High concentration of leptin stimulates myeloid differentiation from human bone marrow CD34+ progenitors: potential involvement in leukocytosis of obese subjects

Human Bone Marrow Adipose Tissue is a Hematopoietic Niche for Leptin-Driven Monopoiesis

During aging, adipose tissue within the bone marrow expands while the trabecular red marrow contracts. The impact of these changes on blood cell formation remains unclear. To address this question, we performed single-cell and single-nuclei transcriptomic analysis on adipose-rich yellow bone marrow (BMY) and adipose-poor trabecular red marrow (BMR) from human subjects undergoing lower limb amputations. Surprisingly, we discovered two distinct hematopoietic niches, in which BMY contains a higher number of monocytes and progenitor cells expressing genes associated with inflammation. To further investigate these niches, we developed an in-vitro organoid system that maintains features of the human bone marrow. We find cells from BMY are distinct in their expression of the leptin receptor, and respond to leptin stimulation with enhanced proliferation, leading to increased monocyte production. These findings suggest that the age-associated expansion of bone marrow adipose tissue drives a pro-inflammatory state by stimulating monocyte production from a spatially distinct, leptin-responsive hematopoietic stem/progenitor cell population.

Significance

This study reveals that adipose tissue within the human bone marrow is a niche for hematopoietic stem and progenitor cells that can give rise to pro-inflammatory monocytes through leptin signaling. Expansion of bone marrow adipose tissue with age and stress may thus underlie inflammageing.

Neutrophils as indicators of obesity-associated inflammation: A systematic review and meta-analysis

INTRODUCTION

The aim of this study is to evaluate and compare the suitability of routine blood neutrophil values as indicators of obesity-associated inflammation.

METHODS

In this systematic review and meta-analysis, we assess absolute neutrophil counts (ANCs) and neutrophil-to-lymphocyte ratio (NLR) values in subjects with and without obesity and analyze the weight of both parameters on the disease. Additionally, correlation studies between ANC and NLR with BMI, a parameter internationally accepted to define obesity are performed.

RESULTS

Quantitative data from 12 (ANC) and 11 (NLR) studies were included, with a total of 4475 participants. The meta-analysis shows that while both parameters are increased in the obesity group, ANC values present higher differences with the control and less heterogeneity among studies. Additionally, unlike NLR, ANC demonstrates a positive and significant correlation with BMI.

CONCLUSION

Overall, this meta-analysis demonstrates that ANC is a more reliable and stable parameter than NLR for the assessment of obesity-related inflammation, which offers clinicians a novel tool to assist in preventing complications related to obesity.

Bone Marrow Adipocytes as Novel Regulators of Metabolic Homeostasis: Clinical Consequences of Bone Marrow Adiposity

PURPOSE OF REVIEW

Bone marrow adipose tissue is a distinctive fat depot located within the skeleton, with the potential to influence both local and systemic metabolic processes. Although significant strides have been made in understanding bone marrow adipose tissue over the past decade, many questions remain regarding their precise lineage and functional roles.

RECENT FINDINGS

Recent studies have highlighted bone marrow adipose tissue's involvement in continuous cross-talk with other organs and systems, exerting both endocrine and paracrine functions that play a crucial role in metabolic homeostasis, skeletal remodeling, hematopoiesis, and the progression of bone metastases. The advancement of imaging techniques, particularly cross-sectional imaging, has profoundly expanded our understanding of the complexities beyond the traditional view of bone marrow adipose tissue as an inert depot. Notably, marrow adipocytes are anatomically and functionally distinct from brown, beige, and classic white adipocytes. Emerging evidence suggests that bone marrow adipocytes, bone marrow adipose tissue originate from the differentiation of bone marrow mesenchymal stromal cells; however, they appear to be a heterogeneous population with varying metabolic profiles, lipid compositions, secretory properties, and functional responses depending on their specific location within the bone marrow. This review provides an up-to-date synthesis of current knowledge on bone marrow adipocytes, emphasizing the relationships between bone marrow adipogenesis and factors such as aging, osteoporosis, obesity, and bone marrow tumors or metastases, thereby elucidating the mechanisms underlying musculoskeletal pathophysiology.

Adipokines from adipose tissue and common variable immunodeficiency: Is there any association?

Adiponectin and leptin are adipokines, secreted by white adipose tissue (WAT), which play an important role in energy homeostasis. Some evidence has shown that adipokine-producing adipose cells present in the bone marrow (BM) appear to exert an influence on hematopoiesis and B cell development. Common variable immunodeficiency (CVID) is one of the most common inborn errors of immunity in humans. In CVID, numerical and/or functional defects of B cells and their precursors result in hypogammaglobulinemia, usually Immunoglobulin (Ig) A and IgG. Manifestations of CVID include immunodeficiency, autoimmunity, inflammation and lymphoproliferation, resulting in a wide range of phenotypes. How adipokines interact and influence the pathophysiology of CVID is still unclear. In this review, we seek to summarize the aspects known so far concerning the interface between adipokines, B cells and CVID. More research is needed to fully understand these interactions; this knowledge is a potential avenue for the discovery of useful biomarkers and may provide new therapeutic targets for the treatment of patients with CVID and related diseases.

Relationship between leptin and white blood cells: a potential role in infection susceptibility and severity-the Olivetti Heart Study

A number of evidence showed an emerging role of leptin on immune system, involving inflammation, and innate and adaptive immunity. Few observational studies have evaluated the relationship between leptin and immunity, albeit with low statistical power and methodological differences. Therefore, the aim of this study was to evaluate the potential role of leptin on the immunity, expressed as white blood cells (WBC)-and its subpopulations, by comprehensive multivariate models in a sample of adult men. A cross-sectional evaluation of a general population comprised 939 subjects participating in the Olivetti Heart Study, with available leptin levels and WBC-and its subpopulations. WBC were significantly and positively associated with leptin, C-reactive protein and HOMA index (p < 0.05), but not with age and anthropometric indices (p > 0.05). The multivariate analysis confirmed the association between leptin and WBC, after accounting for main confounders (p < 0.05). Additional analysis on WBC subpopulations showed a positive and significant correlation between leptin and lymphocytes, monocytes and eosinophils (p < 0.05), but not with neutrophils and basophils (p > 0.05). After stratification by body weight, the positive and significant association between leptin and WBC-and its subpopulations-was found in excess body weight participants. The results of this study indicate a direct relationship between leptin levels and WBC-and its subpopulations-in excess body weight participants. These results support the hypothesis that leptin has modulatory functions on immunity and role in the pathophysiology of immune-related diseases, in particular in those associated with excess body weight.

Time restricted feeding modifies leukocyte responsiveness and improves inflammation outcome

Time restricted eating, the dietary approach limiting food intake to a maximal 10-hour period of daytime is considered beneficial in metabolic dysfunctions, such as obesity and diabetes. Rhythm of food intake and parallel changes in serum nutrient levels are also important entrainment signals for the circadian clock, particularly in tissues involved in metabolic regulation. As both the metabolic state and the circadian clock have large impact on immune functions, we investigated in mice whether time restricted feeding (TRF) affects systemic inflammatory potential. TRF slackened the symptoms in K/BxN serum-transfer arthritis, an experimental model of human autoimmune joint inflammation. Compared to ad libitum conditions TRF reduced the expression of inflammatory mediators in visceral adipose tissue, an integrator and coordinator of metabolic and inflammatory processes. Furthermore, TRF strengthened the oscillation of peripheral leukocyte counts and alongside decreased the pool of both marginated and tissue leukocytes. Our data suggest that the altered leukocyte distribution in TRF mice is related to the attenuated expression of adhesion molecules on the surface of neutrophils and monocytes. We propose that TRF modifies both rhythm and inflammatory potential of leukocytes which contribute to the milder reactivity of the immune system and therefore time-restricted eating could serve as an effective complementary tool in the therapy of autoinflammatory processes.

