Effects of Lactococcus lactis MG1363 producing fusion proteins of bovine lactoferricin-lactoferrampin on growth, intestinal morphology and immune function in weaned piglet

AIMS

We developed a strategy for localized delivery of the LFCA (lactoferricinlactoferrampin), which is actively synthesized in situ by Lactococcus lactis (pAMJ399-LFCA/LLMG1363), and explored the possibility of using pAMJ399-LFCA/LLMG1363 as an alternative additive diet to antibiotics.

METHODS AND RESULTS

The antimicrobial activities of the LFCA derived from pAMJ399-LFCA/LLMG1363 were tested in vitro. The results showed that LFCA had an inhibitory effect on Staphylococcus aureus, Escherichia coli and Salmonella enteritidis. Then, the pAMJ399-LFCA/LLMG1363 was used as an additive diet for piglets. Our data demonstrated that oral administration of pAMJ399-LFCA/LLMG1363 significantly improved the average daily gain, feed-to-gain ratio, intestinal mucosal integrity and decreased the serum endotoxin and d-lactic acid levels. The mRNA expression levels of intestinal tight junction proteins (including occludin, Claudin-1 and ZO-1) were significantly upregulated by pAMJ399-LFCA/LLMG1363 administration. The serum immunoglobulin G (IgG) levels, intestinal secretory immunoglobulin A (sIgA) levels, IL-2, IL-10 and TGF-β levels were significantly increased by pAMJ399-LFCA/LLMG1363. Furthermore, our data revealed that oral administration of pAMJ399-LFCA/LLMG1363 significantly increased the number of general Lactobacillus, and decreased the total viable E. coli counts in the ileum and cecum contents.

CONCLUSIONS

We developed a novel pAMJ399-LFCA/LLMG1363 secreting LFCA, which had probiotic effects on the growth performance, intestinal morphology, intestinal barrier function and immunological indices of weaned piglets.

SIGNIFICANCE AND IMPACT OF THE STUDY

pAMJ399-LFCA/LLMG1363, with probiotic effects on the health of weaned piglets, may be a promising feed additive for weaned piglets.

Long-term culture and characterization of patient-derived primary hepatocytes using conditional reprogramming

Cultivation of primary human hepatocytes (PHHs) often faces obstacles including failure of long-term in vitro culture, weak proliferation ability, rapid loss of liver-specific function and morphology, and tendency of fibrosis. Previous research focused on immortalization methods, such as telomerase and viral, to culture immortalized primary human hepatocytes, which may lose some of the normal properties. However, non-immortalized PHHs often fail to maintain long-term viability and functionality. These highlight the urgent need for developing new culture strategy for PHHs. In the present study, we isolated PHHs from fresh human liver tissues representing different liver diseases and age groups. We used conditional reprogramming, without permanent immortalization, for long-term in vitro primary human hepatocytes cultivation and characterization. For functional characterization, we assessed CYP3A4, 1A1 and 2C9 activities and measured the mRNA expression of albumin , s100a4 , krt8 , krt18 , cyp1a1 , cyp3a4 , cyp2b6 , cyp2c8 , cyp2c9 , and cyp2d6 . Additionally, we compared the DNA fingerprint of the cells against their original liver tissues using short tandem repeat (STR) analysis. We found that PHHs-derived from young patients can survive for more than three months, while the lifespan of primary human hepatocytes derived from adult patients ranges from two to three months, which is longer than most commercial primary hepatocytes. Importantly, the cells at early passages retain strong CYP3A4, 1A1 and 2C9 activities and the DNA fingerprints are identical with their original tissues. Through conditional programming, we achieved, for the first time, a high level of success rate in the long-term in vitro cultivation of primary human hepatocytes-derived patients representing diverse liver disease. Moreover, the conditional programming cell culture technology reported in this paper requires neither co-culture with additive cells, nor complex and expensive components, such as collagen sandwich or spheroid culture. We thus believe that the patient-derived PHHs cultivation using conditional programming may provide a viable and valuable cell model to study liver disease-related mechanisms.

