Persistent delivery of factor IX in mice: gene therapy for hemophilia using implantable microcapsules

Severe hemophilia B is a life-threatening, life long condition caused by absence of or defective coagulation factor IX. Gene therapy could provide an alternative treatment to repeated injection of plasma-derived concentrate or recombinant factor IX. We have previously described the use of implantable microcapsules containing recombinant myoblasts to deliver human factor IX in mice. This study reports the generation of improved myoblast-specific expression vectors. Mouse myoblast clones transfected with the various vectors secreted factor IX in vitro, at rates between 70 and 1000 ng/10(6) cells/day. The recombinant myoblast clones were then encapsulated and implanted into mice. Immunocompetent mice implanted with encapsulated myoblasts had up to 65 ng of factor IX per milliliter in their plasma for up to 14 days, after which antibodies to human factor IX became detectable, and this coincided with decreased factor IX in mouse plasma. In immunodeficient mice, however, factor IX delivery was maintained at a constant level for at least 6 weeks (end of experiment). Interestingly, the highest-secreting myoblast clone in vitro did not deliver the highest level of hFIX in vivo. This discrepancy observed between performance in vitro and in vivo may have important implications for the development of gene therapy protocols based on recombinant cells.

Serum progesterone before and after human chorionic gonadotropin injection depends on the estradiol response to ovarian hyperstimulation during in vitro fertilization-embryo transfer cycles

PURPOSE

Our purpose was to assess if periovulatory serum progesterone is reflective of ovarian responsiveness in controlled ovarian hyperstimulation (COH).

METHODS

One-hundred forty-two in vitro fertilization-embryo transfer cycles in women using GnRH-a suppression and human menopausal gonadotropin (hMG) stimulation were evaluated. Responses were studied according to ovarian response to hMG and age. Outcome measures included peak serum estradiol, serum progesterone and estrogen/progesterone ratios on the day of hCG injection, number of harvested oocytes, fertilization rates, and delivered pregnancy rates.

RESULTS

A periovulatory rise in serum progesterone (> 0.9 ng/ml) occurred only among younger women (< 40 years old) with a good response (P < 0.05). Though the number of oocytes was greater in good responders, fertilization and pregnancy rates were similar among all women regardless of age and ovarian response.

CONCLUSIONS

Periovulatory levels of serum progesterone vary according to ovarian response to COH. Elevations in progesterone do not appear to be a manifestation of poor responders. Reduced periovulatory progesterone may reflect inadequate steroidogenesis.

The in vivo delivery of heterologous proteins by microencapsulated recombinant cells

The microencapsulation of recombinant cells is a novel and potentially cost-effective method of heterologous protein delivery. A 'universal' cell line, genetically modified to secrete any desired protein, is immunologically protected from tissue rejection by enclosure in microcapsules. The microcapsule can then be implanted in different recipients to deliver recombinant proteins in vivo.

Delivery of recombinant gene products to the central nervous system with nonautologous cells in alginate microcapsules

Somatic gene therapy using nonautologous recombinant cells immunologically protected with alginate microcapsules has been successfully used to treat rodent genetic diseases. We now report the delivery of recombinant gene products to the brain in rodents by implanting microencapsulated cells for the purpose of eventually treating neurodegenerative diseases with this technology. Alginate-poly-L-lysine-alginate microcapsules enclosing mouse C2C12 myoblasts expressing the marker gene human growth hormone (hGH) at 95+/-20 ng/million cells/hr were implanted into the right lateral ventricles of mice under stereotaxic guidance. Control mice were implanted similarly with nontransfected but encapsulated cells. Delivery of hGH to the different regions of the brain at various times postimplantation was examined. At 7, 28, 56, and 112 days postimplantation, hGH was detected at high levels around the implantation site and also at lower levels in the surrounding regions, while control mice showed no signal. Immunohistochemical staining of the implanted brains showed that on days 7, 56, and 112 postimplantation, hGH was localized in the tissues around the implantation site. Mice implanted with encapsulated but nontransfected cells showed no signal. Hence, the feasibility of using encapsulated nonautologous cells to deliver recombinant gene products to the brain for extended periods may allow the application of this technology to the treatment of neurodegenerative genetic disorders.

