Differences in free amino acid concentrations in milk between Wistar and Wistar Kyoto rats

Wistar Kyoto (WKY) rats, an animal depression model, display abnormal behaviors such as hypoactivity and depression-like behavior compared with Wistar (WIS) rats as a control. A previous study confirmed a dysfunction of amino acid metabolism in the brain of WKY rats compared with that of WIS rats. At the neonatal stage, free amino acids in milk are important nutrients because they act as immediate nutrients for offspring and may affect later health and behavior of the offspring. Therefore, the present study aimed to investigate free amino acid concentrations in milk and the relationships between free amino acid concentrations in milk and plasma in WIS and WKY rats. The concentrations of ten of the determined free amino acids in milk were significantly higher, but only L-methionine was significantly lower, in WKY rats. Six free amino acids had significantly higher concentrations in colostrum and two free amino acids had higher concentrations in matured milk. Free amino acid concentrations in plasma changed by both genetic background and lactation stage; however, the patterns of change in most free amino acid concentrations except for taurine in plasma were similar between WIS and WKY rats. The transport ratio of free amino acids from plasma to milk was not similar among the free amino acids tested, and each free amino acid was influenced by the genetic background and/or the type of milk.

L-Leucine increases the daily body temperature and affords thermotolerance in broiler chicks

OBJECTIVE

Heat stress poses an increasing threat for poultry production. Some amino acids have been found to play critical roles in affording thermotolerance. Recently, it was found that in ovo administration of L-leucine (L-Leu) altered amino acid metabolism and afforded thermotolerance in heat-exposed broiler chicks.

METHODS

In this study, two doses (35 and 70 μmol/egg) of L-Leu were administered in ovo on embryonic day 7 to determine their effect on rectal temperature (RT), body weight (BW) and thyroid hormones at hatching. Changes in RT, BW, and thermotolerance in post-hatched chicks were also analyzed.

RESULTS

It was found that in ovo administration of L-Leu dose-dependently reduced RT and plasma thyroxine (T4) level just after hatching. In post-hatched neonatal broiler chicks, however, the higher dose of L-Leu administered in ovo significantly increased RT without affecting BW gain. In chicks that had been exposed to heat stress, the RT was significantly lowered by in ovo administration of L-Leu (high dose) in comparison with the control chicks under the same high ambient temperature (HT: 35°C±1°C, 120 min).

CONCLUSION

In ovo administration of L-Leu in a high dose contributed to an increased daily body temperature and afforded thermotolerance under HT in neonatal broiler chicks.

Flavangenol regulates gene expression of HSPs, anti-apoptotic and anti-oxidative factors to protect primary chick brain cells exposed to high temperature

Heat-stress exposure increased the expression of heat-shock proteins (HSPs), B-cell lymphoma 2 (BCL-2) and anti-oxidative enzymes to maintain normal cellular function by attenuating the oxidative reaction and apoptosis. Reducing the stress response or enhancing anti-stress capability is an important goal in animal production. Our previous study indicated a protective role of flavangenol, a pine bark extract, in chicks after three hours of high-temperature exposure. However, the cellular mechanism of flavangenol was not clarified ex vivo. In the current study, we investigated the effect of flavangenol on cellular apoptosis and oxidation in heat-stressed treated chick brain cells (mixed neurons and glia cells). The primary brain cells were isolated from the diencephalon of 14-day-old chicks and cultured at 41.5 °C (to mimic the body temperature of young chicks), and were treated with flavangenol from day 3 of isolation to day 8. Cells were kept bathed in the cell culture dish under a high temperature (HT: 45 °C, 20 or 60 min) on day 8 and were then collected for analysis of cell viability as well as for HSP and other related gene expression. Flavangenol treatment significantly increased cell viability and BCL-2 mRNA expression, and attenuated HSP-70 and BCL-2-associated X protein mRNA expression. Moreover, flavangenol treatment elevated the mRNA expression of glutathione peroxidase in the HT group, which indicates that cellular anti-oxidative ability was strengthened by flavangenol. In conclusion, flavangenol may play a protective role in cells damaged or killed by heat stress by increasing cellular anti-oxidative pathways.

