Sustained transgene expression in rat kidney with naked plasmid DNA and PCR-amplified DNA fragments.

Recently, we developed a kidney-targeted gene transfer technique, in which naked DNA was injected into the renal vein while the renal vein and artery were clamped. Kidney-targeted DNA transfer with only the renal vein clamped is an important modification that may permit less invasive catheter-based gene transfer in future clinical applications. The preparation of PCR-amplified DNA fragments is less time-consuming than that of naked plasmid DNA. We examined rat erythropoietin (Epo) plasmid, pCAGGS-Epo, or PCR-amplified DNA fragment, fCAGGS-Epo, transfer into the rat kidney with only the renal vein clamped. The Epo level peaked at week 3 and then was sustained for 24 weeks, which resulted in significant erythropoiesis. This modified technique, allowing long-term expression of both PCR-amplified DNA fragments and naked plasmid DNA, could potentially be used for catheter-based gene transfer in humans, and could help determine the physiological functions of putative genes.

Kidney-targeted naked DNA transfer by retrograde renal vein injection in rats.

Kidney-targeted gene transfer is expected to revolutionize the treatment of renal diseases. Previous gene transfer methods using nonviral vectors administered via renal arterial, pelvic, or ureteric routes into the glomerulus, tubules, or interstitial fibroblasts have resulted in low-level expression for <1 month. The peritubular capillaries (PTC) network is one of the main targets of kidney transplant rejection and of progressive tubulointerstitial fibrosis, which typifies all progressive renal diseases. To access the PTC, we retrogradely injected a lacZ expression plasmid in Ringer's solution into the renal vein of rats. We detected lacZ expression exclusively in the interstitial fibroblasts near the PTC of the injected kidney by immunoelectron microscopic analysis. Nephrotoxicity attributable to gene transfer was not apparent. We then used a rat erythropoietin (Epo) expression plasmid vector, pCAGGS-Epo, in a reporter assay. We obtained maximal Epo expression when the DNA solution was injected within 5 sec, and with a volume of 1.0 ml. We observed a dose-response relationship between serum Epo levels and the amount of injected DNA up to 100 microg. We detected the transgene-derived Epo mRNA by reverse transcription polymerase chain reaction only in the kidneys injected with pCAGGS-Epo. After an injection of 100 microg of pCAGGS-Epo, the serum Epo levels peaked at 208.3 +/- 71.8 mU/ml at week 5, and gradually decreased to 116.2 +/- 38.7 mU/ml at week 24. A similar pattern was obtained using smaller doses of plasmid, 2 microg or 30 microg of pCAGGS-Epo. Transgene-derived Epo secretion resulted in significant erythropoiesis. This novel technique is simple and safe, allowing high-level and long-term stable gene expression specific to the fibroblasts near the PTC, and should have therapeutic value for future applications in humans.

Rat liver-targeted naked plasmid DNA transfer by tail vein injection.

High levels of foreign gene expression in mouse hepatocytes can be achieved by "hydrodynamics-based transfection," the rapid injection of a large volume of a naked deoxyribonucleic acid (DNA) solution into the tail vein. Rats are more tolerant of the frequent phlebotomies required for monitoring blood parameters than mice and, thus, are more suitable for some biomedical research. Recently, we demonstrated that hydrodynamics-based transfection can also be used to deliver naked plasmid DNA into the normal rat, which is more than 10 times larger than the mouse. We performed the tail vein injection using a syringe with a winged needle equipped with an external tube. Injection of a lac Z expression plasmid, pCAGGS-lac Z by this technique resulted in the exclusive detection of beta-galactosidase in the liver. We also injected a rat erythropoietin (Epo) expression plasmid, pCAGGS-Epo (800 microg). Maximal Epo gene expression was achieved when a 25-mL injection volume (approx 100 mL/kg body wt) was transferred within 15 s.

Rat kidney-targeted naked plasmid DNA transfer by retrograde injection into the renal vein.

