Rapamycin does not adversely affect intrahepatic islet engraftment in mice and improves early islet engraftment in humans.

Objective: In this study we examined the effect of rapamycin (RAPA), a key component of the immunosuppressive regimen in clinical islet transplantation, on islet engraftment and function in vivo. Methods and results: Diabetic C57BL/6 or BALB/C recipient mice were transplanted with 350 syngeneic islets through the portal vein (PV-Tx; C57BL/6 n = 60; BALB/C n = 22) and treated with once-daily oral RAPA (1 mg/kg) or vehicle. No differences in post-transplant blood glucose concentrations and glucose tolerance were observed between RAPA-and vehicle-treated mice. The impact of RAPA on human islet engraftment was assessed in 10 patients with type 1 diabetes treated with 0.1 mg/kg/day rapamycin before islet transplantation. Compared to non pre-treated islet transplant recipents (n = 12), RAPA pre-treated patients had increased blood RAPA concentrations (p = 0.006) and fasting C-peptide concentrations (p = 0.005) in the two weeks post-transplant. RAPA pre-treatment was associated with a reduction in chemokines CCL2 and CCL3 concentrations pre-transplant (p < 0.01), and a dampened chemokine response (p = 0.005) post-transplant. Concordantly, in vitro RAPA inhibited the secretion of CCL2 and CCL3 by monocytes. Conclusion: Rapamycin does not adversely affect intrahepatic islet engraftment in the mouse, and potentially improves islet engraftment in humans by an anti-inflammatory mechanism

Human pancreatic islet preparations release HMGB1: (ir)relevance for graft engraftment.

High levels of donor-derived high-mobility group box 1 (HMGB1) protein have been associated with poor islet graft outcome in mouse models. The aim of our work was to determine whether HMGB1 released by human islets had independent proinflammatory effects that influence engraftment in humans. Human islet preparations contained and released HMGB1 in different amounts, as determined by Western blot and ELISA (median 17 pg/ml/IEQ/24 h; min–max 0–211, n = 74). HMGB1 release directly correlated with brain death, donor hyperamilasemia, and factors related to the pancreas digestion procedure (collagenase and digestion time). HMGB1 release was significantly positively associated with the release of other cytokines/chemokines, particularly with the highly released "proinflammatory" CXCL8/IL-8, CXCL1/GRO-α, and the IFN-γ-inducible chemokines CXCL10/IP-10 and CXCL9/MIG. HMGB1 release was not modulated by Toll-like receptor 2, 3, 4, 5, and 9 agonists or by exposure to IL-1β. When evaluated after islet transplantation, pretransplant HMGB1 release was weakly associated with the activation of the coagulation cascade (evaluated as serum cross-linked fibrin products), but not with the immediate posttransplant inflammatory response. Concordantly, HMGB1 did not affect short-term human islet function. Our data show that human islet HMGB1 release is a sign of "damaged" islets, although without any independent direct role in graft failure

Co-Graft of Allogeneic Immune Regulatory Neural Stem Cells (NPC) and Pancreatic Islets Mediates Tolerance, while Inducing NPC-Derived Tumors in Mice

Data available on the immunomodulatory properties of neural stem/precursor cells (NPC) support their possible use as modulators for immune-mediated process. The aim of this study was to define whether NPC administered in combination with pancreatic islets prevents rejection in a fully mismatched allograft model.Diabetic Balb/c mice were co-transplanted under the kidney capsule with pancreatic islets and GFP(+) NPC from fully mismatched C57BL/6 mice. The following 4 groups of recipients were used: mice receiving islets alone; mice receiving islets alone and treated with standard immunosuppression (IL-2Ralpha chain mAbs + FK506 + Rapamycin); mice receiving a mixed islet/NPC graft under the same kidney capsule (Co-NPC-Tx); mice receiving the islet graft under the left kidney capsule and the NPC graft under the right kidney capsule (NPC-Tx). Our results demonstrate that only the co-transplantation and co-localization of NPC and islets (Co-NPC-Tx) induce stable long-term graft function in the absence of immunosuppression. This condition is associated with an expansion of CD4(+)CD25(+)FoxP3(+) T regulatory cells in the spleen. Unfortunately, stable graft function was accompanied by constant and reproducible development of NPC-derived cancer mainly sustained by insulin secretion.These data demonstrate that the use of NPC in combination with islets prevents graft rejection in a fully mismatched model. However, the development of NPC-derived cancer raises serious doubts about the safety of using adult stem cells in combination with insulin-producing cells outside the original microenvironment

Allo Beta Cell transplantation: specific features, unanswered questions, and immunological challenge

