leptin and Myelodysplastic-Syndromes

Idiopathic non-clonal cytopenia (ICUS) and clonal cytopenia (CCUS) are common in the elderly population. While these entities have similar clinical presentations with peripheral blood cytopenia and less than 10% bone marrow dysplasia, their malignant potential is different and the biological relationship between these disorders and myeloid neoplasms such as myelodysplastic syndrome (MDS) is not fully understood. Aberrant DNA methylation has previously been described to play a vital role in MDS and acute myeloid leukemia (AML) pathogenesis. In addition, obesity confers a poorer prognosis in MDS with inferior overall survival and a higher rate of AML transformation. In this study, we measured DNA methylation of the promoter for the obesity-regulated gene LEP, encoding leptin, in hematopoietic cells from ICUS, CCUS and MDS patients and healthy controls. We investigated whether LEP promoter methylation is an early event in the development of myeloid neoplasms and whether it is associated with clinical outcome.. We found that blood cells of patients with ICUS, CCUS and MDS all have a significantly hypermethylated LEP promoter compared to healthy controls and that LEP hypermethylation is associated with anemia, increased bone marrow blast percentage, and lower plasma leptin levels. MDS patients with a high LEP promoter methylation have a higher risk of progression, shorter progression-free survival, and inferior overall survival. Furthermore, LEP promoter methylation was an independent risk factor for the progression of MDS in a multivariate Cox regression analysis.. In conclusion, hypermethylation of the LEP promoter is an early and frequent event in myeloid neoplasms and is associated with a worse prognosis.

Topics: Aged; Anemia; Clonal Hematopoiesis; DNA Methylation; Humans; Leptin; Leukemia, Myeloid, Acute; Myelodysplastic Syndromes; Obesity

Obesity enhances the risk of developing myelodysplastic syndromes. However, the effect of obesity on survival is unclear. Obese people present with monocytosis due to inflammatory signals emanating from obese adipose tissue. We hypothesized that obesity-induced myelopoiesis would promote the transition of myelodysplastic syndrome to acute myeloid leukemia and accelerate mortality in obesity. Obese Ob/Ob mice or their lean littermate controls received a bone marrow transplant from NUP98-HOXD13 transgenic mice, a model of myelodysplastic syndrome. The metabolic parameters of the mice were examined throughout the course of the study, as were blood leukocytes. Myeloid cells were analyzed in the bone, spleen, liver and adipose tissue by flow cytometry halfway through the disease progression and at the endpoint. Survival curves were also calculated. Contrary to our hypothesis, transplantation of NUP98-HOXD13 bone marrow into obese recipient mice significantly increased survival time compared with lean recipient controls. While monocyte skewing was exacerbated in obese mice receiving NUP98-HOXD13 bone marrow, transformation to acute myeloid leukemia was not enhanced. Increased survival of obese mice was associated with a preservation of fat mass as well as increased myeloid cell deposition within the adipose tissue, and a concomitant reduction in detrimental myeloid cell accumulation within other organs. The study herein revealed that obesity increases survival in animals with myelodysplastic syndrome. This may be due to the greater fat mass of Ob/Ob mice, which acts as a sink for myeloid cells, preventing their accumulation in other key organs, such as the liver.

Topics: Animals; Bone Marrow; Bone Marrow Transplantation; Disease Models, Animal; Homeodomain Proteins; Leptin; Leukemia, Myeloid, Acute; Mice; Mice, Transgenic; Myelodysplastic Syndromes; Myeloid Cells; Nuclear Pore Complex Proteins; Obesity; Survival Rate; Transcription Factors

Topics: Animals; Disease Models, Animal; Leptin; Mice; Myelodysplastic Syndromes; Obesity; Overweight; Survival Rate

