Blood Glucose Homeostasis in the Course of Partial Pancreatectomy--Evidence for Surgically Reversible Diabetes Induced by Cholestasis

Bridging the Gap: Pancreas Tissue Slices From Organ and Tissue Donors for the Study of Diabetes Pathogenesis

Over the last two decades, increased availability of human pancreatic tissues has allowed for major expansions in our understanding of islet biology in health and disease. Indeed, studies of fixed and frozen pancreatic tissues, as well as efforts using viable isolated islets obtained from organ donors, have provided significant insights toward our understanding of diabetes. However, the procedures associated with islet isolation result in distressed cells that have been removed from any surrounding influence. The pancreas tissue slice technology was developed as an in situ approach to overcome certain limitations associated with studies on isolated islets or fixed tissue. In this Perspective, we discuss the value of this novel platform and review how pancreas tissue slices, within a short time, have been integrated in numerous studies of rodent and human islet research. We show that pancreas tissue slices allow for investigations in a less perturbed organ tissue environment, ranging from cellular processes, over peri-islet modulations, to tissue interactions. Finally, we discuss the considerations and limitations of this technology in its future applications. We believe the pancreas tissue slices will help bridge the gap between studies on isolated islets and cells to the systemic conditions by providing new insight into physiological and pathophysiological processes at the organ level.

ARTICLE HIGHLIGHTS

Human pancreas tissue slices represent a novel platform to study human islet biology in close to physiological conditions. Complementary to established technologies, such as isolated islets, single cells, and histological sections, pancreas tissue slices help bridge our understanding of islet physiology and pathophysiology from single cell to intact organ. Diverse sources of viable human pancreas tissue, each with distinct characteristics to be considered, are available to use in tissue slices for the study of diabetes pathogenesis.

Increased risk of incident diabetes after therapy with immune checkpoint inhibitor compared with conventional chemotherapy: A longitudinal trajectory analysis using a tertiary care hospital database

AIMS/HYPOTHESIS

Immune checkpoint inhibitor (ICI) has been emerged as a promising cancer treatment. However, ICI use induces immune-related adverse events, including diabetes mellitus. We compared the risk of new-onset diabetes between patients receiving an ICI and those receiving conventional chemotherapy (CC).

METHODS

Using a tertiary care hospital database, we included cancer patients without a previous history of diabetes who were treated with either CC or an ICI. One-to-five nearest neighbor propensity matching was applied, and the risk of diabetes was estimated using a Cox proportional hazards model. Latent class growth modeling was performed with a trajectory approach to determine distinct clusters that followed similar glucose trajectory patterns over time.

RESULTS

Among 1326 subjects, 1105 received CC, and 221 received an ICI. The risk of new-onset diabetes was significantly higher in the ICI group than the CC group (adjusted hazard ratio 2.454, 95 % confidence interval 1.528-3.940; p < 0.001). The ICI group had a higher proportion of subjects in the trajectory cluster with an increasing glucose pattern than the CC group (10.4 % and 7.4 %, respectively). Within the ICI group, the subjects with an increasing glucose pattern were predominantly male and associated with enhanced lymphocytosis after ICI administration.

CONCLUSIONS

ICI therapy is associated with an increased risk of incident diabetes compared with CC. The glucose levels of patients treated with an ICI, especially males and those with prominent lymphocytosis after ICI treatment, need to be monitored regularly to detect ICI-associated diabetes as early as possible.

Three-Year Observation of Glucose Metabolism After Pancreaticoduodenectomy: A Single-Center Prospective Study in Japan

CONTEXT

The glucose tolerance of patients changes considerably from before to after pancreaticoduodenectomy wherein approximately half of the pancreas is resected.

OBJECTIVE

The aim of this prospective study was to investigate the incidence of and risk factors for diabetes after pancreaticoduodenectomy.

METHODS

This study is a part of an ongoing prospective study, the Kindai Prospective Study on Metabolism and Endocrinology after Pancreatectomy (KIP-MEP) study. Of the 457 patients enrolled to date, 96 patients without diabetes who underwent pancreaticoduodenectomy were investigated in this study. Preoperatively, 1 month post-pancreaticoduodenectomy, and every 6 months thereafter, the glucose metabolism and endocrine function were evaluated using the 75 g oral glucose tolerance test. Various other metabolic, endocrine, and exocrine indices were also examined over a period of up to 36 months.

