Systemic Neutrophil Gelatinase-Associated Lipocalin Alterations in Chronic Pancreatitis: A Multicenter, Cross-Sectional Study

INTRODUCTION

Chronic pancreatitis (CP) is a progressive fibroinflammatory disorder lacking therapies and biomarkers. Neutrophil gelatinase-associated lipocalin (NGAL) is a proinflammatory cytokine elevated during inflammation that binds fatty acids (FAs) such as linoleic acid. We hypothesized that systemic NGAL could serve as a biomarker for CP and, with FAs, provide insights into inflammatory and metabolic alterations.

METHODS

NGAL was measured by immunoassay, and FA composition was measured by gas chromatography in plasma (n = 171) from a multicenter study, including controls (n = 50), acute and recurrent acute pancreatitis (AP/RAP) (n = 71), and CP (n = 50). Peripheral blood mononuclear cells (PBMCs) from controls (n = 16), AP/RAP (n = 17), and CP (n = 15) were measured by cytometry by time-of-flight.

RESULTS

Plasma NGAL was elevated in subjects with CP compared with controls (area under the curve [AUC] = 0.777) or AP/RAP (AUC = 0.754) in univariate and multivariate analyses with sex, age, body mass index, and smoking (control AUC = 0.874; AP/RAP AUC = 0.819). NGAL was elevated in CP and diabetes compared with CP without diabetes ( P < 0.001). NGAL + PBMC populations distinguished CP from controls (AUC = 0.950) or AP/RAP (AUC = 0.941). Linoleic acid was lower, whereas dihomo-γ-linolenic and adrenic acids were elevated in CP ( P < 0.05). Linoleic acid was elevated in CP with diabetes compared with CP subjects without diabetes ( P = 0.0471).

DISCUSSION

Elevated plasma NGAL and differences in NGAL + PBMCs indicate an immune response shift that may serve as biomarkers of CP. The potential interaction of FAs and NGAL levels provide insights into the metabolic pathophysiology and improve diagnostic classification of CP.

Differences in Plasma Fatty Acid Composition Related to Chronic Pancreatitis: A Pilot Study

OBJECTIVES

Chronic pancreatitis (CP) is an inflammatory disease affecting the absorption of fat-soluble nutrients. Signaling in pancreatic cells that lead to inflammation may be influenced by fatty acids (FAs) through diet and de novo lipogenesis. Here, we investigated the relationship between plasma FA composition in CP with heterogeneity of etiology and complications of CP.

MATERIALS AND METHODS

Blood and clinical parameters were collected from subjects with CP (n = 47) and controls (n = 22). Plasma was analyzed for FA composition using gas chromatography and compared between controls and CP and within CP.

RESULTS

Palmitic acid increased, and linoleic acid decreased in CP compared with controls. Correlations between age or body mass index and FAs are altered in CP compared with controls. Diabetes, pancreatic calcifications, and substance usage, but not exocrine pancreatic dysfunction, were associated with differences in oleic acid and linoleic acid relative abundance in CP. De novo lipogenesis index was increased in the plasma of subjects with CP compared with controls and in calcific CP compared with noncalcific CP.

CONCLUSIONS

Fatty acids that are markers of de novo lipogenesis and linoleic acid are dysregulated in CP depending on the etiology or complication. These results enhance our understanding of CP and highlight potential pathways targeting FAs for treating CP.

Exploring the Role of Hyperinsulinemia in Obesity-Associated Tumor Development

Although there has been a long-standing connection between hyperinsulinemia and cancer development, there is a lack of understanding of the role of the insulin receptor on cells that can become cancerous. In a recent issue of Cell Metabolism, Zhang and colleagues, using a diet-induced obesity mouse model, identified a direct function of insulin receptors on pancreatic acinar cells expressing a KRASG12D mutation in promoting obesity-associated pancreatic cancer. Furthermore, insulin receptor signaling from hyperinsulinemia promoted the secretion of digestive enzymes that contributed to acinar to ductal metaplasia. These findings highlight an important connection between obesity, diabetes, and pancreatic tumor development and suggest potential strategies for obesity-associated cancer prevention targeting the insulin receptor signaling pathways.