Neutrophils Actively Contribute to Obesity-Associated Inflammation and Pathological Complications

Obesity is characterized by an increase in body weight associated with an exaggerated enlargement of the adipose tissue. Obesity has serious negative effects because it is associated with multiple pathological complications such as type 2 diabetes mellitus, cardiovascular diseases, cancer, and COVID-19. Nowadays, 39% of the world population is obese or overweight, making obesity the 21st century epidemic. Obesity is also characterized by a mild, chronic, systemic inflammation. Accumulation of fat in adipose tissue causes stress and malfunction of adipocytes, which then initiate inflammation. Next, adipose tissue is infiltrated by cells of the innate immune system. Recently, it has become evident that neutrophils, the most abundant leukocytes in blood, are the first immune cells infiltrating the adipose tissue. Neutrophils then get activated and release inflammatory factors that recruit macrophages and other immune cells. These immune cells, in turn, perpetuate the inflammation state by producing cytokines and chemokines that can reach other parts of the body, creating a systemic inflammatory condition. In this review, we described the recent findings on the role of neutrophils during obesity and the initiation of inflammation. In addition, we discuss the involvement of neutrophils in the generation of obesity-related complications using diabetes as a prime example.

A Population Pharmacokinetic Model of Whole-Blood and Intracellular Tacrolimus in Kidney Transplant Recipients

BACKGROUND AND OBJECTIVE

The tacrolimus concentration within peripheral blood mononuclear cells may correlate better with clinical outcomes after transplantation compared to concentrations measured in whole blood. However, intracellular tacrolimus measurements are not easily implemented in clinical practice. The prediction of intracellular concentrations based on whole-blood concentrations would be a solution for this. Therefore, the aim of this study was to describe the relationship between intracellular and whole-blood tacrolimus concentrations in a population pharmacokinetic (popPK) model.

METHODS

Pharmacokinetic analysis was performed using non-linear mixed effects modelling software (NONMEM). The final model was evaluated using goodness-of-fit plots, visual predictive checks, and a bootstrap analysis.

RESULTS

A total of 590 tacrolimus concentrations from 184 kidney transplant recipients were included in the study. All tacrolimus concentrations were measured in the first three months after transplantation. The intracellular tacrolimus concentrations (n  = 184) were best described with an effect compartment. The distribution into the effect compartment was described by the steady-state whole-blood to intracellular ratio (R_WB:IC) and the intracellular distribution rate constant between the whole-blood and intracellular compartments. Lean body weight was negatively correlated [delta objective function value (ΔOFV) -8.395] and haematocrit was positively correlated (ΔOFV = - 6.752) with R_WB:IC, and both lean body weight and haematocrit were included in the final model.

CONCLUSION

We were able to accurately describe intracellular tacrolimus concentrations using whole-blood concentrations, lean body weight, and haematocrit values in a popPK model. This model may be used in the future to more accurately predict clinical outcomes after transplantation and to identify patients at risk for under- and overexposure. Dutch National Trial Registry number NTR2226.

Benzene Exposure Leads to Lipodystrophy and Alters Endocrine Activity In Vivo and In Vitro

Benzene is a ubiquitous pollutant and mainly accumulates in adipose tissue which has important roles in metabolic diseases. The latest studies reported that benzene exposure was associated with many metabolic disorders, while the effect of benzene exposure on adipose tissue remains unclear. We sought to investigate the effect using in vivo and in vitro experiments. Male adult C57BL/6J mice were exposed to benzene at 0, 1, 10 and 100 mg/kg body weight by intragastric gavage for 4 weeks. Mature adipocytes from 3T3-L1 cells were exposed to hydroquinone (HQ) at 0, 1, 5 and 25 μM for 24 hours. Besides the routine hematotoxicity, animal experiments also displayed significant body fat content decrease from 1 mg/kg. Interestingly, the circulating non-esterified fatty acid (NEFA) level increased from the lowest dose (p_trend < 0.05). Subsequent analysis indicated that body fat content decrease may be due to atrophy of white adipose tissue (WAT) upon benzene exposure. The average adipocyte area of WAT decreased significantly even from 1 mg/kg with no significant changes in total number of adipocytes. The percentages of small and large adipocytes in WAT began to significantly increase or decrease from 1 mg/kg (all p < 0.05), respectively. Critical genes involved in lipogenesis and lipolysis were dysregulated, which may account for the disruption of lipid homeostasis. The endocrine function of WAT was also disordered, manifested as significant decrease in adipokine levels, especially the leptin. In vitro cell experiments displayed similar findings in decreased fat content, dysregulated critical lipid metabolism genes, and disturbed endocrine function of adipocytes after HQ treatment. Pearson correlation analysis showed positive correlations between white blood cell (WBC) count with WAT fat content and plasma leptin level (r = 0.330, 0.344, both p < 0.05). This study shed light on the novel aspect that benzene exposure could induce lipodystrophy and disturb endocrine function of WAT, and the altered physiology of WAT might in turn affect benzene-induced hematotoxicity and metabolic disorders. The study provided new insight into understanding benzene-induced toxicity and the relationship between benzene and adipose tissue.

Western Diet Induces Impairment of Liver-Brain Axis Accelerating Neuroinflammation and Amyloid Pathology in Alzheimer's Disease

Alzheimer's disease (AD) is an aging-dependent, irreversible neurodegenerative disorder and the most common cause of dementia. The prevailing AD hypothesis points to the central role of altered cleavage of amyloid precursor protein (APP) and formation of toxic amyloid-β (Aβ) deposits in the brain. The lack of efficient AD treatments stems from incomplete knowledge on AD causes and environmental risk factors. The role of lifestyle factors, including diet, in neurological diseases is now beginning to attract considerable attention. One of them is western diet (WD), which can lead to many serious diseases that develop with age. The aim of the study was to investigate whether WD-derived systemic disturbances may accelerate the brain neuroinflammation and amyloidogenesis at the early stages of AD development. To verify this hypothesis, transgenic mice expressing human APP with AD-causing mutations (APPswe) were fed with WD from the 3rd month of age. These mice were compared to APPswe mice, in which short-term high-grade inflammation was induced by injection of lipopolysaccharide (LPS) and to untreated APPswe mice. All experimental subgroups of animals were subsequently analyzed at 4-, 8-, and 12-months of age. APPswe mice at 4- and 8-months-old represent earlier pre-plaque stages of AD, while 12-month-old animals represent later stages of AD, with visible amyloid pathology. Already short time of WD feeding induced in 4-month-old animals such brain neuroinflammation events as enhanced astrogliosis, to a level comparable to that induced by the administration of pro-inflammatory LPS, and microglia activation in 8-month-old mice. Also, WD feeding accelerated increased Aβ production, observed already in 8-month-old animals. These brain changes corresponded to diet-induced metabolic disorders, including increased cholesterol level in 4-months of age, and advanced hypercholesterolemia and fatty liver disease in 8-month-old mice. These results indicate that the westernized pattern of nourishment is an important modifiable risk factor of AD development, and that a healthy, balanced, diet may be one of the most efficient AD prevention methods.

Inflammation-Related Markers and Thyroid Function Measures in Pediatric Patients: Is the Grade of Obesity Relevant?

We aimed to investigate the effect of weight status on inflammation-related markers and thyroid function tests in overweight and obese pediatric patients. Children and adolescents diagnosed between January 2017 and January 2019 with overweight or obesity were included in the study. Neutrophil-to-lymphocyte ratio (NLR), platelet-to lymphocyte ratio (PLR) and systemic immune-inflammation index (SII) were calculated for the groups defined according to Body Mass Index (BMI)-for-age z-score: overweight (≥1 BMI-for-age z-score), obese (≥2 BMI-for-age z-score) and severely obese (≥3 BMI-for-age z-score). Severely obese patients had significantly higher value of white blood cells (WBC) counts (median = 7.92) compared with overweight patients (7.37, p = 0.014). Absolute lymphocyte count was significantly associated with obesity degree in children (Spearman’s Rho coefficient ρ = 0.228. p = 0.035), whereas absolute polymorphonuclear neutrophils (PMNCs) count was significantly higher in severely obese adolescents than overweight adolescents (overweight: 4.04 vs. severely obese: 5.3 (p = 0.029)). In 8.19% of patients an elevated thyroid-stimulating hormone (TSH) level was found, and 3.36% of patients had a low level of free thyroxine with an elevated level of TSH. Total absolute WBC count may be a reliable inflammation-related marker in obese pediatric patients without metabolic syndrome, but needs to be validated in the context of all possible covariates. Subclinical and overt hypothyroidism may develop from an early age in overweight or obese patients.

