Prostaglandin E1 (PGE1), but not prostaglandin E2 (PGE2), alters luteal and endometrial luteinizing hormone (LH) occupied and unoccupied LH receptors and mRNA for LH receptors in ovine luteal tissue to prevent luteolysis

Loss of luteal progesterone secretion at the end of the ovine estrous cycle is via uterine PGF₂α secretion. However, uterine PGF₂α secretion is not decreased during early pregnancy in ewes. Instead, the embryo imparts a resistance to PGF₂α. Prostaglandins E (PGE; PGE₁ + PGE₂) are increased in endometrium and uterine venous blood during early pregnancy in ewes to prevent luteolysis. Chronic intrauterine infusion of PGE₁ or PGE₂ prevents spontaneous or IUD, estradiol-17β, or PGF₂α-induced premature luteolysis in nonbred ewes. The objective was to determine whether chronic intrauterine infusion of PGE₁ or PGE₂ affected mRNA for LH receptors, occupied and unoccupied receptors for LH in luteal and caruncular endometrium, and luteal function. Ewes received Vehicle, PGE₁, or PGE₂ every 4 h from days 10 to 16 of the estrous cycle via a cathether installed in the uterine lumen ipsilateral to the luteal-containing ovary.Jugular venous blood was collected daily for analysis of progesterone and uterine venous blood was collected on day-16 for analysis of PGF₂α and PGE. Corpora lutea and caruncular endometrium were collected from day-10 preluteolytic control ewes and day-16 ewes treated with Vehicle, PGE₁ or PGE₂ for analysis of the mRNA for LH receptors and occupied and unoccupied receptors for LH. Luteal weights on day-16 in ewes treated with PGE₁ or PGE₂ and day-10 control ewes were similar (P ≥ 0.05), but were greater (P ≤ 0.05) than in day-16 Vehicle-treated ewes. Progesterone profiles on days 10–16 differed (P ≤ 0.05) among treatment groups: PGE₁ > PGE₂ > Vehicle-treated ewes. Concentrations of PGF₂α and PGE in uterine venous plasma on day-16 were similar (P ≥ 0.05) in the three treatment groups. Luteal mRNA for LH receptors and unoccupied and occupied LH receptors were similar (P ≥ 0.05) in day-10 control ewes and day-16 ewes treated with PGE₂ and were lower (P ≤ 0.05) in day-16 Vehicle-treated ewes. PGE₂ prevented loss (P ≤ 0.05) of day-16 luteal mRNA for LH receptors and occupied and unoccupied LH receptors. Luteal and caruncular tissue mRNA for LH receptors and occupied and unoccupied LH receptors were greater (P ≤ 0.05) on day-16 of PGE₁-treated ewes than any treatment group. mRNA for LH receptors and occupied and unoccupied receptors for LH in caruncules were greater (P ≤ 0.05) in day-16 Vehicle or PGE₂-treated ewes than in day-10 control ewes. It is concluded that PGE₁ and PGE₂ share some common mechanisms to prevent luteolysis; however, only PGE₁ increased luteal and endometrial mRNA for LH receptors and occupied and unoccupied LH receptors. PGE₂ prevents a decrease in luteal mRNA for LH receptors and occupied and unoccupied receptors for LH without altering endometrial mRNA for LH receptors or occupied and unoccupied receptors for LH.     

IGF-I mediated inhibition of leptin receptor expression in porcine hepatocytes

A study was conducted to elucidate hormonal control of leptin receptor gene expression in primary cultures of porcine hepatocytes. Hepatocytes were isolated from swine and seeded into T-25 flasks. Cultures were established in medium containing fetal bovine serum for one day and switched to serum-free medium (William's E medium and 1 ng/mL insulin) for the remainder of the 3 d culture period. For the final 24 h, medium was supplemented with porcine growth hormone (GH, 100 or 500 ng/mL), insulin-like growth factor 1 (IGF-1, 50 to 250 ng/mL) or triiodothyronine (T3, 100 ng/mL). RNA was extracted and relative quantitative RT-PCR was performed with primers for long form leptin receptor. Receptor expression was calculated relative to 18S rRNA. Insulin had no effect (P > 0.05), while T3 increased leptin receptor mRNA abundance (P < 0.05). Treatment with GH or IGF-I reduced leptin receptor expression (P < 0.05). Phosphorylation of ERK1/2 in response to acute leptin treatment was inhibited by previous exposure to GH or IGF-I. Hepatocytes secreted IGF-I under basal conditions and this was enhanced by GH addition. These data suggest porcine hepatocytes may be less sensitive to leptin stimulation due to the actions of endogenous IGF-I on leptin receptor expression.     