Reduction in voluntary food intake, but not fasting, stimulates hypothalamic gonadotropin-inhibitory hormone precursor mRNA expression in chicks under heat stress

Heat stress is an issue of rising concern across the globe. Recently, we found that mRNA expression of gonadotropin-inhibitory hormone (GnIH), an orexigenic neuropeptide, was increased in the heat-exposed chick brain when food intake was reduced. The aim of the current study was to examine mRNA expression of GnIH and of the glucocorticoid receptors (GRs) in the hypothalamus as well as the plasma corticosterone (CORT) and metabolites in 14-d-old chicks exposed to a high ambient temperature (HT; 40 ± 1 °C for 1 or 5 h) or a control thermoneutral temperature (CT; 30 ± 1 °C), either with free access to food or fasted. Heat stress caused a voluntary reduction of food intake and reduced plasma triacylglycerol concentration, but increased rectal temperature and plasma CORT and glucose concentrations (P < 0.05). Heat stress also increased (P < 0.05) the expression of diencephalic GnIH mRNA in chicks when they reduced food intake voluntarily, but did not do so under fasting conditions. Although the expression of GR mRNA was not altered as a result of heat stress, its expression was decreased (P < 0.05) in fasted chicks at 5 h in comparison with fed chicks. In addition, the rectal temperature of fasted chicks was lower than that of fed chicks under both CT and HT. In conclusion, voluntary reduction of food intake caused an increase in brain GnIH mRNA expression, plasma CORT, and body temperature in chicks under heat stress. Interestingly, brain GnIH mRNA expression was not induced by heat stress in fasted chicks and was not accompanied by a decrease in rectal temperature. These results suggest that the increased expression of brain GnIH mRNA in chicks under heat stress could be a consequence of a mechanism mediated by the voluntary reduction of food intake, but that it is not a consequence of fasting.

Central NPY-Y5 sub-receptor partially functions as a mediator of NPY-induced hypothermia and affords thermotolerance in heat-exposed fasted chicks

Exposure of chicks to a high ambient temperature (HT) has previously been shown to increase neuropeptide Y (NPY) mRNA expression in the brain. Furthermore, it was found that NPY has anti‐stress functions in heat‐exposed fasted chicks. The aim of the study was to reveal the role of central administration of NPY on thermotolerance ability and the induction of heat‐shock protein (HSP) and NPY sub‐receptors (NPYSRs) in fasted chicks with the contribution of plasma metabolite changes. Six‐ or seven‐day‐old chicks were centrally injected with 0 or 375 pmol of NPY and exposed to either HT (35 ± 1°C) or control thermoneutral temperature (CT: 30 ± 1°C) for 60 min while fasted. NPY reduced body temperature under both CT and HT. NPY enhanced the brain mRNA expression of HSP‐70 and ‐90, as well as of NPYSRs‐Y5, ‐Y6, and ‐Y7, but not ‐Y1, ‐Y2, and ‐Y4, under CT and HT. A coinjection of an NPYSR‐Y5 antagonist (CGP71683) and NPY (375 pmol) attenuated the NPY‐induced hypothermia. Furthermore, central NPY decreased plasma glucose and triacylglycerol under CT and HT and kept plasma corticosterone and epinephrine lower under HT. NPY increased plasma taurine and anserine concentrations. In conclusion, brain NPYSR‐Y5 partially afforded protective thermotolerance in heat‐exposed fasted chicks. The NPY‐mediated reduction in plasma glucose and stress hormone levels and the increase in free amino acids in plasma further suggest that NPY might potentially play a role in minimizing heat stress in fasted chicks.

Usefulness of the 99mTc-MDP Scan in the Detection of Calcified Liver Metastases

A 99mTc-MDP scan was done on a patient with liver metastases from a medullary thyroid carcinoma who, in addition, had a familial history of multiple endocrine neoplasm, type 2. The scan revealed accumulation in several areas of calcified liver metastases.

