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  1. Raised leptin concentrations in feto-placental tissues from women with preeclampsia
    Singh HJ, Abu Bakar A, Che Romli A, Nila A
    Hypertens Pregnancy, 2005;24(2):191-9.
    PMID: 16036403
    The aim of this study was to estimate the levels of leptin in the amnion, chorion laeve, and placenta and to examine for any differences in leptin levels in these tissues from preeclamptic and normotensive pregnant women.
    Matched MeSH terms: Leptin/metabolism*
  2. Fulltext A Study on the Immunohistochemical Expressions of Leptin and Leptin Receptor in Clear Cell Renal Cell Carcinoma
    Perumal K, Mun KS, Yap NY, Razack AHA, Gobe GC, Ong TA, et al.
    Biomed Res Int, 2020;2020:3682086.
    PMID: 32802842 DOI: 10.1155/2020/3682086
    Background: The mechanisms that link obesity and cancer development are not well-defined. Investigation of leptin and leptin receptor expressions may help define some of the mechanisms. These proteins are known for associating with the immune response, angiogenesis and, signalling pathways such as JAK2/STAT3, PI3K, and AKT pathways. Tissue proteins can be easily detected with immunohistochemistry (IHC), a technique widely used both in diagnostic and research laboratories. The identification of altered levels of leptin and leptin receptor proteins in tumour tissues may lead to targeted treatment for cancer.

    Objective: The objective of this study was to use IHC to compare leptin and leptin receptor expressions in clear cell renal cell carcinomas (ccRCC) in non-obese and obese patients to determine the association between these proteins with the clinicopathological features and prognosis of ccRCC. Patients and Methods. The study involved 60 patients who underwent nephrectomy of which 34 were obese, as assessed using body mass index (BMI). Nephrectomy samples provided tissues of ccRCC and adjacent non-cancerous kidney. The intensity and localization of leptin and leptin receptor protein expressions were evaluated using IHC and correlated with clinicopathological features and clinical outcomes. Aperio ImageScope morphometry and digital pathology were applied to assess the IHC results. The chi-square test was used to determine if there was any significant association between the proteins and the clinicopathological features. The Kaplan-Meier test was used to determine the overall survival, disease-free survival, and recurrence-free survival. A value of p < 0.05 was considered significant.

    Results: There was neither significant difference in the overall cellular and nuclear expressions of leptin and leptin receptor between non-cancerous kidney and ccRCC tissues nor in non-obese and obese individuals with ccRCC.

    Conclusion: In this present study, it was revealed that leptin and leptin receptor were not associated with tumour characteristics and progression of ccRCC patients. Interestingly, nuclear expression of leptin was significantly associated with overall survival. However, the significance of these proteins as biomarkers in other RCC histotypes is still unclear.

    Matched MeSH terms: Leptin/metabolism; Receptors, Leptin/metabolism
  3. Subcellular localization of leptin and leptin receptor in breast cancer detected in an electron microscopic study
    Al-Shibli SM, Amjad NM, Al-Kubaisi MK, Mizan S
    Biochem Biophys Res Commun, 2017 Jan 22;482(4):1102-1106.
    PMID: 27914811 DOI: 10.1016/j.bbrc.2016.11.165
    Leptin (LEP) and leptin receptor (LEPR) have long been found associated with breast cancer. So far no high-resolution method such as electron microscopy has been used to investigate the subcellular localization of leptin and leptin receptor in breast cancer. We collected cancer and non-cancer breast tissues from 51 women with invasive ductal breast cancer. Leptin and leptin receptor in the tissues were estimated using immunohistochemistry (IHC). LEP and LEPR were localized at subcellular level by immunocytochemistry (ICC) using ultra-fine gold particle conjugated antibody, and visualized with transmission electron microscopy (TEM). IHC showed high presence of LEP and LEPR in 65% and 67% respectively of the breast cancer samples, 100% and 0% respectively of the adipose tissue samples, and no high presence in the non-cancer breast tissue samples. On TEM views both LEP and LEPR were found highly concentrated within the nucleus of the cancer cells, indicating that nucleus is the principal seat of action. However, presence of high concentration of LEP does not necessarily prove its over-expression, as often concluded, because LEP could be internalized from outside by LEPR in the cells. In contrast, LEPR is definitely over-expressed in the ductal breast cancer cells. Therefore, we hypothesize that over-expression of LEPR, rather than that of LEP has a fundamental role in breast carcinogenesis in particular, and probably for LEP-LEPR associated tumors in general.