[Results for the treatment of fresh type thoracolumbar vertebral fracture according to the intraoperative CT scan]

Objective: To evaluate the value of intraoperative CT scanning in the treatment of fresh thoracolumbar burst fractures. Methods: From January 2008 to January 2015 , 161 patients with thoracolumbar fractures in Department of Orthopedics, Luohe City Central Hospital, were divided into two groups: 79 cases were treatment group which were treated with intraoperative CT scan and decompression mode was determined according to CT scan results during the period from October 2012 to January 2015. 82 patients as the observation group were treated without intraoperative CT scan and direct laminectomy were performed during the period. In the treatment group, it is no further decompression of the spinal canal when the CT showed a reduction of the fracture block into the spinal canal, if the intraoperative CT showed that the fractures still occupied the spinal dura mater according to the three-dimensional CT information, the position and the size of the fracture of the spinal canal were determined, and the unilateral laminectomy was performed corresponding to the position of the lamina and intervertebral ligamentum flavum. The operative time, bleeding volume, neurological function, height of the anterior vertebral compression and Cobb angle were compared between the two groups. Results: In the treatment group, CT scan showed 48 cases (60.8%) entered the spinal canal fracture completely or basically reset.31 cases (39.2%) still occupied the spinal canal compression spinal dura mater. There were significant differences in the operation time and bleeding volume between the two groups. The treatment group was less than the control group. There was no infection, secondary spinal cord injury, loose fixation and other complications. There was no difference in the ASIA classification before and after operation(χ(2)=0.268 vs χ(2)=1.372, P>0.05). The anterior vertebral height and COBB angle of the two groups were significantly improved compared with those before operation. There was no significant difference between the two groups in the postoperative height and COBB angle[(40.3±11.8)° vs(82.1±4.2)°, (-10.3±2.6)° vs(6.9±3.3)°, P<0.05], but after 2 years the difference was statistically significant between the two groups, to retain the rear ligament complex treatment group was significantly better than the control group. Conclusions: Patients of thoracolumbar vertebral fracture in hyperextension position combined with internal fixation can achieve good correction effect. Orthopedic postoperative CT scan and according to the results of the scan precision treatment can simplify the operation, there was no difference in clinical efficacy compared with total laminectomy, but some patients avoid the spinal canal decompression and part were treated by small fenestration laminectomy decompression, which is conducive to the protection of spinouts ligament complex integrity.

[Research progress on non-coding RNAs in the molecular pathogenesis of hepatocellular carcinoma]

Primary liver cancer arises from chronic liver disease, and cirrhotic liver gradually develops into dysplastic nodules that eventually form malignant tumors. In recent years, molecular biotechnology development has deepened people's understanding on the pathogenesis of liver cancer. Epigenetic modifications play a significant role in DNA methylation, non-coding RNAs, chromatin remodeling, and histone modification. This review focuses on the progress of currently implicated non-coding RNAs in the molecular pathogenesis of hepatocellular carcinoma, and its potential application in improving the diagnosis and treatment.

[Comparison of percutaneous endoscopic lumbar discectomy versus transforaminal lumbar interbody fusion in treating upper lumbar disc herniation]

Objective: To compare the efficacy of percutaneous endoscopic transforaminal discectomy (PTED) and transforaminal lumbar interbody fusion (TLIF) in the treatment of high lumbar disc herniation. Methods: The clinical data of patients with high lumbar disc herniation from February 2010 to February 2015 were retrospective analyzed. According to the inclusion criteria, a total of 63 cases were enrolled, including PTED group 33 cases, TLIF group 30 cases. The improvement of the two groups before and after surgery was assessed by visual analogue scale (VAS) and Oswestry dysfunction index (ODI). The operative time, intraoperative blood loss, drainage volume at 48 h postoperatively, hospitalization time, number of fluoroscopy, complication, recurrence rate and postoperative recovery were compared between the two groups. The follow-up period was 12 to 33 months. Results: The operation time, intraoperative blood loss, drainage amount and hospitalization time in PTED group were significantly less than those in TLIF group[(71±19) vs (121±22) min, (30±21) vs (317±50) ml, 0 vs (93±29) ml, (3.5±1.9) vs (12.5±2.1) d]. The number of fluoroscopy in PTED group was significantly higher than TLIF group[(16.2±8.3) vs (6.7±4.2)](all P<0.05). There was no significant difference in VAS score and ODI improvement rate between the two groups after operation (both P>0.05). There was no significant difference between the two groups in the excellent rate of surgery and the recurrence rate (both P>0.05). Conclusions: PTED has the advantages of less trauma and bleeding, rapid postoperative recovery in the treatment of upper lumbar disc herniation compared with TLIF, and the curative effect and recurrence rate are similar with TLIF. Therefore, PTED is an effective method for the treatment of upper lumbar disc herniation.