The Effect of Short-Term Feeding of a High-Coconut Oil or High-Fat Diet on Neuroinflammation and the Performance of an Object-Place Task in Rats

The consumption of high-fat and high-sugar diets, in the form of junk food, and binge eating are now common. Increasing evidence suggests that a high-fat diet (HFD) can induce neuroinflammation and alter behavior. I aimed to study the effects of diets of differing fat content on neuroinflammation and spatial memory using an object-place (OP) task. Thirty-two adult male rats were allocated to four groups and fed a regular diet (Regular diet), a control diet (Control diet), an HFD (60% of calories from lard), or a high-coconut oil diet (HCOD; 60% of calories from coconut oil) for 3 days. Their water intake, food consumption, body mass, and metabolic variables were measured. HFD-fed rats showed significantly poorer performance on the OP task, as assessed using the discrimination index (- 0.208 ± 0.094), than the Regular (0.462 ± 0.078; P < 0.0001) and Control (0.379 ± 0.081; P = 0.0003) groups. However, no significant difference was observed in spatial memory between the HCOD and Regular groups. The concentrations of neuroinflammatory markers (interleukin [IL]-1β, IL-6, tumor necrosis factor α, and nuclear factor κB) were also measured in the hippocampus and prefrontal cortex. HFD-fed rats showed significantly higher levels of neuroinflammatory markers than the Regular and Control diet-fed groups. HCOD feeding did not induce neuroinflammation in the hippocampus and prefrontal cortex compared with the Regular and Control groups.

The hematologic consequences of obesity

The prevalence of obesity is increasing and progressively influencing physician-patient interactions. While there is a sizable amount of data demonstrating that obesity is a state of low-grade inflammation, to our knowledge, there is no single review summarizing its effects on hematologic parameters and thrombotic risk. We performed a literature search which largely surfaced observational studies, with a few systematic reviews and meta-analyses of these studies. We took care to review the mechanisms driving an inflammatory state and obesity's effect on white blood cells, red blood cells, platelets, and thrombotic risk. There is an observed relative, and sometimes absolute leukocytosis driven by this inflammatory state. Obesity is also associated with increased platelet counts and an increased risk for venous thromboembolism (VTE). Lastly, the association between obesity, iron deficiency (ID), and red blood cell counts may be present but remains uncertain. Recognizing the above associations may provide clinicians with reassurance regarding otherwise unexplained hematologic abnormalities in obese individuals. We hope this review will prompt future studies to further understand the underlying mechanisms driving these abnormalities and identify modifiable risk factors and potential therapeutic targets to prevent the development of probable obesity-associated conditions with significant morbidity and mortality, such as ID and VTE.

CIN or not: An approach to the evaluation and management of chronic idiopathic neutrophilia

Neutrophilia refers to an increase in the number of circulating neutrophils in the peripheral blood. Some common etiologies include infection, inflammatory conditions, myeloproliferative disorders, malignancies, endocrinopathies, drugs, and anemia. Rare disorders such as leukocyte adhesion deficiency can also cause neutrophilia. In many cases, there is an elevation of neutrophil count that persists for months or even years with no clear underlying cause in an otherwise asymptomatic patient. This is referred to as chronic idiopathic neutrophilia (CIN). Despite being a condition encountered by many physicians, there is a paucity of literature addressing CIN. Certain conditions such as stress, exercise, smoking, obesity, and obstructive sleep apnea have been associated with CIN and may provide explanations for neutrophilia previously thought to be idiopathic. Herein, we present a review of the literature on CIN and propose a systematic approach to this commonly encountered clinical condition.

Circulating leptin levels predict the decline in renal function with age in a sample of adult men (The Olivetti Heart Study)

Leptin (LPT) is associated with a number of cardiovascular risk factors, such as high blood pressure (BP), insulin resistance and excess in body weight. Some studies find an unfavorable cross-sectional association between LPT and renal disease, in particular in patients with already known kidney dysfunction. There are few data on the relationship between LPT and changes in renal function over time in subjects without evidence of kidney dysfunction. Hence, the aim of this study is to estimate the predictive role of LPT on the decline in renal function occurring in an 8-year follow-up observation of a sample of adult apparently healthy men (The Olivetti Heart Study). The study includes 319 untreated normotensive and nondiabetic men without clinical evidence of renal dysfunction (creatinine clearance-CrCl > 60 mL/min/1.73 m²) at baseline. At baseline, LPT is significantly and positively associated with BMI, abdominal circumference, BP and Homa index, no relationship is found with CrCl. At the end of the 8-year follow-up, a significant association is detected between baseline LPT and changes occurring in BP. Moreover, an inverse correlation with changes in CrCl is found (r = - 0.12). This unfavorable relationship between baseline LPT and decline in renal function is also confirmed in the multivariate analyses, after adjustment for all potential confounders (R² = 0.42, p < 0.01). The results of this prospective investigation suggest a predictive role of circulating LPT levels on decline in renal function over time, independently of main potential confounders, in normotensive and nondiabetic men with normal renal function at baseline.

Relationship of leukocytes, platelet indices and adipocytokines in metabolic syndrome patients

AIMS

The current study aimed to explore the correlation between leukocytes and platelets indices with adipocytokines (leptin and adiponectin) and MetS components.

METHODS

A total of 100 healthy subjects and 200 patients diagnosed with different MetS components were enrolled in the study. Eligible patients were allocated into four groups (50 patients). Group1 include patients with 2 criteria of MetS components, group 2 with 3 criteria, group 3 with 4 criteria and group 4 had patients with 5 criteria.

RESULTS

Regarding white blood cell indices, data showed that total leukocyte and neutrophil count as well as neutrophil/lymphocyte (N/L) ratio were significantly increased in all groups of MetS patients when compared to the healthy group. Additionally, platelets count, platelet distribution width (PDW), and main platelet volume (MPV) levels and platelets/lymphocyte (P/L) ratio were significantly higher in all patients with MetS as compared to the healthy subjects. Serum leptin concentration and leptin-to-adiponectin ratio (LAR) were elevated significantly, while adiponectin level was significantly diminished in all MetS groups when compared to the control.

CONCLUSION

leukocytes and platelets indices were associated with hyperleptinemia and hypoadiponectinemia as well as MetS components. The study also suggested the necessary role of leukocytes, platelet indices, and LAR as markers in early diagnoses of individuals with MetS components.