RESULTS

Of the 96 patients analyzed in this study, 33 were newly diagnosed with diabetes. The cumulative diabetes incidence at 36 months following pancreaticoduodenectomy was 53.8%. The preoperative insulinogenic index and ΔC-peptide in the glucagon stimulation test were significantly lower in the progressors to diabetes than in the nonprogressors. Multivariate Cox regression analysis demonstrated that the insulinogenic index was the only significant risk factor for new-onset diabetes.

CONCLUSION

The majority of patients developed new-onset diabetes after pancreaticoduodenectomy, and a low value of the insulinogenic index was suggested to be a risk factor for diabetes. Preoperative assessment for the prediction of the onset of diabetes serves as useful information for patients and is important for postoperative glycemic control and diabetes management in patients who require pancreaticoduodenectomy.

The Impact of Pancreatic Head Resection on Blood Glucose Homeostasis in Patients with Chronic Pancreatitis

BACKGROUND

Chronic pancreatitis (CP) often leads to recurrent pain as well as exocrine and/or endocrine pancreatic insufficiency. This study aimed to investigate the effect of pancreatic head resections on glucose metabolism in patients with CP.

METHODS

Patients who underwent pylorus-preserving pancreaticoduodenectomy (PPPD), Whipple procedure (cPD), or duodenum-preserving pancreatic head resection (DPPHR) for CP between January 2011 and December 2020 were retrospectively analyzed with regard to markers of pancreatic endocrine function including steady-state beta cell function (%B), insulin resistance (IR), and insulin sensitivity (%S) according to the updated Homeostasis Model Assessment (HOMA2).

RESULTS

Out of 141 pancreatic resections for CP, 43 cases including 31 PPPD, 2 cPD and 10 DPPHR, met the inclusion criteria. Preoperatively, six patients (14%) were normoglycemic (NG), 10 patients (23.2%) had impaired glucose tolerance (IGT) and 27 patients (62.8%) had diabetes mellitus (DM). In each subgroup, no significant changes were observed for HOMA2-%B (NG: p = 0.57; IGT: p = 0.38; DM: p = 0.1), HOMA2-IR (NG: p = 0.41; IGT: p = 0.61; DM: p = 0.18) or HOMA2-%S (NG: p = 0.44; IGT: p = 0.52; DM: p = 0.51) 3 and 12 months after surgery, respectively.

CONCLUSION

Pancreatic head resections for CP, including DPPHR and pancreatoduodenectomies, do not significantly affect glucose metabolism within a follow-up period of 12 months.

Hemoglobin A1c Is a Predictor of New Insulin Dependence After Partial Pancreatectomy: A Multi-Institutional Analysis

BACKGROUND

Pancreatic diseases have long been associated with impaired glucose control. This study sought to identify the incidence of new insulin-dependent diabetes mellitus (IDDM) after pancreatectomy and the predictive accuracy of hemoglobin A1c (HbA1c) or blood glucose.

METHODS

Patients who underwent partial pancreatectomy and had preoperative HbA1c available at two academic institutions were assessed for new IDDM on discharge in relation to complication rates and survival.

RESULTS

Of the 267 patients analyzed, 67% had abnormal HbA1c levels prior to surgery (mean 6.8%, glucose 135 mg/dL). Two hundred eight (77.9%) were not insulin-dependent prior to surgery, and 35 (16.8%) developed new IDDM after resection. On multivariable regression, increasing HbA1c and preoperative glucose were the only significant predictors for new IDDM. Optimal predictive cutoffs (HbA1c of 6.25% and glucose of 121 mg/dL) were determined in a discovery group (n = 143) and confirmed in a validation group (n = 124) with a diagnostic sensitivity of 72.7% and specificity of 84.8%. Patients with new IDDM after resection had higher rates of severe complications (OR 3.39), increased TPN at discharge (OR 4.32), and increased rates of discharge to nursing facilities (OR 2.57) (all P < 0.05). New IDDM was also associated with a decreased cancer-specific survival.

CONCLUSION

Preoperative HbA1c ≥ 6.25% and blood glucose ≥ 121 mg/dL can accurately identify patients at increased risk of IDDM. These diagnostics may help identify patients in a preoperative setting that may benefit from interventions such as diabetes education or enhanced glucose control preoperatively.