[Clinical observation of postprandial hypotension in patients with hypertensive and coronary heart disease]

Objective: To explore the prevalence and clinical characteristics of postprandial hypotension(PPH) in patients with essential hypertension and coronary heart disease. Methods: A total of 197 patients with essential hypertension and coronary heart disease, who had been treated in the First Department of Cardiology of the Second Hospital of Hebei Medical University from December, 2013 to December, 2014 were included. The patients' blood pressure before breakfast, lunch and dinner and 30, 60, 90, 120 minutes after the meal were monitored. Subjects were classified into PPH group (n=37) and non-PPH group (NPPH, n=160) according to postprandial decrease in systolic blood pressure, to explore the clinical characteristics and related factors and the major adverse cardiac and cerebral vascular events of PPH. Results: Among 197 patients, 37 cases (18.8%) showed at least once postprandial decline in systolic blood pressure greater than and equal to 20 mmHg. The incidence of PPH after breakfast and dinner were higher than lunch (P<0.05). There was no significant difference in the incidence of PPH among different age groups, among patients accompanied with different diseases, and among patients with different dining position (all P>0.05). According to the baseline systolic blood pressure, patients can be divided into 4 groups(<120 mmHg, 120-129 mmHg, 130-139 mmHg, >140 mmHg), the higher the level of the baseline systolic blood pressure was, the higher the incidence of PPH was. And the incidence of major adverse cardiac and cerebral vascular events in patients during hospitalization were increased by PPH. Conclusions: The prevalence of PPH in the patients with essential hypertension and coronary heart disease is 18.8%. The incidence of PPH after breakfast and dinner is higher than lunch. The baseline systolic blood pressure is considered to be the risk factor of PPH. And PPH could lead to an increase of the incidence of major adverse cardiac and cerebral vascular events.

Stabilization of warfarin-binding pocket of VKORC1 and VKORL1 by a peripheral region determines their different sensitivity to warfarin inhibition

Essentials VKORL1 and VKORC1 have a similar overall structure and warfarin-binding pocket. A peripheral region stabilizing this pocket controls warfarin sensitivity of the VKOR paralogs. A human single nucleotide polymorphism in this region renders VKORL1 sensitive to warfarin. A group of warfarin-resistant mutations in VKORC1 acts by disrupting peripheral interactions.

SUMMARY

Background The human genome encodes two paralogs of vitamin-K-epoxide reductase, VKORC1 and VKORL1, that support blood coagulation and other vitamin-K-dependent processes. Warfarin inhibits both enzymes, but VKORL1 is relatively resistant to warfarin. Objectives To understand the difference between VKORL1 and VKORC1, and the cause of warfarin-resistant (WR) mutations in VKORC1. Methods We performed systematic mutagenesis and analyzed warfarin responses with a cell-based activity assay. Mass spectrometry analyses were used to detect cellular redox state. Results VKORC1 and VKORL1 adopt a similar intracellular redox state with four-transmembrane-helix topology. Most WR mutations identified in VKORC1 also confer resistance in VKORL1, indicating that warfarin inhibits these paralogs at a common binding site. A group of WR mutations, distant from the warfarin-binding site, show significantly less resistance in VKORL1 than in VKORC1, implying that their different warfarin responses are determined by peripheral interactions. Remarkably, we identify a critical peripheral region in which single mutations, Glu37Lys or His46Tyr, drastically increase the warfarin sensitivity of VKORL1. In the background of these warfarin-sensitive VKORL1 mutants, WR mutations showing relative less resistance in wild-type VKORL1 become much more resistant, suggesting a structural conversion to resemble VKORC1. At this peripheral region, we also identified a human single nucleotide polymorphism that confers warfarin sensitivity of VKORL1. Conclusions Peripheral regions of VKORC1 and VKORL1 primarily maintain the stability of their common warfarin-binding pocket, and differences of such interactions determine their relative sensitivity to warfarin inhibition. This new model also explains most WR mutations located at the peripheral regions of VKORC1.