Encapsulation of various recombinant mammalian cell types in different alginate microcapsules

Microencapsulation of recombinant "universal" cells with immunoprotective membranes is an alternate approach to somatic gene therapy. Therapeutic gene products secreted by these cells can be delivered to different patients without immunosuppression or genetic modification of the host's cells. The encapsulation of different mammalian cell types (epithelial cells, fibroblasts, and myoblasts) is compared among three alginate-based microcapsules: (1) calcium-linked alginate microcapsules with a solubilized core and a poly-L-lysine-alginate-laminated surface; (2) barium-linked alginate beads with a gelled core; and (3) a hybrid formulation of barium-linked alginate beads with a poly-L-lysine-alginate-laminated surface. The mechanical stability of the different microcapsule types, as measured with a cone-and-plate shearing apparatus, was superior in the two barium-linked alginate beads. All cell types maintained high viability (65-90%) in culture after encapsulation. The recombinant gene products secreted by these cells (human growth hormone MW = 22,000, human factor IX MW = 57,000, and murine beta-glucuronidase MW = 300,000) were able to traverse the three microcapsule types at similar rates. Cell numbers within the microcapsules increased twofold to > 20-fold over 4 weeks, depending on the cell type. Epithelial and myoblast cell numbers were not affected by microcapsule formulation; however, fibroblasts proliferated the most in the calcium-linked alginate spheres. These results show that for culturing fibroblasts in a mechanically stable environment the classical calcium-linked microcapsules are adequate. However, where mechanical stability is a more critical requirement, the solid barium-linked gelled beads are more appropriate choices.

Squamous cell carcinoma of the bladder: a ten-year retrospective study

BACKGROUND

There is a limited amount of information available on treatment efficacy and optimal management of squamous cell carcinoma of bladder. The goal of this study was to assess the long-term outcome of patients with squamous cell carcinoma of the bladder treated using different modalities.

MATERIALS AND METHODS

Retrospective analysis of the medical records of 22 patients with squamous cell carcinoma of the bladder treated at Chang Gung Memorial Hospital from 1986 though 1996 was performed. The follow-up period ranged from 12 months to 111 months.

RESULTS

The treatment modalities included transurethral resection in 7 patients, radical cystectomy with urinary diversion in 6 patients, preoperative radiation followed by total cystectomy in 8 patients, and partial cystectomy in one patient. The overall 5-year survival rate was 9%. Only 6 patients (27.3%) in this series were alive two years after diagnosis. Treatment using a combination of modalities including preoperative radiation followed by total cystectomy resulted in a 5-year survival rate of 12.5% in 8 patients. Total cystectomy alone in 6 patients resulted in a 5-year survival rate of 0%. However, the difference in survival rates between these 2 treatment groups was not statistically significant.

CONCLUSION

Our results suggest that no definite significance concerning the role of preoperative radiation followed by total cystectomy could be drawn. The results were probably because most of our patients had locally advanced bladder cancer. Another consideration is the small sample size, which may have affected the significance. Although, cystectomy did not improve the 5-year survival rate of patients in this series, it improved the 2-year survival rate.

The utility of serum progesterone and inhibin A for monitoring natural-cycle IVF-ET

PURPOSE

Our purpose was to assess the value of monitoring serum P and inhibin A to determine how values might improve the clinical monitoring of natural cycle in vitro fertilization (IVF)-embryo transfer (ET) patients.

METHODS

All patients (n = 26) who underwent natural-cycle IVF-ET (n = 35) were analyzed. Groups were evaluated according to patients who had a spontaneous luteinizing hormone (LH) surge (group I) and women receiving human chorionic gonadotropin (hCG) who underwent subsequent oocyte aspiration (group II). Group II was further evaluated according to women who did (n = 10) and did not (n = 7) have an ET. All cycles were evaluated with serial transvaginal ultrasonography and serum estradiol, progesterone, and inhibin A. When follicle maturity was achieved, hCG, 10,000 IU, was administered intramuscularly if a LH surge was not detected. Transvaginal ultrasound-guided aspiration was performed 34-36 hr after hCG administration followed by a 48-hr transcervical ET.