Excess body weight has been implicated in the pathogenesis of myelodysplastic syndrome (MDS). We thus explored the role of serum fetuin-A reflecting ectopic hepatic fat deposition when storage capacity of adipocytes has been exceeded, free leptin reflecting overall fat mass and adiponectin reflecting visceral fat mass, all potential mediators of the effects of obesity on insulin resistance and, consequently, to MDS risk.. In a hospital-based case-control study, we studied 101 cases with incident, histologically confirmed primary MDS and 101 controls matched on gender, age and date of diagnosis, between 2004 and 2007. Serum fetuin-A, adiponectin, leptin, leptin receptor, free leptin and insulin were determined.. Higher serum fetuin-A, lower adiponectin and lower free leptin were all individually and independently associated with higher risk of MDS before and after controlling for matching and risk factors, such as age, gender, date of diagnosis, body mass index (BMI), family history of lymphohematopoietic cancer, smoking history and serum insulin. Interestingly, we have shown that these associations were prominent among overweight/obese individuals and persisted after controlling for BMI and serum insulin indicating that their effects are above and beyond insulinemia only.. Elevated serum fetuin-A but lower adiponectin and free leptin are associated with higher risk of MDS particularly among overweight/obese individuals. These findings suggest that the association between excessive weight gain and the risk of MDS could be mediated by fetuin-A, adiponectin and free leptin, which may have potential clinical and preventive implications.

Topics: Adiponectin; Aged; Aged, 80 and over; alpha-2-HS-Glycoprotein; Anthropometry; Body Mass Index; Confidence Intervals; Female; Humans; Insulin Resistance; Leptin; Male; Middle Aged; Myelodysplastic Syndromes; Obesity; Odds Ratio; Overweight; Prognosis; Receptors, Leptin

A number of cytokines secreted from the bone marrow stromal cells and circulating hormones related to bone, adipose tissue and glucose metabolism might be involved in the pathogenesis of myelodysplastic syndromes (MDS).. Serum levels of cytokines related to the metabolism of bone tissue [osteocalcin and parathyroid hormone (PTH)], adipose tissue (adiponectin, leptin and ghrelin) and glucose [insulin and insulin-like growth factor-1 (IGF-1)] were determined in 72 patients suffering from MDS, mostly of the low-risk group according to FAB classification, and 41 healthy individuals (controls).. Adiponectin and osteocalcin serum levels were significantly elevated in the MDS patients. Leptin, insulin and IGF-1 serum levels were reduced. No difference was found in the serum levels of PTH and ghrelin. Leptin levels were reversibly associated with patient blast count.. Increased serum levels of adiponectin and low levels of IGF-1 in MDS patients may counterbalance the increased rate of apoptosis in the pool of hematopoietic progenitors. Osteocalcin secreted by osteoblasts regulates the renewal and proliferation of hematopoietic stem cells. Hormones and cytokines either secreted by the cells of the bone marrow stroma or transferred by the microcirculation act on hematopoietic progenitors and may regulate their differentiation, apoptosis and proliferation rate in MDS.

Topics: Adiponectin; Aged; Apoptosis; Blood Glucose; Bone Marrow; Cell Differentiation; Cell Proliferation; Cytokines; Female; Ghrelin; Hematopoietic Stem Cells; Hormones; Humans; Insulin; Insulin-Like Growth Factor I; Leptin; Male; Myelodysplastic Syndromes; Osteoblasts; Osteocalcin; Parathyroid Hormone; Risk Factors

Adiponectin plays a protective role in several malignancies, including myeloblastic leukemia, whereas leptin may increase the proliferation of progenitor cells and may stimulate leukemic cell growth in vitro. We investigated the role of adiponectin and leptin levels in the etiopathogenesis of myelodysplastic syndromes (MDS), a preleukemic condition with increasing incidence which has recently been associated with obesity.. In a case-control study, 101 cases with incident, histologically confirmed primary MDS and 101 controls matched on gender and age were studied between 2004 and 2007, and blood samples were collected.. Higher serum adiponectin levels were associated with lower risk of MDS by bivariate analysis and after adjusting for age, gender, body mass index and serum levels of leptin (p < 0.001). Subjects in the third quartile for leptin levels had a lower risk of MDS than controls, and low leptin concentrations were observed in low-risk MDS patients with normal or good prognostic karyotype after adjusting for age, gender and body mass index.. Circulating adiponectin and leptin may play an important role in MDS etiopathogenesis. Future studies are needed to confirm these associations and to explore underlying mechanisms.

