Viability of liver grafts from fasted donor rats: relationship to sinusoidal endothelial cell apoptosis

Previous studies have shown that livers from fasted donors appear to tolerate long-term preservation better than livers from fed donors, but the mechanism is not clear. Some studies have shown that the apoptosis of sinusoidal endothelial cells (SEC) appeared to be a pivotal mechanism of ischemia/reperfusion injury in liver transplantation. The purpose of the present investigation was to evaluate the relation of SEC apoptosis to liver viability in rats after liver transplantation, comparing findings for fasted and fed donors. Wistar rats were used as donors and recipients. The fed group had access to solid feed and water ad libitum. The fasted group was allowed access only to water for 4 days prior to liver harvest. All rat livers were preserved with University of Wisconsin (UW) solution at 2 °C for 24 h. After preservation, the livers were orthotopically transplanted, and survival time was measured. Apoptosis was determined by in-situ staining for apoptotic cells, using a TdT-mediated dUTP-digoxigenin nick-end labeling (TUNEL) assay and electron microscope (EM) examination separately. The 14-day survival rates after 24-h preservation were 0% (0/11) for recipients of livers from fed donors and 91% (10/11) for recipients of livers from fasted donors. There was no significant difference in the numbers of TUNEL-positive SEC after 24-h preservation between the two groups. However, at 6 h after transplantation, the number of TUNEL-positive SEC was significantly higher in the fed group than in the fasted group. These results suggest that donor fasting decreases SEC apoptosis after reperfusion alone, and that this may be related to the protection of the liver graft from reperfusion injury. Received: December 22, 2000 / Accepted: February 15, 2001     

Bone-Resorbing Cytokines from Peripheral Blood Mononuclear Cells after Hormone Replacement Therapy: A Longitudinal Study

Conflicting results have been reported in several cross-sectional studies measuring cytokine production from adherent monocytes in pre- and postmenopausal women. Furthermore, the target cells for the action of estrogen are still debated. We therefore assessed in a longitudinal manner the cytokine production from different fractions of peripheral blood mononuclear cells (PBMC) cultured for 48 h. PBMC were obtained from 30 postmenopausal women before and after 6 months of hormone replacement therapy (HRT). Women were randomly allocated to two groups: an adherent PBMC group (n= 20) and a total PBMC group (n= 9). After 6 months of treatment, urinary pyridinoline levels were markedly decreased in both groups (353 ± 24 vs 114 ± 13 μg/mmol creatinine and 325 ± 35 vs 164 ± 31 μg/mmol creatinine respectively, p<0.01). Culture supernatants were assayed for interleukin 1β (IL-1β), interleukin 6 (IL-6), soluble IL-6 receptor (IL-6rs) and tumor necrosis factor alpha (TNF-α). In the adherent PBMC group, HRT induced a nonsignificant trend toward decreased levels of IL-1β (35 ± 10 vs 13 ± 5 pg/ml), TNF-α (333 ± 58 vs 222 ± 30 pg/ml) and IL-6 (115 ± 70 vs 17 ± 10 pg/ml). In contrast, in the total PBMC group, HRT induced a consistent and dramatic decrease in levels of IL-1β (104 ± 22 vs 25 ± 8 pg/ml), IL-6 (5950 ± 1041 vs 1011 ± 361 pg/ml), IL-6rs (148 ± 33 vs 35 ± 12 pg/ml) (p<0.01) and TNF-α (1468 ± 315 vs 585 ± 207 pg/ml, p= 0.05). We then evaluated whether HRT had the same effect in vitro. Adherent or total PBMC of 8 postmenopausal women were cultured with or without 10⁻⁸M 17β-estradiol or tibolone for 48 h. Production of IL-1β, TNF-α, IL-6 and IL-6rs was not affected by the presence of 17β-estradiol or tibolone in cultures of these cell fractions. In conclusion, our data indicate that non-adherent PBMC could mediate the response to HRT. HRT may exert its action indirectly via noncirculating cells, as suggested by the absence of an in vitro effect. Received: 11 July 2000 / Accepted: 15 January 2001     

Evaluation of water and electrolyte transport of tubular epithelial cells under osmotic and hydraulic pressure for development of bioartificial tubules