    Matched MeSH terms: Leptin/metabolism*; Receptors, Leptin/metabolism*
  4. Fulltext Helicobacter pylori and gut microbiota modulate energy homeostasis prior to inducing histopathological changes in mice
    Khosravi Y, Bunte RM, Chiow KH, Tan TL, Wong WY, Poh QH, et al.
    Gut Microbes, 2016;7(1):48-53.
    PMID: 26939851 DOI: 10.1080/19490976.2015.1119990
    Helicobacter pylori have been shown to influence physiological regulation of metabolic hormones involved in food intake, energy expenditure and body mass. It has been proposed that inducing H. pylori-induced gastric atrophy damages hormone-producing endocrine cells localized in gastric mucosal layers and therefore alter their concentrations. In a recent study, we provided additional proof in mice under controlled conditions that H. pylori and gut microbiota indeed affects circulating metabolic gut hormones and energy homeostasis. In this addendum, we presented data from follow-up investigations that demonstrated H. pylori and gut microbiota-associated modulation of metabolic gut hormones was independent and precedes H. pylori-induced histopathological changes in the gut of H. pylori-infected mice. Thus, H. pylori-associated argumentation of energy homeostasis is not caused by injury to endocrine cells in gastric mucosa.
    Matched MeSH terms: Leptin/metabolism
  5. Leptin and reproductive dysfunction in obese men
    Almabhouh FA, Md Mokhtar AH, Malik IA, Aziz NAAA, Durairajanayagam D, Singh HJ
    Andrologia, 2020 Feb;52(1):e13433.
    PMID: 31773771 DOI: 10.1111/and.13433
    Infertility is somewhat more prevalent in men who are obese. They are also reported to have low sperm concentration, higher fraction of spermatozoa that look morphologically abnormal, higher DNA fragmentation index and evidence of oxidative stress. The precise cause for this remains uncertain. Leptin levels in serum and percentage body fat correlate positively, and obese men therefore usually have elevated serum leptin levels. Although leptin is important for normal reproductive function, but when present in excess, leptin could seriously affect reproductive function in men. Reports on the findings of sperm parameters in obese men, particularly those who are subfertile or infertile, seem to be similar to those reported from studies on normal-weight rats treated with leptin. Collectively, the observations reported in human and experimental animal studies point to leptin as a possible link between infertility and obesity. Herein, we review some findings on sperm function in obese subfertile or infertile men and those from animal studies following leptin treatment, and discuss the possible link between leptin and reproductive dysfunction in obese men. The large amounts of leptin secreted by the adipose tissue and its higher circulating levels could indeed be responsible for the higher prevalence of infertility in obese men.
    Matched MeSH terms: Leptin/metabolism*
  6. Leptin enhances N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced tumour growth in gastric mucosa of male Sprague-Dawley rats
    Isyraqiah F, Kutty MK, Durairajanayagam D, Singh HJ
    Mol Biol Rep, 2019 Dec;46(6):5967-5975.
