Background
Both types of diabetes are characterized by beta‐cell failure and death, leading to insulin insufficiency. Very limited information is currently available about the ultrastructural ...alterations of beta cells in human diabetes. Our aim was to provide a comprehensive ultrastructural analysis of human pancreatic islets in type 1 (T1D) and type 2 (T2D) diabetic patients.
Methods
We performed a morphometric electron microscopy evaluation of beta cells obtained from the pancreas of 8 nondiabetic (ND), 5 T1D, and 8 T2D organ donors.
Results
A lower amount of beta cells was found in both T1D and T2D than in ND islets, whereas alpha cells were increased only in T2D. An increased number of bi‐hormonal cells (showing both insulin and glucagon granules in their cytoplasm) were found in T1D. Insulin granules were less represented in T2D than in ND beta cells, whereas no significant changes were found in T1D. Volume density of the endoplasmic reticulum was increased in T2D and unchanged in T1D; mitochondria number and volume were significantly higher in T2D than in ND beta cells, whereas no significant differences were found in T1D. In both T1D and T2D, more beta cells showed signs of apoptosis than in ND.
Conclusions
Our results show that in each type of diabetes, beta cells exhibit specific ultrastructural alterations, whose better understanding might improve therapeutic strategies.
•Hepatic expression of FNDC5/Irisin mRNA is highly expressed in patients with HCC.•There is correlation between FNDC5/Irisin mRNA and key regulators of lipogenesis.•There is correlation between ...FNDC5/Irisin mRNA and inflammatory markers.•There is correlation between FNDC5/Irisin mRNA and the oncogene NOTCH1
The fibronectin type III domain containing 5 (FNDC5)/Irisin, a novel energy-regulating hormone, is associated with lipid and carbohydrate metabolism. It is produced in low amounts by normal hepatic tissue, while in human hepatocellular carcinoma (HCC), in which aberrant de novo lipogenesis (DNL) occurs, the hepatic expression of FNDC5/Irisin is still unknown. The gene expression of FNDC5/Irisin, associated to key regulators of DNL, inflammation and cancer progression was evaluated in liver tissue of 18 patients with HCC undergoing liver transplantation and of 18 deceased donors.
Hepatic mRNA expression of FNDC5/Irisin and stearoyl-CoA desaturase (SCD-1), main enzymatic regulator of DNL, were significantly higher in HCC patients than in donors (p<0.0001 and p=0.015, respectively). The hepatic mRNA expression of the neurogenic locus notch homolog protein 1 (NOTCH1) tended to be higher in HCC patients than in donors (p=0.06). Only in HCC patients, hepatic FNDC5/Irisin strongly correlated with the transcription factor sterol regulatory element–binding factor 1, SCD-1, NOTCH1, tumor necrosis factor-α and Interleukin-6 mRNA expression. Further, in HCC patients, FNDC5/Irisin mRNA tended to correlate to plasma lipid profile namely triglycerides, palmitic/linoleic acid and polyunsaturated fatty acid/saturated fatty acid ratios.
In conclusion, HCC-liver tissue over-expressed FNDC5/Irisin in association with gene expression of mediators involved in lipogenesis, inflammation and cancer, suggesting a possible protective role of the hormone from the liver damage.
It has been reported that the incretin system, including regulated GLP-1 secretion and locally expressed DPP-4, is present in pancreatic islets. In this study we comprehensively evaluated the ...expression and role of DPP-4 in islet alpha and beta cells from non-diabetic (ND) and type 2 diabetic (T2D) individuals, including the effects of its inhibition on beta cell function and survival.
Isolated islets were prepared from 25 ND and 18 T2D organ donors; studies were also performed with the human insulin-producing EndoC-βH1 cells. Morphological (including confocal microscopy), ultrastructural (electron microscopy, EM), functional (glucose-stimulated insulin secretion), survival (EM and nuclear dyes) and molecular (RNAseq, qPCR and western blot) studies were performed under several different experimental conditions.
DPP-4 co-localized with glucagon and was also expressed in human islet insulin-containing cells. Furthermore, DPP-4 was expressed in EndoC-βH1 cells. The proportions of DPP-4 positive alpha and beta cells and DPP-4 gene expression were significantly lower in T2D islets. A DPP-4 inhibitor protected ND human beta cells and EndoC-βH1 cells against cytokine-induced toxicity, which was at least in part independent from GLP1 and associated with reduced NFKB1 expression. Finally, DPP-4 inhibition augmented glucose-stimulated insulin secretion, reduced apoptosis and improved ultrastructure in T2D beta cells.
These results demonstrate the presence of DPP-4 in human islet alpha and beta cells, with reduced expression in T2D islets, and show that DPP-4 inhibition has beneficial effects on human ND and T2D beta cells. This suggests that DPP-4, besides playing a role in incretin effects, directly affects beta cell function and survival.