Changes in Plasma Fatty Acid Abundance Related to Chronic Pancreatitis: A Pilot Study

Objectives

Chronic pancreatitis (CP) is an inflammatory disease that affects the absorption of nutrients like fats. Molecular signaling in pancreatic cells can be influenced by fatty acids (FAs) and changes in FA abundance could impact CP-associated complications. Here, we investigated FA abundance in CP compared to controls and explored how CP-associated complications and risk factors affect FA abundance.

Methods

Blood and clinical parameters were collected from subjects with (n=47) and without CP (n=22). Plasma was analyzed for relative FA abundance using gas chromatography and compared between controls and CP. Changes in FA abundance due to clinical parameters were also assessed in both groups.

Results

Decreased relative abundance of polyunsaturated fatty acids (PUFAs) and increased monounsaturated fatty acids (MUFAs) were observed in subjects with CP in a sex-dependent manner. The relative abundance of linoleic acid increased, and oleic acid decreased in CP subjects with exocrine pancreatic dysfunction and a history of substance abuse.

Conclusions

Plasma FAs like linoleic acid are dysregulated in CP in a sex-dependent manner. Additionally, risk factors and metabolic dysfunction further dysregulate FA abundance in CP. These results enhance our understanding of CP and highlight potential novel targets and metabolism-related pathways for treating CP.

Physical Activity Delays Obesity-Associated Pancreatic Ductal Adenocarcinoma in Mice and Decreases Inflammation

BACKGROUND & AIMS

Obesity is a risk factor for pancreatic ductal adenocarcinoma (PDAC), a deadly disease with limited preventive strategies. Lifestyle interventions to decrease obesity might prevent obesity-associated PDAC. Here, we examined whether decreasing obesity by increased physical activity (PA) and/or dietary changes would decrease inflammation in humans and prevent PDAC in mice.

METHODS

Circulating inflammatory-associated cytokines of overweight and obese subjects before and after a PA intervention were compared. PDAC pre-clinical models were exposed to PA and/or dietary interventions after obesity-associated cancer initiation. Body composition, tumor progression, growth, fibrosis, inflammation, and transcriptomic changes in the adipose tissue were evaluated.

RESULTS

PA decreased the levels of systemic inflammatory cytokines in overweight and obese subjects. PDAC mice on a diet-induced obesity (DIO) and PA intervention, had delayed weight gain, decreased systemic inflammation, lower grade pancreatic intraepithelial neoplasia lesions, reduced PDAC incidence, and increased anti-inflammatory signals in the adipose tissue compared to controls. PA had additional cancer prevention benefits when combined with a non-obesogenic diet after DIO. However, weight loss through PA alone or combined with a dietary intervention did not prevent tumor growth in an orthotopic PDAC model. Adipose-specific targeting of interleukin (IL)-15, an anti-inflammatory cytokine induced by PA in the adipose tissue, slowed PDAC growth.

CONCLUSIONS

PA alone or combined with diet-induced weight loss delayed the progression of PDAC and reduced systemic and adipose inflammatory signals. Therefore, obesity management via dietary interventions and/or PA, or modulating weight loss related pathways could prevent obesity-associated PDAC in high-risk obese individuals.

Abstract 2522: Pathway and immune profile analysis of cyst-derived versus PanIN-derived pancreatic ductal adenocarcinomas

Introduction: Pancreatic cystic lesions (PCL) are common and a subset of mucinous cysts will transform into pancreatic ductal adenocarcinoma (PDAC). However, predicting which of these mucinous PCL may progress to PDAC and warrant surgery remains a clinical challenge. Moreover, identifying those clinically emergent mucinous PCL for which a surveillance approach is best is a dire clinical need. Therefore, we aimed to identify molecular signatures that distinguished between PDAC with and without clinical evidence of a PCL to identify novel biomarkers.

Methods: We leveraged data from the Oncology Research Information Exchange Network (ORIEN) multi-institute sequencing project and analyzed 66 PDAC cases recruited to ORIEN from The Ohio State University Wexner Medical Center and Moffitt Cancer Center for which tumor whole transcriptome sequencing datasets were generated. We separated the cases based on whether a tumor had originated from a cystic lesion (n=16) or presumably through the pancreatic intraepithelial neoplasia (PanIN) pathway (n=50). We then performed differential expression and pathway analysis using both Gene-Set Enrichment Analysis (GSEA) and Pathway Analysis with Down-weighted Genes (PADOG) algorithms. Based on the emerging importance of the immune landscape in PDAC development, we also analyzed immune profiles using a novel tool, Tumor-immune Microenvironment Deconvolution Web-portal for Bulk Transcriptomics (TIMEx).