Uptake of leptin and albumin via separate pathways in proximal tubule cells

The adipokine leptin and oncotic protein albumin are endocytosed in the proximal tubule via the scavenger receptor megalin. Leptin reduces megalin expression and activates cell signalling pathways that upregulate fibrotic protein expression. The aim of this study was to investigate if leptin uptake in proximal tubule cells was via the albumin-megalin endocytic complex. In immortalised proximal tubule Opossum kidney cells (OK) fluorescent leptin and albumin co-localised following 5 min exposure, however there was no co-localisation at 10, 20 and 30 min exposure. In OK cells, acute exposure to leptin for 2 h did not alter NHE3, ClC-5, NHERF1 and NHERF2 mRNA. However, acute leptin exposure increased NHERF2 protein expression in proximal tubule cells. In OK cells, immunoprecipitation experimentation indicated leptin did not bind to ClC-5. Leptin uptake in OK cells was enhanced by bafilomycin and ammonium chloride treatment, demonstrating that uptake was not dependent on lysosomal pH. Thus, it is likely that two pools of megalin exist in proximal tubule cells to facilitate separate uptake of leptin and albumin by endocytosis.     

Leptin in the bovine corpus luteum: receptor expression and effects on progesterone production

In cattle, leptin has been implicated in the control of ovarian function and has been shown to modulate steroid production by theca and granulosa cells in a number of species. However, a direct effect of leptin on bovine luteal function has not been demonstrated. This study was conducted to determine if the leptin receptor (OB-R) is expressed in the bovine corpus luteum (CL), and to examine the effects of leptin on progesterone production by dispersed luteal cells in vitro. RT-PCR was used to detect the presence of OB-R and, more specifically, the long, biologically active isoform (OB-Rb), in CL, collected on days 2-18 of the oestrous cycle (n=18). The effects of leptin on progesterone production were investigated in dispersed luteal cells prepared from CL collected on days 5 and 8 (n=14) of the cycle. The dispersed luteal cells were cultured for 24 hr with recombinant human leptin and/or LR3-IGF-1 and/or LH. OB-Rs, in particular, OB-Rb, were expressed in the CL at all stages of development. Progesterone production by luteal cells was increased (P<0.001) by treatment with LH (10 ng/ml) but treatment with leptin alone had no effect. However, in the presence of IGF-1 (100 ng/ml), leptin (10 ng/ml) caused a significant (P<0.005) increase in progesterone production. In conclusion, we have shown that the leptin receptor is expressed in the bovine CL and have demonstrated a modulatory effect of leptin on luteal progesterone production in vitro.     

Growth and antrum formation of bovine primary follicles in long-term culture in vitro

Successful antral formation in vitro from bovine preantral follicles (145–170 μm) has been described previously, but antrum formation from the primary follicle (50–70 μm) has not yet been achieved in vitro. The aim of the study was to establish an optimal culture system supporting the growth and maturation of bovine primary follicles (50–70 μm) in vitro. Bovine primary follicles were cultured in a three-dimensional culture system for 13 or 21 days in alpha-minimum essential medium. Various treatments including follicle stimulating hormone (FSH), luteinizing hormone (LH), 17β-estradiol (E₂), basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) were tested. The follicular diameter and antrum formation rate were recorded, and follicular maturation markers (P450 aromatase, CYP19A1; anti-Mullerian hormone, AMH; growth differentiation factor-9, GDF9; bone morphogenetic protein-15, BMP15; and type III transforming growth factor β receptor, TGFβR3) were analyzed by real-time RT-PCR. After 21 days of culture under each treatment condition, the follicular diameter was significantly enlarged in the presence of FSH + LH + E₂ + bFGF or FSH + LH + E₂ + bFGF + EGF (p < 0.05). An addition of 50 ng/ml bFGF or bFGF + 25 ng/ml EGF initiated antrum formation by day 19 and day 17 of culture, and the antral cavity formation rate was 16.7% and 33.3% by 21 days of culture, respectively. The expression of follicular maturation markers (CYP19A1, AMH, GDF9, BMP15 and TGFβR3) was significantly altered. We conclude that addition of 50 ng/ml bFGF + 25 ng/ml EGF to media containing FSH + LH + E₂ turned out to be the most effective optimized culture conditions to support the growth and maturation of bovine primary follicles in vitro.     