    PMID: 31444698 DOI: 10.1007/s11033-019-05030-z
    Individuals who are obese are at a greater risk of developing gastric cancer. They are however also hyperleptinaemic. Chronic leptin treatment has been shown to upregulate numerous cancer-causing genes in the stomach of male Sprague-Dawley rats. It is however unclear if leptin enhances the effect of gastric carcinogens in vivo. This study was therefore done to investigate the effect of leptin on gastric carcinogenesis in rats treated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Twenty-four, 6-week old male Sprague-Dawley rats were divided equally into three groups: G1 served as age-matched controls; G2 was treated with MNNG in drinking water ad libitum (200 mg L-1); G3 was given leptin and MNNG. Rats were euthanized after 40 weeks of treatment and their stomachs were removed for histopathology, microarray, and RT-qPCR analysis. Fisher's exact test and one-way ANOVA were used to analyse the data. Fifty percent of the MNNG-treated rats developed gastric hyperplasia (p leptin treatment however induced hyperplasia, dysplasia, hypertrophy, and adenocarcinoma in 75% (6/8) of the rats; with upregulation of microRNAs, olfactory receptors, Hey2 (transcription factor), Tmed2 (vesicular trafficking), and Lcn11 (cell proliferation) genes. It appears that leptin enhances MNNG- induced tumour growth in stomachs of Sprague-Dawley rats and its role in gastric cancer requires further scrutiny.
    Matched MeSH terms: Leptin/metabolism*
  7. Fulltext Leptin and Associated Mediators of Immunometabolic Signaling: Novel Molecular Outcome Measures for Neurostimulation to Treat Chronic Pain
    Kinfe TM, Buchfelder M, Chaudhry SR, Chakravarthy KV, Deer TR, Russo M, et al.
    Int J Mol Sci, 2019 Sep 24;20(19).
    PMID: 31554241 DOI: 10.3390/ijms20194737
    Chronic pain is a devastating condition affecting the physical, psychological, and socioeconomic status of the patient. Inflammation and immunometabolism play roles in the pathophysiology of chronic pain disorders. Electrical neuromodulation approaches have shown a meaningful success in otherwise drug-resistant chronic pain conditions, including failed back surgery, neuropathic pain, and migraine. A literature review (PubMed, MEDLINE/OVID, SCOPUS, and manual searches of the bibliographies of known primary and review articles) was performed using the following search terms: chronic pain disorders, systemic inflammation, immunometabolism, prediction, biomarkers, metabolic disorders, and neuromodulation for chronic pain. Experimental studies indicate a relationship between the development and maintenance of chronic pain conditions and a deteriorated immunometabolic state mediated by circulating cytokines, chemokines, and cellular components. A few uncontrolled in-human studies found increased levels of pro-inflammatory cytokines known to drive metabolic disorders in chronic pain patients undergoing neurostimulation therapies. In this narrative review, we summarize the current knowledge and possible relationships of available neurostimulation therapies for chronic pain with mediators of central and peripheral neuroinflammation and immunometabolism on a molecular level. However, to address the needs for predictive factors and biomarkers, large-scale databank driven clinical trials are needed to determine the clinical value of molecular profiling.
    Matched MeSH terms: Leptin/metabolism*
  8. The role of leptin and ghrelin in appetite regulation in the Australian Spinifex hopping mouse, Notomys alexis, during long-term water deprivation
    Donald JA, Hamid NKA, McLeod JL
    Gen Comp Endocrinol, 2017 04 01;244:201-208.
    PMID: 27102941 DOI: 10.1016/j.ygcen.2016.04.015
    Water deprivation of the Spinifex hopping mouse, Notomys alexis, induced a biphasic pattern of food intake with an initial hypophagia that was followed by an increased, and then sustained food intake. The mice lost approximately 20% of their body mass and there was a loss of white adipose tissue. Stomach ghrelin mRNA was significantly higher at day 2 of water deprivation but then returned to the same levels as water-replete (day 0) mice for the duration of the experiment. Plasma ghrelin was unaffected by water deprivation except at day 10 where it was significantly increased. Plasma leptin levels decreased at day 2 and day 5 of water deprivation, and then increased significantly by the end of the water deprivation period. Water deprivation caused a significant decrease in skeletal muscle leptin mRNA expression at days 2 and 5, but then it returned to day 0 levels by day 29. In the hypothalamus, water deprivation caused a significant up-regulation in both ghrelin and neuropeptide Y mRNA expression, respectively. In contrast, hypothalamic GHSR1a mRNA expression was significantly down-regulated. A significant increase in LepRb mRNA expression was observed at days 17 and 29 of water deprivation. This study demonstrated that the sustained food intake in N. alexis during water deprivation was uncoupled from peripheral appetite-regulating signals, and that the hypothalamus appears to play an important role in regulating food intake; this may contribute to the maintenance of fluid balance in the absence of free water.
