Our study was approved by the ethics committee of Beijing Jishuitan Hospital. Written informed consent was obtained from each patient prior to performance of any study procedures in accordance with the Declaration of Helsinki.
In this retrospective study, a total of 36 patients enrolled in, who were newly diagnosed with MM at the Department of Hematology, Beijing Jishuitan Hospital, during the period from October 2015 to March 2017. Diagnosis, staging, treatment and response evaluation of MM patients were performed according to the IMWG consensus.[16, 17] These patients received abdominal and pelvic CT before chemotherapy initiation or changed regimen when relapsed as part of the standardized staging examination. We followed these patients from diagnosed until the end of this study, unless the death or withdrawn. The median of follow- up of these NDMM patients was 677 days, range from 26 to 981.
For each NDMM case, 2 matched healthy people were randomly selected from the database supported by Radiology department of our hospital. The subjects included in this database were participants of an ongoing study since June 2014 investigating degeneration of the spine in the Department of Orthopedics, Beijing Jishuitan Hospital. These control cases were matched using the following criteria: age, sexual, height, weight and BMI.
Disease activity and treatment response
Patients received blood test including blood routine test, biochemistry (lactate dehydrogenase, calcium, creatinine), immune globulin and β2 globulin test et al for CRAB criteria and ISS staging. They also detected the bone marrow plasma by flowcytometry represented as tumor burden and cytogenetic detection including deletion 17p13, translocation t(4;14), translocation t(14;16) , translocation t(11;14) , deletion 13q14, gain 1q21 >3 copies by Fluorescence in situ hybridization (FISH) of CD38+ purified plasma cells. Patients received chemotherapy based on the proteasome inhibitor and evaluated the effect post 4 cycles before autologous hematopoietic stem cell transplantation. Patients achieving at least a partial response (PR) after induction therapy were classified as treatment responders. Treatment regimens and patients disposition are summarized in Figure 1.
Abdominal fat compartment quantitative assessment
All simulation scans were obtained in the supine position using a CT scanner compliant with five phantom (Mindways Software Inc., America) of Quantitative computed tomography (QCT) under whole abdomen. All studies were performed on an 80-slice CT scanner (Toshiba Medical Systems Corp., Tokyo, Japan) after an overnight fast. After generally calibration, the instrument parameters was setting as follows: 120 kV, 250 mA, 40 cm FOV, 120 cm bed height, 1 mm slice thickness, and 512 × 512 matrix. Scans generally extended from the last thoracic vertebrae (T12) to the sacrum (S1) and six slices of T12/L1, L1/L2, L2/L3, L3/L4, L4/L5 and L5/S1 vertebral interface used as anatomic markers. Visceral fat area (VFA) and total fat area (TFA) at each level were obtained, respectively, and the subcutaneous fat area (SFA) was calculated using the following equation: SFA = TFA -VFA. These measurements and analysis were performed by a radiologist blinded to patient information.
Enzyme-Linked Immunosorbent Assay (ELISA) to Detect the Adiponectin in Plasma
Blood samples of 25 NDMM patients were collected to detect the baseline levels of total adiponectin. Plasma samples from 17 healthy people were used as normal controls which collected from the rest of their routine blood test. Adiponectin was measured using Human ELISA kit (Abcam Inc. Burlingame, CA) in accordance with the manufacturer’s protocol. First, within 4 hours of collection, EDTA-anticoagulated blood was centrifuged at 1000g for 15 minutes. The separated plasma was centrifuged again at 10,000×g for 10 minutes at 4 °C to obtain platelet-poor plasma, which was then aliquotted and stored at -80 °C until testing. All samples were analysed in duplicate. Concentrations greater than 25 pg/ml for adiponectin were detectable. The color intensity was measured at 450 nm using a microplate reader (Bio-Rad, Berkeley, CA, USA), and the resulting data were analysed using CurveExpert 1.4. The personnel who performed the Elisa assays were blinded to the samples’ clinical backgrounds
The body mass index (BMI) was defined as the individual’s body weight in kilograms divided by height squared in meters (kg/m2). The ratio of VFA/SFA was calculated to display the distribution of abdominal fat. The median values and ranges are reported for continuous variables, and proportions are reported for categorical variables. Shapiro-Wilk tests were used to estimate the normality of the distribution of the parameters. Variables with a normal distribution were then analyzed with a two-sided t test. None of the values of fat area followed a normal distribution. The comparison of NDMM and healthy people were conducted by Mann-Whitney U nonparametric tests. To analyze the association between baseline characteristics and abdominal fat compartment, Mann-Whitney U nonparametric tests were conducted for sex, DS stage, adverse cytogenetics and chemotherapy response with fat components. The correlation of fat area and continuously quantities like age, height, weight, BMI, BM stage, LDH were analyzed by Spearman test. All procedures were performed using a statistical package (SPSS 16.0, SPSS, Inc., Chicago, IL), with P < 0.05 regarded as significant.