Dysfunction of Persisting β Cells Is a Key Feature of Early Type 2 Diabetes Pathogenesis

Type 2 diabetes is characterized by peripheral insulin resistance and insufficient insulin release from pancreatic islet β cells. However, the role and sequence of β cell dysfunction and mass loss for reduced insulin levels in type 2 diabetes pathogenesis are unclear. Here, we exploit freshly explanted pancreas specimens from metabolically phenotyped surgical patients using an in situ tissue slice technology. This approach allows assessment of β cell volume and function within pancreas samples of metabolically stratified individuals. We show that, in tissue of pre-diabetic, impaired glucose-tolerant subjects, β cell volume is unchanged, but function significantly deteriorates, exhibiting increased basal release and loss of first-phase insulin secretion. In individuals with type 2 diabetes, function within the sustained β cell volume further declines. These results indicate that dysfunction of persisting β cells is a key factor in the early development and progression of type 2 diabetes, representing a major target for diabetes prevention and therapy.

Endocrine and Metabolic Insights from Pancreatic Surgery

Although it is well established that diabetes can also develop as a result of diseases or maneuvers on the exocrine pancreas, the complex relationship between glucose disorders and underlying pancreatic disease is still debated. There is evidence that several features linked to pancreatic diseases can modify endocrine and metabolic conditions before and after surgery. However, pancreatic surgery provides a rare opportunity to correlate in vivo endocrine and metabolic pathways with ex vivo pancreatic samples, to examine the endocrine and metabolic effects of acute islet removal, and finally to clarify the pathogenesis of diabetes. This approach could therefore represent a unique method to shed light on the molecular mechanisms, predicting factors, and metabolic consequences of insulin resistance, islet plasticity, β cell failure, and type 2 diabetes.

Prediction of exocrine and endocrine insufficiency after pancreaticoduodenectomy using volumetry

Objectives: The aim of this study is to evaluate the use of pancreatic volumetric assessment to predict exocrine and endocrine insufficiency after pancreaticoduodenectomy.Methods: Thirty-seven patients who underwent pancreaticoduodenectomy were included in the study. Endocrine function was assessed in all patients without a history of diabetes using an oral glucose tolerance test. A 13C-labeled mixed triglyceride (MTG) breath test evaluated exocrine function before and after resection. Volumetric measurements were performed on CT or MRI.Results: The volumetric measurements could not predict pre- or postoperative diabetes. Moreover, the resected volume was significantly lower in patients who developed diabetes after resection. Comparing patients with a normal and disturbed postoperative MTG, postoperative volumes and parenchymal thickness were significantly different. The parenchymal thickness on postoperative imaging is withheld as a predictive factor (OR = .85 [95% CI .71-1.01], p = .049). The best cutoff value to predict exocrine insufficiency is a parenchymal thickness of less than 11.4 mm (AUC = .76, p = .025, sensitivity = 88.9%, specificity = 70.0%).Conclusions: Pancreatic remnant volumetry and parenchymal thickness measurement after pancreaticoduodenectomy are correlated with exocrine insufficiency, but with limited predictive value. None of the preoperative measurements are withheld to predict postoperative exocrine function. Pre- and postoperative volumetry appear to have no use in predicting postoperative diabetes.

Bile Modulates Secretion of Incretins and Insulin: A Study of Human Extrahepatic Cholestasis

OBJECTIVE

Changes in bile flow after bariatric surgery may beneficially modulate secretion of insulin and incretins, leading to diabetes remission. However, the exact mechanism(s) involved is still unclear. Here, we propose an alternative method to investigate the relationship between alterations in physiological bile flow and insulin and incretin secretion by studying changes in gut-pancreatic function in extrahepatic cholestasis in nondiabetic humans.

METHODS

To pursue this aim, 58 nondiabetic patients with recent diagnosis of periampullary tumors underwent an oral glucose tolerance test (OGTT), and a subgroup of 16 patients also underwent 4-hour mixed meal tests and hyperinsulinemic-euglycemic clamps.

RESULTS

The analysis of the entire cohort revealed a strong inverse correlation between total bilirubin levels and insulinogenic index. When subjects were divided on the basis of bilirubin levels, used as a marker of altered bile flow, subjects with high bilirubin levels displayed inferior glucose control and decreased insulin secretion during the OGTT. Altered bile flow elicited a markedly greater increase in glucagon and glucagon-like peptide 1 (GLP-1) secretion at fasting state, and following the meal, both glucagon and GLP-1 levels remained increased over time. Conversely, Glucose-dependent insulinotropic polypeptide (GIP) levels were comparable at the fasting state, whereas the increase following meal ingestion was significantly blunted with high bilirubin levels. We reveal strong correlations between total bilirubin and glucagon and GLP-1 levels.

