<p>Macrophages are an important key effector cell in the immune system which can practically be found in every tissue. Macrophages have for a long time been considered a population of cells only responsible for pro-inflammatory responses and anti-microbial activities. But over the past decade, many have come to realize the amazing plasticity of macrophages in response to different stimulations. The anti-microbial and pro-inflammatory macrophage is known as classically activated macrophages but newly discovered phenotypes have been revealed named wound-healing macrophages and regulatory macrophages. Through systematic screening we have identified an inducible macrophage activation state which has both wound-healing and regulatory capabilities activated by the novel cytokine combination IL-4/IL-10 with or without TGF-β.</p>

This study was designed to examine if a sphingolipid-enriched lipid fraction from wheat gluten could affect the incidence of type I diabetes in BioBreeding diabetes prone (BBdp) rats. Wheat gluten was extracted with a chloroform-methanol (CM) mixture to isolate most of the lipids. Isolated lipids were subjected to silica gel column chromatography and saponification to remove most of neutral lipids and phospholipids, leaving behind a lipid fraction enriched in sphingolipids. This sphingolipid-enriched lipid fraction was used in a BBdp rat feeding study. BBdp rats were fed with one of five diets from weaning at 23 days of age until 125 days of age: a hydrolyzed casein based diet (HC), a NTP-2000 standard rodent diet (NTP-2000), a wheat gluten based diet (WG), a sphingolipid-free wheat gluten based diet (WGSLF), and a hydrolyzed casein plus sphingolipid-enriched lipid fraction diet (HC+SL). The yield of sphingolipid-enriched lipid fraction was about 0.62% of wheat gluten. The content of glycosylceramide in sphingolipid-enriched lipid fraction was increased more than five fold compared to that in total isolated lipids. Rats fed the NTP-2000 diet had the highest incidence of diabetes; while rats on the HC diet had the lowest diabetes incidence. There was no significant difference with regard to the onset age of diabetes among rats in the five diet groups. The addition of sphingolipid-enriched fraction to the HC diet caused a significant increase in the incidence of diabetes in BBdp rats in the first 80 days of the study. However, the ultimate diabetes incidence at day 125 was not changed. The removal of lipids from wheat gluten did not change the diabetes incidence in BBdp rats at any stages of the feeding study. These findings suggest that the sphingolipid-enriched fraction from wheat gluten acted as a possible promoter but not as a trigger of the development of type I diabetes in BBdp rats. There must be something that remains in wheat gluten after chloroform-methanol extraction that serves as a trigger for type I diabetes in these rodents. Type I diabetes in this animal model for the human disease seems to be caused by multiple factors, most likely, by the interaction of sphingolipids and some other unknown substances in wheat gluten. / Master of Science

Type I diabetes (T1D) is an autoimmune disease characterized by the destruction of insulin-producing β cells in the pancreas. Destruction of the body's own proteins, cells, and tissues is precipitated by the dysfunction of cytokine production, protein modification, and signaling pathways in immune cell subtypes. Tumor Necrosis Factor α (TNFα) and its receptors Tumor Necrosis Factor 1 (TNFR1) also known as p55 and TNFRSF1A, and Tumor Necrosis Factor 2 (TNFR2) also known as P75 and TNFRSF1B play a crucial role in this autoimmune process. TNFα has been shown to stimulate cell death through TNFR1 signaling by the caspase system, while promoting cell survival through TNFR2 signaling using the Nuclear Factor Kappa-Light-Chain-Enhancer of Activated B cells (NF-𝜅B) pathway. Recent findings show a defect in immuno-proteasomes found in autoreactive T cells in people with T1D. This defect causes improper signaling transduction when TNFα binds to TNFR2. The inability to save the cell by activating the NF-𝜅B pathway eventually leads instead to apoptosis using the caspase system. A decrease in TNFα or increase in soluble TNFα receptors might be an explanation for these autoreactive T cells to evade the host immune system, and allow them to cause destruction of the pancreas. We hypothesize that patients with T1D will show abnormal distribution of TNFα and its receptors at basal levels, as well as when stimulated with interleukins, cytokines, and bacteria such as interleukin-2 (IL-2), lipotechoic acid (LTA), granulocyte macrophage-colony stimulating factor (GM-CSF), and Bacillus Calmette-Guérin (BCG). To test this hypothesis, we obtained peripheral blood from T1D patients (n=102) and controls (n=89) and performed in vitro stimulation assays. After a 48-hour incubation, tissue culture supernatants were collected and analyzed for TNF and its receptors production by ELISA, as well as densities of cell membrane receptors by flow cytometry. The data from this study showed significant differences in basal levels of TNFα, TNFR1, and TNFR2 on both the membrane and in the serum between patients and controls. Patients contained a greater percentage of CD4, 8, and 14 - TNFR2 and not TNFR1 double positive cells than their healthy control counterparts. Patient's sera also contained higher levels of all three markers, sTNFα, sTNFR1, and sTNFR2 than the controls. However, no significant differences were found between patient and controls when stimulated with the various compounds listed above.

