.

CONCLUSION

The mother's nutritional status during lactation affects the biodistribution of 99mTc-O4Na in the offspring, and this condition must be considered when nuclear medicine examinations are indicated.