Restraint stress in lactating mice alters the levels of sulfur-containing amino acids in milk

It is well known that maternal stress during the gestation and lactation periods induces abnormal behavior in the offspring and causes a lowering of the offspring’s body weight. Various causes of maternal stress during the lactation period, relating to, for example, maternal nutritional status and reduced maternal care, have been considered. However, little is known about the effects on milk of maternal stress during the lactation period. The current study aimed to determine whether free amino acids, with special reference to sulfur-containing amino acids in milk, are altered by restraint stress in lactating mice. The dams in the stress group were restrained for 30 min at postnatal days 2, 4, 6, 8, 10 and 12. Restraint stress caused a reduction in the body weight of lactating mice. The concentration of taurine and cystathionine in milk was significantly higher in the stress group, though stress did not alter their concentration in maternal plasma. The ratio of taurine concentration in milk to its concentration in maternal plasma was significantly higher in the stress group, suggesting that stress promoted taurine transportation into milk. Furthermore, taurine concentration in milk was positively correlated with corticosterone levels in plasma. In conclusion, restraint stress in lactating mice caused the changes in the metabolism and in the transportation of sulfur-containing amino acids and resulted in higher taurine concentration in milk. Taurine concentration in milk could also be a good parameter for determining stress status in dams.

Dietary L-serine modifies free amino acid composition of maternal milk and lowers the body weight of the offspring in mice

The growth of offspring is affected not only by the protein in maternal milk but also by the free amino acids (FAAs) contained in it. L-Serine (L-Ser) is known as an important FAA for the development of the central nervous system and behavioral activity. However, it is not clear whether L-Ser is transported into the pool of FAAs contained in milk and thereby affects the growth of offspring. Using mice, the current study investigated the effects of dietary L-Ser during pregnancy and lactation on milk and plasma FAA composition, as well as on growth, behavior, and plasma FAAs of offspring. Dietary L-Ser did not significantly affect the maternal, anxiety-like, or cognitive behaviors of either the dam or the offspring. The FAA composition notably differed between plasma and milk in dams. In milk, dietary L-Ser increased free L-Ser levels, while glutamic acid, L-alanine, D-alanine and taurine levels were decreased. The body weight of the offspring was lowered by dietary L-Ser. The concentrations of plasma FAAs in 13-day-old offspring (fed only milk) were not altered, but 20-day-old offspring (fed both milk and parental diet) showed higher plasma L-Ser and D-Ser concentrations as a result of the dietary L-Ser treatment. In conclusion, the present study found that dietary L-Ser transported easily from maternal plasma to milk and that dietary L-Ser treatment could change the FAA composition of milk, but that an enhanced level of L-Ser in milk did not enhance the plasma L-Ser level in the offspring.

l-Serine Enhances Light-Induced Circadian Phase Resetting in Mice and Humans

Background: The circadian clock is modulated by the timing of ingestion or food composition, but the effects of specific nutrients are poorly understood.Objective: We aimed to identify the amino acids that modulate the circadian clock and reset the light-induced circadian phase in mice and humans.Methods: Male CBA/N mice were orally administered 1 of 20 l-amino acids, and the circadian and light-induced phase shifts of wheel-running activity were analyzed. Antagonists of several neurotransmitter pathways were injected before l-serine administration, and light-induced phase shifts were analyzed. In addition, the effect of l-serine on the light-induced phase advance was investigated in healthy male students (mean ± SD age 22.2 ± 1.8 y) by using dim-light melatonin onset (DLMO) determined by saliva samples as an index of the circadian phase.Results: l-Serine administration enhanced light-induced phase shifts in mice (1.86-fold; P < 0.05). Both l-serine and its metabolite d-serine, a coagonist of N-methyl-d-aspartic acid (NMDA) receptors, exerted this effect, but d-serine concentrations in the hypothalamus did not increase after l-serine administration. The effect of l-serine was blocked by picrotoxin, an antagonist of γ-aminobutyric acid A receptors, but not by MK801, an antagonist of NMDA receptors. l-Serine administration altered the long-term expression patterns of clock genes in the suprachiasmatic nuclei. After advancing the light-dark cycle by 6 h, l-serine administration slightly accelerated re-entrainment to the shifted cycle. In humans, l-serine ingestion before bedtime induced significantly larger phase advances of DLMO after bright-light exposure during the morning (means ± SEMs-l-serine: 25.9 ± 6.6 min; placebo: 12.1 ± 7.0 min; P < 0.05).Conclusion: These results suggest that l-serine enhances light-induced phase resetting in mice and humans, and it may be useful for treating circadian disturbances.

