Predictors of 30-day follow-up visit completion after primary bariatric surgery: an analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program data registry

BACKGROUND

Adherence to follow-up visits is often unsatisfactory after bariatric surgery.

OBJECTIVES

To identify predictors, including surgery type and preoperative demographics, body mass index (BMI), medical conditions, and smoking status, of 30-day follow-up visit completion.

SETTING

Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program participating centers (2015-2018).

METHODS

Patients who underwent primary Roux-en-Y gastric bypass or sleeve gastrectomy were included in this analysis. Data were analyzed using weighted logistic regression. Subanalyses included stratification of the sample by sex and age (<45, 45-60, and >60 years).

RESULTS

Patients (n = 566,774) were predominantly female (79.6%), White (72.4%), non-Hispanic (77.9%), and middle-aged (44.5 ± 11.9 years), with a mean BMI of 45.3 ± 7.8 kg/m². More than 95% of patients completed the 30-day visits. In the whole-sample analysis, older age (odds ratio [OR], 1.02) and the presence of non-insulin-dependent diabetes (OR, 1.04), hypertension (OR, 1.03), hyperlipidemia (OR, 1.10), obstructive sleep apnea (OR, 1.15), and gastroesophageal reflux disease (OR, 1.16) were positive predictors of the 30-day visit completion (P_s < .01). Conversely, sleeve gastrectomy procedure (OR, .86), Black race (OR, .87), Hispanic ethnicity (OR, .94), and the presence of insulin-dependent diabetes (OR, .96) and smoking (OR, .83) were negative predictors (P_s < .01). Several differences emerged in subanalyses. For example, in sex stratification, Hispanic ethnicity lost its significance in men. In age stratification, BMI and male sex emerged as positive predictors in the age groups of <45 and 45-60 years, respectively.

CONCLUSION

Although challenged by small effect sizes, this analysis identified subgroups at a higher risk of being lost to follow-up after bariatric surgery.

CXCL12/CXCR4 transactivates HER2 in lipid rafts of prostate cancer cells and promotes growth of metastatic deposits in bone

Chemokines and their receptors function in migration and homing of cells to target tissues. Recent evidence suggests that cancer cells use a chemokine receptor axis for metastasis formation at secondary sites. Previously, we showed that binding of the chemokine CXCL12 to its receptor CXCR4 mediated signaling events resulting in matrix metalloproteinase-9 expression in prostate cancer bone metastasis. A variety of methods, including lipid raft isolation, stable overexpression of CXCR4, cellular adhesion, invasion assays, and the severe combined immunodeficient-human bone tumor growth model were used. We found that (a) CXCR4 and HER2 coexist in lipid rafts of prostate cancer cells; (b) the CXCL12/CXCR4 axis results in transactivation of the HER2 receptor in lipid rafts of prostate cancer cells; (c) Src kinase mediates CXCL12/CXCR4 transactivation of HER2 in prostate cancer cells; (d) a pan-HER inhibitor desensitizes CXCR4-induced transactivation and subsequent matrix metalloproteinase-9 secretion and invasion; (e) lipid raft-disrupting agents inhibited raft-associated CXCL12/CXCR4 transactivation of the HER2 and cellular invasion; (f) overexpression of CXCR4 in prostate cancer cells leads to increased HER2 phosphorylation and migratory properties of prostate cancer cells; and (g) CXCR4 overexpression enhances bone tumor growth and osteolysis. These data suggest that lipid rafts on the cell membrane are the key site for CXCL12/CXCR4-induced HER2 receptor transactivation. This transactivation contributes to enhanced invasive signals and metastatic growth in the bone microenvironment.

Bone marrow stromal cells enhance prostate cancer cell invasion through type I collagen in an MMP-12 dependent manner

At the cellular level, the process of bone metastasis involves many steps. Circulating cancer cells enter the marrow, proliferate, induce neovascularization, and ultimately expand into a clinically detectable, often symptomatic, metastatic deposit. Although the initial establishment and later expansion of the metastatic deposit in bone require tumor cells to possess invasive capability, the exact proteases responsible for this phenotype are not well known. The objective of our study was to take an unbiased approach to determine which proteases were expressed and functional during the initial interactions between prostate cancer cells and bone marrow stromal (BMS) cells. We found that the combination of human prostate cancer PC3 and BMS cells stimulates the invasive ability of cancer cells through type I collagen. The use of inhibitors for each of the major protease families indicated that 1 or more MMPs was/were responsible for the BMS-induced invasion. Gene profiling and semiquantitative RT-PCR analysis revealed an increased expression of several MMP genes because of PC3/BMS cell interaction. However, only MMP-12 showed an increase in protein expression. Downregulation of MMP-12 expression in PC3 cells by siRNA inhibited the enhanced invasion induced by PC3/BMS cell interaction. In vivo, MMP-12 was found to be primarily expressed by prostate cancer cells growing in bone. Our data suggest that BMS cells induce MMP-12 expression in prostate cancer cells, which results in invasive cells capable of degradation of type I collagen.