Carbon Monoxide Inhibits Islet Apoptosis via Induction of Autophagy

AIM

Carbon monoxide (CO) functions as a therapeutic molecule in various disease models because of its anti-inflammatory and antiapoptotic properties. We investigated the capacity of CO to reduce hypoxia-induced islet cell death and dysfunction in human and mouse models.

RESULTS

Culturing islets in CO-saturated medium protected them from hypoxia-induced apoptosis and preserved β cell function by suppressing expression of proapoptotic (Bim, PARP, Cas-3), proinflammatory (TNF-α), and endoplasmic reticulum (ER) stress (glucose-regulated protein 94, grp94, CHOP) proteins. The prosurvival effects of CO on islets were attenuated when autophagy was blocked by specific inhibitors or when either ATG7 or ATG16L1, two essential factors for autophagy, was downregulated by siRNA. In vivo, CO exposure reduced both inflammation and cell death in grafts immediately after transplantation, and enhanced long-term graft survival of CO-treated human and mouse islet grafts in streptozotocin-induced diabetic non-obese diabetic severe combined immunodeficiency (NOD-SCID) or C57BL/6 recipients.

INNOVATION

These findings underline that pretreatment with CO protects islets from hypoxia and stress-induced cell death via upregulation of ATG16L1-mediated autophagy.

CONCLUSION

Our results suggested that CO exposure may provide an effective means to enhance survival of grafts in clinical islet cell transplantation, and may be beneficial in other diseases in which inflammation and cell death pose impediments to achieving optimal therapeutic effects. Antioxid. Redox Signal. 28, 1309-1322.

Optimization of Growth Temperature of β-Ga₂O₃ Thin Films for Solar-Blind Photodetectors

Monoclinic gallium oxide thin films were deposited on c-plane sapphire substrates at various substrate temperatures ranging from 450 °C to 700 °C by radio frequency magnetron sputtering technology. X-ray diffraction results showed that the deposited β-Ga2O3 films were oriented at ( 2 ¯ 01) direction. As the substrate temperature increased, the intensity of β-Ga2O3 peaks increased and bandgap decreased accordingly. Metal/semiconductor/metal structured solar-blind photodetectors based on β-Ga2O3 thin films growing at various substrate temperatures had been fabricated. The growth temperatures of thin films had no obvious influence on dark current and response to 365 nm light illuminations. The photoelectric properties such as responsivity and response speed of the thin films to 254 nm light illuminations were growth temperature dependent. At an applied bias of 50 V, the photodetectors prepared with 450 °C grown film had the highest responsivity of 2.18 A/W, and the photodetectors prepared with 700 °C grown film had the shortest rising time of 0.95 s under 254 nm light illuminations.

Electrical and Optical Properties of In₂O₃ Thin Films Deposited on Sapphire Substrate

In2O3 thin films were prepared on c-plane sapphire substrates using laser molecular beam epitaxy technique. The X-ray diffraction (XRD) patterns revealed that the In2O3 thin films were highly oriented along the (111) direction. The intensity of (222) diffraction peaks mainly depend on growth temperature, and the crystallite sizes mainly depend on oxygen pressure. The carrier concentrations exhibit a decrease with increasing growth temperature and oxygen pressure, meantime, the resistivity increase. The red shift of In2O3 thin films respect to that of bulk In2O3 can be explained by defect energy levels formation, the blue shift of In2O3 thin films depends on carrier concentration, can be explained by Burstein-Moss band-filling effect.

Association of Serum 25(OH) D Levels with Infarct Volumes and Stroke Severity in Acute Ischemic Stroke

BACKGROUND

The aim of this study is to investigate whether 25-hydroxyvitamin D [25(OH) D] is associated with initial stroke severity and infarct volume, using diffusion-weighted imaging (DWI) in patients with acute ischemic stroke.