The association between obesity and dengue virus (DENV) infection in hospitalised patients

Both obesity and DENV infections are growing public health concerns that have far-ranging socioeconomic effects, especially in developing countries. Despite the increasing prevalence of these conditions, there is a scarcity of data investigating the potential relationships between these two entities. Our study aims to examine the influence of obesity on various clinical and laboratory parameters amongst patients with DENV infections. A total of 335 hospitalized patients aged >12 years who were DENV non-structural protein 1 (NS1) antigen-positive were enrolled in this study. Clinical and laboratory variables were compared between patients with and without obesity. Multivariate analysis showed that the following admission clinical findings and laboratory results were independently associated with obesity; chills and rigors (AOR:2.653, 95% CI: 1.286–5.474), higher temperature (AOR:1.485, 95% CI: 1.080–2.042), higher systolic BP (AOR:1.057, 95% CI:1.037–1.078), raised haematocrit (AOR: 1.953, 95% CI: 1.010–3.778), elevated creatinine (AOR:3.504, 95% CI:1.351–9.008) and elevated ALT (AOR: 4.146, 95% CI:1.878–9.154). Obesity was found to be significantly associated with hospitalization >3 days (AOR: 1.990, 95% CI: 1.134–3.494) and the presence of increasing haematocrit with decreasing platelets (AOR: 2.134, 95% CI = 1.235–3.688). Serial assessment of laboratory data revealed that peak haematocrit was significantly higher and nadir platelets levels were significantly lower in obese patients. Both peak and admission levels of leukocyte counts, AST, ALT and creatinine were significantly higher in the obese group. Conversely, both admission and nadir albumin levels were lower for the obese group, although only nadir albumin levels achieved statistical significance. These findings support closer clinical monitoring of obese patients who present with DENV infections, as this patient cohort may possess an increased tendency towards developing more severe clinical manifestations of DENV infections as compared to non-obese patients.

Increased Serum Leptin Levels in New-Onset, Untreated Female Patients with Coronary Artery Disease and Positively Associated with Inflammatory Markers

BACKGROUND/AIMS

Previous studies have suggested that leptin was associated with atherosclerosis and involved in inflammation. Gender differences between leptin and inflammatory markers have been evaluated less in untreated patients with stable coronary artery disease (CAD).

METHODS

In this study, a total of 394 consecutive Chinese patients who received coronary artery angiography were enrolled, including 243 patients with CAD and 151 non-CAD controls. The baseline clinical characteristics were collected and serum leptin levels were determined using ELISA.

RESULTS

The relation of serum leptin levels to inflammatory markers was found only in female patients. Leptin and white blood cell count (WBCC) as well as its subsets were significantly higher in female patients than female controls. In female patients, leptin was positively associated with C-reactive protein (CRP; r = 0.28, p = 0.016), WBCC (r = 0.261, p = 0.02), neutrophil, r = 0.268, p = 0.018, and monocyte, r = 0.228, p = 0.044. Multivariable regression analysis revealed that leptin was significantly and independently associated with CRP (β = 0.317, p = 0.004), WBCC (β = 0.278, p = 0.020), neutrophil (β = 0.262, p = 0.032), and monocyte (β = 0.245, p = 0.032).

CONCLUSIONS

The serum leptin levels were higher in female patients and independently associated with CRP, WBCC, and its subsets, suggesting a potential interaction between leptin and inflammation in female CAD patients.

Effects of iron supplementation in mice with hypoferremia induced by obesity

Iron is an important micronutrient, but it can also act as a dangerous element by interfering with glucose homeostasis and inflammation, two features that are already disturbed in obese subjects. In this work, we study the effects of systemic iron supplementation on metabolic and inflammatory responses in mice with hypoferremia induced by obesity to better characterize whether iron worsens the parameters that are already altered after 24 weeks of a high-fat diet (HFD). Mice were maintained on a control diet or a HFD for 24 weeks and received iron-III polymaltose (50 mg/kg/every 2 days) during the last two weeks. Glucose homeostasis (basal glucose and insulin test tolerance) and systemic and visceral adipose tissue (VAT) inflammation were assessed. Iron levels were measured in serum. The Prussian blue reaction was used in isolated macrophages to detect iron deposition. Iron supplementation resulted in an increased number of VAT macrophages that were positive for Prussian blue staining as well as increased serum iron levels. Systemic hepcidin, leptin, resistin, and monocyte chemoattractant protein-1 (MCP-1) levels were not altered by iron supplementation. Local adipose tissue inflammation was also not made worse by iron supplementation because the levels of hepcidin, MCP-1, leptin, and interleukin (IL)-6 were not altered. In contrast, iron supplementation resulted in an increased production of IL-10 by adipose tissue and VAT macrophages. Leukocytosis and VAT plasminogen activator inhibitor-1 (PAI-1) level were reduced, but insulin resistance was not altered after iron supplementation. In conclusion, systemic iron supplementation in mice with hypoferremia induced by obesity did not worsen inflammatory marker or adipose tissue inflammation or the metabolic status established by obesity. Iron deposition was observed in adipose tissue, mainly in macrophages, suggesting that these cells have mechanisms that promote iron incorporation without increasing the production of inflammatory mediators.

Impaired Mobilization of Vascular Reparative Bone Marrow Cells in Streptozotocin-Induced Diabetes but not in Leptin Receptor-Deficient db/db Mice

Diabetes is associated with impaired mobilization of bone marrow stem/progenitor cells that accelerate vascularization of ischemic areas. This study characterized mobilization of vascular reparative bone marrow progenitor cells in mouse models of diabetes. Age-matched control or streptozotocin (STZ)-induced diabetic, and db/db mice with lean-controls were studied. Mobilization induced by G-CSF, AMD3100 or ischemia was evaluated by flow cytometric enumeration of circulating Lin(-)Sca-1(+)cKit(+) (LSK) cells, and by colony forming unit (CFU) assay. The circulating WBCs and LSKs, and CFUs were reduced in both models with a shorter duration (10-12 weeks) of diabetes compared to their respective controls. Longer duration of STZ-diabetes (≥20 weeks) induced impairment of G-CSF- or AMD3100-mobilization (P < 0.01, n = 8). In db/db mice, mobilization by G-CSF or AMD3100 was either increased or unaffected (P < 0.05, n = 6 to 8). Proliferation, migration, and ischemia-induced mobilization, of LSK cells were impaired in both models. Leptin receptor antagonist, PESLAN-1, increased G-CSF- or AMD3100-mobilization of WBCs and LSKs, compared to the untreated. Leptin increased basal WBCs, decreased basal and AMD3100-mobilized LSK cells, and had no effect on G-CSF. These results suggest that mobilopathy is apparent in STZ-diabetes but not in db/db mice. Leptin receptor antagonism would be a promising approach for reversing diabetic bone marrow mobilopathy.

Immuno-metabolism and adipose tissue: The key role of hematopoietic stem cells

The field of immunometabolism has come a long way in the past decade, leading to the emergence of a new role for white adipose tissue (WAT) that is now recognized to stand at the junction of immune and metabolic regulations. Interestingly, a crucial role of the abundant and heterogeneous immune population present in WAT has been proposed in the induction and development of metabolic diseases. Although a large body of data focused on mature immune cells, only few scattered studies are dedicated to leukocyte production, and the activity of hematopoietic stem cells (HSC) in these pathological states. Considering that blood cell production and the differentiation of HSCs and their progeny is orchestrated, in part, by complex interacting signals emanating from their microenvironment, it thus seems worth to better understand the relationships between metabolism and HSC. This review discusses the alterations of hematopoietic process described in metabolic diseases and focused on the emerging data concerning HSC present in WAT.

Comparison of gestational diabetes mellitus rates in women with increased and normal white blood cell counts in early pregnancy

AIM

To compare the rates of gestational diabetes mellitus (GDM) among Thai or other South-East Asian women with increased and normal peripheral white blood cell (WBC) counts in early pregnancy. The risk of GDM in relation to WBC count was also determined.

METHODS

We included singleton pregnant women who sought their first antenatal care in our institution between May 2010 and December 2011. Subjects were 595 gravidas with an increased WBC count while controls were 595 pregnancies with a normal WBC count. Data of pregnant women were collected. The WBC of each woman was obtained from a complete blood count performed in the first trimester. The rates of GDM between both groups were compared. The odds ratio (OR) with 95% confidence interval (CI) of GDM development in the subject group was determined by multivariate analysis.

RESULTS

Data on 570 subjects with increased WBC and 575 controls with normal WBC were obtained. The rate of GDM was significantly higher in subjects compared to controls at 13.2% versus 5.2% (P<0.001) with a crude OR of 2.75 (95% CI, 1.77-4.28). By multivariate analysis, the subject group was found at increased risk of GDM compared to the control group, with an adjusted OR of 2.20 (95% CI, 1.39-3.47).