Kidney-targeted gene transfer is expected to revolutionize the treatment of renal diseases. Recently, we demonstrated that naked plasmid deoxyribonucleic acid (DNA) can be transferred into renal interstitial fibroblasts near the peritubular capillaries (PTCs) in normal rats, by retrograde injection into the renal vein with the renal vein and artery clamped. The PTC network is a main target of kidney transplant rejection and of progressive tubulointerstitial fibrosis, which typifies all progressive renal diseases. We retrogradely injected a lacZ expression plasmid in Ringer's solution into the renal vein of rats using a 24-gage catheter. We detected lacZ expression exclusively in the interstitial fibroblasts near the PTCs of the kidney by immunoelectron microscopy. Nephrotoxicity from the gene transfer was not apparent. We then used a rat erythropoietin (Epo) expression plasmid vector pCAGGS-Epo in a reporter assay. We obtained maximal Epo expression when the DNA solution was injected within 5 s in a volume of 1.0 mL. We detected transgene-derived Epo messenger ribonucleic acid by reverse transcriptase polymerase chain reaction only in the kidneys receiving pCAGGS-Epo. In this article, protocols for naked plasmid DNA transfer into rat kidney using this hydrodynamics-based transfection method and the immunoelectron microscopic technique to determine the lacZ gene transfer site are described in detail.

[Diagnosis and therapy for beta2-microglobulin amyloidosis in the K/DOQI guideline].

According to the Kidney disease outcomes quality initiative (K/DOQI) guideline, in order to decrease risk of beta2-microglobulin amyloidosis, noncuprophane (EVIDENCE), high-flux dialyzers (OPINION) should be used. No currently available therapy, except kidney transplantation, can stop disease progression of beta2-microglobulin amyloidosis or provide symptomatic relief (EVIDENCE). Screening for beta2-microglobulin amyloidosis, including measurement of serum levels of beta2-microglobulin, is not recommended (OPINION).

Effects of viral interleukin 10 introduced by in vivo electroporation on arthrogen-induced arthritis in mice.

OBJECTIVE: Viral interleukin 10 (vIL-10) has a variety of immunomodulatory properties. We examined the applicability of vIL-10 gene transfer to the treatment of mice with arthrogen-collagen-induced arthritis (CIA), which is induced by anti-type II collagen antibodies. METHODS: One day after anti-type II collagen antibodies were injected into mice, 400 microg of plasmid DNA expressing vIL-10 (pCAGGS-vIL-10) was injected into the bilateral tibialis anterior muscles followed by in vivo electroporation consisting of four 50-ms electric pulses of 100 V (pCAGGS-vIL-10 mice). pCAGGS (400 microg) was similarly injected into control mice (pCAGGS mice). RESULTS: We observed high serum vIL-10 levels in the pCAGGS-vIL-10 mice, but no vIL-10 was detected in the serum of the pCAGGS mice. Using quantitative real-time polymerase chain reaction, we observed that the ratios of IL-6, tumor necrosis factor-a, and IL-1beta transcripts to those of G6PDH in the joints were significantly lower in the pCAGGS-vIL-10 mice than in the pCAGGS mice (p < 0.05). The pCAGGS-vIL-10 mice showed significant therapeutic effects: the severity of the macroscopic arthritis was significantly suppressed from Days 5 to 21 (p < 0.0001), and the histologically observable development of arthritis was also suppressed in these mice on Day 21 (p < 0.0001). CONCLUSION: These results demonstrated that pCAGGS-vIL-10 gene transfer by in vivo electroporation suppressed arthrogen-CIA.

A novel type of encephalopathy associated with mushroom Sugihiratake ingestion in patients with chronic kidney diseases.

BACKGROUND: The etiology of encephalopathy in uremic patients is multiple. We recently encountered a novel type of encephalopathy which occurred exclusively in patients with chronic kidney diseases after ingestion of a mushroom called Sugihiratake. While the exact etiology of this encephalopathy remained mysterious, we aimed to describe its clinical features. METHODS: A total of 32 patients with chronic kidney diseases who had presented with encephalopathy following ingestion of Sugihiratake were enrolled from seven prefectures in Japan., with 24 of the 32 patients undergoing regular hemodialysis. The patient's clinical data were from surveillance by The Japanese Society of Nephrology. RESULTS: There was a significant association between Sugihiratake ingestion and the occurrence of encephalopathy in 524 hemodialysis patients questioned for a recent ingestion of this mushroom (P= 0.0006). The latent asymptomatic period before the onset of symptoms varied from 1 to 31 days (mean 9.1 +/- 7.3) days. The patient's symptoms consisted of disturbed consciousness in 30 patients (93.8%), convulsions in 25 (78.1%), myoclonus in 15 (46.9%), dysarthria in ten (31.3%), ataxia in eight (25.0%), paresis or paralysis in seven (21.9%), and skin parasthesia in two patients (6.3%). Nine (27.2%) patients died, mostly due to respiratory failure. The other patients were either discharged or still in hospitals with various degrees of clinical improvement. CONCLUSION: Patients with chronic kidney diseases are at risk of having serious encephalopathy following Sugihiratake ingestion and must refrain from eating it. Physicians, in those parts of the world, where this mushroom harvesting is common, should be aware of this complication.