METHODS

We studied a total of 235 patients who were admitted within 24 hours of acute ischemic stroke onset. Initial stroke severity was assessed using the NIH Stroke Scale (NIHSS) score. Infarct volume was measured using DWI. Multivariable linear and logistic regression analyses were used to test whether 25(OH) D represents an independent predictor of infarct volume and stroke severity (NIHSS score of ≥6).

RESULTS

Among 235 study patients, the median age was 64 years (IQR 56-75 years), and 125 (53.2%) were women. In multivariable models adjusted for other significant risk factors, 25(OH) D levels in the lowest and second interquartiles were associated with an increased risk of a NIHSS≥6 (with highest 25 (OH) D quartile as reference) with odd ratios (OR) 3.02(95% confidence interval [CI]:1.59-6.34) and 5.85(2.90-11.54). The median DWI infarct volumes for the serum 25(OH) D level quartiles (lowest to highest) were 12.35, 6.55, 2.44, and 1.59 ml. The median DWI infarct volume in the lowest serum 25(OH) D level quartile was larger than that in the other 3 quartiles (P<0.001). The median adjusted DWI infarct volume in the lowest serum 25(OH) D level quartile was statistically significantly larger than that in the other 3 quartiles (P<0.01).

CONCLUSION

In conclusion, reduced serum 25(OH) D levels in acute ischemic stroke are an early predictor of larger volumes of ischemic tissue and worse neurological deficit (assessed by the NIHSS).

[Impact of Myocardial Infarction and Abnormalities of Cardiac Conduction System on Sudden Cardiac Death]

Sudden cardiac death （SCD）, most commonly seen in coronary heart disease, is a kind of sudden death caused by series of cardiac parameters, which usually combines with myocardial infarction. However, some SCDs （including early myocardial infarction） happen suddenly and cause death in a very short time. In these circumstances, typical morphological changes are lack in macroscopic or microscopic fields, which make such SCDs become the emphasis and difficulty in the present research. SCD caused by myocardial infarction and abnormalities of cardiac conduction system （CCS） is related to atherosclerosis of coronary artery closely. This paper reviews cardiac dysfunction caused by myocardial infarction and diseases of CCS from morphology and molecular biology, and explores potential relationship between them. This paper aims to provide clues to the mechanism of myocardial infarction related sudden death and possible assistance for forensic diagnosis of SCD.

Effect of liver histopathology on islet cell engraftment in the model mimicking autologous islet cell transplantation

BACKGROUND

The inflammatory milieu in the liver as determined by histopathology is different in individual patients undergoing autologous islet cell transplantation. We hypothesized that inflammation related to fatty-liver adversely impacts islet survival. To test this hypothesis, we used a mouse model of fatty-liver to determine the outcome of syngeneic islet transplantation after chemical pancreatectomy.

METHODS

Mice (C57BL/6) were fed a high-fat-diet from 6 weeks of age until attaining a weight of ≥28 grams (6-8 weeks) to produce a fatty liver (histologically > 30% fat);steatosis was confirmed with lipidomic profile of liver tissue. Islets were infused via the intra-portal route in fatty-liver and control mice after streptozotocin induction of diabetes. Outcomes were assessed by the rate of euglycemia, liver histopathology, evaluation of liver inflammation by measuring tissue cytokines IL-1β and TNF-α by RT-PCR and CD31 expression by immunohistochemistry.

RESULTS

The difference in the euglycemic fraction between the normal liver group (90%, 9/10) and the fatty-liver group (37.5%, 3/8) was statistically significant at the 18^th day post- transplant and was maintained to the end of the study (day 28) (p = 0.019, X² = 5.51). Levels of TNF-α and IL-1β were elevated in fatty-liver mice (p = 0.042, p = 0.037). Compared to controls cytokine levels were elevated after islet cell transplantation and in transplanted fatty-liver mice as compared to either fatty- or islet transplant group alone (p = NS). A difference in the histochemical pattern of CD31 could not be determined.

CONCLUSION

Fatty-liver creates an inflammatory state which adversely affects the outcome of autologous islet cell transplantation.

[The clinicopathological associations between TGF-β1 and papillary thyroid carcinoma: a Meta-analysis.]