Results: When grouped by tumor origin, cyst-derived PDAC gene expression sets are enriched in immune signaling pathways, specifically NOTCH signaling (p=0.04), and demonstrate significant downregulation in amino acid metabolism, mitochondrial import and Gsα signaling pathways. Furthermore, GSEA based on TIMEx signatures indicated that multiple immune cell-specific profiles had significant enrichment scores in either the cyst-derived (for example, plasma cell: normalized enrichment score=-1.53; p=0.007) or non-cyst-derived (for example, neutrophil: normalized enrichment score=2.24; p=0.0001) PDAC cohorts.

Conclusions: Our data suggest that cyst-derived and non-cyst-derived PDACs differ by immune profile, enhanced NOTCH pathway usage and in the metabolic processing of multiple amino acids. These initial findings support future studies to assess the accuracy of risk stratifying PCLs based on their amino acid, metabolic, or immune profiles, and exploration into mechanisms to explain these findings.

Citation Format: Margaret A. Park, Somashekar G. Krishna, Maria C. Genilo-Delgado, Kristyn Gumpper-Fedus, Darwin L. Conwell, Phil A. Hart, Mary E. Dillhoff, Maria F. Gomez, Toni L. Basinski, Aamir N. Dam, Jason B. Klapman, Jason B. Fleming, Mokenge Malafa, Amir Mohammadi, Barbara A. Centeno, Kun Jiang, Daniel Jeong, Dung-Tsa Chen, Mengyu Xie, Aik Choon Tan, Brooke L. Fridley, Jamie K. Teer, Zobeida Cruz-Monserrate, Jennifer B. Permuth. Pathway and immune profile analysis of cyst-derived versus PanIN-derived pancreatic ductal adenocarcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2522.

Altered Plasma Fatty Acid Abundance Is Associated with Cachexia in Treatment-Naïve Pancreatic Cancer

Cachexia occurs in up to 80% of pancreatic ductal adenocarcinoma (PDAC) patients and is characterized by unintentional weight loss and tissue wasting. To understand the metabolic changes that occur in PDAC-associated cachexia, we compared the abundance of plasma fatty acids (FAs), measured by gas chromatography, of subjects with treatment-naïve metastatic PDAC with or without cachexia, defined as a loss of > 2% weight and evidence of sarcopenia (n = 43). The abundance of saturated, monounsaturated, and polyunsaturated FAs was not different between subjects with cachexia and those without. Oleic acid was significantly higher in subjects with cachexia (p = 0.0007) and diabetes (p = 0.015). Lauric (r = 0.592, p = 0.0096) and eicosapentaenoic (r = 0.564, p = 0.015) acids were positively correlated with age in cachexia patients. Subjects with diabetes (p = 0.021) or both diabetes and cachexia (p = 0.092) had low palmitic:oleic acid ratios. Linoleic acid was lower in subjects with diabetes (p = 0.018) and correlated with hemoglobin (r = 0.519, p = 0.033) and albumin (r = 0.577, p = 0.015) in subjects with cachexia. Oleic or linoleic acid may be useful treatment targets or biomarkers of cachexia in patients with metastatic PDAC, particularly those with diabetes.

A review of physical activity in pancreatic ductal adenocarcinoma: Epidemiology, intervention, animal models, and clinical trials

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest types of cancer, and the increasing incidence of PDAC may be related to the prevalence of obesity. Physical activity (PA), a method known to mitigate obesity by increasing total energy expenditure, also modifies multiple cellular pathways associated with cancer hallmarks. Epidemiologic evidence has shown that PA can lower the risk of developing a variety of cancers, reduce some of the detrimental side effects of treatments, and improve patient's quality of life during cancer treatment. However, little is known about the pathways underlying the correlations observed between PA interventions and PDAC. Moreover, there is no standard dose of PA intervention that is ideal for PDAC prevention or as an adjuvant of cancer treatments. In this review, we summarize relevant literature showing how PDAC patients can benefit from PA, the potential of PA as an adjuvant treatment for PDAC, the studies using preclinical models of PDAC to study PA, and the clinical trials to date assessing the effects of PA in PDAC.