Intraoperative 5-aminolevulinic acid-induced photodynamic diagnosis of metastatic brain tumors with histopathological analysis

BACKGROUND

Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) is a promising real-time navigation method in the surgical resection of malignant gliomas. In order to determine whether this method is applicable to metastatic brain tumors, we evaluated the usefulness of intraoperative fluorescence patterns and histopathological features in patients with metastatic brain tumors.

METHODS

We retrospectively reviewed the cases of 16 patients with metastatic brain tumors who underwent intraoperative 5-ALA fluorescence-guided resection. Patients were given 20 mg/kg of 5-ALA orally 2 h prior to the surgery. High-powered excitation illumination and a low-pass filter (420, 450, or 500 nm) were used to visualize the fluorescence of protoporphyrin IX (PpIX), the 5-ALA metabolite. We evaluated the relationships between the fluorescence and histopathological findings in both tumoral and peritumoral brain tissue.

RESULTS

Tumoral PpIX fluorescence was seen in only 5 patients (31%); in the remaining 11 patients (69%), there was no fluorescence in the tumor bulk itself. In 14 patients (86%), vague fluorescence was seen in peritumoral brain tissue, at a thickness of 2-6 mm. The histopathological examination found cancer cell invasion of adjacent brain tissue in 75% of patients (12/16), at a mean ± SD depth of 1.4 ± 1.0 mm (range 0.2-3.4 mm) from the microscopic border of the tumor. There was a moderate correlation between vague fluorescence in adjacent brain tissue and the depth of cancer cell invasion (P = 0.004).

CONCLUSION

Peritumoral fluorescence may be a good intraoperative indicator of tumor extent, preceding more complete microscopic gross total resection.

TRIAL REGISTRATION

Institutional Review Board of Osaka Medical College No. 42, registered February 17, 1998, and No. 300, registered April 1, 2008. They were retrospectively registered.

Exposure of C57BL/6J mice to long photoperiod during early life stages increases body weight and alters plasma metabolomic profiles in adulthood

Perinatal photoperiod is an important regulator of physiological phenotype in adulthood. In this study, we demonstrated that postnatal (0–4 weeks old) exposure of C57BL/6J mice to long photoperiod induced persistent increase in body weight until adulthood, compared with the mice maintained under short photoperiod. The expression of peroxisome proliferator‐activated receptor δ, a gene involved in fatty acid metabolism, was decreased in 10‐week‐old mice exposed to long photoperiod during 0–4 or 4–8 weeks of age. Plasma metabolomic profiles of adult mice exposed to a long photoperiod during the postnatal period (0–4 LD) were compared to those in the mice exposed to short photoperiod during the same period. Cluster analysis revealed that both carbon metabolic pathway and nucleic acid pathway were altered by the postnatal photoperiod. Levels of metabolites involved in glycolysis were significantly upregulated in 0–4 LD, suggesting that the mice in 0–4 LD use the glycolytic pathway for energy expenditure rather than the fatty acid oxidation pathway. In addition, the mice in 0–4 LD exhibited high levels of purine metabolites, which have a role in neuroprotection. In conclusion, postnatal exposure of C57BL/6J mice to long photoperiod induces increase in body weight and various changes in plasma metabolic profiles during adulthood.