Our aim was to develop bioartificial tubules using tubular epithelial cells and artificial membranes and evaluate the function of water and electrolyte transport by various tubular epithelial cells. The cells were cultivated onto extracellular matrix (ProNectin F) coating polycarbonate membrane. Water transport from the apical to the basolateral site of cells was examined using a modified Ussing chamber module. Water transport under colloidal osmotic pressure on the apical site and hydraulic pressure on the basolateral site were higher in JTC-12, LLC-PK1 cells than in MDCK cells. Water transport under osmotic plus hydraulic pressure was highest in LLC-PK1 cells. We made bioartificial tubules using LLC-PK1 cells and polysulfone hollow fiber cartridges. Water and Na ion transport function was high, and BUN and creatinine passage was recognized in these bioartificial tubules. BUN and creatinine concentrations of reabsorption fluid in these bioartificial tubules were significantly lower than those concentrations of control media and of noncell attached polysulfone hollow fiber cartridges. Though LLC-PK1 cells were more preferable cells for the use of bioartificial tubules in terms of water and electrolyte transport, the passage of BUN and creatinine was not appropriate for clinical use. To select more preferable cells for bioartificial tubules which transport water and electrolytes and do not induce passage of uremic toxins is necessary.     

Persistence and survival of autologous muscle derived cells versus bovine collagen as potential treatment of stress urinary incontinence

PURPOSE: We explored the use of autologous muscle derived cells as a method of treating stress urinary incontinence. We determined whether urethral muscle derived cell injection is feasible and compared it with bovine collagen injection. MATERIALS AND METHODS: Muscle derived cells isolated from female Sprague-Dawley rats were first transduced with retrovirus carrying the transgene for beta-galactosidase. We injected approximately 1 to 1.5 x 106 cells into the bladder wall and proximal urethra of 6 autologous animals. Tissue was harvested after 3 and 30 days, sectioned, stained for fast myosin heavy chain and assayed for beta-galactosidase. To compare muscle derived cell and bovine collagen injections 100 microl. of commercially available bovine collagen were also injected in Sprague-Dawley female rats. Tissue was harvested in 3 animals each after 3 and 30 days, sectioned and stained for trichrome. Subsequently, 3 adult SCID mice were used to compare the level of transgene expression at each time point after injecting 1.5 x 106 cells per injection, which were transduced with adenovirus carrying the transgene for beta-galactosidase. RESULTS: A large number of cells expressing beta-galactosidase were observed in the bladder and urethral wall 3 and 30 days after autologous cell injection in Sprague-Dawley rats. The persistence of primary muscle derived cells at 3 days was similar to that of collagen. However, at 30 days there was significant cell persistence while only a minimal amount of injected bovine collagen was detectable. Approximately 88% of the beta-galactosidase expression at day 3 remained at day 30 in SCID mice. CONCLUSIONS: We present 2 new findings important for the emerging field of urological tissue engineering, including the feasibility of injecting autologous skeletal muscle derived cells into the lower urinary tract and the greater persistence of such injected cells versus injected bovine collagen. Therefore, autologous muscle derived cell injection may be an attractive alternative treatment option for stress urinary incontinence.     

Erythropoietin modulates angiotensin II- or noradrenaline-induced Ca(2+) mobilization in cultured rat vascular smooth-muscle cells.

BACKGROUND: It has been reported that human recombinant erythropoietin (rHuEpo) modulates the sensitivity of the cardiovascular system to angiotensin II (Ang II) or noradrenaline (NA). In the present study, we explored the effect of rHuEpo on the responsiveness of Ang II- or NA-induced cytosolic free calcium ([Ca(2+)]i) mobilization in cultured rat vascular smooth-muscle cells (VSMC). METHODS: [Ca(2+)]i concentrations in VSMC were measured by using the calcium-sensitive fluorescent dye fura-2. RESULTS: The addition of rHuEpo (250 U/ml) alone induced elevation in [Ca(2+)]i, which remained significantly elevated above basal level for at least 60 min in the presence of extracellular Ca(2+). Pre-incubation with specific protein kinase C (PKC) inhibitor calphostin C (1 micromol/l) significantly reduced the peak and the sustained elevations of [Ca(2+)]i. Pre-treatment with rHuEpo for 60 min increased both basal [Ca(2+)]i and the changes in [Ca(2+)]i by Ang II or NA in a dose-dependent manner in the presence of extracellular Ca(2+). The synergistic effects of rHuEpo with Ang II or NA were also retained when VSMC were bathed in the Ca(2+)-free medium after the pre-incubation of rHuEpo. Conversely, they were diminished in the presence of extracellular Ca(2+) combined with intracellular Ca(2+) release inhibitor 8-(NN-diethylamino)octyl-1,3,4,5-trimethoxybenzoate (TMB-8). The synergistic effects of rHuEpo were also diminished by PKC depletion or by PKC inhibitor. CONCLUSIONS: These observations suggest that rHuEpo has synergistic effects on Ang II- or NA-induced [Ca(2+)]i mobilization, particularly on intracellular Ca(2+) release, in VSMC. This may be a potential mechanism contributing to hypertension associated with rHuEpo therapy.     