Low plasma leptin level at admission predicts delirium in critically ill patients: A prospective cohort study

The pathophysiology of delirium remains poorly understood. Low leptin level has been associated with features leading to delirium such as dysregulated immune functions and loss of neuroprotective effects. The purpose of the present study was to investigate the relationship between plasma leptin level at intensive care unit (ICU) entry and subsequent occurrence of delirium in critically ill patients. This single-center prospective cohort study in China allocated 336 critically ill patients admitted to ICU between 05/2015 and 05/2016 into a delirium group (n = 102) and non-delirium group (n = 234) based on whether delirium occurred during their stay at the ICU. Patients were examined at least twice daily and delirium was diagnosed using the Confusion Assessment Method for the ICU (CAM-ICU). Blood samples were obtained after ICU entry. Plasma leptin concentrations were measured by ELISA. Delirium occurred in 30.4% (102/336) of patients. Patients who developed delirium showed significantly lower leptin level at ICU entry than those who did not (6.1 ± 3.2 vs. 9.2 ± 5.9 ng/mL; P < 0.001). Low plasma leptin level at ICU entry was independently associated with subsequent occurrence of delirium (OR, 0.865; 95%CI, 0.802–0.934; P < 0.001). Other independent risk factors for delirium included increasing age (OR, 1.050; 95%CI, 1.020–1.080; P = 0.001) and Acute Physiology and Chronic Health Evaluation-II (APACHE-II) score (OR, 1.148; 95%CI, 1.092–1.208; P < 0.001). Patients who developed delirium had a prolonged duration of ICU stay and higher mortality. Low plasma leptin level at ICU entry was associated with the occurrence of delirium in critically ill patients.     

An effective technique for the processing of saliva for the analysis of leptin and adiponectin

The recovery of protein from saliva has been extensively investigated as a method to monitor health. The aim of this study was to compare filtration and centrifugation as two methods of saliva processing necessary for determining the levels of salivary leptin and adiponectin. Thirty-seven healthy patients (median age of 45 years; range 35–73) participated in the study. Unstimulated whole saliva was collected by a drooling technique. An aliquot was filtered using a Millex-Millipore^® (0.45 μm PVDF Dura Pore membrane) syringe and a second aliquot was centrifuged at 15 000 × g for 15 min at 4 °C. Leptin and adiponectin levels were analyzed using an ELISA kit for serum (RayBio^®, GA, USA) with minor modifications. Leptin and adiponectin levels following the filtration technique yielded comparable results with those after centrifugation. Correlation was observed between filtered and centrifuged salivary leptin levels ((r = 0.9155; 95% CI 0.8362–0.9573; p < 0.0001) with concordance correlation coefficient k 0.9114 (95% CI 0.8332–0.9539)). Less correlation was observed for adiponectin ((r = 0.5718; 95% CI 0.3041–0.7558; p = 0.0002) with concordance correlation coefficient k 0.5586 (95% CI 0.2977–0.7419)). Using a Bland–Altman plot, similar measurements for both adipocytokines were observed with mean difference within a 95% CI, and interpreted as no systematic differences between the two processing techniques. This study showed that filtration is an alternative saliva processing technique to retrieve supernatant for protein analysis. Filtered saliva yielded leptin and adiponectin concentrations comparable with those obtained from centrifuged saliva.     

High plasma leptin levels are associated with impaired diastolic function in patients with coronary artery disease

Background and aimsObese subjects have elevated leptin levels, which have been associated with increased risk of cardiovascular events. Because leptin has direct cellular effects on various tissues, we tested the hypothesis that leptin levels are associated with cardiac structure or function in patients with coronary artery disease (CAD).Methods and resultsThe study population consisted of 1 601 CAD patients, of whom 42% had type 2 diabetes mellitus. Plasma leptin was measured in fasted state and an echocardiography performed. Leptin levels were not related to LV dimensions or LV ejection fraction (NS for all), but higher leptin levels were associated with elevated E/E’ (9.43 vs. 11.94 in the lowest and the highest leptin quartile, respectively; p = 0.018 for trend). Correspondingly, a decreasing trend was observed in E/A (1.15 vs. 1.06; p = 0.037). These associations were independent of obesity and other relevant confounding variables.ConclusionWe conclude that elevated plasma leptin levels are associated with impaired left ventricular diastolic function in patients with CAD independently of obesity and other confounding variables. Leptin may be one of the mechanistic links explaining the development of congestive heart failure in obese subjects.     