CONCLUSION

Thai or other South-East Asian women with an increased WBC count in early pregnancy had a significantly higher rate of GDM than women having a normal WBC count. Our results demonstrate that WBC count is an independent risk factor for GDM.

Lungs, bone marrow, and adipose tissue. A network approach to the pathobiology of chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) often suffer other concomitant disorders, such as cardiovascular diseases and metabolic disorders, that influence significantly (and independently of lung function) their health status and prognosis. Thus, COPD is not a single organ condition, and disturbances of a complex network of interorgan connected responses occur and modulate the natural history of the disease. Here, we propose a novel hypothesis that considers a vascularly connected network with (1) the lungs as the main external sensor of the system and a major source of "danger signals"; (2) the endothelium as an internal sensor of the system (also a potential target tissue); and (3) two key responding elements, bone marrow and adipose tissue, which produce both inflammatory and repair signals. According to the model, the development of COPD, and associated multimorbidities (here we focus on cardiovascular disease as an important example), depend on the manner in which the vascular connected network responds, adapts, or fails to adapt (dictated by the genetic and epigenetic background of the individual) to the inhalation of particles and gases, mainly in cigarette smoke. The caveats and limitations of the hypothesis, as well as the experimental and clinical research needed to test and explore the proposed model, are also briefly discussed.

Short duration of sleep is associated with hyperleptinemia in Taiwanese adults

BACKGROUND

Higher plasma levels of leptin have been associated with increased cardiometabolic risk. The aim of this study was to investigate the association between short duration of sleep and hyperleptinemia in Taiwanese adults.

METHODS

We examined the association between duration of sleep and hyperleptinemia in 254 men and women recruited from the physical examination center at a regional hospital in southern Taiwan. Hyperleptinemia was defined as a plasma leptin level of 8.13 ng/mL and above. Short sleep duration was defined as < 6.5 h/day. Multiple logistic regression analysis was used to assess the association between short duration of sleep and hyperleptinemia.

RESULTS

In females, short duration of sleep (< 6.5 h/day; OR = 2.15, 95% CI = 0.99-4.78), greater hip circumference (OR = 3.00, CI = 1.13-8.78), higher percent body fat (OR = 1.75, CI = 1.07-2.95), and higher white blood cell counts (OR = 1.67, CI = 1.26-2.28) were associated with an increased risk of hyperleptinemia. In males, greater body weight was significantly associated with an increased risk of hyperleptinemia (OR = 3.55, 95% CI = 1.46-10.23). There was also a trend of association (p = 0.096) between short duration of sleep and an increased risk of hyperleptinemia (OR = 4.98, 95% CI = 0.80-42.40).

CONCLUSIONS

In this study of healthy Taiwanese adults, short duration of sleep was significantly associated with hyperleptinemia in women, and the association was independent of adiposity.

Is there a link between neutrophil-lymphocyte ratio and microvascular complications in geriatric diabetic patients?

BACKGROUND

Chronic inflammation plays an important role on development and progression of Type 2 diabetes (T2DM) through immunologic inflammatory mechanisms. Neutrophil to lymphocyte ratio (NLR) is a new, simple and cheap marker of subclinical inflammation. NLR has recently been used as a systemic inflammation marker in chronic diseases as well as a predictor of prognosis in cardiovascular diseases and malignancies.

AIM

The objective of the present study was to investigate the relationship between NLR and microvascular complications of diabetes mellitus (DM) in elderly population.

SUBJECTS AND METHODS

Two hundred and forty-two patients with DM (145 diabetic patients with complications, 97 diabetic patients without complications) and 218 control subjects were enrolled in this study. NLR and microvascular complications because of DM were evaluated and compared with other inflammatory markers.

RESULTS

NLR was higher in the diabetic group (2.21±1.14) than in the controls (2.18±0.76). Furthermore, there was a statistically significant difference between NLR levels in diabetic patients with and without complications (2.46±1.26 vs 2.04±0.51, respectively; p<0.001). The results of themultiple logistic regression analysis depicted that NLR is also an independent predictor for microvascular complications (odds ratio 2.217; 95%confidence interval 1.086-4.526, p=0.029). Receiver operating curve analysis suggested that the optimum NLR cutoff point for microvascular complication was 2.89 with 96.72% specificity, 94.4% positive predictive value.

CONCLUSION

Increased NLR levels may be associated with microvascular complications of DM in the elderly population.

A high-fat diet increases IL-1, IL-6, and TNF-α production by increasing NF-κB and attenuating PPAR-γ expression in bone marrow mesenchymal stem cells

It is well established that a high-fat diet (HFD) can lead to overweight and ultimately to obesity, as well as promoting low-grade chronic inflammation associated with increased levels of such mediators as TNF-α, IL-1, and IL-6. Bone marrow mesenchymal stem cells (MSCs), which are involved in hematopoietic niches and microenvironments, can be affected by these cytokines, resulting in induction of NF-κB and inhibition of PPAR-γ. Because this phenomenon could ultimately lead to suppression of bone marrow adipogenesis, we set out to investigate the effect of an HFD on the expression of PPAR-γ and NF-κB, as well as the production of IL-1, IL-6, and TNF-α in MSCs. Two-month-old male Wistar rats were fed a HFD diet and evaluated by means of leukograms and myelograms along with blood total cholesterol, triglyceride, and C-reactive protein levels. MSCs were isolated, and PPAR-γ and NF-κB were quantified, as well as IL-1, IL-6, and TNF-α production. Animals that were fed a HFD showed higher levels of blood total cholesterol, triglycerides, and C-reactive protein with leukocytosis and bone marrow hyperplasia. MSCs from HFD animals showed increased production of IL-1, IL-6, and TNF-α and increased NF-κB and reduced PPAR-γ expression. Therefore, ingestion of an HFD induces alterations in MSCs that may influence modulation of hematopoiesis.

A high-fat diet increases interleukin-3 and granulocyte colony-stimulating factor production by bone marrow cells and triggers bone marrow hyperplasia and neutrophilia in wistar rats

It is well established that the excessive consumption of a high-fat diet (HFD) results in overweight, obesity and an increase in leptin concentrations, which triggers a chronic inflammatory condition that is associated with a high white blood cell count. Two-month-old male Wistar rats were fed a control (CON) diet or an HFD for 12 weeks. After this period, hemogram, myelogram and biochemical parameters were evaluated along with the cell cycle and the percentage of CD34+ cells in the bone marrow as well as cell proliferation and differentiation assays and the production of stem cell factor, interleukin 3 (IL-3), granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF). The HFD animals exhibited leukocytosis and neutrophilia with increased C-reactive protein, leptin, cholesterol and triglyceride concentrations. In the HFD group, the bone marrow revealed myeloid hyperplasia, especially of the granulocytic compartment with a higher percentage of CD34+ cells and a higher percentage of cells in the G2/S/M cell cycle phases. In addition, the HFD bone marrow cells had a higher capacity to proliferate and differentiate into granulocytic cells in an in vitro system and a higher capacity to produce IL-3 and G-CSF. These data led us to infer that the HFD induces leukocytosis and neutrophilia suggesting alterations in hematopoiesis system modulation.