CONCLUSIONS

Our findings suggest that acute extrahepatic cholestasis determines major impairment in enteroendocrine gut-pancreatic secretory function. The altered bile flow may determine a direct deleterious effect on β-cell function, perhaps mediated by the impairment of incretin hormone function.

Perspectives on diabetes mortality as the result of residual confounding and reverse causality by common disease

Type 2 diabetes (T2D) is associated with major global health burdens, including 2 to 4 times increased rates of morbidity and mortality from cardiovascular disease. However, T2D remains an exclusion diagnosis in individuals with arbitrarily elevated blood-glucose levels. While it is well-established that diabetes is associated with an elevated risk of cardiovascular disease and cancer, it has recently been shown that heart failure and cancer may precede, and even contribute to, the development of T2D. In the present review, we have summarized these findings and discuss their potential implications for our understanding of the T2D disease entity, including its treatment and associated increased mortality. We suggest that the existence of a hitherto unrecognized distinct T2D subtype, secondary to heart failure and/or cancer, may substantially contribute to the excess mortality reported in T2D patients with mild disease. Treatment and clinical care of this subtype needs to be defined separately from the general T2D phenotype.

Systems biology of the IMIDIA biobank from organ donors and pancreatectomised patients defines a novel transcriptomic signature of islets from individuals with type 2 diabetes

AIMS/HYPOTHESIS

Pancreatic islet beta cell failure causes type 2 diabetes in humans. To identify transcriptomic changes in type 2 diabetic islets, the Innovative Medicines Initiative for Diabetes: Improving beta-cell function and identification of diagnostic biomarkers for treatment monitoring in Diabetes (IMIDIA) consortium ( www.imidia.org ) established a comprehensive, unique multicentre biobank of human islets and pancreas tissues from organ donors and metabolically phenotyped pancreatectomised patients (PPP).

METHODS

Affymetrix microarrays were used to assess the islet transcriptome of islets isolated either by enzymatic digestion from 103 organ donors (OD), including 84 non-diabetic and 19 type 2 diabetic individuals, or by laser capture microdissection (LCM) from surgical specimens of 103 PPP, including 32 non-diabetic, 36 with type 2 diabetes, 15 with impaired glucose tolerance (IGT) and 20 with recent-onset diabetes (<1 year), conceivably secondary to the pancreatic disorder leading to surgery (type 3c diabetes). Bioinformatics tools were used to (1) compare the islet transcriptome of type 2 diabetic vs non-diabetic OD and PPP as well as vs IGT and type 3c diabetes within the PPP group; and (2) identify transcription factors driving gene co-expression modules correlated with insulin secretion ex vivo and glucose tolerance in vivo. Selected genes of interest were validated for their expression and function in beta cells.

RESULTS

Comparative transcriptomic analysis identified 19 genes differentially expressed (false discovery rate ≤0.05, fold change ≥1.5) in type 2 diabetic vs non-diabetic islets from OD and PPP. Nine out of these 19 dysregulated genes were not previously reported to be dysregulated in type 2 diabetic islets. Signature genes included TMEM37, which inhibited Ca²⁺-influx and insulin secretion in beta cells, and ARG2 and PPP1R1A, which promoted insulin secretion. Systems biology approaches identified HNF1A, PDX1 and REST as drivers of gene co-expression modules correlated with impaired insulin secretion or glucose tolerance, and 14 out of 19 differentially expressed type 2 diabetic islet signature genes were enriched in these modules. None of these signature genes was significantly dysregulated in islets of PPP with impaired glucose tolerance or type 3c diabetes.

CONCLUSIONS/INTERPRETATION

These studies enabled the stringent definition of a novel transcriptomic signature of type 2 diabetic islets, regardless of islet source and isolation procedure. Lack of this signature in islets from PPP with IGT or type 3c diabetes indicates differences possibly due to peculiarities of these hyperglycaemic conditions and/or a role for duration and severity of hyperglycaemia. Alternatively, these transcriptomic changes capture, but may not precede, beta cell failure.