Central infusion of leptin improves insulin resistance and suppresses β-cell function,but not β-cell mass,primarily through the sympathetic nervous system in a type 2 diabetic rat model

AimsWe investigated whether hypothalamic leptin alters β-cell function and mass directly via the sympathetic nervous system (SNS) or indirectly as the result of altered insulin resistant states.Main methodsThe 90% pancreatectomized male Sprague Dawley rats had sympathectomy into the pancreas by applying phenol into the descending aorta (SNSX) or its sham operation (Sham). Each group was divided into two sections, receiving either leptin at 300 ng/kg bw/h or artificial cerebrospinal fluid (aCSF) via intracerebroventricular (ICV) infusion for 3 h as a short-term study. After finishing the infusion study, ICV leptin (3 μg/kg bw/day) or ICV aCSF (control) was infused in rats fed 30 energy % fat diets by osmotic pump for 4 weeks. At the end of the long-term study, glucose-stimulated insulin secretion and islet morphometry were analyzed.Key findingsAcute ICV leptin administration in Sham rats, but not in SNSX rats, suppressed the first- and second-phase insulin secretion at hyperglycemic clamp by about 48% compared to the control. Regardless of SNSX, the 4-week administration of ICV leptin improved glucose tolerance during oral glucose tolerance tests and insulin sensitivity at hyperglycemic clamp, compared to the control, while it suppressed second-phase insulin secretion in Sham rats but not in SNSX rats. However, the pancreatic β-cell area and mass were not affected by leptin and SNSX, though ICV leptin decreased individual β-cell size and concomitantly increased β-cell apoptosis in Sham rats.SignificanceLeptin directly decreases insulin secretion capacity mainly through the activation of SNS without modulating pancreatic β-cell mass.     

The ovulatory and LH responses to the male effect in dominant and subordinate goats

The objective of this study was to evaluate the LH and ovulatory response of dominant and subordinate dairy does following the introduction of males. A behavioral study was carried out to determine the individual success index (SI) of 35 anestrous does according to their ability to dominate other females. The 8 highest-ranking (highest SI) and the 8 lowest-ranking does (lowest SI) in terms of dominance were separated from the rest of the herd and placed together in the same pen, where a male was later introduced. Blood samples for plasma LH determinations were obtained from the 16 females at 30 min intervals from 0 to 6, 12 to 18 and 33 to 39 h after the introduction of the male, using an intravenous catheter. After day 8, plasma progesterone was also measured daily in order to determine the occurrence of ovulation. None of the does showed LH pulses during the sampling period prior to the introduction of the male. The dominant does showed significantly (p < 0.05) more LH pulses (2.0 ± 0.18 ng/ml vs. 1.2 ± 0.25 ng/ml) and a higher mean plasma LH concentration (0.25 ± 0.03 ng/ml vs. 0.14 ± 0.03 ng/ml) than the subordinate goats during the first 6 h of exposure to the male. There were no differences in LH pulsatility or concentrations at other times. The frequency of goats that ovulated tended to be greater in high-ranked than low-ranked does (87% vs. 37%). It could be concluded that the immediate LH response to the presence of the male (number of LH pulses) is higher in the dominant, compared to the subordinate goats, and this is associated with a higher number of dominant goats ovulating in response to the male effect.     

Effect of prostaglandins E2 and F2α on in vitro development and hatching of caprine blastocysts