Leptin receptor in childhood acute leukemias

Ob-R receptor is encoded by db gene and belongs to class I cytokine receptors family. Its expression was observed in hematopoietic CD34+ stem cells, erythropoietic, myeloid and lymphoblastic lineages cell lines and in human leukemic blast cells in lymphomas, acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and chronic myeloid leukemia (CML). The studies on human bone marrow cells show that JAK/STAT pathway plays a substantial role in signal transduction in young bone marrow cells. The aim of the study was to examine the relationship between leptin receptor expression and the proliferation of neoplastic hematopoietic cells in bone marrow. The study was performed in a total of 57 children of both sexes aged 3 months to 16 years. A group of 46 patients with acute leukemia involved 25 children with ALLB, 11 children with ALLT and 10 children with ANNL. The control group consisted of 11 non-obese children with non-malignant hematological disturbances. The tests were performed on bone marrow samples. The assessments of membrane expression of Ob-R and the antigens determining the phenotype of bone marrow cells were performed using a flow cytometry method. In acute lymphoblastic leukemia, a significant decrease of Ob-R expression on leukemic blasts was observed in comparison with respective populations of normal bone marrow cells. Also in progenitor cells populations a significant decrease of CD34+Ob-R+w ALLT and ALLB was observed in comparison with the cells from normal bone marrow. No statistically significant differences in the percentage of Ob-R+ cells in ANNL bone marrow and in control bone marrow were observed.

Mechanisms linking obesity, inflammation and altered metabolism to colon carcinogenesis

Due to its prevalence, obesity is now considered a global epidemic. It is linked to increased risk of colorectal cancer, the third most common cancer and the second leading cause of death among adults in Western countries. Obese adipose tissue differs from lean adipose tissue in its immunogenic profile, body fat distribution and metabolic profile. Obese adipose tissue releases free fatty acids, adipokines and many pro-inflammatory chemokines. These factors are known to play a key role in regulating malignant transformation and cancer progression. Obese adipose tissue is infiltrated by macrophages that participate in inflammatory pathways activated within the tissue. Adipose tissue macrophages consist of two different phenotypes. M1 macrophages reside in obese adipose tissue and produce pro-inflammatory cytokines, and M2 macrophages reside in lean adipose tissue and produce anti-inflammatory cytokines, such as interleukin-10 (IL-10). The metabolic networks that confer tumour cells with their oncogenic properties, such as increased proliferation and the ability to avoid apoptosis are still not well understood. We review the interactions between adipocytes and immune cells that may alter the metabolism towards promotion of colorectal cancer.

Resistive exercises, with or without whole body vibration, prevent vertebral marrow fat accumulation during 60 days of head-down tilt bed rest in men

Fat accumulates in the bone marrow of lumbar vertebrae with bed rest. Exercise with or without whole body vibration may counter this effect. Our objectives were to measure 1) the vertebral fat fraction (VFF) of men subjected to bed rest who performed resistive exercises with (RVE, n = 7) or without whole body vibration(RE, n = 8) or no exercise (CTR, n = 9) using three MRI techniques; and 2) changes in peripheral blood counts. Twenty-four healthy men (age: 20-45 yr) underwent -6° head-down tilt (HDT) bed rest for 60 days. MRI was performed using three techniques (fat saturation, proton spectroscopy, and in and out of phase) to measure the fat fraction of L(3), L(4), and/or L(5) at baseline, mid-HDT, and end-HDT. Erythrocytes and leukocytes were counted at HDT days 19, 33, 47, 54, and 60. The mean absolute VFF was increased in the CTR group at mid-HDT and end-HDT (+3.9 ± 1.3 and +3.6 ± 1.2%, respectively, both P < 0.05). The RE group had a smaller VFF change than the CTR group at mid-HDT (-0.9 ± 1.2 vs. +3.9 ± 1.3%, P < 0.05). The RVE group had a smaller VFF change than the CTR group at end-HDT (-2.6 ± 1.9 vs. +3.5 ± 1.2%, P < 0.05). Erythrocyte counts were increased in all groups at HDT day 19 and HDT day 33 and in the RE group at HDT day 54 (all P < 0.05). Bed rest for 60 days at -6° HDT increased lumbar VFF in men beyond natural involution. RVE and RE regimens effectively prevented VFF accumulation. Higher erythrocyte counts were not altered by RVE or RE. Whole body vibration, along with RE administered to people with prolonged immobility, may prevent fat accumulation in their bone marrow.

Expression patterns of leptin receptor (OB-R) isoforms and direct in vitro effects of recombinant leptin on OB-R, leptin expression and cytokine secretion by human hematopoietic malignant cells

Several studies have implicated leptin in the pathophysiology of neoplasias. We investigated the direct effect of leptin on malignant hematopoietic tissue that included: primary acute myeloid leukemia (AML) cells, leukemic cell lines and bone marrow biopsies from multiple myeloma (MM) patients. PBMC, T-cells, B-cells and monocytes from healthy subjects served as controls. We defined the patterns of OB-R isoform expression in AML cells and leukemic cell lines in comparison to control cells by RT-PCR. rLeptin upregulated the expression of OB-R and endogenous leptin in AML blasts and certain cell lines but not in control cells. Cytometric Bead Array analysis of pro- and anti-inflammatory cytokines showed that rleptin upregulates IL-6 secretion by AML cells, various cytokines by the leukemic cell lines tested and IL-10 secretion by control PBMC, contributed by monocytes. Western immunoblotting revealed that the effect of rleptin was independent of JAK-2/phospho-JAK-2 protein levels. Finally, MM biopsies stained positive for leptin and, to a lesser extend, OB-R. Immunoreactivity was confined mostly to the nucleus of the myeloma cells. Normal myelocytes, promyelocytes and megakaryocytes stained weakly positive, and erythroid cells were constantly negative. We propose that the leptin/OB-R system is strongly and directly involved in supporting the growth of hematopoietic malignancies.

Bone marrow fat accumulation after 60 days of bed rest persisted 1 year after activities were resumed along with hemopoietic stimulation: the Women International Space Simulation for Exploration study

Immobility in bed and decreased mobility cause adaptations to most human body systems. The effect of immobility on fat accumulation in hemopoietic bone marrow has never been measured prospectively. The reversibility of marrow fat accumulation and the effects on hemopoiesis are not known. In the present study, 24 healthy women (age: 25-40 yr) underwent -6 degrees head-down bed rest for 60 days. We used MRI to noninvasively measure the lumbar vertebral fat fraction at various time points. We also measured hemoglobin, erythropoietin, reticulocytes, leukocytes, platelet count, peripheral fat mass, leptin, cortisol, and C-reactive protein during bed rest and for 1 yr after bed rest ended. Compared with baseline, the mean (+/-SE) fat fraction was increased after 60 days of bed rest (+2.5+/-1.1%, P<0.05); the increase persisted 1 yr after the resumption of regular activities (+2.3+/-0.8%, P<0.05). Mean hemoglobin levels were significantly decreased 6 days after bed rest ended (-1.36+/-0.20 g/dl, P<0.05) but had recovered at 1 yr, with significantly lower mean circulating erythropoietin levels (-3.8+/-1.2 mU/ml, P<0.05). Mean numbers of neutrophils and lymphocytes remained significantly elevated at 1 yr (+617+/-218 neutrophils/microl and +498+/-112 lymphocytes/microl, both P<0.05). These results constitute direct evidence that bed rest irreversibly accelerated fat accumulation in hemopoietic bone marrow. The 2.5% increase in fat fraction after 60 days of bed rest was 25-fold larger than expected from historical ambulatory controls. Sixty days of bed rest accelerated by 4 yr the normal bone marrow involution. Bed rest and marrow adiposity were associated with hemopoietic stimulation. One year after subjects returned to normal activities, hemoglobin levels were maintained, with 43% lower circulating erythropoietin levels, and leukocytes remained significantly elevated across lineages. Lack of mobility alters hemopoiesis, possibly through marrow fat accumulation, with potentially wide-ranging clinical consequences.

Angiogenesis in the New Zealand obese mouse model fed with high fat diet

Background

Obesity and its complications lead to vascular injury, atherosclerosis, diabetes and pathological angiogenesis. One of the models to study the obesity and its entanglements is the New Zealand Obese mice model. Aim of this study was to check the effect of high fat diet on changes in biochemical parameters as well as on process of angiogenesis in NZO mice.

Methods

NZO mice were fed with standard (ST) or high fat (HF) diet for seven weeks. Body weight and serum biochemical parameters were monitored. The PECAM1 positive vessel-like structures immunostaining, as well as the gene expression of the matrigel penetrating cells by microarray (confirmed by real-time PCR method) were analyzed.