RESULTS

No differences were seen in cycles the day prior to (d-1) and the day of a spontaneous LH surge, (n = 18) or hCG (d-0)(n = 17) in group I or group II with respect to lead follicular diameter (d-1, 15.3 +/- 0.6 vs. 14.2 +/- 0.9 mm; d-0, 17.4 +/- 0.8 vs. 17.8 +/- 0.6 mm) and serum estradiol (d-1, 148 +/- 15 vs. 150 +/- 15 pg/ml; d-0, 218 +/- 15 vs. 199 +/- 16 pg/ml), respectively. However, serum progesterone was significantly elevated in group I compared with group II on d-1 (0.82 +/- 0.6 vs. 0.48 +/- 0.04 ng/ml; P < 0.05) and d-0 (1.1 +/- 0.12 vs. 0.63 +/- 0.08 ng/ml; P < 0.05). Inhibin A was significantly greater on d-1 in group I (24 +/- 2.5 vs. 15 +/- 2.2 pg/ml; P < 0.05). In group II, cycles that resulted in an ET (n = 10) compared with group II cycles that did not (n = 7) revealed a significant difference in serum progesterone (0.51 +/- 0.05 vs. 0.7 +/- 0.07 ng/ml; P < 0.05) and inhibin A (15 +/- 2.5 vs. 37.3 +/- 5 pg/ml; P < 0.05) the day of hCG.

CONCLUSIONS

The possible application of serum progesterone and inhibin A in managing natural-cycle IVF-ET is suggested. These assays may predict women who should be set up for egg retrieval, while cancelling others in spite of the absence of an LH surge.

Development of engineered cells for implantation in gene therapy

Human gene therapy is based on the technology of genetic engineering of cells, either through ex vivo or in vivo methods of gene transfer. Many autologous cell types have been successfully modified to deliver recombinant gene products. An alternate form of gene therapy based on genetic modification of non-autologous cells is described. Protection within immuno-isolating devices would allow implantation of well-established recombinant cell lines in different allogeneic hosts, potentially offering a more cost-effective approach to gene therapy. Implantation with microencapsulated fibroblasts and myoblasts has resulted in successful recombinant product delivery in vivo. Correction of disease phenotypes in animal models of human genetic diseases has also been achieved. Cell types such as myoblasts which can differentiate terminally within the implantation device are particularly promising for the future development of this method of gene therapy.

The early effect of pelvic floor muscle exercise after transurethral prostatectomy

PURPOSE

We evaluate the early effect of pelvic floor muscle exercise on the frequency of urination, terminal dribbling, urinary incontinence and satisfaction with life in patients after transurethral prostatectomy.

MATERIALS AND METHODS

From February to October 1996, 50 patients who had undergone transurethral prostatectomy were selected for study. The first 25 men served as a control group and the next 25 were the experimental group. Pelvic floor muscle exercise was started after removal of the Foley catheter postoperatively in the experimental group. The patients were evaluated before pelvic floor muscle exercise and weekly at our outpatient department after discharge from the hospital. Results for the later 25 patients treated with the pelvic floor muscle exercise program were compared to those of the prior 25 patients.

RESULTS

There was a statistically significant difference (p <0.05) in the strength of pelvic floor muscle contractions at 4 weeks, length of between void interval (p <0.01), terminal dribbling at week 4 (p <0.05) and urinary incontinence at weeks 3 and 4 between the 2 groups after pelvic floor muscle exercise. During this study no complication or mortality occurred and there were no cases of hospitalization for either group. After pelvic floor muscle exercise patients in the experimental group had better satisfaction with life than the control group (p <0.01).

CONCLUSIONS

We conclude that pelvic floor muscle exercise seems to help reduce symptoms within the first 4 weeks after transurethral prostatectomy, and provides better psychological and social quality of life.