ICOS-Dependent and -Independent Functions of Memory CD4 T Cells in Allograft Rejection

Donor-reactive memory T cells undermine the survival of transplanted organs through multiple pathways. We have previously reported that memory CD4 T cells resist treatment with anti-CD154 antibody and donor-specific transfusion (DST/MR1) and promote cardiac allograft rejection via generation of effector CD4 T cells and alloantibody. We hypothesized that the helper functions of memory CD4 T cells are independent of T-cell costimulation through CD154 but instead are regulated by alternative costimulatory pathways. This study investigated how blocking ICOS/B7RP-1 interactions affects functions of donor-reactive memory CD4 T cells. Treatment with blocking anti-ICOS mAb synergized with DST/MR1 and prolonged mouse cardiac allograft survival despite the presence of donor-reactive memory CD4 T cells. While blocking ICOS did not diminish the expansion of preexisting memory CD4 T cells or the induction of allospecific effector T cells, it did inhibit recruitment of the activated memory and effector T cells into the graft. In addition, anti-ICOS mAb treatment in combination with DST/MR1 prevented help provided by memory CD4 T cells for production of donor-specific IgG antibody. These results demonstrate the potential efficacy of ICOS blockade in sensitized transplant patients and provide the foundation for rational use of ICOS blockade in combination with other graft-prolonging strategies.     

Monocyte Infiltration and Kidney Allograft Dysfunction During Acute Rejection

Multiple cell types infiltrate acutely rejecting renal allografts. Typically, monocytes and T cells predominate. Although T cells are known to be required for acute rejection, the degree to which monocytes influence this process remains incompletely defined. Specifically, it has not been established to what degree monocytes impact the clinical phenotype of rejection or how their influence compares to that of T cells. We therefore investigated the relative impact of T cells and monocytes by correlating their presence as measured by immunohistochemical staining with the magnitude of the acute change in renal function at the time of biopsy in 78 consecutive patients with histological acute rejection. We found that functional impairment was strongly associated with the degree of overall cellular infiltration as scored using Banff criteria. However, when cell types were considered, monocyte infiltration was quantitatively associated with renal dysfunction while T-cell infiltration was not. Similarly, renal tubular stress, as indicated by HLA-DR expression, increased with monocyte but not T-cell infiltration. These data suggest that acute allograft dysfunction is most closely related to monocyte infiltration and that isolated T-cell infiltration has less acute functional impact. This relationship may be useful in assigning acute clinical relevance to biopsy findings.     

Essential Role of Sphingosine-1-Phosphate Receptor 1-Bearing CD8+CD44+CCR7+ T Cells in Acute Skin Allograft Rejection

A subset of naturally formed sphingosine‐1‐phosphate receptor 1 (S1P1)‐bearing CD8⁺CD44⁺CCR7⁺ memory T cells has been identified in transplant recipient BALB/c (H‐2^d) mice. The frequency of this subset of memory T cells is significantly increased in the spleen, lymph nodes and skin grafts in the recipient BALB/c mice during acute skin allograft rejections. The immune‐reconstitution with CD8⁺CD44⁺CCR7⁺S1P1⁺ memory T cells facilitates acute skin allograft rejection in SCID mice. Being Th1‐polarized and cytotoxic, CD8⁺CD44⁺CCR7⁺S1P1⁺ memory T cells proliferate and differentiate immediately into effectors upon encountering allo‐antigens. A siRNA against S1P1 inhibits CD8⁺CD44⁺CCR7⁺S1P1⁺ memory T cell‐mediated acute skin allograft rejection in SCID mice by means of knocking‐down S1P1‐expression. CCL21 mutant (CCL21‐ΔCT) has been used to compete with wild‐type CCL21 in the course of binding to CCR7. Combined administration of siRNA S1P1 and CCL21‐ΔCT significantly prolongs the survival of skin allograft in the recipient BALB/c mice by means of inhibiting accumulation of CD8⁺CD44⁺CCR7⁺S1P1⁺ memory T cells in the spleen and the skin grafts. Our data provide direct evidence that S1P1 and CCR7 are involved in the proliferation and trafficking of CD8⁺CD44⁺CCR7⁺S1P1⁺ memory T cells. S1P1 may serve as a functional marker for CD8⁺CD44⁺CCR7⁺ memory T cells. Targeting CD8⁺CD44⁺CCR7⁺S1P1⁺ T cells may be a useful strategy to prolong the survival of allograft transplant.