Pretreatment plasma intact parathyroid hormone and serum calcium levels, but not serum phosphate levels, predict the response to maxacalcitol therapy in dialysis patients with secondary hyperparathyroidism.

BACKGROUND: The treatment strategy for secondary hyperparathyroidism is generally determined empirically with regards to present parathyroid function and serum calcium (Ca) and inorganic phosphate (Pi) levels. More evidence is needed to avoid the aimless continuation of active vitamin D therapy. METHODS: Nondiabetic dialysis patients whose plasma intact parathyroid hormone (iPTH) levels were greater than 300 pg/ml were included in the study. Maxacalcitol was intravenously injected three times a week. The treatment was continued for 48 weeks, unless the iPTH level was reduced to less than 300 pg/ml or unfavorable events occurred. The patients whose plasma iPTH levels were below 300 pg/ml within 48 weeks were defined as those who had been successfully treated. RESULTS: Findings for 146 patients were analyzed, and 96 patients were successfully treated. Serum Pi levels did not significantly increase during the therapy. The pretreatment plasma iPTH levels and serum Ca levels were lower in the patients who were successfully treated with maxacalcitol. A logistic regression study and classifying by stratum analyses revealed that the pretreatment serum Ca levels and plasma iPTH levels were significantly related to the result of maxacalcitol therapy, while the serum Pi levels were not. Analyses using a receiver-operating characteristic curve revealed that the areas under curves obtained for iPTH and Ca were significantly greater than those obtained for Pi (P < 0.0001). CONCLUSIONS: Serum Ca levels and parathyroid function were correlated with the results of maxacalcitol therapy. Pretreatment serum Pi levels could not predict the result.

Intact PTH assay overestimates true 1-84 PTH levels after maxacalcitol therapy in dialysis patients with secondary hyperparathyroidism.

BACKGROUND: Although the so-called intact parathyroid hormone (iPTH) assay detects not only true 1-84 PTH (1-84PTH) but also large C-terminal PTH fragments, it remains inconclusive whether the 1-84PTH assay is more useful in clinical practice. Previous studies have shown that the results of these two PTH assays in dialysis patients are closely correlated. METHODS: Chronic dialysis patients whose plasma iPTH levels were >400 pg/ml were selected for inclusion in the present study. Following a 4 week wash-out time during which all vitamin D administration was halted, maxacalcitol was intravenously injected at the end of dialysis sessions three times per week for 24 weeks, at an initial dosage of 10 micro g. RESULTS: Ninety-seven patients with secondary hyperparathyroidism were included in our analysis. Their serum calcium levels were elevated from the start levels while phosphate levels remained unchanged. The plasma 1-84PTH levels constantly declined throughout the 24 weeks. Although the patients' plasma 1-84PTH and iPTH levels were closely correlated with each other both at the beginning of the study and after 24 weeks of maxacalcitol therapy, the ratio of 1-84PTH/iPTH consistently decreased throughout the study period (P<0.01). The changes in the ratio were significantly correlated with changes in serum calcium levels. CONCLUSIONS: Twenty-four weeks of intravenous maxacalcitol injection therapy significantly reduced the 1-84PTH/iPTH ratio. Estimated 1-84PTH levels from iPTH levels using a conversion formula obtained before the treatment were 21.0+/-20.4% higher than measured 1-84PTH levels after the therapy. Thus, iPTH measurement has a potential risk to overestimate 1-84PTH levels when evaluating the efficacy of maxacalcitol therapy in dialysis patients with secondary hyperparathyroidism.