A therapeutic trial of acupuncture in neurogenic bladder of spinal cord injured patients--a preliminary report

Eighty patients with spinal cord injury (SCI) and neurogenic bladder were studied. Among them, 28 (70%) cases in the control group and 32 (80%) cases in the electroacupuncture group achieved ultimately balanced voiding and were selected for further analysis. The acupuncture group received electroacupuncture at four acupoints: Chung Chi (Conception Vessel CV3), Kuan Yuan (CV4), and bilateral Tzu Liao (Urinary Bladder UB32), in addition to conventional intermittent catheterization program (ICP). Whereas the control group underwent conventional bladder training program with ICP only. The results revealed that the time of achieving balanced voiding was statistically significantly shorter with electroacupuncture than in the control group: 57.1 +/- 22.6 vs 85.2 +/- 27.4 days (P < 0.005) for upper motor neuron lesions, and 55.4 +/- 22.6 vs 83.4 +/- 26.1 days (P < 0.01) for lower motor neuron lesions. However, there was almost no difference between upper motor neuron lesions and lower motor neuron lesions. When acupuncture commenced was alos a factor to influence the results. Those who received acupuncture within 3 weeks after injury had significantly shortened the total days to achieve a balanced bladder, as compared to those who received acupuncture 3 weeks after injury (46.6 +/- 13.2 vs 65.8 +/- 15.4 days, P < 0.005). Our study implied that acupuncture might be beneficial in the management of neurogenic bladder of SCI, and the earlier the patient received electro-acupuncture therapy, the sooner the bladder balanced. On the other hand, we also found that complete spinal cord injury, either with pronounced detrusor-sphincter dyssynergia in upper motor neuron lesion or with persistent areflexic bladder in lower motor neuron-lesion, was not affected by acupuncture.

Suppression of immunological response against a transgene product delivered from microencapsulated cells

A potential obstacle to successful gene therapy for some patients is the in vivo production of neutralizing antibodies against the recombinant therapeutic product delivered. To mimic this clinical situation, we implanted microencapsulated recombinant cells producing human growth hormone into C57B1/6 mice to provoke antihuman growth hormone antibody production. We then investigated the efficacy of different immunosuppressive treatments to inhibit the development of neutralizing antibodies. The experimental mice were treated with either an immunosuppressive drug (FK506 or cyclophosphamide), a cytokine (interferon-gamma [IFN-gamma] or interleukin-12 [IL-12], or a monoclonal antibody (anti-CD4, anti-gp39, or CTLA4-Ig). Serum human growth hormone and mouse anti-human growth hormone antibody levels were measured by enzyme-linked immunosorbent assay (ELISA) for 4 weeks. There were three patterns of response noted among the seven treatment groups. First, the mice receiving IFN-gamma, IL-12, anti-gp39, or CTLA4-Ig were similar to the untreated controls-no suppression of anti-hGH antibodies and no improvement in delivery of hGH. Next, the mice receiving FK506 or cyclosphosphamide showed > or = 90% suppression of antibodies but also no improvement in product delivery. Last, the mice receiving anti-CD4 showed almost complete antibody suppression over 1 month postimplantation. Furthermore, only anti-CD4 permitted a sustained level of human growth hormone delivery to day 28, in contrast to the controls whose human growth hormone delivery was undetectable by day 14 postimplantation. Hence, the use of anti-CD4 inhibited formation of neutralizing antibodies against a recombinant gene product delivered in vivo, and allowed prolonged delivery of a foreign protein. Its role as adjunct treatment for appropriate patients receiving gene therapy should be examined further.

Osteopontin stimulates a subpopulation of quiescent human prostate epithelial cells with high proliferative potential to divide in vitro

BACKGROUND

Osteopontin (OPN) is a secreted extracellular matrix (ECM) protein found in bone, as well as associated with epithelial cells. The main objective of these studies was to test in vitro the hypothesis that interaction with OPN stimulates proliferation of a quiescent subpopulation of prostate epithelial cells with high proliferative potential.

METHODS

To simulate conditions that restrict proliferation and inhibit terminal differentiation of basal cells in vivo, control cultures grew on substrate coated with collagen (CO) or fibronectin (FN), in medium containing low levels of growth factors.