•An incretin system, including regulated GLP-1 secretion and locally expressed DPP-4, has been found in pancreatic islets.•In the present study we have assessed the role of direct DPP-4 inhibition on beta cells from non-diabetic and type 2 diabetic individuals.•We found that DPP-4 is expressed in human beta cells and its inhibition has several protective effects.•This was due, at least in part, to reduced expression of NFKB and its target genes.•Therefore, DPP-4, besides playing a role in incretin effects, can directly affect beta cell function and survival.
Recently osteopontin (OPN), a protein of the extracellular matrix, has generated in hepatocellular carcinoma (HCC) a significant interest as a prognostic factor. Aim of this study was to confirm, in ...liver tissues of subjects with HCV-positive HCC undergoing liver transplantation (RL, n=10) and of donors (DL, n=14), the increase of OPN plasma and tissue concentration, the OPN splicing isoforms expression profiling together with those of thrombin, and to evaluate a possible association between OPN measurements. Their association with Notch-1, IV-Collagen-7s domain, IL-6 and TNF-α were also evaluated. Real-Time PCR experiments and immunometric assay were performed. mRNA expression resulted higher in RL than in DL for all analyzed genes and several correlations were found between them. The more relevant association were between OPN-a and OPN-b (p<0.0001), between thrombin and OPN-a (p=0.007), between 7s-collagen and OPN isoforms (p<0.05) and between Notch-1 with OPN-c (p=0.004). Both OPN plasma and liver tissue extract concentrations were assessed confirming the trend observed at the mRNA level. An important association was found between OPN plasma and protein (p<0.0001, r=0.96) even splitting patients in DL (p<0.0001, r=0.93) and RL (p<0.0001, r=0.96). A reduction of OPN plasma levels was found at 6months after transplantation. Considering MELD score as liver disease severity, the mRNA expression of our markers as well as of OPN plasma and tissue concentrations resulted increased as a function of clinical severity. Our results might be considered a useful starting point to validate OPN as a prognostic and diagnostic marker of HCC.
Abstract Purpose To retrospectively evaluate agreement between modified RECIST (mRECIST) assessed at Computed Tomography (CT) and pathology in a large series of patients with hepatocellular carcinoma ...(HCC) who were transplanted after transarterial chemoembolization (TACE). Materials and methods IRB approval was obtained. The study included 178 patients (M/F = 155/23; mean age 55.8 ± 6.3 years) with HCC who were transplanted after TACE from January 1996 to December 2010 and with at least one CT examination before liver transplantation (LT). Two blinded independent readers retrospectively reviewed CT examinations, to assess tumor response to TACE according to mRECIST. Patients were classified in responders (complete and partial response) and non-responders (stable and progressive disease). On the explanted livers, percentage of tumor necrosis was classified as 100, >50 and <50%. Results The mean interval between latest CT and LT was 57.4 ± 39.8 days. At latest CT examination, the objective response rate was 78.1% (139/178), with 86 cases (48.3%) of complete response (CR). A good intra- ( k = 0.75 and 0.86) and inter-observer ( k = 0.81) agreement was obtained. On a per-patient basis, agreement between mRECIST and pathology was obtained in 120 patients (67.4%), with 19 cases (10.7%) of underestimation and 39 cases (21.9%) of overestimation of tumor response at CT. CT sensitivity and specificity in differentiating between responders and non-responders were 93 and 82.9%, respectively. Out of 302 nodules, sensitivity and specificity of CT in detecting complete necrosis were 87.5 and 68.9%, respectively. Conclusions CT can overestimate tumor response after TACE. Nonetheless, mRECIST assessed at CT after TACE are reproducible and reliable in differentiating responders and non-responders.
To improve the efficiency of pancreatic islet transplantation, we performed in-vitro and in-vivo experiments with isolated human pancreatic islets coated by multi-layer nano-encapsulation using ...differently charged polymers chitosan and poly(sodium styrene sulfonate) to obtain up to 9 layers. The islet coating (thickness: 104.2 ± 4.2 nm) was uniform, with ≥ 90% cell viability and well preserved beta- and alpha-cell ultrastructure. Nano-encapsulated islets maintained physiological glucose-stimulated insulin secretion by both static incubation and perifusion studies. Notably, palmitate- or cytokine-induced toxicity was significantly reduced in nano-coated islets. Xenotransplantation of nano-encapsulated islets under the kidney capsule of streptozotocin-induced C57Bl/6J diabetic mice allowed long term normal or near normal glycemia, associated with minimal infiltration of immune cell into the grafts, well preserved islet morphology and signs of re-vascularization. In summary, the multi-layer nano-encapsulation approach described in the present study provides a promising tool to effectively protect human islets both in-vitro andin-vivo conditions.
Conformal coating of pancreatic islets with biocompatible polymers using layer-by-layer nano-encapsulation approach may represent a way to protect the transplanted islet cells without any immunosuppression. As an alternative to conventional macro- or micro-encapsulation methods, nano-encapsulation approach appears more advantageous as it provides decreased diffusion space, a robust response to physiological stimulation and reduced coating thickness. This versatile technique is likely to provide immune isolation of the transplanted islet cells with well preserved cell viability and function and warrants a successful outcome of prolonged engraftment in diabetic animals. Display omitted
Aims/hypothesis
Beta cell destruction in human type 1 diabetes occurs through the interplay of genetic and environmental factors, and is mediated by immune cell infiltration of pancreatic islets. In ...this study, we explored the role of mast cells as an additional agent in the pathogenesis of type 1 diabetes insulitis.