Objective:To comprehensively evaluate the association between the positive expression rate of transforming growth factor beta 1 (TGF-β1) and papillary thyroid carcinoma (PTC) by using Meta-analysis.Method:Search the CNKI, Wan fang, VIP and PubMed database for accumulating papers studying on the relationship between the positive expression of TGF-β1 and PTC in Chinese and English. Revman 5.3 was used to analyze the included trials.Result:A total of 6 studies comprising 617 samples was included in the meta-analysis. The TGF-β1 were found in 243 patients (64.63%) of 376 PTC patients, and the total positive expression rate is 46.19%. Performing the subgroup analysis according to age, gender, lymphatic metastasis and TNM, the results showed that there was a significant association between the positive expression rate of TGF-β1 and lymphatic metastasis (OR=5.44, 95%CI3.31-8.93,P <0.000 01).Conclusion:This meta-analysis confirmed significant associations between the expression of TGF-β1 and PTC with lymph node metastasis. TGF-β1 may be used as a predictive factor for prognosis of PTC with lymph node metastasis.

[Establishment of cut-off value of serum pro-gastrin-releasing peptide for diagnosis of small cell lung cancer and evaluation on the clinical diagnosis efficiency]

Objective: To determine critical reference value (cut-off value) of serum pro-gastrin-releasing peptide (ProGRP) and neuron specific enolase(NSE) in the diagnosis of small cell lung cancer(SCLC). To evaluate the clinical significance of serum levels of ProGRP and NSE in diagnosis and differential diagnosis in SCLC. Methods: Three hundred and fifty-two SCLC patients, 163 non small cell lung cancer(NSCLC)patients , 193 benign pulmonary disease patients and 140 healthy people visiting in National Cancer Hospital were analyzed retrospectively from January 2014 to July 2017.The levels of serum ProGRP and NSE of people were determined using electrochemiluminescent immunoassay respectively . Reference value ranges of the makers were determined by using the method of ROC curves. Results: In NSCLC group, benign lung disease group, healthy control group and mixed group (NSCLC+ lung benign diseases+ healthy control group) as a reference, the cut-off values were 58.3, 62.3, 57.8, 61.3 ng/L. In the diagnosis and differential diagnosis of SCLC and NSCLC, benign lung diseases, healthy controls and mixed group, AUC of ProGRP was 0.940 (0.919-0.961), 0.941 (0.921-0.960), 0.959 (0.944-0.975), 0.946 (0.928-0.963) respectively. The sensitivities of ProGRP were 86.4%, 84.9%, 86.4% and 84.7% respectively. The specificities of ProGRP were 95.7%, 96.9%, 99.3%, 98% respectively. In all groups the Youden's index of ProGRP and NSE were 0.821 vs 0.612, 0.818 vs 0.674, 0.857 vs 0.810, 0.827 vs 0.674. In healthy controls, no statistically significant difference was found between ProGRP and NSE (P>0.05) in the diagnosis of AUC. However, in the remaining 3 groups, the ProGRP diagnosis of AUC was significantly greater than that of NSE (P<0.01). Compared with single marker detection, the sensitivity of combined detection of ProGRP and NSE in diagnosis of SCLC increased to 95.5%, 94%, 96.6% and 94% in each group. There was no significant difference between ProGRP and ProGRP+ NSE in the diagnosis of AUC when compared with the NSCLC group and the mixed group (P>0.05). However, when combined with a healthy control group and a benign lung disease group, the ProGRP+ NSE combination was the highest for AUC diagnosis, compared with ProGRP and NSE (P<0.01). In the SCLC ED group serum ProGRP and NSE levels[776.33(3 103.4)ng/L, 52.14(60.59)μg/L]were higher than those in the SCLC LD group[295.59(799.65)ng/L, 23.36(22.97)μg/L], respectively (all P<0.001). The serum ProGRP levels of N0, N1, N2 and N3 in TNM staging were 113.0(343.65), 167.04(724.56), 427.42(1 388.62), 735.99(1 709.95)ng/L respectively (all P<0.001). Serum ProGRP and NSE levels were not statistically different between the sex groups and the age groups (all P>0.05). Conclusion: To establish the cut-off value of serum ProGRP is helpful for the diagnosis and differential diagnosis of SCLC.