The expanding field of tissue engineering provides a new approach to regenerative medicine for common ailments such as cardiovascular disease and type-I diabetes. Biomaterials can be administered as a delivery vehicle to introduce therapeutic cells to sites of damaged or diseased tissue. A specific class of biomaterials, termed hydrogels, is suitable for this application as they can provide a biocompatible, biodegradable scaffold that mimics the physical properties of the native soft tissue. Injectable hydrogels are increasingly being developed for biomedical applications due to their ability to be delivered in a minimally invasive manner. One potential use for such materials is in the delivery of therapeutics such as cells or growth factor-releasing particles. In this study, the first aim was to determine the interactive effects between collagen-based hydrogels and additives (cells and microspheres) for cardiac regeneration. The results demonstrated that the addition of either cells or microspheres to a collagen-based hydrogel decreased its gelation time and increased its viscosity. Increased cross-linker concentrations resulted in lower cell viability. However, this cell loss could be minimized by delivering cells with the cross-linker neutralizing agent, glycine. As a potential application of these materials, the second aim of this study was to develop a hydrogel for use as an ectopic islet transplant site. Specifically, collagen-chitosan hydrogels were synthesized and characterized, with and without laminin, and tested for their ability to support angiogenic and islet cell survival and function. Matrices synthesized with lower chitosan content (20:1 collagen:chitosan) displayed greater cell compatibility for both angiogenic cells and for islets and weaker mechanical properties, while matrices with higher chitosan content (10:1 collagen:chitosan) had the opposite effect. Laminin did not affect the physical properties of the matrices, but did improve angiogenic cell and islet survival and function. Overall the proposed collagen-based hydrogels can be tailored to meet the physical property requirements for cardiac and islet tissue engineering applications and demonstrated promising cell support capabilities.

Advances in medical treatment are leading away from generalized care towards intelligent systems or devices which can sense and respond to their environment. With these devices, the burden of monitoring and dosing for treatment can be removed from the doctor (or the patient) and be placed on the device itself. Implicit closed-loop control systems will allow the device to respond to its environment and release therapeutic agent in response to a specific stimulus. Environmentally responsive hydrogels show great promise in being incorporated in such an intelligent device, such as pH-responsive hydrogels which can swell and deswell in response to changes in the pH of the media. Thus, pH changes can be exploited for controlled and intelligent drug delivery when used in combination with these pH-responsive hydrogels. In this work, heterogeneous, thermal-redox initiated free-radical polymerizations were developed to synthesize novel pH-responsive hydrogels, microparticles, and nanogels. The specific disease of interest was type I diabetes, which requires daily doses of insulin both at a basal amount and either a postprandial or preprandial bolus in order to maintain blood glucose levels within safe limits. To allow pH-responsive hydrogels to be sensitive to glucose, glucose oxidase was incorporated which oxidizes glucose to gluconic acid. A novel inverse-emulsion polymerization method was developed for the synthesis of poly[2-(diethylaminoethyl methacrylate)-grafted-polyethylene glycol monoethyl ether monomethacrylate] (P(DEAEM-g-PEGMMA)) nanogels (100-400 nm) for intelligent insulin delivery. The new polymerization method allowed the incorporation of hydrophilic components, such as glucose oxidase and catalase, as well as PEG surface tethers of lengths 400 Da up to 2000 Da. Surface tethers successfully decreased the surface charge of the nanogels. Insulin loading and release was determined for microparticles which were able to imbibe substantial amounts of insulin from solution when swollen, entrap the insulin when collapsed, and then release the insulin in response to either a pH or glucose stimulus. / text

The expanding field of tissue engineering provides a new approach to regenerative medicine for common ailments such as cardiovascular disease and type-I diabetes. Biomaterials can be administered as a delivery vehicle to introduce therapeutic cells to sites of damaged or diseased tissue. A specific class of biomaterials, termed hydrogels, is suitable for this application as they can provide a biocompatible, biodegradable scaffold that mimics the physical properties of the native soft tissue. Injectable hydrogels are increasingly being developed for biomedical applications due to their ability to be delivered in a minimally invasive manner. One potential use for such materials is in the delivery of therapeutics such as cells or growth factor-releasing particles. In this study, the first aim was to determine the interactive effects between collagen-based hydrogels and additives (cells and microspheres) for cardiac regeneration. The results demonstrated that the addition of either cells or microspheres to a collagen-based hydrogel decreased its gelation time and increased its viscosity. Increased cross-linker concentrations resulted in lower cell viability. However, this cell loss could be minimized by delivering cells with the cross-linker neutralizing agent, glycine. As a potential application of these materials, the second aim of this study was to develop a hydrogel for use as an ectopic islet transplant site. Specifically, collagen-chitosan hydrogels were synthesized and characterized, with and without laminin, and tested for their ability to support angiogenic and islet cell survival and function. Matrices synthesized with lower chitosan content (20:1 collagen:chitosan) displayed greater cell compatibility for both angiogenic cells and for islets and weaker mechanical properties, while matrices with higher chitosan content (10:1 collagen:chitosan) had the opposite effect. Laminin did not affect the physical properties of the matrices, but did improve angiogenic cell and islet survival and function. Overall the proposed collagen-based hydrogels can be tailored to meet the physical property requirements for cardiac and islet tissue engineering applications and demonstrated promising cell support capabilities.