Prostaglandin E₂ has been shown to increase the ovine embryo hatching rate, and PGF_2α to reduce the development of rabbit, bovine, and rat embryos. The objective was to determine the effects of PGE₂ and PGF_2α on development of caprine embryos. Estrus was synchronized in does (n = 25) with medroxyprogesterone acetate (MAP) intravaginal sponges for 12 days, and superovulated with 20 units of FSH. On day 6 following estrus, embryos were flushed (n = 128) and incubated individually per well in 25 μl droplets of TCM-199 and BSA (8 mg/ml) for 6 days at 38.5 °C in a 5% CO₂: air with one of the following treatments: (1) control (0.0002% EtOH), (2) PGE₂ (7 ng/ml), (3) PGF_2α (7 ng/ml), (4) low PGE₂:high PGF_2α (3.5 ng/ml:14 ng/ml), (5) balanced PGE₂:PGF_2α (7 ng/ml:7 ng/ml), or (6) high PGE₂:low PGF_2α (14 ng/ml:3.5 ng/ml). Treatment with PGE₂ alone reduced (P < 0.05) the hatching rate (1/15; 7%). The hatching rate of embryos treated with PGF_2α alone (9/18; 50%), low PGE₂:high PGF_2α (8/16; 50%), and balanced PGE₂:PGF_2α (11/16; 69%) were similar to control (6/18; 33%). In contrast, the hatching rate was non-significantly increased (13/18; 72%) with the high PGE₂:low PGF_2α treatment. None of the treatments affected development from the morula to blastocyst stage. From the current data, it can be concluded that PGE₂ alone reduced hatching rate, and PGF_2α alone had no effect on the development of caprine embryos. High concentrations of PGE₂ with PGF_2α improved the hatching rates. Thus, uterine concentrations of PGE₂ may need to reach a threshold level to improve embryo hatching, as previously reported, while increased uterine concentrations of PGF_2α during early pregnancy would not affect development of the embryo.     

Effects of human chorionic gonadotropin combined with clomiphene on Serum E2, FSH,LH and PRL levels in patients with polycystic ovarian syndrome

ObjectiveEffects of human chorionic gonadotropin combined with clomiphene on serum E₂, FSH, LH and PRL levels in patients with polycystic ovarian syndrome were analyzed.Methods90 patients with polycystic ovarian syndrome treated from January 2015 to March 2016 were randomly and evenly divided into control group and observation group. Patients in the control group were only treated with clomiphene. On the basis of the treatment in control group, human chorionic gonadotropin was added in the treatment of observation group. The changes of E₂, FSH, LH, PRL levels were compared between two groups before and after the treatment. Clinical curative effects of patients in the two groups was evaluated. Adverse reactions during treatment in two groups were observed and recorded. The incidence of adverse reactions was calculated.ResultsSerum E₂, FSH, LH and PRL levels in the two groups decreased significantly after treatment compared with that before treatment. The difference is statistical significant (P < 0.05). After the treatment, E₂, FSH, LH and PRL levels in the observation group were lower than that in the control group and the difference is statistical significant (P < 0.05). Total effective rate was 64.44% in the control group and 93.33% in the observation group. There were statistically significant difference in clinical curative effects in the two groups (P < 0.05). Different degrees of adverse reactions were found in both groups during treatment, such as nausea, vomiting, anorexia, liver dysfunction. There were 2 cases of nausea, 2 cases of vomiting, 3 cases of anorexia and 1 case of liver dysfunction from the 45 patients in control group. The total incidence of adverse reactions was 17.78% (8/45). There were 1 case of nausea, 1 case of vomiting, 1 case of anorexia and no liver dysfunction from the 45 patients in observation group. The total incidence of adverse reactions was 6.67% (3/45). The total incidence of adverse reactions in the observation group was significantly higher than that in the control group and the difference was not statistically significant (P > 0.05).ConclusionCombined use of human chorionic gonadotropin can significantly reduce serum E₂, FSH, LH and PRL levels, improve clinical curative effects and reduce the incidence of adverse reactions. Human chorionic gonadotropin has high application value on the treatment of polycystic ovary syndrome.     

Expression of leptin and its receptor genes in the ovarian follicles of cycling and early pregnant pigs

Leptin is a polypeptide hormone produced primarily by adipocytes. It has been implicated in the regulation of satiety and energy homeostasis. Leptin has been suggested to play a role in reproduction based on its involvement in the regulation of the hypothalamic–pituitary–gonadal axis via endocrine, paracrine and/or autocrine pathways. The aim of the present study was to localize the cellular distribution of leptin and the long isoform of leptin receptor (OB-Rb) genes in porcine ovarian antral follicles and to compare the expression levels of leptin and OB-Rb mRNAs in porcine granulosa cells (GC), theca interna (TIC) and theca externa (TEC) cells during the luteal phase of the estrous cycle and in early pregnancy. The expression of leptin and OB-Rb genes was detected in GC, TIC and TEC. Significantly higher levels of leptin gene expression in GC were observed during the mid- and late-luteal phases of the cycle than on days 30 to 32 of pregnancy. On days 14 to 16 of pregnancy, leptin mRNA expression was higher than that on days 14 to 16 of the cycle. The expression of the OB-Rb gene in GC and TEC increased during pregnancy in comparison with the analyzed luteal phases of the cycle. Our results validate the hypothesis that locally produced leptin plays a role in the regulation of porcine reproduction at the ovarian level and exerts a direct effect on porcine follicles. The differences in OB-Rb gene expression in porcine GC and theca cells also suggest that their sensitivity to leptin varies in the ovaries of pregnant and cyclic pigs.     