Type 1 diabetes (T1D) presents a persistent medical challenge, demanding innovative strategies for sustained glycemic control and enhanced patient well-being. Beta cells are specialized cells in the pancreas that produce insulin, a hormone that regulates blood sugar levels. When beta cells are damaged or destroyed, insulin production decreases, which leads to T1D. Allo Beta Cell Transplantation has emerged as a promising therapeutic avenue, with the goal of reinstating glucose regulation and insulin production in T1D patients. However, the path to success in this approach is fraught with complex immunological hurdles that demand rigorous exploration and resolution for enduring therapeutic efficacy. This exploration focuses on the distinct immunological characteristics inherent to Allo Beta Cell Transplantation. An understanding of these unique challenges is pivotal for the development of effective therapeutic interventions. The critical role of glucose regulation and insulin in immune activation is emphasized, with an emphasis on the intricate interplay between beta cells and immune cells. The transplantation site, particularly the liver, is examined in depth, highlighting its relevance in the context of complex immunological issues. Scrutiny extends to recipient and donor matching, including the utilization of multiple islet donors, while also considering the potential risk of autoimmune recurrence. Moreover, unanswered questions and persistent gaps in knowledge within the field are identified. These include the absence of robust evidence supporting immunosuppression treatments, the need for reliable methods to assess rejection and treatment protocols, the lack of validated biomarkers for monitoring beta cell loss, and the imperative need for improved beta cell imaging techniques. In addition, attention is drawn to emerging directions and transformative strategies in the field. This encompasses alternative immunosuppressive regimens and calcineurin-free immunoprotocols, as well as a reevaluation of induction therapy and recipient preconditioning methods. Innovative approaches targeting autoimmune recurrence, such as CAR Tregs and TCR Tregs, are explored, along with the potential of stem stealth cells, tissue engineering, and encapsulation to overcome the risk of graft rejection. In summary, this review provides a comprehensive overview of the inherent immunological obstacles associated with Allo Beta Cell Transplantation. It offers valuable insights into emerging strategies and directions that hold great promise for advancing the field and ultimately improving outcomes for individuals living with diabetes

ISLET VOLUME AND INDEXES OF β-CELL FUNCTION IN HUMANS

Islet volume and endocrine pancreas architecture (islet size distribution) may be independent determinants of beta cell function. Furthermore, the accuracy of HOMA indexes in predicting β-cell mass has never been assessed. Here, we investigated the relationships between islet volume, islet density and islet size distribution, estimated after pancreatic tissue digestion, with established indexes of β-cell function in humans. We included in this study 42 patients who were candidates for islet autotransplantation and had well-characterized glucose metabolism. Indexes of insulin secretion were calculated and compared with the islet volume, as a surrogate of β-cell mass, obtained after digestion of pancreas. Islet counting analysis showed considerable interindividual variation in islet density and size. Islet volume, but not density nor size, was the only independent determinant of β-cell function assessed by insulin HOMA β-cell. Islet volume was significantly reduced in the patients with overt hyperglycemia, but not in patients with impaired fasting glucose. Insulin HOMA β-cell predicted islet volume better than other measures of fasting insulin secretion. In conclusion, the present study documented a close direct relationship between indexes of β-cell function and islet volume in humans. The insulin HOMA β-cell provides a more reliable estimate of pancreatic islet volume than fasting glucose before islet isolation

Human induced pluripotent stem cells differentiate into insulin-producing cells able to engraft in vivo

AIMS: New sources of insulin-secreting cells are strongly required for the cure of diabetes. Recent successes in differentiating embryonic stem cells, in combination with the discovery that it is possible to derive human induced pluripotent stem cells (iPSCs) from somatic cells, have raised the possibility that patient-specific beta cells might be derived from patients through cell reprogramming and differentiation. In this study, we aimed to obtain insulin-producing cells from human iPSCs and test their ability to secrete insulin in vivo. METHODS: Human iPSCs, derived from both fetal and adult fibroblasts, were differentiated in vitro into pancreas-committed cells and then transplanted into immunodeficient mice at two different stages of differentiation (posterior foregut and endocrine cells). RESULTS: IPSCs were shown to differentiate in insulin-producing cells in vitro, following the stages of pancreatic organogenesis. At the end of the differentiation, the production of INSULIN mRNA was highly increased and 5 ± 2.9 % of the cell population became insulin-positive. Terminally differentiated cells also produced C-peptide in vitro in both basal and stimulated conditions. In vivo, mice transplanted with pancreatic cells secreted human C-peptide in response to glucose stimulus, but transplanted cells were observed to lose insulin secretion capacity during the time. At histological evaluation, the grafts resulted to be composed of a mixed population of cells containing mature pancreatic cells, but also pluripotent and some neuronal cells. CONCLUSION: These data overall suggest that human iPSCs have the potential to generate insulin-producing cells and that these differentiated cells can engraft and secrete insulin in vivo

Prognostic impact of a 3-MicroRNA signature in cytological samples of small cell lung cancer