    Matched MeSH terms: Leptin/metabolism*
  9. Fulltext Helicobacter pylori infection can affect energy modulating hormones and body weight in germ free mice
    Khosravi Y, Seow SW, Amoyo AA, Chiow KH, Tan TL, Wong WY, et al.
    Sci Rep, 2015;5:8731.
    PMID: 25736205 DOI: 10.1038/srep08731
    Helicobacter pylori, is an invariably commensal resident of the gut microbiome associated with gastric ulcer in adults. In addition, these patients also suffered from a low grade inflammation that activates the immune system and thus increased shunting of energy to host defense mechanisms. To assess whether a H. pylori infection could affect growth in early life, we determined the expression levels of selected metabolic gut hormones in germ free (GF) and specific pathogen-free (SPF) mice with and without the presence of H. pylori. Despite H. pylori-infected (SPFH) mice display alteration in host metabolism (elevated levels of leptin, insulin and peptide YY) compared to non-infected SPF mice, their growth curves remained the same. SPFH mice also displayed increased level of eotaxin-1. Interestingly, GF mice infected with H. pylori (GFH) also displayed increased levels of ghrelin and PYY. However, in contrast to SPFH mice, GFH showed reduced weight gain and malnutrition. These preliminary findings show that exposure to H. pylori alters host metabolism early in life; but the commensal microbiota in SPF mice can attenuate the growth retarding effect from H. pylori observed in GF mice. Further investigations of possible additional side effects of H. pylori are highly warranted.
    Matched MeSH terms: Leptin/metabolism
  10. SDF7, a group of Scoparia dulcis Linn. derived flavonoid compounds, stimulates glucose uptake and regulates adipocytokines in 3T3-F442a adipocytes
    Beh JE, Khoo LT, Latip J, Abdullah MP, Alitheen NB, Adam Z, et al.
    J Ethnopharmacol, 2013 Oct 28;150(1):339-52.
    PMID: 24029250 DOI: 10.1016/j.jep.2013.09.001
    Adipocytes are major tissues involved in glucose uptake second to skeletal muscle and act as the main adipocytokines mediator that regulates glucose uptake mechanism and cellular differentiation. The objective of this study were to examine the effect of the SDF7, which is a fraction consists of four flavonoid compounds (quercetin: p-coumaric acid: luteolin: apigenin=8: 26: 1: 3) from Scoparia dulcis Linn., on stimulating the downstream components of insulin signalling and the adipocytokines expression on different cellular fractions of 3T3-F442a adipocytes.
    Matched MeSH terms: Leptin/metabolism
  11. Leptin and its receptor: can they help to differentiate chromophobe renal cell carcinoma from renal oncocytoma?
    Ng KL, Del Vecchio SJ, Samaratunga H, Morais C, Rajandram R, Vesey DA, et al.
    Pathology, 2018 Aug;50(5):504-510.
