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C Ricordi

Publications and source records attributed to C Ricordi.

At least 19 recordsLinked to original sources
PubMed1995

Hematopoietic progenitor cell content of vertebral body marrow used for combined solid organ and bone marrow transplantation.

While cadaveric vertebral bodies (VB) have long been proposed as a suitable source of bone marrow (BM) for transplantation (BMT), they have rarely been used for this purpose. We have infused VB BM immediately following whole organ (WO) transplantation to augment donor cell chimerism. We quantified the hematopoietic progenitor cell (HPC) content of VB BM as well as BM obtained from the iliac crests (IC) of normal allogenic donors (ALLO) and from patients with malignancy undergoing autologous marrow harvest (AUTO). Patients undergoing WO/BM transplantation also had AUTO BM harvested in the event that subsequent lymphohematopoietic reconstitution was required. Twenty-four VB BM, 24 IC BM-ALLO, 31 IC AUTO, and 24 IC WO-AUTO were harvested. VB BM was tested 12 to 72 hr after procurement and infused after completion of WO grafting. IC BM was tested and then used or cryopreserved immediately. HPC were quantified by clonal assay measuring CFU-GM, BFU-E, and CFU-GEMM, and by flow cytometry for CD34+ progenitor cells. On an average, 9 VB were processed during each harvest, and despite an extended processing time the number of viable nucleated cells obtained was significantly higher than that from IC. Furthermore, by HPC content, VB BM was equivalent to IC BM, which is routinely used for BMT. We conclude that VB BM is a clinically valuable source of BM for allogeneic transplantation.

Animals↗
PubMed1995

A selective decrease in the beta cell mass of human islets transplanted into diabetic nude mice.

Streptozocin-induced diabetic nude mice (blood glucose 493 +/- 14 mg/dl) received aliquots of 2000 human islet equivalents (IE) under the kidney capsule and were then followed for up to 30 days with measurement of blood glucose concentration and body weight. Characterization of islet aliquots before the implantation included the assessment of the endocrine beta cell and nonbeta cell mass, estimated by point counting morphometry of immunostained sections. Islet transplantation was followed by a rapid decrease in blood glucose levels and by a progressive increase in body weight; 15 days after transplantation mean glycemic levels were 102 +/- 11 mg/dl and further decreased to 70 +/- 3 mg/dl at 30 days. Despite the progressive improvement in the glucose levels, the beta cell mass of the islet grafts significantly decreased over time from 2.63 +/- 0.2 mg, at the time of transplantation, to 1.16 +/- 0.1 and 0.86 +/- 0.1 mg 15 and 30 days, respectively, after transplantation. In contrast, the endocrine nonbeta cell mass remained stable from before the implantation to 30 days after. Therefore, the endocrine nonbeta cell/beta cell ratio increased from 14% at the time of transplantation, to 35% and 37%, 15 and 30 days, respectively, after transplantation. The rate of replication of the transplanted beta cells was similar in the grafts harvested at 15 and 30 days, with the percentage of beta cells positive for bromo-2' deoxyuridine (BrdU) incorporation being in the range of approximately 0.1% 6 hr after the BrdU injection. These data demonstrate that an important decrease in beta cell mass takes place immediately after islet transplantation--the most dramatic decrease occurring in the first 15 days and persisting even after revascularization has occurred. However, endocrine nonbeta cell mass remained stable indicating that engrafted nonbeta cells are less likely to die than beta cells. The finding that the nonbeta/beta cell ratio of a human islet graft can increase over time, raises questions about whether such a change in islet structure could have an influence upon function.

Animals↗
PubMed1995

Long-term (> 3-year) insulin independence in a patient with pancreatic islet cell transplantation following upper abdominal exenteration and liver replacement for fibrolamellar hepatocellular carcinoma.

In the University of Pittsburgh experience, the most successful setting for human islet allografts is in patients undergoing upper abdominal exenteration with total pancreatectomy and liver transplantation for the indication of malignancy (cluster). In this group of patients 6/11 were insulin-independent for long periods. We report herein the metabolic course or the longest survivor (> 3 years). This patient has been free of exogenous insulin since the third postoperative month and has sustained her body weight without total parenteral nutrition since the 4th postoperative month. The patient has some postprandial hyperglycemia but average capillary glucoses are near-normal to normal as are glycosylated hemoglobin values. The clearance of glucose during the administration of an intravenous glucose load has been well preserved and is currently normal. C-peptide stimulates significantly in response to intravenously injected glucose. The absolute levels of stimulation during the test have declined possibly related to improvements in renal function, decreased immunosuppression or the natural history of cells transplanted into the portal site. The kinetics of the C-peptide response to intravenously injected glucose shows a persistent abnormality of first-phase insulin release and a prolonged second phase release. Basal glucagon levels are low but stimulate to a mixed meal. This patient's results demonstrate long-term function of islet cells from a single donor transplanted into the portal vein using FK506 as an immunosuppressant agent.