BACKGROUND: Small cell lung cancer (SCLC) is a highly aggressive neoplasm that accounts for approximately 10% to 15% of lung cancers. In most cases, the diagnosis relies on cytology and needs to be confirmed by immunohistochemistry. Although several genetic and molecular abnormalities have been recorded, molecular markers able to predict the prognosis are still lacking. MicroRNA (miRNA) signatures have been recently proposed as useful biomarkers in lung cancer because of their high stability during standard sample processing. METHODS: Cytological samples for 50 patients with SCLC were collected from primary tumors (n = 25) and metastases (n = 25) by means of fine-needle aspiration (FNA) or bronchial washing (BW); they were fixed in ethanol (FNA) or Duboscq-Brazil fluid (BW). The 3-miRNA panel expression (miR-192, miR-200c, and miR-205) was quantified with a TaqMan polymerase chain reaction miRNA assay and was compared with overall survival (OS) and clinicopathological data. RESULTS: All samples had sufficient RNA for the miRNA expression analysis to be performed, regardless of the sample source or the fixative medium. Patients with a low expression level of the 3-miRNA panel were associated with better OS in univariate (P = .032) and multivariate analyses (P = .022). Moreover, in the group of patients older than the mean age of our cohort (65.8 years), a significant OS advantage (P = .013) was seen for patients with a low expression level of the 3-miRNA panel. CONCLUSIONS: A specific 3-miRNA signature is potentially useful for predicting survival for patients with SCLC, and it may be feasible with cytological samples taken during standard diagnostic procedures

A multistep cytological approach for patients with jaundice and biliary strictures of indeterminate origin

AIMS. Fluorescence in situ hybridisation (FISH) increases the sensitivity for detecting pancreatobiliary tract cancer over routine cytology. In this study, diagnostic accuracy and costs of cytology and FISH in detecting cancer in patients with jaundice with biliary strictures were assessed. METHODS. Brushing specimens from 109 patients with jaundice were obtained during endoscopic retrograde cholangiopancreatography and examined by cytology and FISH. The specimens were considered FISH-positive for malignancy if at least five polysomic cells or 10 cells with homozygous or heterozygous 9p21/p16 deletion were detected. Definitive diagnosis of the stricture as benign or malignant relied on surgical pathology (45 cases) or clinical-radiological follow-up >18\u2005months (64 cases). We calculated costs of cytology and FISH based on the reimbursement from the Piedmont region, Italy (respectively, \u20ac33 and \u20ac750). RESULTS. Ninety of 109 patients had evidence of malignancy (44 pancreatic carcinomas, 36 cholangiocarcinomas, 5 gallbladder carcinomas, 5 other cancers), while 19 had benign strictures. Routine cytology showed 42% sensitivity, but 100% specificity for the diagnosis of malignancy, while FISH-polysomy showed 70% sensitivity with 100% specificity and FISH-polysomy plus homozygous or heterozygous 9p21/p16 deletion showed 76% sensitivity with 100% specificity. The cost per additional correct diagnosis of cancer obtained by FISH, in comparison with cytology, was \u20ac1775 using a sequential cytological approach (ie, performing FISH only in patients with negative or indeterminate cytology). CONCLUSIONS. FISH should be recommended as the second step in detecting cancer in patients with jaundice with pancreatobiliary tract strictures and cytology negative or indeterminate for malignancy

Frequency of O6-methylguanine-DNA methyltransferase promoter methylation in cytological samples from small cell lung cancer

BACKGROUND: In a phase II study for patients with relapsed small cell lung cancer (SCLC), the administration of Temozolomide, an alkylating agent used in gliomas and anaplastic astrocytoma, showed a effective activity when O(6) -methylguanine-DNA methyltransferase (MGMT) gene promoter was methylated. METHODS: We tested the feasibility of MGMT promoter status evaluation in small biopsies and cytological specimens routinely processed for diagnostic purposes. We tested samples from 56 patients with SCLC: 30 tissue biopsies, 17 fine-needle aspiration biopsy, 8 bronchial washing, and 1 was a sputum. Biopsies and fine-needle aspiration biopsy were fixed in formalin, bronchial washing and sputum in Dubosq Brazil. DNA was extracted after macrodissection of the areas containing the maximum number of cancer cells. MGMT promoter methylation status was assessed by methylation specific PCR. RESULTS: Methylation analysis was obtained in 54 samples (54/56) and failed in two bronchial wash. MGMT promoter was methylated in 35.2% of the cases without any significant difference between histological and cytological samples (37.9% vs. 32%). CONCLUSION: MGMT promoter methylation is present in SCLC and cytological samples are perfectly adequate for methylation analysis, even if they were taken during routine diagnostic procedures, using different fixative and with low number and percentage of cancer cells