RESULTS

Under growth-restricting conditions, most prostate epithelial cells with high proliferative potential, seeded in control secondary cultures, were quiescent within the time frame of the studies, as indicated by the small number of large colonies in these cultures. Growing prostate epithelial cells (PR) under the same growth-restricting conditions, but on substrate coated with OPN instead of CO or FN, stimulated proliferation of a subpopulation of single cells with high proliferative ability as indicated by: 1) dose-dependent increase in the percentage of single cells incorporating bromodeoxyuridine, i.e., proliferating PR; and 2) subsequent dose-dependent increase in the percentage of large colonies. The OPN effect was not merely due to preferential attachment to OPN, because PR attachment to OPN, CO, or FN was identical. PR attachment to OPN was inhibited in the presence of GRGDTP or an antibody against the integrin subunit alphav, but not in the presence of an RGES peptide or a nonspecific IgG.

CONCLUSIONS

Integrin-mediated OPN/PR interaction stimulates proliferation of a quiescent subpopulation of prostate epithelial cells with high proliferative potential, possibly stem cells.

TPA-mediated regulation of osteopontin in human malignant glioma cells

Malignant gliomas are the most common primary intracranial neoplasms in adults and are largely refractory to post-surgical therapy despite intensive therapeutic efforts. Using a number of different brain tumor-derived cell lines we have demonstrated that the mRNA for osteopontin (OPN), which is substantially over-expressed by some tumors in comparison with normal tissues, is preferentially expressed in high grade and metastatic brain tumors compared to low grade brain tumors. One glioma-derived cell line, U105MG, which does not express significant amounts of OPN mRNA, could be induced dose-dependently by the tumor-promoting and PKC-activating phorbol ester, TPA, to over-express OPN mRNA in a PKC-dependent manner. Unexpectedly, treatment of U105MG cells with Ca2+ ionophore (A23187) completely inhibited TPA-mediated induction of OPN while treatment with the intracellular Ca2+ antagonist TMB-8 had no significant effect. Elucidation of regulatory mechanisms for OPN induction in glioma cells should facilitate rational design of novel therapeutics for human malignant gliomas.

Improvements in the efficiency of care after implementing a clinical-care pathway for transurethral prostatectomy

OBJECTIVE

To investigate the efficiency of care, length of hospital stay and admission charges after implementing a clinical-care pathway for transurethral prostatectomy (TURP).

PATIENTS AND METHODS

Changes in the length of hospital stay and admission charges were identified by comparing a series of 100 patients undergoing TURP and treated after implementing a clinical-care pathway with 100 patients treated by the same physicians before implementation.

RESULTS

After implementing the care pathway, the mean length of hospital stay and admission charges were significantly lower (P < 0.01). The shorter length of stay was caused by a significant reduction (P < 0.05) in patient-related psychological/social delay after implementation. The number of laboratory tests and use of pharmacological agents were also significantly lower (P < 0.001) after implementation, with the decreases in these last variables significantly greater (P < 0.001) among junior physicians.

CONCLUSIONS

The advantages of the TURP clinical-care pathway were the shorter hospital stay, arising from reduced patient-related psychological or social delay, and reduced admission charges consequent on the decreased use of laboratory tests and drugs, particularly for patients treated by junior physicians. These results suggest that physicians are likely to modify their management methods to improve efficiency when a clinical path is implemented.

Measuring human chorionic gonadotropin in the absence of implantation with use of highly sensitive urinary assays for intact beta-core and free beta epitopes

OBJECTIVE

To determine if human chorionic gonadotropin (hCG) can be absorbed from the uterine cavity in the absence of an embryo.

DESIGN

Prospective study.

SETTING

University-based assisted reproduction program.

PATIENT(S)

Eight functionally agonadal patients (age range, 33-46 years) who were taking hormone replacement therapy so that they could receive donated oocytes.

INTERVENTION(S)

Intrauterine instillation of 50 microL of hCG (10,000 IU) during a mock cycle before an attempt at oocyte donation.

MAIN OUTCOME MEASURE(S)

Spot urine measurements of different hCG epitopes (intact beta, beta-core, and free beta) at timed intervals (12, 20, 44, and 68 hours after instillation).

RESULT(S)

All hCG epitopes were detected in the urine at the first sampling interval, and levels decreased in subsequent sampling intervals. Measurement of the serum hCG level confirmed that systemic absorption had occurred and that the urine measurements were not a result of specimen contamination through the cervix.

CONCLUSION(S)

hCG may be systemically absorbed into the blood through the uterine cavity, even in the absence of implantation, and its metabolites may be measured with use of highly sensitive urinary assays.