Slow-Myofiber Commitment by Semaphorin 3A Secreted from Myogenic Stem Cells

Recently, we found that resident myogenic stem satellite cells upregulate a multi-functional secreted protein, semaphorin 3A (Sema3A), exclusively at the early-differentiation phase in response to muscle injury; however, its physiological significance is still unknown. Here we show that Sema3A impacts slow-twitch fiber generation through a signaling pathway, cell-membrane receptor (neuropilin2-plexinA3) → myogenin-myocyte enhancer factor 2D → slow myosin heavy chain. This novel axis was found by small interfering RNA-transfection experiments in myoblast cultures, which also revealed an additional element that Sema3A-neuropilin1/plexinA1, A2 may enhance slow-fiber formation by activating signals that inhibit fast-myosin expression. Importantly, satellite cell-specific Sema3A conditional-knockout adult mice (Pax7CreER^T2 -Sema3A^fl °^x activated by tamoxifen-i.p. injection) provided direct in vivo evidence for the Sema3A-driven program, by showing that slow-fiber generation and muscle endurance were diminished after repair from cardiotoxin-injury of gastrocnemius muscle. Overall, the findings highlight an active role for satellite cell-secreted Sema3A ligand as a key "commitment factor" for the slow-fiber population during muscle regeneration. Results extend our understanding of the myogenic stem-cell strategy that regulates fiber-type differentiation and is responsible for skeletal muscle contractility, energy metabolism, fatigue resistance, and its susceptibility to aging and disease. Stem Cells 2017;35:1815-1834.

Central administration of neuropeptide Y differentially regulates monoamines and corticosterone in heat-exposed fed and fasted chicks

Recently, we demonstrated that brain neuropeptide Y (NPY) mRNA expression was increased in heat exposed chicks. However, the functions of brain NPY during heat stress are unknown. This study was conducted to investigate whether centrally administered NPY affects food intake, rectal temperature, monoamines, stress hormones and plasma metabolites in chicks under high ambient temperatures (HT). Five or six-day-old chicks were centrally injected with 0, 188 or 375pmol of NPY and exposed to either HT (35±1°C) or a control thermoneutral temperature (CT; 30±1°C) for 3h whilst fed or fasted. NPY increased food intake under both CT and HT. NPY reduced rectal temperature 1 and 2h after central administration under CT, but not under HT. Interestingly, NPY decreased brain serotonin and norepinephrine concentrations in fed chicks, but increased concentrations of brain dopamine and its metabolites in fasted and fed chicks, respectively. Plasma epinephrine was decreased by NPY in fed chicks, but plasma concentrations of norepinephrine and epinephrine were increased significantly by NPY in fasted-heat exposed chicks. Furthermore, NPY significantly reduced plasma corticosterone concentrations in fasted chicks. Plasma glucose and triacylglycerol were increased by NPY in fed chicks, but triacylglycerol declined in fasted NPY-injected chicks. In conclusion, brain NPY may attenuate the reduction of food intake during heat stress and the increased brain NPY might be a potential regulator of the monoamines and corticosterone to modulate stress response in heat-exposed chicks.

Effects of nutritional status on hormone concentrations of the somatotropin axis and metabolites in plasma and colostrum of Japanese Black cows

We aimed to determine the effects of nutritional status on concentrations of somatotropic axis hormones (growth hormone (GH) and insulin-like growth factor 1 (IGF-1)), insulin and metabolites (glucose, total protein and nonesterified fatty acids (NEFA)) in the plasma and colostrum in late antepartum cows. Eight pregnant Japanese Black cows were randomly assigned to two experimental groups (n = 4 per group). Control cows (CON) received 100% of their nutritional requirements until parturition, whereas restricted group cows (RES) received 60% of their nutritional requirements. Blood samples were taken during the antepartum period, and blood and colostrum samples were collected on days 0, 1, and 3 after calving. Compared to the CON group, the RES group had higher concentrations of GH and NEFA in plasma, but significantly lower concentrations of glucose and insulin in plasma. The concentrations of GH in plasma after calving were significantly higher, but total plasma protein was significantly lower in RES than in CON cows. Compared to the CON group, the RES group had significantly higher concentrations of GH in colostrum, but significantly lower total concentrations of protein in colostrum. Concentrations of IGF-1 were not different between the two groups. These findings suggest that maternal nutritional status during late gestation influences concentrations of GH and total protein in the blood and colostrum of Japanese Black cows.