Abdominal Neoplasms↗
PubMed1995

Growth factor/matrix-induced proliferation of human adult beta-cells.

Proliferation of human beta-cells in vitro is desirable for both transplantation and biological studies. In this study, human pancreatic islets obtained from cadavers were kept in tissue culture plates that favored cell attachment. When the cells attached to the matrix produced by the rat-bladder carcinoma cell line 804G, 5'-bromo-2'-deoxyuridine (BrdU) labeling increased from 4.7 +/- 2.5 to 13.2 +/- 2.2%, while cells simultaneously labeled for insulin and BrdU increased from 0 to 32%. Addition of the growth factor hepatocyte growth factor/scatter (HGF/SF) increased BrdU labeling to 17.5 +/- 1.8 and the percentage of double positive (BrdU + insulin) cells to 69%. This is the first in vitro demonstration that human beta-cells grown in monolayer culture are able to replicate when exposed to selected matrices and growth factors. These experiments add further evidence that HGF/SF is an important mitogenic agent for human beta-cells.

Adult↗
PubMed1994

Evidence for superantigen involvement in insulin-dependent diabetes mellitus aetiology.

Insulin-dependent diabetes mellitus (IDDM) is a T-cell-mediated autoimmune disease whose onset is believed to be triggered by unknown environmental factors acting on a predisposing genetic background. Islet-infiltrating T (IIT) cells from two IDDM patients, who had died at the onset of the disease from brain swelling as a complication of ketoacidosis, were analysed. The results provided evidence for the involvement of a pancreatic islet cell membrane-bound superantigen as a diabetes aetiopathogenetic factor. There was a selective expansion of a T-cell receptor (TCR) variable segment of the beta-chain (V beta 7) in these IIT cells in association with unselected V alpha-chain segments; extensive junctional diversity of the TCR V beta 7 chains; and evidence of positive selection, after exposure to diabetic islet cell membrane preparations, of V beta 7+ T-cell clones among peripheral blood lymphocytes from non-diabetic individuals.

Amino Acid Sequence↗
PubMed1994

Bone marrow augmentation of donor-cell chimerism in kidney, liver, heart, and pancreas islet transplantation.

We have previously postulated that donor cell chimerism in organ transplantation is needed to attain a tolerant state. Here we show that donor cell chimerism can be augmented in organ recipients if they are infused perioperatively with 3 x 10(8) per kg of unmodified donor bone marrow cells and are kept on a conventional immunosuppressive regimen of tacrolimus (FK506) and prednisolone. 36 patients took part, of whom the first 18 patients have good transplanted kidney (n = 10), liver (n = 7), and heart (n = 7) function when followed up between 4 and 16 months. All patients are well. We found persistent multilineage leucocyte chimerism in blood of 17 recipients by flow cytometry and PCR techniques to detect donor alleles or Y chromosomes in female recipients of male organs. The use of the 5-antigben HLA matched same sex donor precluded detection of chimerism in one patient.

Adult↗
PubMed1994

Mixed xenogeneic chimerism (mouse+rat-->mouse) to induce donor-specific tolerance to sequential or simultaneous islet xenografts.

We previously reported that donor-specific rat islet xenografts were accepted by fully xenogeneic (rat-->mouse) chimeras when the islets were transplanted at least six weeks following reconstitution. The purpose of the present study was to examine whether a similar outcome would occur for mixed xenogeneic (mouse+rat-->mouse) chimeras if the islets were placed coincident with the time of bone marrow infusion. As with fully xenogeneic chimeras (rat-->mouse), synchronous donor-specific F344 rat (Rt1A1) islet xenografts were significantly prolonged (MST > 139 days) in mixed xenogeneic (mouse+rat-->mouse) chimeras, while MHC-disparate third-party WF rat (Rt1Au) grafts were rejected (MST = 21.2 days). The transplanted donor-specific islets were functional to maintain euglycemia and they were regulated in function to respond to a glucose challenge. For potential clinical application, it would be of obvious benefit if the islet xenografts could be placed at the time of bone marrow transplantation. We therefore performed similar studies using donor islets administered simultaneously with bone marrow. Donor-specific islet xenografts were permanently accepted by all mouse recipients (n = 5). When MHC-disparate third-party rat islets were transplanted, only 3 of 8 islet xenografts were rejected; the other 5 remained functional from 77 to 90 days posttransplantation. Although prolonged and functional, the MHC-disparate islets that were accepted exhibited histologic evidence of fibrosis and rejection, while those matched to the donor did not. These data therefore suggest that donor-specific islet xenografts are permanently accepted if placed simultaneously or sequentially following mixed xenogeneic bone marrow reconstitution.