Topics: Adiponectin; Aged; Biomarkers; Biomarkers, Tumor; Case-Control Studies; Female; Humans; Leptin; Leukemia; Male; Middle Aged; Myelodysplastic Syndromes; Obesity; Precancerous Conditions; Predictive Value of Tests; Prognosis

Leptin, the adipocyte hormone, and its receptor have been implicated in the differentiation/proliferation of hematopoietic cells. Given that the deregulated expression of a variety of growth factors and/or their receptors has been implicated in the pathogenesis of certain leukemias, we aimed to characterize the potential differences in the expression pattern of the two major leptin receptor transcript variants in peripheral blood mononuclear cells (PBMC) between different hematologic malignancies. Using RT-PCR and Southern blotting, we compared the expression levels of the two major leptin receptors, the longest (OB-R(L)) and the shortest (OB-R(S)) splice variants, in PBMC from patients with myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), healthy individuals and two human hematopoietic cell lines (HL-60 and K562). Expression of the OB-R(S) transcript clearly exceeded that of OB-R(L) in all patients and controls and in the HL-60 cells, but this was reversed in the K562 cell line. However, the expression of the OB-R(L) was significantly lower in MDS compared to controls and tended to be so in AML, while OB-R(S) tended to be higher in MDS and AML patients compared to controls, but this difference was not significant. Serum leptin levels and circulating soluble leptin receptor levels were slightly but not significantly higher in AML and MDS. These alterations in the expression of the leptin receptor isoforms in MDS and AML patients could suggest a potential role of leptin and its signaling in hematopoietic malignancies, which requires further examination.

Topics: Adult; Aged; Alternative Splicing; Female; Gene Expression Regulation, Leukemic; HL-60 Cells; Humans; K562 Cells; Leptin; Leukemia, Myeloid, Acute; Leukocytes, Mononuclear; Male; Middle Aged; Myelodysplastic Syndromes; Protein Isoforms; Receptors, Cell Surface; Receptors, Leptin; Signal Transduction

The receptor for the gene product of the obesity gene, leptin, was recently reported to be expressed on murine and human hematopoietic progenitor cells. Therefore, we studied the expression of the leptin receptor, OB-R, in normal myeloid precursors, human leukemia cell lines, and primary leukemic cells using reverse-transcriptase polymerase chain reaction. In normal hematopoiesis, OB-R was expressed in CD34(+) cells. Normal promyelocytes (CD34(-)33(+) and CD34(-)13(+)) expressed only very low levels of the short, presumably nonsignaling isoform. Both the long and short isoforms of OB-R were expressed in 10 of 22 samples from patients with newly diagnosed primary or secondary acute myeloid leukemia (AML), with a higher incidence of the long isoform in primary AML (87.6% v 28.6%; P =.01). The incidence of OB-R expression was higher in recurrent than in newly diagnosed AML (P <.001), and samples from four patients with refractory AML showed strong expression of both isoforms. Both OB-R isoforms were also expressed in newly diagnosed and recurrent acute promyelocytic leukemia cells but were essentially absent in samples of chronic or acute lymphocytic leukemia. In vitro growth of myeloid leukemic cell lines and of blasts from 14 primary AMLs demonstrated that recombinant human leptin alone induced low level proliferation, significantly (P <.05) increased proliferation induced by recombinant human granulocyte colony-stimulating factor, interleukin 3, and stem cell factor in a subset of AML and increased colony formation (P <.005). Also, leptin reduced apoptosis induced by cytokine withdrawal in MO7E and TF-1 cells. Serum leptin levels correlated only with body mass index (P <. 001) and gender (P =.03). Results confirm the reported expression of leptin receptor in normal CD34(+) cells and demonstrate the frequent expression of leptin receptors in AML blasts. While normal promyelocytes lack receptor expression, leukemic promyelocytes express both isoforms. We also demonstrate proliferative effects of leptin alone and in combination with other physiologic cytokines, and anti-apoptotic properties of leptin. These findings could have implications for the pathophysiology of AML.

Topics: Apoptosis; Carrier Proteins; Cell Division; Humans; Leptin; Leukemia, Myeloid; Myelodysplastic Syndromes; Protein Isoforms; Proteins; Receptors, Cell Surface; Receptors, Cytokine; Receptors, Leptin; Tumor Cells, Cultured