Methods
Pancreatic tissue from donors without diabetes and with type 1 and 2 diabetes was studied using different microscopy techniques to identify islet-infiltrating cells. The direct effects of histamine exposure on isolated human islets and INS-1E cells were assessed using cell-survival studies and molecular mechanisms.
Results
A larger number of mast cells were found to infiltrate pancreatic islets in samples from donors with type 1 diabetes, compared with those from donors without diabetes or with type 2 diabetes. Evidence of mast cell degranulation was observed, and the extent of the infiltration correlated with beta cell damage. Histamine, an amine that is found at high levels in mast cells, directly contributed to beta cell death in isolated human islets and INS-1E cells via a caspase-independent pathway.
Conclusions/interpretation
These findings suggest that mast cells might be responsible, at least in part, for immune-mediated beta cell alterations in human type 1 diabetes. If this is the case, inhibition of mast cell activation and degranulation might act to protect beta cells in individuals with type 1 diabetes.
► Islets from type 2 diabetic subjects have several transcriptome alterations. ► The ubiquitin–proteasome system (UPS) is deranged in human type 2 diabetic islets. ► Environmental factors can affect ...islet UPS.
To shed light on islet cell molecular phenotype in human type 2 diabetes (T2D), we studied the transcriptome of non-diabetic (ND) and T2D islets to then focus on the ubiquitin–proteasome system (UPS), the major protein degradation pathway. We assessed gene expression, amount of ubiquitinated proteins, proteasome activity, and the effects of proteasome inhibition and prolonged exposure to palmitate. Microarray analysis identified more than one thousand genes differently expressed in T2D islets, involved in many structures and functions, with consistent alterations of the UPS. Quantitative RT-PCR demonstrated downregulation of selected UPS genes in T2D islets and beta cell fractions, with greater ubiquitin accumulation and reduced proteasome activity. Chemically induced reduction of proteasome activity was associated with lower glucose-stimulated insulin secretion, which was partly reproduced by palmitate exposure. These results show the presence of many changes in islet transcriptome in T2D islets and underline the importance of the association between UPS alterations and beta cell dysfunction in human T2D.
To search for clues suggesting that beta cells may generate by transdifferentiation in humans, we assessed the presence of cells double positive for exocrine (amylase, carboxypeptidase A) and ...endocrine (insulin) markers in the pancreas of non-diabetic individuals (ND) and patients with type 2 diabetes (T2D). Samples from twelve ND and twelve matched T2D multiorgan donors were studied by electron microscopy, including amylase and insulin immunogold labeling; carboxypeptidase A immunofluorescence light microscopy assessment was also performed. In the pancreas from four T2D donors, cells containing both zymogen-like and insulin-like granules were observed, scattered in the exocrine compartment. Nature of granules was confirmed by immunogold labeling for amylase and insulin. Double positive cells ranged from 0.82 to 1.74 per mm2, corresponding to 0.26±0.045% of the counted exocrine cells. Intriguingly, cells of the innate immune systems (mast cells and/or macrophages) were adjacent to 33.3±13.6% of these hybrid cells. No cells showing co-localization of amylase and insulin were found in ND samples by electron microscopy. Similarly, cells containing both carboxypeptidase A and insulin were more frequently observed in the diabetic pancreata. These results demonstrate more abundant presence of cells containing both acinar markers and insulin in the pancreas of T2D subjects, which suggests possible conversion from one cellular type to the other and specific association with the diseased condition.
Lymphoepithelioma-like hepatocellular carcinoma(LELHCC) is a rare form of undifferentiated carcinoma of the liver characterized by the presence of an abundant lymphoid infiltrate. Here,a case of ...LEL-HCC is described. An 81-year-old woman with a chronic hepatitis C infection was referred to the general surgery department of our hospital in August 2013 with a diagnosis of HCC. A past ultrasound examination had revealed a 60 mm-diameter nodular lesion in the third segment of the liver. After a needle biopsy,the lesion was diagnosed as HCC. The patient underwent surgery with a liver segmentectomy. Two additional nodes on the gastric wall were detected during the surgical operation. The histology of the removed specimen showed a poorly differentiated HCC with significant lymphoid stroma. Immunohistochemical studies revealed that the epithelial component was reactive for CK CAM5.2,CK8,CK18,CEA(polyclonal) and was focally positive for hepar-1 and that the lymphoid infiltrate was positive for CD3,CD4 and CD8. The tumor cells were negative for Epstein-Barr virus. The gastric nodes were ultimately determined to be two small gastrointestinal stromal tumors(GISTs).The synchronous occurrence of HCC and GIST is another very uncommon finding rarely described in the literature. Here,we report the clinicopathological features of our case,along with a review of the few cases present in the literature.
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