Results

Mice fed with HF diet developed obesity. Number of newly created vessels with lumen was correlated with hyperglycemia and animal weight gain. The number of PECAM1 positive cells in matrigel tended to increase during HF diet. Microarray results revealed changes in gene expression (activation of the oxidative stress and insulin resistance, inhibition of apoptosis and cell differentiation), however without markers of endothelial cell network maturation.

Conclusion

Observed changes in the NZO mice on HF diet argue for the hyperglycemia related activation of angiogenesis, leading to the formation of pathological, immature network.

Impaired leptin activity in New Zealand Obese mice: model of angiogenesis

Leptin is prompt to drive angiogenesis, effecting proper vascularisation. Tissue remodeling (including adipose organ) is associated with the angiogenic response. The aim of this study was to investigate the effect of hyperleptinemia on angiogenesis in subcutaneous (s.c.) in vivo matrigel model in mice on a high fat (HF) diet. HF promoted adipose tissue accumulation and biochemical changes resembling metabolic syndrome. However, the impact of this dietary treatment on angiogenesis, measured in s.c. matrigel model was not significant. Changes in leptin concentration were not accompanied by significant angiogenic response. This lack of leptin activity and impaired signal transduction at the molecular level suggests malfunction of the leptin receptor in NZO mice.

Impaired ex vivo leukotriene B4 production characterizes the metabolic syndrome and is improved after weight reduction

CONTEXT

Neutrophil (polymorphonuclear neutrophil) production of leukotriene B4 (LTB4) may be associated with alterations in immune and inflammatory function that characterize the metabolic syndrome (MetS).

OBJECTIVE

We investigated whether polymorphonuclear neutrophil production of LTB(4) and its metabolites 20-hydroxy-LTB4 (20-OH-LTB4) and 20-carboxyl-LTB4 were altered in subjects with features of the MetS before and after weight reduction.

DESIGN, SETTING, PATIENTS, AND INTERVENTION

In a case-controlled comparison, men and postmenopausal women with features of the MetS were matched with controls. Subjects with MetS were then matched and randomly assigned to either a 12-wk weight reduction study followed by 4-wk weight stabilization or 16-wk weight maintenance.

MAIN OUTCOME MEASURES

Measurements were performed at baseline and at the end of the 16-wk period. Stimulated neutrophil LTB4 and its metabolites were measured by HPLC.

RESULTS

In the case-controlled study, body mass index, waist circumference, blood pressure, fasting triglycerides, and glucose were all significantly increased in subjects with features of the MetS (P < 0.05). Production of LTB4 and 20-OH-LTB4 was significantly lower compared with controls (P < 0.005). The weight loss intervention resulted in a 4.6-kg reduction in body weight and 6.6-cm decrease in waist circumference relative to controls and a significant increase in LTB4 and 20-OH-LTB4.

CONCLUSIONS

Subjects with features of the MetS have lower stimulated LTB4, which is not due to increased metabolism of LTB4. Weight reduction restored the production of neutrophil LTB4, suggesting that in addition to modifying cardiovascular risk, weight loss may also help with the management of perturbed inflammatory responses in overweight subjects.

Association of peripheral total and differential leukocyte counts with metabolic syndrome and risk of ischemic cardiovascular diseases in patients with type 2 diabetes mellitus

BACKGROUND

There is increasing evidence that leukocytes play a central role in obesity, glucose intolerance, type 2 diabetes mellitus (T2DM), and cardiovascular diseases, but the role of differential leukocytes in metabolic syndrome (MetS) and atherosclerosis is largely unknown. The aim of this study was to examine the relationship between the component features of MetS and peripheral leukocyte counts and to explore whether leukocyte counts are associated with clustering of MetS and macrovascular diseases in patients with T2DM.

METHODS

1872 subjects with T2DM who enrolled in a diabetes disease management program were studied. The definition of MetS was modified from that outlined by the criteria of NCEP-ATP III. Areas under the receiver-operating characteristic curve and odds ratios at various intervals of the WBC counts were computed.

RESULTS

The peripheral total leukocyte, monocyte, and neutrophil cell counts are increased parallel to the clustering of components of MetS. When white cell counts were analyzed per quartile and as continuous variables after adjustment for age, sex, and other known risk factors with multiple regression analysis, peripheral total leukocyte, monocyte, neutrophils, and lymphocyte counts were independently and significantly associated with specific features of clustering of MetS and prevalence of ischemic cardiovascular diseases. Leukocyte counts, especially neutrophil/lymphocyte ratio, in addition with MetS is associated with the risk of ischemic cardiovascular diseases.

CONCLUSION

Our results indicate that differential leukocyte counts are associated with MetS and that peripheral leukocytes may play a role in the pathogenesis of macrovascular complications in patients with T2DM.

Role of adipose tissue as an inflammatory organ in human diseases

Reviews on the inflammatory role of adipose tissue outside the field of metabolism are rare. There is increasing evidence provided by numerous basic research studies from nearly all internal medicine subspecializations that adipocytes and adipocytokines are involved in primary inflammatory processes and diseases. Therefore, it is the aim of the present review to discuss and to summarize the current knowledge on the inflammatory role of adipocytokines and special types of regional adipocytes such as retroorbital, synovial, visceral, subdermal, peritoneal, and bone marrow adipocytes in internal medicine diseases. Future clinical and therapeutic implications are discussed.

Systematic review: adipose tissue, obesity and gastrointestinal diseases

BACKGROUND

Obesity is increasingly being recognized as a risk factor for a number of benign and malignant gastrointestinal conditions. However, literature on the underlying pathophysiological mechanisms is sparse and ambiguous. Insulin resistance is the most widely accepted link between obesity and disease, particularly colorectal cancer. The recognition that intra-abdominal fat is immunologically active sheds new light not only on the pathogenesis of obesity-related gastrointestinal conditions, but also on inflammatory conditions such as Crohn's disease.

AIM

To describe the biology of adipose tissue, its impact on the immune system and explores the possible underlying mechanisms linking obesity to gastrointestinal diseases. It also looks at the role of mesenteric fat in determining severity and course of Crohn's disease.

METHODS

Relevant English-language literature and abstracts cited on MEDLINE database were reviewed.

RESULTS

Our recent finding of an association between obesity and subclinical bowel inflammation suggests that, apart from promoting generalized immune activation, fat also evokes local immune responses. We propose that the proinflammatory milieu promoted by obesity could underlie many of these associations and that the mechanism implicating insulin resistance may merely represent an epiphenomenon. In Crohn's disease, on the other hand, intra-abdominal fat may provide a protective mechanism.

CONCLUSION

The potential of adipose tissue as a therapeutic target is vast and needs exploration.

Leukocytosis in obese individuals: possible link in patients with unexplained persistent neutrophilia

BACKGROUND

Recently, it was shown that fat tissue produces and releases inflammatory cytokines, and that obesity may be regarded as a state of low-grade inflammation. In this regard, we aimed to establish an association between obesity and persistent leukocytosis.

PATIENTS AND METHODS

We present clinical observations of obese subjects primarily referred for further evaluation of leukocytosis without a cause and validated the link between leukocytosis and elevated body mass index (BMI) in a cross-sectional study.

RESULTS

During 1999-2005, 327 patients were referred for further investigation because of persistent leukocytosis. Of these, 15.3% were asymptomatic obese, mostly females, with mild persistent neutrophilia accompanied by elevated acute-phase reactants. After careful evaluation, no recognized cause for leukocytosis was found other than the fact that the patients were obese. During a mean follow-up of 45.6 months, the leukocytosis and the elevated acute-phase reactants persisted and no new causes for leukocytosis were evident. Furthermore, in a cross-sectional analysis of 3716 non-smoker subjects, 62 were found to have leukocytosis. Compared with the population with a normal white blood count range, these subjects with leukocytosis had higher BMI, serum C-reactive protein (CRP) levels, waist circumference, and neutrophil and platelet count (all P < 0.0005). After logistic regression analysis, only BMI was shown to be associated with leukocytosis (P < 0.0005).