Cyclic GMP-dependent protein kinase inhibits osteopontin and thrombospondin production in rat aortic smooth muscle cells

Vascular lesions resulting from injury are characterized by a thickening of the intima brought about in part through the production of increased amounts of extracellular matrix proteins by the vascular smooth muscle cells (VSMCs). In this study, we tested the hypothesis that cGMP-dependent protein kinase (PKG), an important mediator of NO and cGMP signaling in VSMCs, inhibits the production of two extracellular matrix proteins, osteopontin and thrombospondin, which are involved in the formation of the neointima. VSMCs deficient in PKG were stably transfected with cDNAs encoding either the holoenzyme PKG-Ialpha or the constitutively active catalytic domain of PKG-I in order to directly examine the effects of PKG on osteopontin and thrombospondin production. Cells expressing either of the PKG constructs had dramatically reduced levels of osteopontin and thrombospondin-1 protein compared with control-transfected PKG-deficient cells. PKG transfection also altered the morphology of the VSMCs. These results indicate that PKG may be involved in suppressing extracellular matrix protein expression, which is one important characteristic of synthetic secretory VSMCs. Suppression of these matrix proteins may underlie the effects of NO-cGMP signaling to inhibit VSMC migration and phenotypic modulation.

Predictors of outcome in emphysematous pyelonephritis

PURPOSE

We identified and quantified prognostic factors for emphysematous pyelonephritis.

MATERIALS AND METHODS

The clinical information, laboratory data and radiological findings from 38 patients with emphysematous pyelonephritis were retrospectively analyzed.

RESULTS

There were no significant differences between the nonsurvivor and survivor groups with respect to age, gender, diabetes mellitus history, presence of bacteremia, identity of infecting organisms, blood glucose level, leukocyte count, urinary white blood count, presence or absence of urinary tract obstruction or urolithiasis, and modes of treatment. There were significant differences between the nonsurvivor and survivor groups, however, with respect to platelet count (84,300 +/- 119,500 versus 220,400 +/- 161,800/mm.3, p = 0.001), serum creatinine level (3.61 +/- 1.25 versus 2.19 +/- 1.32 mg./dl., p = 0.003) and urinary red blood counts (56.47 +/- 41.86 versus 27.65 +/- 36.14, p = 0.028). Patients with radiological type I emphysematous pyelonephritis were significantly more likely to die than those with type II (69 versus 18%, p = 0.002).

CONCLUSIONS

Serum creatinine level is the most reliable predictor of outcome in patients with emphysematous pyelonephritis. By calculating likelihood ratios, patients with creatinine levels greater than 1.4 mg./dl. and platelet counts 60,000/mm.3 or less were at high risk. The posttest probability of death increased from 69 and 18% to 92 and 53% for type I and II emphysematous pyelonephritis, respectively. Patients with creatinine levels 1.4 mg./dl. or less and platelet counts greater than 60,000/mm.3 were at much lower risk. Posttest mortality risk in these patients dropped from 69 and 18% to 27 and 4% for type I and II emphysematous pyelonephritis, respectively.

Delivery of recombinant gene product to canines with nonautologous microencapsulated cells

An alternative and potentially cost-effective approach to somatic gene therapy is to engineer a universal cell line secreting the desired product suitable for implantation into different patients without immune rejection. Encapsulating these cells in immunoprotective alginate microcapsules showed that this approach was effective in treating murine models of human diseases. We now report that this approach is also effective in delivering recombinant gene products to large animals. Canine MDCK cells encapsulated in alginate microcapsules were able to deliver recombinant human growth hormone to nonautologous dogs in vivo. However, the same microcapsules capable of prolonged delivery in mice soon disappeared after implantation in dogs. In contrast, when these microcapsules were modified by using a higher concentration of alginate cross-linked with barium instead of calcium, and by fabricating the alginate as a gelled bead without solubilizing the core, more prolonged and higher levels of recombinant product were obtained. Laminating the surface of the beads with poly-L-lysine and alginate provided an even more mechanically stable device that lasted for >2 months instead of <14 days in vivo and delivered >20 ng of human growth hormone/ml of plasma within the first week. The apparent disappearance of the growth hormone from the circulation after day 14 was due to rapid clearance by anti-human growth hormone antibodies and not due to loss of cell viability. However, all microcapsules provoked an inflammatory reaction, causing mild omentitis, and eventually disappeared from the intraperitoneal cavity. In conclusion, systemic delivery of recombinant gene products with nonautologous cells protected in alginate microcapsules has been shown to be feasible in canine recipients. While improved level and duration of delivery have been achieved by increasing the mechanical stability of the microcapsules, further improvements in biocompatibility and stability will be required for human application.