The expanding field of tissue engineering provides a new approach to regenerative medicine for common ailments such as cardiovascular disease and type-I diabetes. Biomaterials can be administered as a delivery vehicle to introduce therapeutic cells to sites of damaged or diseased tissue. A specific class of biomaterials, termed hydrogels, is suitable for this application as they can provide a biocompatible, biodegradable scaffold that mimics the physical properties of the native soft tissue. Injectable hydrogels are increasingly being developed for biomedical applications due to their ability to be delivered in a minimally invasive manner. One potential use for such materials is in the delivery of therapeutics such as cells or growth factor-releasing particles. In this study, the first aim was to determine the interactive effects between collagen-based hydrogels and additives (cells and microspheres) for cardiac regeneration. The results demonstrated that the addition of either cells or microspheres to a collagen-based hydrogel decreased its gelation time and increased its viscosity. Increased cross-linker concentrations resulted in lower cell viability. However, this cell loss could be minimized by delivering cells with the cross-linker neutralizing agent, glycine. As a potential application of these materials, the second aim of this study was to develop a hydrogel for use as an ectopic islet transplant site. Specifically, collagen-chitosan hydrogels were synthesized and characterized, with and without laminin, and tested for their ability to support angiogenic and islet cell survival and function. Matrices synthesized with lower chitosan content (20:1 collagen:chitosan) displayed greater cell compatibility for both angiogenic cells and for islets and weaker mechanical properties, while matrices with higher chitosan content (10:1 collagen:chitosan) had the opposite effect. Laminin did not affect the physical properties of the matrices, but did improve angiogenic cell and islet survival and function. Overall the proposed collagen-based hydrogels can be tailored to meet the physical property requirements for cardiac and islet tissue engineering applications and demonstrated promising cell support capabilities.

Macrophages are an important key effector cell in the immune system which can practically be found in every tissue. Macrophages have for a long time been considered a population of cells only responsible for pro-inflammatory responses and anti-microbial activities. But over the past decade, many have come to realize the amazing plasticity of macrophages in response to different stimulations. The anti-microbial and pro-inflammatory macrophage is known as classically activated macrophages but newly discovered phenotypes have been revealed named wound-healing macrophages and regulatory macrophages. Through systematic screening we have identified an inducible macrophage activation state which has both wound-healing and regulatory capabilities activated by the novel cytokine combination IL-4/IL-10 with or without TGF-β.

To date there have been no complete reports of the nutrient intakes of persons with Type I diabetes mellitus who use continuous subcutaneous insulin infusion (CSII) pumps. The purpose of this study was to describe the sample population and to determine the nutrient intake of adult Type I diabetics from the Salt Lake City, Utah area, who use CSII. Seven male and 15 female CSII users, ages 25 to 53, completed a questionnaire and a three-day diet record as instructed. Diet records were coded and household measurements of foods were converted to gram weights for computerized nutrient analysis. Nutrient intake is reported as group mean and standard deviation for sex and age. The average duration of diabetes was 17 years. The average length of CSII use was l.6 years. Review of the medical charts revealed that weight gain since beginning CSII averaged 5.5 pounds irrespective of the duration of pump use. The dietary intake of protein, calcium, phosphorus, vitamin A, thiamin, riboflavin, niacin, vitamin B12 , and ascorbic acid met or exceeded the Recommended Dietary Allowances (RDA) for both men and women. For males, mean nutrient intakes were below the RDA for zinc (82.7%), folate (82.2%), and vitamin 86 (69.0%). For females, intakes were also below the RDA for zinc (64.0%), folate (58.3%), and vitamin 86 (69.0%), as well as for iron (58.5%) and magnesium (88.0%). The average percent of kilocalories from protein, carbohydrate and fat, (approximately 17%, 43%, and 40%) was similar for both the males and females. The day-to-day variation in carbohydrate intake for both sexes was not significantly different. Intake of added sugar in the diet was 6.6% and 5.8% of total kilocalories (14.8% and 13.9% of the carbohydrate kilocalories) for males and females, respectively. In conclusion, dietary intake for this small group of CSII users was adequate in most nutrients . Of concern is the apparent inadequate intakes of zinc, folate, vitamin s6 and iron for women, as compared to the current RDA standards. The distribution of kilocalories from protein, carbohydrate and fat approaches the 1979 recommendations by the American Diabetes Association. Weight gain may be a problem for some CSII pump users, and should be monitored.

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