Leptin controls rabbit ovarian function in vivo and in vitro: Possible interrelationships with ghrelin

The aim of these in vivo and in vitro studies was to examine the role of leptin in the control of plasma hormone concentrations, reproduction, and secretory activity of ovarian granulosa cells.In in vivo experiments, 15 female European domestic rabbit (Oryctolagus cuniculus) were treated with leptin (5 μg animal⁻¹ d⁻¹ for 1 wk before induction of ovulation with 25 IU equine chorionic gonadotropin and 0.25 IU human chorionic gonadotropin), and 15 females constituted the control group (treated with phosphate-buffered saline). Plasma concentrations of progesterone (P₄), testosterone (T), estradiol (E₂), estrone sulfate (ES), and insulin-like growth factor I (IGF-I) were determined at the estimated day of ovulation by radioimmunoassay (RIA), and number, viability, and body weight of newborns were recorded at parturition. In in vitro experiments, granulosa cells were isolated from periovulatory ovarian follicles of five control and five females treated with ghrelin (10 μg animal⁻¹ d⁻¹ for 1 wk before induced ovulation). Isolated cells were cultured for 2 d with and without leptin (0, 1, 10, or 100 ng/mL medium). Secretion of P₄, T, E₂, IGF-I, and prostaglandin F (PGF) was assessed in culture medium by RIA.In in vivo experiments, leptin administrations reduced plasma P₄, T, E₂, ES, and IGF-I levels. Leptin treatments did not affect ovarian weight or total number and body mass of newborns, but the proportion of pregnant females and number of live newborns were significantly higher in leptin-treated females than that in control females. In in vitro experiments, leptin significantly decreased (at 1 and 10 ng/mL) or increased (at 100 ng/mL) P₄ secretion, promoted E₂ and IGF-I (both at 100 ng/mL) secretion, and reduced T (at 1 and 10 ng/mL) and PGF (at 10 ng/mL) secretion. Granulosa cells from ghrelin-treated animals secreted less P₄, T, E₂, and PGF, but not IGF-I, than that secreted by granulosa cells from control animals. Furthermore, pretreatment of animals with ghrelin suppressed or even reversed subsequent leptin effects on P₄, T, E₂, IGF-I, and PGF secretion by cultured granulosa cells.These observations (1) show for the first time that leptin can increase the number of live newborns in rabbits, (2) confirm previous data on the ability of leptin to control ovarian secretory activity both directly and via upstream mechanisms, (3) demonstrate the involvement of ghrelin in the control of rabbit ovarian secretory functions, and (4) suggest an antagonistic interrelationship between leptin and ghrelin in the rabbit.     

Effects of considering the rate of comminution of particles and microbial contamination on accuracy of in situ studies of feed protein degradability in ruminants

Ruminal degradation of dry matter (DM) and crude protein (CP) in samples of soybean meal (SBM), barley grain (BG) and lucerne hay (LH) were measured by an in situ ruminal technique considering either only the outflow rate of particles from the rumen (k_p) or, both k_p and rate of particle comminution (k_c). The effect of correction for the microbial contamination using an ¹⁵N technique was also determined for LH. Degradation and transit studies were completed on three wethers cannulated in the rumen and duodenum and fed a mixed diet of LH and concentrate (2:1 on DM), at an intake level of 50 g DM/kg BW^0.75. Transit studies of concentrates and forages were completed with SBM and LH samples marked with Yb and Eu, respectively. Mean values of k_c were higher in SBM than in LH (0.357 versus 0.204 h, P < 0.05). The same trend was observed for k_p (0.0587 versus 0.0452/h; P < 0.1). Apparent estimates of the proportion of rumen undegraded CP obtained using both rates were 0.884, 0.745 and 0.825 of those obtained using only k_p (0.535, 0.247 and 0.303 for SBM, BG and LH, respectively). Differences occurred for SBM and LH (P < 0.01) and for BG (P < 0.05). The pattern of microbial contamination of LH, expressed as a proportion of residual DM or CP, fitted exponential curves with asymptotic values of 0.076 and 0.586, respectively. Correction for microbial contamination reduced (P < 0.05) estimates of undegraded CP from 0.303 to 0.238, which was further reduced to 0.178 (P < 0.01) when the effect of k_c was also considered.     