    PMID: 29970253 DOI: 10.1016/j.pathol.2018.01.007
    One of the challenges in differentiating chromophobe renal cell carcinoma (chRCC) from benign renal oncocytoma (RO) is overlapping morphology between the two subtypes. The aim of this study was to investigate the usefulness of expression of leptin (Ob) and its receptor (ObR) in discriminating chRCC from RO. Sections from paraffin-embedded, formalin-fixed tumour nephrectomy specimens of 45 patients, made up of 30 chRCC (15 eosinophilic variant and 15 non-eosinophilic variant) and 15 RO, were used in this study. Samples (30) of clear cell RCC (ccRCC), the most common histological subtype, were used to verify staining patterns found by others in our cohort of Australasian patients. Matched morphologically normal non-cancer kidney tissues were included for each specimen. Sections were batch-immunostained using antibodies against Ob and ObR. Stained sections were digitally scanned using Aperio ImageScope, and the expression pattern of Ob and ObR was studied. In this cohort, male to female ratio was 2:1; median age was 64 (45-88 years); and median tumour size was 3.8 cm (range 1.2-18 cm). There were 47 (62.7%) T1, seven T2, 20 T3 and one T4 stage RCC. Two patients with ccRCC presented with metastases. Nuclear expression of Ob was significantly higher in RO compared with chRCC. The increased nuclear expression of Ob in RO compared with chRCC may be a useful aid in the difficult histological differentiation of RO from chRCC, especially eosinophilic variants of chRCC.
    Matched MeSH terms: Leptin/metabolism*
  12. Fulltext Potential mechanisms linking psychological stress to bone health
    Ng JS, Chin KY
    Int J Med Sci, 2021;18(3):604-614.
    PMID: 33437195 DOI: 10.7150/ijms.50680
    Chronic psychological stress affects many body systems, including the skeleton, through various mechanisms. This review aims to provide an overview of the factors mediating the relationship between psychological stress and bone health. These factors can be divided into physiological and behavioural changes induced by psychological stress. The physiological factors involve endocrinological changes, such as increased glucocorticoids, prolactin, leptin and parathyroid hormone levels and reduced gonadal hormones. Low-grade inflammation and hyperactivation of the sympathetic nervous system during psychological stress are also physiological changes detrimental to bone health. The behavioural changes during mental stress, such as altered dietary pattern, cigarette smoking, alcoholism and physical inactivity, also threaten the skeletal system. Psychological stress may be partly responsible for epigenetic regulation of skeletal development. It may also mediate the relationship between socioeconomic status and bone health. However, more direct evidence is required to prove these hypotheses. In conclusion, chronic psychological stress should be recognised as a risk factor of osteoporosis and stress-coping methods should be incorporated as part of the comprehensive osteoporosis-preventing strategy.
    Matched MeSH terms: Leptin/metabolism
  13. Fulltext Asperuloside Enhances Taste Perception and Prevents Weight Gain in High-Fat Fed Mice
    Ishaq M, Tran D, Wu Y, Nowak K, Deans BJ, Xin JTZ, et al.
    Front Endocrinol (Lausanne), 2021;12:615446.
    PMID: 33927690 DOI: 10.3389/fendo.2021.615446
    Asperuloside is an iridoid glycoside found in many medicinal plants that has produced promising anti-obesity results in animal models. In previous studies, three months of asperuloside administration reduced food intake, body weight, and adipose masses in rats consuming a high fat diet (HFD). However, the mechanisms by which asperuloside exerts its anti-obesity properties were not clarified. Here, we investigated homeostatic and nutrient-sensing mechanisms regulating food intake in mice consuming HFD. We confirmed the anti-obesity properties of asperuloside and, importantly, we identified some mechanisms that could be responsible for its therapeutic effect. Asperuloside reduced body weight and food intake in mice consuming HFD by 10.5 and 12.8% respectively, with no effect on mice eating a standard chow diet. Fasting glucose and plasma insulin were also significantly reduced. Mechanistically, asperuloside significantly reduced hypothalamic mRNA ghrelin, leptin, and pro-opiomelanocortin in mice consuming HFD. The expression of fat lingual receptors (CD36, FFAR1-4), CB1R and sweet lingual receptors (TAS1R2-3) was increased almost 2-fold by the administration of asperuloside. Our findings suggest that asperuloside might exert its therapeutic effects by altering nutrient-sensing receptors in the oral cavity as well as hypothalamic receptors involved in food intake when mice are exposed to obesogenic diets. This signaling pathway is known to influence the subtle hypothalamic equilibrium between energy homeostasis and reward-induced overeating responses. The present pre-clinical study demonstrated that targeting the gustatory system through asperuloside administration could represent a promising and effective new anti-obesity strategy.