Human beta cell mass and function in diabetes: Recent advances in knowledge and technologies to understand disease pathogenesis

BACKGROUND

Plasma insulin levels are predominantly the product of the morphological mass of insulin producing beta cells in the pancreatic islets of Langerhans and the functional status of each of these beta cells. Thus, deficiency in either beta cell mass or function, or both, can lead to insufficient levels of insulin, resulting in hyperglycemia and diabetes. Nonetheless, the precise contribution of beta cell mass and function to the pathogenesis of diabetes as well as the underlying mechanisms are still unclear. In the past, this was largely due to the restricted number of technologies suitable for studying the scarcely accessible human beta cells. However, in recent years, a number of new platforms have been established to expand the available techniques and to facilitate deeper insight into the role of human beta cell mass and function as cause for diabetes and as potential treatment targets.

SCOPE OF REVIEW

This review discusses the current knowledge about contribution of human beta cell mass and function to different stages of type 1 and type 2 diabetes pathogenesis. Furthermore, it highlights standard and newly developed technological platforms for the study of human beta cell biology, which can be used to increase our understanding of beta cell mass and function in human glucose homeostasis.

MAJOR CONCLUSIONS

In contrast to early disease models, recent studies suggest that in type 1 and type 2 diabetes impairment of beta cell function is an early feature of disease pathogenesis while a substantial decrease in beta cell mass occurs more closely to clinical manifestation. This suggests that, in addition to beta cell mass replacement for late stage therapies, the development of novel strategies for protection and recovery of beta cell function could be most promising for successful diabetes treatment and prevention. The use of today's developing and wide range of technologies and platforms for the study of human beta cells will allow for a more detailed investigation of the underlying mechanisms and will facilitate development of treatment approaches to specifically target human beta cell mass and function.

Vessel Network Architecture of Adult Human Islets Promotes Distinct Cell-Cell Interactions In Situ and Is Altered After Transplantation

Islet-cell hormone release is modulated by signals from endothelial and endocrine cells within the islet. However, models of intraislet vascularization and paracrine cell signaling are mostly based on the rodent pancreas. We assessed the architecture and endocrine cell interaction of the vascular network in unperturbed human islets in situ and their potential to re-establish their endogenous vascular network after transplantation in vivo. We prepared slices of fresh pancreas tissue obtained from nondiabetic patients undergoing partial pancreatectomy. In addition, we transplanted human donor islets into the anterior chamber of the mouse eye. Next, we performed three-dimensional in situ and in vivo imaging of islet cell and vessel architecture at cellular resolution and compared our findings with mouse and porcine islets. Our data reveal a significantly different vascular architecture with decreased vessel diameter, reduced vessel branching, and shortened total vessel network in human compared with mouse islets. Together with the distinct cellular arrangement in human islets, this limits β to endothelial cell interactions, facilitates connection of α and β cells, and promotes the formation of independent β-cell clusters within islets. Furthermore, our results show that the endogenous vascular network of islets is significantly altered after transplantation in a donor age-related mechanism. Thus, our study provides insight into the vascular architecture and cellular arrangement of human islets with apparent consequences for intercellular islet signaling. Moreover, our findings suggest that human islet engraftment after transplantation can be improved by using alternative, less mature islet-cell sources.

Diabetes and cancer, common threads and missing links

Diabetes mellitus is a serious and growing health problem worldwide and is associated with severe acute and chronic complications. Accruing epidemiological and clinical evidence have suggested that an increased cancer incidence is associated with diabetes as well as certain diabetes risk factors and diabetes medications. Several pathophysiological mechanisms for this relationship have been postulated, including insulin resistance and hyperinsulinemia, enhanced inflammation, aberrant metabolic state, endoplasmic reticulum stress, and deregulation of autophagy. In addition to these potential mechanisms, a number of common risk factors, including obesity, may be behind the association between diabetes and cancer. Furthermore, different anti-diabetic medications may modify cancer risk and mortality in patients with diabetes. This Review discusses evidence to support the relationship between diabetes and cancer development as well as the underlying mechanisms. We also discuss the relationship of current diabetes treatments and cancer risk or prognosis. Understanding the mechanisms that connect type 2 diabetes or diabetes treatments to cancer are crucial for establishing the fundamental strategies concerning about primary prevention, early detection and effective therapy against these diseases.