Gene therapy in pediatrics

There has been a rapid proliferation of gene therapy trials in humans in the last few years. Gene therapy in pediatric patients has included treatment of classical genetic diseases as well as cancer and AIDS. Despite hundreds of trials involving thousands of patients, to date no disease has been cured with gene therapy. Setbacks in these trials have led to the development of new vectors for gene transfer, more specific targeting of therapy and increased efforts to understand the pathophysiology of diseases.

Microcapsules as bio-organs for somatic gene therapy

Current human gene therapy relies on genetic modification of the patient's own cells. An alternate non-autologous approach is to use universal cell lines engineered to secrete therapeutic products. Protection with immuno-isolation devices would allow the same recombinant cell line to be used for different patients, thus potentially lowering the cost of treatment. The feasibility of this idea has now been demonstrated in vitro and in vivo. Recombinant gene products with potential therapeutic applications (human growth hormone, factor IX, lysosomal enzymes, adenosine deaminase) have been expressed from genetically modified cells after encapsulation with alginate-poly-L-lysine-alginate or hydroxyethyl methacrylate-methyl methacrylate. We have also demonstrated the feasibility of this idea in vivo. After intraperitoneal implantation, genetically modified mouse Ltk- fibroblasts or C2C12 myoblasts encapsulated in alginate-poly-L-lysine-alginate could deliver recombinant gene products (human growth hormone, human factor IX) to the systemic circulation of mice. The clinical efficacy of this novel approach to gene therapy has now been shown in murine models of human diseases. In the Snell dwarf mice deficient in growth hormone production, implantation of encapsulated mouse myoblasts engineered to secrete mouse growth hormone resulted in increases in body weight, length and organ sizes, some to > 25% above those of the controls. In the Gus/Gus mice suffering from the lysosomal storage disease mucopolysaccharidosis type VII due to deficient beta-glucuronidase, implantation of encapsulated mouse fibroblasts engineered to secrete mouse beta-glucuronidase resulted in delivery of normal levels of the enzyme in the plasma and significant correction of the organ histopathology. Hence, delivery of recombinant gene products through bioartificial devices appears to be a promising strategy for the treatment of genetic diseases.

Non-autologous transplantation with immuno-isolation in large animals--a review

Transplantation has become a successful method for the management of functional failure of a variety of tissues or organs. However, the majority of clinical transplantations use non-autologous allogeneic donor tissue implanted from one human to another. In order to prevent rejection of the allogeneic tissue, methods to overcome the immune barrier are necessary. Although prevention of organ rejection is currently achieved with pharmacological immune suppression, the undesirable side effects of this method have incited interest in novel methods to overcome the immune barrier. One such novel method of preventing immune reaction is immuno-isolation, in which the non-autologous tissues are physically isolated from the host tissues by placement in devices with perm-selective membranes. The membranes of these devices allow release of the therapeutic product required from the transplanted tissues, as well as diffusion of nutrients and waste necessary for survival of the non-autologous tissues. The membranes also prevent host immune mediators from contacting the non-autologous cells, thus preventing immune rejection. This technology has been tested for efficacy in large animal models, and is currently in the process of clinical trials in humans. This review will discuss the progress made in using immuno-isolation of non-autologous tissues in large animals. Immuno-isolation can be subdivided into two major areas of interest based on whether the non-autologous tissue used in the immuno-isolation device is genetically altered (gene therapy) or not. Studies using non-genetically altered non-autologous cells for immune-isolation have been dominated by the use of pancreatic islet cells for the treatment of diabetes. This work has been tested in large animal models of diabetes, including canine and primate model animals, and human clinical trials are underway. As well, there has also been work on treatment of neurological disorders such as Parkinson's disease or chronic pain using non-autologous immuno-isolated adrenal chromaffin cells or dopaminergic PC12 cells in large animals such as sheep and primates. This work will be reviewed in detail as to the types of disorders, immuno-isolation devices used and the type of large animals involved. Immune-isolation for gene therapy is a more recently developed field of research. In this case, the non-autologous cells used are first genetically altered to secrete a recombinant therapeutic product before placement in the immune-isolation devices. Genetic engineering of the non-autologous cells is beneficial, as it allows the use of a cell type that tolerates well the environment of the immune-isolation device, while still delivering the therapeutic product of interest. This form of gene therapy has been tested in our laboratory for delivery of marker products such as human growth hormone to canines. As several large animal models of human genetic disorders are available, such as canines affected with hemophilia or the lysosomal storage disease mucopolysaccharidosis, testing the efficacy of immuno-isolation for gene therapy in large animal models is an important prelude to human clinical trials. This review will discuss the topics outlined above, as well as some further considerations of the usefulness of large animal models in studying immune-isolation for non-autologous transplantation. Large animals may be more appropriate model organisms than rodents in which to study immune-isolation, as issues such as biocompatibility and immune response in a larger animal can be addressed. As well, large animal studies of immune isolation may provide data that are more relevant than rodent studies to the eventual application to human clinical trials.