Animals↗
PubMed1994

Acceleration of chronic failure of intrahepatic canine islet autografts by a short course of prednisone.

A topic of current interest in islet transplantation is the selection of an optimal site for long-term graft survival since the intrahepatic site may be characterized by long-term failure. Additionally, the use of immunosuppressive agents such as prednisone may adversely affect long-term graft function. In this study, we examined the long-term outcome of intrahepatic canine islet autografts and compared this with results obtained in animals treated with a short-term course of steroids or steroids plus insulin. Islets were isolated using the automated method and were purified on discontinuous Euro-Collins Ficoll gradients (densities: 1.108, 1.096, 1.037). Prednisone-treated dogs were hyperglycemic during treatment but returned to normoglycemia after steroid withdrawal. Control and insulin-treated animals were normoglycemic following autotransplant, with no difference in plasma glucose levels between controls and the insulin-treated animals. All control dogs became diabetic at 11, 14, 17, and 19 months following islet autograft. Prednisone-treated dogs had more rapid onset of diabetes at 7, 11, and 12 months following ITx. Prednisone-treated dogs given insulin became hyperglycemic at 10, 14, 18, and 19 months post ITx. Graft failure was preceded by a decline in IVGTT Kg values and diminished insulin secretion. At the time of graft failure islets showed no lymphocytic infiltration and islets stained positive for glucagon but few insulin-containing cells were seen. Thus, even when an initially adequate B cell mass was transplanted, the intrahepatic site was characterized by long-term canine autograft failure. A short course of prednisone accelerated the time to graft failure and insulin treatment reversed this acceleration.

Animals↗
PubMed1994

Control of cytosolic free calcium in cultured human pancreatic beta-cells occurs by external calcium-dependent and independent mechanisms.

Changes in cytosolic intracellular free Ca2+ ([Ca2+]i) in response to glucose, glyburide, cholinergic agonists, and elevated [K+]o (external potassium concentration) were measured in cultured human islet beta-cells. In the absence of glucose, the mean resting [Ca2+]i in single beta-cells was 84.5 +/- 4.7 nM (n = 86) and remained unchanged in low external [Ca2+]o (Ca2+ concentration) (< 0.2 microM) at 23-25 C. Glucose (5.6-33 mM) induced a slow dose-related [Ca2+]i rise up to 300.0 +/- 50.6 nM (n = 19). This [Ca2+]i rise always occurred with a delay that varied from cell to cell (approximately 10-120 sec), and the steady state [Ca2+]i exhibited a sigmoidal dependence on glucose concentration (midpoint at 14.9 mM). The glucose-induced rise in [Ca2+]i was attenuated by about 62% in low external [Ca2+]o and was not affected by dantrolene, a drug that inhibits Ca2+ release from the endoplasmic reticulum. In the absence or presence of glucose, cholinergic receptor agonists evoked a biphasic increase in [Ca2+]i up to 350 nM; the delayed component of the [Ca2+]i rise was blocked by dantrolene. A rapid elevation of [K+]o to 40 mM also elicited a biphasic rise in [Ca2+]i, which peaked at about 250 nM and was inhibited by the Ca2+ channel antagonist nifedipine. Glyburide (4 microM) in the absence of glucose also induced a [Ca2+]o-dependent rise in [Ca2+]i. Increasing the concentration of glucose from 4 to 16.7 mM evoked a biphasic pattern of insulin secretion from perifused isolated islets at 37 C. Finally, in the presence of 4 mM glucose, a cholinergic muscarinic receptor agonist stimulated insulin secretion. A glucose-stimulated [Ca2+]i rise was also studied at 24 and 37 C in cultured rat islet cells. Our results suggest that the Ca2+ required for glucose-induced and muscarinic agonist-potentiated insulin release enters the cytosol from both extracellular and intracellular Ca2+ stores.

Calcium↗