    Matched MeSH terms: Leptin/metabolism
  14. Fulltext Maternal Serum and Breast Milk Adiponectin: The Association with Infant Adiposity Development
    Mohamad M, Loy SL, Lim PY, Wang Y, Soo KL, Mohamed HJJ
    Int J Environ Res Public Health, 2018 Jun 12;15(6).
    PMID: 29895806 DOI: 10.3390/ijerph15061250
    The prevalence of childhood obesity is increasing at an alarming rate in Malaysia. Metabolic changes during pregnancy are critical to the development of infant adiposity, due to imbalanced adipokines production. Hence, we aimed to investigate the association of maternal serum and breast milk adipokines with infant adiposity development. The study was conducted from April 2010 until December 2012. A total of 155 healthy pregnant mothers aged 19 to 40 years were recruited during the first and second trimester in Kelantan, Malaysia. Data consisted of maternal sociodemographic details, anthropometry and clinical biochemistry analysis; and the infant’s anthropometry and feeding patterns. Maternal fasting serum and breast milk samples were analysed for adiponectin and leptin levels. Data collection was performed in the second and third trimester of pregnancy, and continued with follow-up visits at birth, two, six, and 12 months postpartum. Multiple linear regression (MLR) analyses were performed to examine the associations between maternal serum and breast milk adiponectin and leptin and infant adiposity development. MLR models showed that, in the first year, as maternal serum and breast milk adiponectin increased, infant weight, BMI-for-age Z scores and abdominal circumference significantly decreased (p < 0.05). Maternal serum and/or breast milk adiponectin was associated with first-year infant adiposity development.
    Matched MeSH terms: Leptin/metabolism
  15. Exploring the potential of tocotrienol from Bixa orellana as a single agent targeting metabolic syndrome and bone loss
    Wong SK, Chin KY, Suhaimi FH, Ahmad F, Ima-Nirwana S
    Bone, 2018 11;116:8-21.
    PMID: 29990585 DOI: 10.1016/j.bone.2018.07.003
    Metabolic syndrome (MetS) is associated with osteoporosis due to the underlying inflammatory and hormonal changes. Annatto tocotrienol has been shown to improve medical complications associated with MetS or bone loss in animal studies. This study aimed to investigate the effects of annatto tocotrienol as a single treatment for MetS and osteoporosis in high-carbohydrate high-fat (HCHF) diet-induced MetS animals. Three-month-old male Wistar rats were randomly divided into five groups. The baseline group was euthanized at the onset of the study. The normal group received standard rat chow and tap water. The remaining groups received HCHF diet and treated with three different regimens orally daily: (a) tocopherol-stripped corn oil (the vehicle of tocotrienol), (b) 60 mg/kg annatto tocotrienol, and (c) 100 mg/kg annatto tocotrienol. At the end of the study, measurements of MetS parameters, body compositions, and bone mineral density were performed in animals before sacrifice. Upon euthanasia, blood and femur of the rats were harvested for the evaluations of bone microstructure, biomechanical strength, remodelling activities, hormonal changes, and inflammatory response. Treatment with annatto tocotrienol improved all MetS parameters (except abdominal obesity), trabecular bone microstructure, bone strength, increased osteoclast number, normalized hormonal changes and inflammatory response in the HCHF animals. In conclusion, annatto tocotrienol is a potential agent for managing MetS and osteoporosis concurrently. The beneficial effects of annatto tocotrienol may be attributed to its ability to prevent the hormonal changes and pro-inflammatory state in animals with MetS.
    Matched MeSH terms: Leptin/metabolism
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