Encapsulation of Human Islets Using a Biomimetic Self-Assembled Nanomatrix Gel for Protection against Cellular Inflammatory Responses

The major concern of pancreatic islet transplantation is that the implanted islets are exposed to the immune system of the recipient. To overcome this challenge, the peptide amphiphile (PA) nanomatrix gel was used for immunoisolation of islets through microencapsulation. The PA can self-assemble to form a nanomatrix gel with an extracellular matrix-mimicking, islet nurturing microenvironment and a semipermeable immune barrier. In this study, the islet protective effect of the PA nanomatrix gel was evaluated by coculture of PA-encapsulated human islets with differentiated U937 cells (human monocyte cell-line) for 3 and 7 days. The coculture of the bare islets with the differentiated U937 cells stimulated proinflammatory cytokine (IL-1β and TNF-α) secretion and caused islet death after 7 days, which simulated an early inflammatory response environment after islet transplantation. The PA-encapsulated islets, however, did not stimulate proinflammatory cytokine secretion and maintained islet viability up to 7 days. More insulin-producing β cells were observed when islets were PA-encapsulated than control islets with the differentiated U937 cells for 7 days compared to the bare islets. This result was also confirmed by dithizone staining analysis. Further evaluation of islet functionality was assessed by a glucose-stimulated insulin secretion test. The PA-encapsulated islets showed greater insulin secretion response to glucose stimulation than the bare islets with the differentiated U937 cells after 3 and 7 days. These results demonstrated that islet encapsulation with the PA nanomatrix gel was able to improve islet survival and function in the presence of inflammatory responses, which will increase the success rate of islet engraftment and the efficacy of islet transplantation.

Adipose stem cells from chronic pancreatitis patients improve mouse and human islet survival and function

BACKGROUND

Chronic pancreatitis has surgical options including total pancreatectomy to control pain. To avoid surgical diabetes, the explanted pancreas can have islets harvested and transplanted. Immediately following total pancreatectomy with islet autotransplantation (TP-IAT), many islet cells die due to isolation and transplantation stresses. The percentage of patients remaining insulin free after TP-IAT is therefore low. We determined whether cotransplantation of adipose-derived mesenchymal stem cells (ASCs) from chronic pancreatitis patients (CP-ASCs) would protect islets after transplantation.

METHODS

In a marginal mass islet transplantation model, islets from C57BL/6 mice were cotransplanted with CP-ASCs into syngeneic streptozotocin-treated diabetic mice. Treatment response was defined by the percentage of recipients reaching normoglycemia, and by the area under the curve for glucose and c-peptide in a glucose tolerance test. Macrophage infiltration, β-cell apoptosis, and islet graft vasculature were measured in transplanted islet grafts by immunohistochemistry. mRNA expression profiling of 84 apoptosis-related genes in islet grafts transplanted alone or with CP-ASCs was measured by the RT² Profiler™ Apoptosis PCR Array. The impact of insulin-like growth factor-1 (IGF-1) on islet apoptosis was determined in islets stimulated with cytokines (IL-1β and IFN-γ) in the presence and absence of CP-ASC conditioned medium.

RESULTS

CP-ASC-treated mice were more often normoglycemic compared to mice receiving islets alone. ASC cotransplantation reduced macrophage infiltration, β-cell death, suppressed expression of TNF-α and Bcl-2 modifying factor (BMF), and upregulated expressions of IGF-1 and TNF Receptor Superfamily Member 11b (TNFRSF11B) in islet grafts. Islets cultured in conditioned medium from CP-ASCs showed reduced cell death. This protective effect was diminished when IGF-1 was blocked in the conditioned medium by the anti-IGF-1 antibody.

CONCLUSION

Cotransplantation of islets with ASCs from the adipose of chronic pancreatitis patients improved islet survival and islet function after transplantation. The effects are in part mediated by paracrine secretion of IGF-1, suppression of inflammation, and promotion of angiogenesis. ASCs from chronic pancreatitis patients have the potential to be used as a synergistic therapy to enhance the efficacy of islet transplantation following pancreatectomy.