Prostate cancer-associated membrane type 1-matrix metalloproteinase: a pivotal role in bone response and intraosseous tumor growth

Membrane type 1-matrix metalloproteinase (MT1-MMP) is a major mediator of collagen I degradation. In human samples, we show that prostate cancer cells in skeletal metastases consistently express abundant MT1-MMP protein. Because prostate cancer bone metastasis requires remodeling of the collagen-rich bone matrix, we investigated the role of cancer cell-derived MT1-MMP in an experimental model of tumor-bone interaction. MT1-MMP-deficient LNCaP human prostate cancer cells were stably transfected with human wild-type MT1-MMP (MT1wt). Furthermore, endogenous MT1-MMP was down-regulated by small interfering RNA in DU145 human prostate cancer cells. Intratibial tumor injection in severe combined immunodeficient mice was used to simulate intraosseous growth of metastatic tumors. LNCaP-MT1wt cells produced larger osseous tumors than Neo control cells and induced osteolysis, whereas DU145 MT1-MMP-silenced transfectants induced osteogenic changes. In vitro assays showed that MT1wt overexpression enhanced collagen I degradation, whereas MT1-MMP-silencing did the opposite, suggesting that tumor-derived MT1-MMP may contribute directly to bone remodeling. LNCaP-MT1wt-derived conditioned medium stimulated in vitro multinucleated osteoclast formation. This effect was inhibited by osteoprotegerin, a decoy receptor for receptor activator of nuclear factor kappaB ligand, and by 4-[4-(methanesulfonamido) phenoxy] phenylsulfonyl methylthiirane, an MT1-MMP inhibitor. Our findings are consistent with the hypothesis that prostate cancer-associated MT1-MMP plays a direct and/or indirect role in bone matrix degradation, thus favoring intraosseous tumor expansion.

Heterogeneous Activation of MMP-9 Due to Prostate Cancer-Bone Interaction

OBJECTIVES

To determine whether matrix metalloproteinase (MMP)-9 activation resulting from prostate cancer cell-bone interaction is dependent on the tumor cell type and/or the nature of the bone microenvironment.

METHODS

In vitro co-cultures of human prostate cancer cells (PC3 and C4-2B) and mouse, human fetal, or human adult tissues were performed. In vivo the tumor cells were intratibially injected in SCID mice or intraosseously inoculated into fetal or adult bone xenografts in SCID mice. MMP-2 and MMP-9 expression and activation were determined by gelatin zymography in conditioned media obtained in vitro and in lysates derived from the in vivo studies at different time points.

RESULTS

Activation of MMP-9 occurred when PC3 cells interacted with human adult or fetal bone, either in vitro or in vivo at early time points. With C4-2B cells, activation of MMP-9 only happened in the human adult bone microenvironment at early time points after intraosseous inoculation of tumor cells. No activation of MMP-9 occurred when PC3 or C4-2B cells interacted with mouse bone, either in vitro or in vivo.

CONCLUSIONS

The results of our study have shown that the activation of MMP-9 when human prostate cancer cells interact with bone depends on the particular identity of the tumor cells and the type of bone tissue used. These findings have broad implications for experimental models attempting to define tumor-microenvironmental interactions in bone metastasis.

Quantitative assessment of small intraosseous prostate cancer burden in SCID mice using fluorescence imaging

BACKGROUND

Experimental bone metastases are typically analyzed when the skeletal tumor burden is large enough to be detected by imaging or histology. By this time, the bone microenvironment is usually destroyed, preventing useful analysis of tumor-bone interactions.

METHODS

Small intraosseous tumors generated by intratibial injection of C4-2B prostate cancer cells transfected with green fluorescent protein (GFP) were assessed using in vivo and ex vivo fluorescence imaging, radiography, histology, and fluorometric analysis of bone lysates.

RESULTS

Ex vivo fluorescence imaging and fluorometric analysis were capable of detecting tiny bone tumors as early as 10 days after injection. Ex vivo fluorescence imaging allowed simple quantification of small skeletal tumor burden and was useful in measuring the effect of systemic therapy.

CONCLUSIONS

Ex vivo fluorescence imaging is a sensitive and easy method to quantify small skeletal tumor burden. This technique allows investigation of tumor-bone interactions while the bone microanatomy is still intact.

Inhibition of human prostate cancer growth, osteolysis and angiogenesis in a bone metastasis model by a novel mechanism-based selective gelatinase inhibitor

Metastasis to the bone is a major clinical complication in patients with prostate cancer (PC). However, therapeutic options for treatment of PC bone metastasis are limited. Gelatinases are members of the matrix metalloproteinase (MMP) family and have been shown to play a key role in PC metastasis. Herein, we investigated the effect of SB-3CT, a covalent mechanism-based MMP inhibitor with high selectivity for gelatinases, in an experimental model of PC bone metastases. Intraperitoneal (i.p.) treatment with SB-3CT (50 mg/kg) inhibited intraosseous growth of human PC3 cells within the marrow of human fetal femur fragments previously implanted in SCID mice, as demonstrated by histomorphometry and Ki-67 immunohistochemistry. The anti-osteolytic effect of SB-3CT was confirmed by radiographic images. Treatment with SB-3CT also reduced intratumoral vascular density and bone degradation in the PC3 bone tumors. A direct inhibition of bone marrow endothelial cell invasion and tubule formation in Matrigel by SB-3CT in vitro was also demonstrated. The use of the highly selective gelatinase inhibitors holds the promise of effective intervention of metastases of PC to the bone.