CONCLUSIONS

Obesity is recognized as a possible cause for reactive leukocytosis. Awareness of this 'obesity-associated leukocytosis' may help the clinician to avoid more extensive and unnecessary diagnostic work-up, particularly in similar obese subjects.

Human subcutaneous adipose cells support complete differentiation but not self-renewal of hematopoietic progenitors

Adipose tissue is now considered as an endocrine organ implicated in energy regulation, inflammation and immune response, and as a source of multipotent cells with a broad range of differentiation capacities. Some of these cells are of a mesenchymal type which can -- like their bone marrow (BM) counterpart -- support hematopoiesis, since in a previous study we were able to reconstitute lethally irradiated mice by cells isolated from adipose tissue. In the present study, we established that cells derived from the stroma-vascular fraction of human subcutaneous fat pads support the complete differentiation of hematopoietic progenitors into myeloid and B lymphoid cells. However, these cells are unable to maintain the survival and self-renewal of hematopoietic stem cells. These features, similar to those of BM adipocytes, are the opposite of those of other cell types derived from mesenchymal progenitors such as BM myofibroblasts or osteoblasts. Because it is abundant and accessible, adipose tissue could be a convenient source of cells for the short-term reconstitution of hematopoiesis in man.

Expression of leptin receptors in mononuclear cells from myelodysplastic syndromes and acute myeloid leukemias

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.

Association between serum leptin concentration and white blood cell count in middle-aged Japanese men and women

BACKGROUND

Leptin's hematopoietic or proinflammatory role has been experimentally reported. We investigated whether serum leptin concentrations are associated with white blood cell (WBC) counts in humans.

METHODS

Serum leptin concentrations of Japanese civil servants aged 40 to 59 years (1082 men and 200 women) were analyzed in relation to their WBC count. Serum leptin concentrations and WBC counts were measured by radioimmunoassay and automated particle counter respectively, using samples obtained at the time of the participants' annual health checkups.

RESULTS

The geometric mean (+/-geometric standard deviation) leptin concentrations were 3.25 +/- 1.82 ng/mL and 6.25 +/- 3.99 ng/mL, and the geometric mean WBC counts, 5770 +/- 1269/mm(3) and 5107 +/- 1228/mm(3), in men and women respectively. The WBC count adjusted for age, body mass index (BMI), physical activity, and drinking and smoking habits increased together with the increase in leptin concentration. Multiple linear regression against WBC count by the leptin concentration and those covariates revealed a significant and independent association with serum leptin concentration especially in women (standardized beta = 0.31, p < 0.001), and also in men (standardized beta = 0.17, p < 0.001). BMI was not significantly associated with WBC counts in the multivariate model adjusting for leptin levels in both sexes.

CONCLUSIONS

Our results are in line with leptin's hematopoietic or proinflammatory functions. The increased WBC counts often observed in obese people would be mediated by the increased leptin concentration.

Peripheral total and differential leukocyte count in diabetic nephropathy: the relationship of plasma leptin to leukocytosis

OBJECTIVE

Because of increasing evidence that white blood cells (WBCs) play a role in the development and progression of diabetes complications, this study aimed to investigate the relation of circulating total and differential leukocyte counts to nephropathy in patients with type 2 diabetes. Plasma leptin levels were also measured to investigate their role in peripheral leukocytosis.

RESEARCH DESIGN AND METHODS

For this study, 1,480 subjects with type 2 diabetes who were enrolled in a disease management program were stratified according to urinary microalbumin and serum creatinine measurements. The total and differential leukocyte profiles of peripheral blood were measured and plasma leptin was examined by enzyme-linked immunosorbent assay. Demographic and potential metabolic confounding factors were analyzed with linear and logistic regression to calculate the effects of leukocyte count on diabetic nephropathy.

RESULTS

The peripheral total WBC, monocyte, and neutrophil counts increased in parallel with the advancement of diabetic nephropathy. In contrast, the lymphocyte count decreased. When WBC counts were analyzed per quartile and as continuous variables after adjusting for age, sex, and other known risk factors with multiple regression analysis, peripheral total WBC, monocyte, neutrophil, and lymphocyte counts were independently and significantly associated with diabetic nephropathy. Plasma leptin levels increased in patients with nephropathy and correlated significantly with total WBC count (r = 0.194, P = 0.014).

CONCLUSIONS

Because leukocytes are activated and secrete cytokines in the diabetic state and leptin stimulates leukocyte proliferation and differentiation, our results suggest that circulating leukocytes contribute to the development and progression of nephropathy, partially through the effects of leptin, in patients with type 2 diabetes.

Correlations among serum leptin levels, complete blood count parameters and peripheral CD34(+) cell count in prepubertal obese children

Leptin is a hormone produced by adipocytes that helps reduce body weight by depressing appetite and increasing metabolic activity. Leptin also promotes early hematopoiesis. The main aim of this study was to compare complete blood count (CBC) parameters and peripheral blood CD34(+) cell counts in prepubertal obese and nonobese children. Relationships between leptin levels and CBC parameters and peripheral CD34(+) progenitor cell counts in the obese group were also investigated. Thirty one healthy, prepubertal, obese children and 30 nonobese, age-matched prepubertal controls were included in the study. A fasting blood sample was collected from each subject, and CBC findings, serum leptin level, and peripheral blood CD34(+) progenitor cell count were recorded. In the obese group, the mean results for body mass index (BMI), BMI standard deviation score (BMI SDS), and serum leptin level were significantly higher than the corresponding control findings. There were no significant differences between the groups with respect to CBC parameters and CD34(+) cell percentage. In both the obese and control groups, the girls' serum leptin levels were significantly higher than the boys'. In the obese group, serum leptin level was strongly correlated with BMI and with BMI SDS (Pearson correlation coefficients r=0.70, p<0.001, and r=0.59, p<0.001, respectively) in both girls and boys. None of the CBC parameters nor CD34(+) progenitor cell percentage was correlated with leptin, BMI, or BMI SDS. The results indicate that serum leptin levels in obese children are positively correlated with BMI. However, in contrast to adults, high leptin level in childhood obesity does not seem to be associated with altered CBC parameters or increased peripheral CD34(+) progenitor cell count.

[Adipose tissue, plastic and reconstructive surgery: come back to sources]

The adipose tissue represents a large amount of adult tissue. For long time, it was considered as a filling tissue and used in plastic and reconstructive surgery. It was always studied for its main involvement in energy metabolism and energy disorders as diabetes and obesity. More recently, its endocrine functions emerged and thus play a key role in many physiological functions as inflammation and immunity. The presence of preadipocytes throughout life was demonstrated using primary culture technology from cells derived from adipose tissue. In recent papers, cells derived from adipose tissue were used for haematopoiesis, vascularisation or skeletal muscle recovery. Differentiation into functional cardiomyocytes, osteoblasts and neural cells was obtained in vitro. These spectacular data, the fact that adipose tissue is easy to sample and the possibility to create cell or tissue banks open numerous and promising perspectives in regenerative medicine.

Human bone marrow adipocytes support complete myeloid and lymphoid differentiation from human CD34 cells

In humans, the role of bone marrow (BM) adipocytes in supporting haematopoiesis has been questioned. A co-culture system of CD34(+) cells seeded onto either BM undifferentiated mesenchymal stem cells or differentiated adipocytes showed that BM adipocytes did not support the maintenance of immature progenitors but enabled their complete differentiation along the myeloid and lymphoid pathways. These properties appear to be opposite to those of osteoblasts, although both cell types share a common mesenchymal progenitor. These results suggest that stromal cells play a variety of roles in the haematopoietic microenvironment, which could be significant in situations such as osteoporosis or ageing.