Progranulin concentration in relation to bone mineral density among obese individuals

OBJECTIVE

Adipose tissue, particularly visceral adipose tissue, secretes a variety of cytokines, among which progranulin is a glycoprotein related to the immune system. Along with other secreted proteins, progranulin may be associated with bone mineral density. The aim of this study was to find out whether there are associations between the progranulin and bone mineral density among obese people.

SUBJECTS AND METHODS

This cross-sectional study was conducted on 244 obese participants (aged 22-52). Serum progranulin, high sensitive C-reactive protein, oxidised-low dencity lipoprotein, tumor necrosis factor-α, parathormone, vitamin D, and interleukins of 1 β, 4, 6, 10, 13, and 17 concentrations were measured. Anthropometric measurements, body composition and bone mineral density were also assessed.

RESULTS

Serum progranulin was directly associated with interleukin-6 and interleukin-1β, while it had a negative association with interleukin-17 and tumor necrosis factor-α. We also observed a statistically significant direct association between progranulin concentration and visceral fat, abdominal fat, waist, abdominal and hip circumferences, hip T-score, and Z-score and T-score for the lumbar region. A partial correlation test has also shown a significant positive correlation regarding serum progranulin and the hip Z-score. Moreover, progranulin level is inversely associated with ospteopenia (P = 0.04 and CI: 0.17,0.96).

CONCLUSION

Our study revealed that central obesity may be related to increased progranulin concentration. In addition, progranulin concentration was directly related to bone formation parameters, which indicates the protective effects of progranulin on bone density. Further studies are needed to clarify the exact mechanisms underlying these associations.

Metabolically healthy/unhealthy components may modify bone mineral density in obese people

Link between obesity and bone health is controversial. It seems that maybe the difference in metabolic status leads to this difference. We studied relation between metabolically healthy/unhealthy components with bone mineral density. Results showed metabolically unhealthy obesity (MUHO) phenotypes have better bone status at hip site than metabolically healthy obesity (MHO). Also, component metabolic can effect on BMD in different sites.

PURPOSE/INTRODUCTION

This cross-sectional study aimed to compare total BMD and L-L4 BMD in MHO and MUHO base on Karelis criteria.

METHODS

We enrolled 272 Iranian obese women and men (BMI ≥ 30). According to Karelis criteria, the participants were grouped base to MHO and MUHO. The body composition and BMD were assessed for all cases. Serum HDL-C, LDL-C, total cholesterol, triglyceride (TG), fasting blood glucose, homeostatic model assessment-insulin resistance (HOMA-IR), and hypersensitive C-reactive protein (hs-CRP) levels were quantified by ELISA method.

RESULTS

Our results demonstrate MUHO phenotype have high total BMD more than MHO (P = 0.01, CI = 0.12 to 0.21). Also, the results of logistic regression analysis showed MUHO have strongly associated with total BMD (β = -0.42, CI = - 0.31 to - 0.04, P = 0.009), but did not affected L2-L4 BMD (β = - 0.09, CI = - 0.14 to 0.08, P = 0.578); this represents that there was discordance in MUHO subjects. Our evidence implicated that HOMA-IR, high level serum TG, hs-CRP, and low level serum HDL had mediatory effect on relationship between obesity and high BMD at the hip region in MUHO subjects (P < 0.05).

CONCLUSION

Present evidence indicates that, could be a novel link between difference in MUH phenotype and MH phenotype with bone status. Also, component metabolic can effect on BMD in different sites.

Atherosclerosis: A Classic Inflammatory Disease

Atherosclerosis is an inflammatory disease due to a diet high in saturated fat, hypercholesterolemia, obesity, hypoglycemia, etc. mainly mediated by the infiltration of macrophage and T cells into the vascular wall. Once the endothelial is damaged monocytes penetrate the tissue and are transformed in scavenger cells. Upon stimulation of Th1 cells, a group of cytokines is released and contributes to the inflammatory response of atherosclerotic tissue. When macrophages proliferate they amplify inflammatory response through the secretion of growth factors and cytokines such as TNF and IL-1. In addition, chemokines such as RANTES and other C-C chemokines are generated, and matrix metalloprotinease 9 (MMP-9) are produced by activated monocytes. However, the immune system in atherosclerosis still remains unclear. Here, in this study we revisited the inter-relationship between atherosclerosis and inflammation.

Cholesterol, Cytokines and Diseases

A high level of cholesterol is associated with obesity, cardiovascular diseases and atherosclerosis. Immune response in atherosclerosis is mediated by chemokines which attract monocytes, leading to the innate immune response characterised by the production of cytokines. The immunoregulatory cytokines are an important bridge between innate and adductive immunity. TH1 cytokines are involved as effector T cells in inflammatory response, while TH2 cytokines can be anti-inflammatory such as IL-10 and IL-4. It is well known that statins enhance the production of TH2 cytokines whereas the secretion of TH1 cytokines is suppressed. For this purpose, we studied the significance of anti-inflammatory effect and suppression of inflammation by statins. In this paper we revisited the role of cholesterol and cytokines IL-18, IL-10, IL-12, TNF-α, interferon-γ, and chemokines in inflammatory diseases.

Visfatin/NAMPT/PBCEF and Cytokine Concentration in Multiple Sclerosis Patients Compared to Healthy Subjects

The aim of the study is to measure IL-1 β, TNF-α, hs-CRP levels and Nampt/visfatin/PBCEF concentrations in patients with multiple sclerosis and to compare them with those of healthy control subjects. In a case-control study a total number of 192 people were recruited. Ninety-six of them were suffering from multiple sclerosis, age 34.80±8.75 years (mean±SD), who were referred form the Iranian Multiple Sclerosis Society. They included relapsing remitting (82 subjects) and both primary and secondary progressive (14 subjects) types of MS. The diagnosis was made according to the diagnostic criteria by a neurology consultant. Ninety-six healthy individuals were recruited from the Iranian Multicenter Osteoporosis Study (IMOS) as the control group. Following an overnight fasting, peripheral blood was taken from all subjects and centrifuged in order to separate serum for measurement of serum visfatin, Interleukin-1beta (IL-1β), TNF-α, and hs-CRP concentrations. Fat tissue mass was measured using DXA. Levels of visfatin, TNF-α and hs-CRP were significantly higher in MS patients. Besides, significant correlation was found between visfatin levels and those of TNF-α, IL-1β, hs-CRP in MS patients. Regarding the control group, significant correlation was found between visfatin levels and levels of TNF-α. However, we did not find any significant correlation between fat tissue mass and visfatin, TNF-α, IL-1β or hs-CRP levels in the MS group. However, there was a significant correlation between fat tissue mass and TNF-α level in the study population. Our findings demonstrated that proinflammatory factor levels were, although not significantly, higher in RRMS patients compared to PPMS and SPMS patients. The results suggest that levels of visfatin and pro-inflammatory cytokines are higher in MS patients compared to healthy subjects. Their higher levels may be, in part, attributable to the MS phenotypes independent of fat mass in patients. We believe that these results may shed some light on a potentially novel source of visfatin as well as explaining its regulating role in the inflammation process.