Relationship between zinc levels and plasma leptin in hemodialysis patients

Recent evidences suggested a possible relationship between zinc deficiency and leptin levels in pathogenesis of anorexia in chronic kidney disease. The present study addressed the relationship between zinc and leptin in hemodialysis (HD) patients.MethodsFifty HD patients (54.3 ± 12.7 years old, 62% men) were studied and compared to 21 healthy volunteers (50.7 ± 15.7 years old, 43% men). Biochemical data, serum zinc, plasma leptin, IL-6, TNF-α and C-Reactive Protein levels were determined. Anthropometric parameters, food intake and appetite score were also assessed.ResultsThe leptin levels were higher in HD patients (16.1 μg/mL (0.21–118.25) vs 6.0 μg/mL (0.50–23.10)) in healthy volunteers (p = 0.04), whereas serum zinc levels were lower (54.5 ± 16.3 μg/dL) compared to healthy volunteers (78.4 ± 9.4 μg/dL) (p = 0.0001). The plasma leptin was correlated negatively with plasma zinc (r = ?0.33; p = 0.007), energy (r = ?0.38; p = 0.002) and protein intake (r = ?0.34; p = 0.006) and, positively correlated with BMI (r = 0.54; p = 0.0001), % body fat (r = 0.70; p = 0.0001) and conicity index (r = 0.46; p = 0.001). Plasma zinc was associated with hemoglobin (r = 0.30; p = 0.04) and negatively associated with TNF-α (r = ?0.37; p = 0.002) and C-Reactive Protein (r = ?0.37; p = 0.004). There was no correlation among Zn, leptin and appetite score in these patients.ConclusionThis study showed that low plasma zinc levels are negatively associated with high leptin levels in HD patients.     

2-Hexadecynoic acid inhibits plasmodial FAS-II enzymes and arrests erythrocytic and liver stage Plasmodium infections

Acetylenic fatty acids are known to display several biological activities, but their antimalarial activity has remained unexplored. In this study, we synthesized the 2-, 5-, 6-, and 9-hexadecynoic acids (HDAs) and evaluated their in vitro activity against erythrocytic (blood) stages of Plasmodium falciparum and liver stages of Plasmodium yoelii infections. Since the type II fatty acid biosynthesis pathway (PfFAS-II) has recently been shown to be indispensable for liver stage malaria parasites, the inhibitory potential of the HDAs against multiple P. falciparum FAS-II (PfFAS-II) elongation enzymes was also evaluated. The highest antiplasmodial activity against blood stages of P. falciparum was displayed by 5-HDA (IC₅₀ value 6.6 μg/ml), whereas the 2-HDA was the only acid arresting the growth of liver stage P. yoelii infection, in both flow cytometric assay (IC₅₀ value 2-HDA 15.3 μg/ml, control drug atovaquone 2.5 ng/ml) and immunofluorescence analysis (IC₅₀ 2-HDA 4.88 μg/ml, control drug atovaquone 0.37 ng/ml). 2-HDA showed the best inhibitory activity against the PfFAS-II enzymes PfFabI and PfFabZ with IC₅₀ values of 0.38 and 0.58 μg/ml (IC₅₀ control drugs 14 and 30 ng/ml), respectively. Enzyme kinetics and molecular modeling studies revealed valuable insights into the binding mechanism of 2-HDA on the target enzymes. All HDAs showed in vitro activity against Trypanosoma brucei rhodesiense (IC₅₀ values 3.7–31.7 μg/ml), Trypanosoma cruzi (only 2-HDA, IC₅₀ 20.2 μg/ml), and Leishmania donovani (IC₅₀ values 4.1–13.4 μg/ml) with generally low or no significant toxicity on mammalian cells. This is the first study to indicate therapeutic potential of HDAs against various parasitic protozoa. It also points out that the malarial liver stage growth inhibitory effect of the 2-HDA may be promoted via PfFAS-II enzymes. The lack of cytotoxicity, lipophilic nature, and calculated pharmacokinetic properties suggests that 2-HDA could be a useful compound to study the interaction of fatty acids with these key P. falciparum enzymes.