Evolutionary origins of two tightly linked mutations in arylsulfatase-A pseudodeficiency

Deficient arylsulfatase A activity causes the neurodegenerative disease metachromatic leukodystrophy. However, some individuals with deficient enzyme activity appear clinically normal. This "pseudodeficiency" allele commonly found among many reported populations (frequency approximately 0.10) is associated with two A-->G transitions in cis in the arylsulfatase A gene causing the simultaneous loss of an N-glycosylation and a polyadenylation signal. To understand the evolutionary relationship between such common and tightly linked mutations, we studied 400 individuals in the African, European, Indian and East Asian populations and found none carrying the polyadenylation mutation alone. However, the N-glycosylation mutation could occur independently. Its frequency varied from 0.01 in Indians, 0.06 in Europeans, 0.21 in East Asians to 0.32 in Africans. The frequencies of both mutations occurring together ranged from almost non-existent in the Africans and East Asians, to 0.075 in the Europeans and 0.125 in the Indians. These frequencies were significantly different among populations. Haplotype analysis among homozygous pseudodeficiency individuals and eight multi-generation families with six polymorphic enzymes showed that, of the five haplotypes found in the general population, only one was linked to the double mutations. Alleles among the four populations with only the N-glycosylation mutation also supported linkage to the same haplotype except in some Europeans whose alleles were discordant. These results are consistent with the hypothesis that the N-glycosylation mutation may be a recurrent event among the Europeans but first occurred in an ancestral allele before the emergence of modern Homo sapiens from Africa at approximately 100,000-200,000 years ago. Subsequently, the polyadenylation mutation occurred in this ancient allele with the N-glycosylation mutation, an event that likely took place after the divergence between the European and East Asian lineages.

Phosphorylation of osteopontin by Golgi apparatus casein kinase

Osteopontin (OPN) is a ubiquitous multiphosphorylated secretory glycoprotein. Twenty-seven phosphorylated serines have been identified in bovine milk OPN (E. S. Sorensen et al. (1995) Protein Sci. 4, 2040-2049). Nineteen of these phosphoacceptor sites are fully conserved in rat OPN, all displaying the consensus for the Golgi apparatus casein kinase, G-CK (S-x-E/Sp). Here we show that rat OPN is indeed phosphorylated more readily than casein itself by G-CK from either rat mammary gland or liver. OPN is also phosphorylated by casein kinases-1 and -2 (CK1, CK2), though less readily than casein. If OPN kinase activities are normalized in terms of casein phosphorylation, OPN phosphorylation rate by G-CK is 78-fold and 19-fold higher than those measured with CK2 and CK1, respectively. These data, in conjunction with the specific location of G-CK to the Golgi apparatus, where CK2 and CK1 are hardly detectable, support the view that G-CK is the main if not the only physiological agent committed to the phosphorylation of OPN.