ENDOSCOPIC SUBURETERAL GLUTARALDEHYDE CROSS-LINKED COLLAGEN INJECTION FOR THE TREATMENT OF SECONDARY VESICOURETERAL REFLUX: COMPARISON WITH PRIMARY VESICOURETERAL REFLUX IN ADULTS

Vesicoureteral Reflux, a Scarred kidney, and Minimal Proteinuria: An Unusual Cause of Adult Secondary Hypertension

Hypertension affects about 65 million individuals in the United States. In adult patients, primary aldosteronism and renovascular causes are described as most prevalent. Vesicoureteral reflux as a cause of hypertension, while commonly described in pediatric populations, is less prevalent in the adult population especially in the absence of proteinuria. We present the case of a 31-year-old female presenting with early onset hypertension. Workup for renovascular hypertension was unrevealing. She was found to have right-sided vesicoureteral reflux with a unilateral scarred kidney. Patient underwent a nephrectomy with marked improvement in blood pressure control.

Injectable biomaterials for incontinence and vesico-ureteral reflux: current status and future promise

Many injectable biomaterials have been produced as bulking agents for compression of urethral sphincter or ureteral orifice for treating adult stress incontinence or vesico-ureteral reflux in pediatrics. The agents being developed include glutaraldehyde crosslinked collagen, dextranomer/hyaluronic acid copolymer, pyrolytic carbon-coated zirconium oxide beads, polydimethyl-siloxane microparticles, polytetrafluoroethylene paste, autologous fats, autologous chondrocytes, and others. Though less invasive nature of these agents has gained their popularity as a quick solution of the disease symptoms, most of such treatments fail to produce good long-term efficacy. The failure is likely caused by the rapid degradation of material implants and the lack of tissue regeneration/integration properties. We thus believe that a good injectable biomaterial for incontinence should possess the following two properties: (1) to resist degradation and to reside in the implantation sites for a long period of time or (2) to enhance tissue regeneration and to establish permanent periurethral or subureteric tissue. Here we report some recent results for supporting this hypothesis.

The effect of microsphere degradation rate on the efficacy of polymeric microspheres as bulking agents: An 18-month follow-up study

The injection of bulking substances has been proposed as a new therapy to treat urinary incontinence and vesicoureteral reflux. Our previous study demonstrated that poly(lactic-co-glycolic acid) (PLGA) microspheres have the potential to serve as a bulking agent for urological injection therapies. Hybrid tissues exhibiting a bulking effect were formed in vivo by PLGA microsphere injection, but long-term volume stability was not proven. In this study, we hypothesized that the biodegradation rate of the bulking substance (polymer microspheres) would affect the duration of volume conservation of the induced hybrid tissue. To test this hypothesis, rapidly degrading 75:25 PLGA microspheres and slowly degrading poly(L-lactic acid) (PLLA) microspheres were used as injectable bulking agents for the injection therapy. In vitro degradation tests showed that the mass losses of PLLA and PLGA were 16 and 96% of the initial masses, respectively, at 30 weeks. PLLA and PLGA microspheres were injected into the subcutaneous dorsum of mice. Both types of microspheres were easily injectable through 24-gauge needles. Histological examinations at various time points indicated that host cells from the surrounding tissues migrated to the spaces between both types of injected microspheres and formed new hybrid tissue structures. Lymphocyte migration was noted around the implanted PLGA and PLLA microspheres, but the inflammatory reaction diminished with time. Importantly, the volume of the PLLA hybrid tissues slowly decreased to 52% of the initial volume at 12 months and maintained that volume until 18 months, whereas the volume of the PLGA hybrid tissues rapidly decreased to 22% at 6 months, and the PLGA hybrid tissues disappeared at 11 months. These results show that the biodegradation rate of the bulking substance may be useful for controlling the duration of volume conservation of the induced hybrid tissue.

Submucosal injection of poly(lactic-co-glycolic acid) microspheres in rabbit bladder as a potential treatment for urinary incontinence and vesicoureteral reflux: preliminary results

Endoscopic injection of bulking agents has been gaining attention as a therapy for urinary incontinence and vesicoureteral reflux because this therapy is simpler, less operation time-consuming and less painful than traditional surgical operations. The ideal bulking agent for the injection therapies must be easily injectable, biocompatible, volume-stable, non-antigenic and non-migratory. We evaluated poly(lactic-co-glycolic acid) (PLGA) microspheres as an injectable bulking agent for urologic injection therapies. To determine whether PLGA microspheres meet the requirements of an ideal bulking agent, PLGA microspheres were injected into the submucosal sites of a rabbit bladder wall. The microspheres were easily injectable. Two and five weeks post-implantation, histological examinations indicated that host cells from the surrounding bladder tissues migrated to the space between the injected microspheres and formed new hybrid tissue structures. Lymphocyte migration was noted around the implanted microspheres, but the inflammatory reaction diminished at 5 weeks. The hybrid tissue volume did not significantly decrease over time. There was no evidence of microsphere migration to the distant organs. Although long-term studies are needed to evaluate the therapeutic potential of this method, these preliminary results suggest the possibility of PLGA microspheres as a potentially useful injection material for urinary injection therapies.

Vesicoureteral reflux – current treatment options

Vesicoureteral reflux has long been recognised as a major child and public health problem. Widespread recognition and screening of at-risk populations has the potential to significantly reduce long-term morbidity in both children and adults. Advances in pharmacotherapy, materials science and surgery, have caused many experts to reassess established dictums of treatment. Concern regarding the overuse of antibiotics and surgery has led to efforts to tailor therapy more narrowly for those who are at the highest risk from recurrent urinary tract infection and pyelonephritis. Children after a certain age, without underlying voiding dysfunction, might not require treatment at all. Newer surgical and anaesthetic techniques have the potential of transforming surgical correction from a painful experience to an ambulatory procedure, with a rapid return to daily activities. Both the promise and pitfalls of these newest advances will be discussed in this review.

Poly(lactic-co-glycolic acid) microspheres as a potential bulking agent for urological injection therapy: Preliminary results

Injection of bulking substances has been introduced as a new therapy to treat urinary incontinence and vesicoureteral reflux. Currently available bulking substances for the injection therapies include liquid or particulated silicone, collagen gel, and polytetrafluoroethylene paste. However, these materials have shown shortcomings such as inflammation, rapid volume decrease, and particle migration to distant organs. In the present study, we evaluated poly(lactic-co-glycolic acid) (PLGA) microspheres as a potential injectable bulking agent for the injection therapies. PLGA microspheres (52 microm in average diameter) were injectable through various gauges of needles, as the injected microspheres showed no tendency to obstruct the needles and microsphere size exclusion was not observed upon injection through the needles. After injection of PLGA microspheres into the subcutaneous dorsum of mice, inflammation, new tissue volume change, and microsphere migration were examined. Host cells from the surrounding tissues migrated to the implanted microspheres and formed new hybrid tissue structures. The volume of the newly generated tissues was maintained approximately constant for 7 weeks. Histological analyses showed no evidence of migration of the implanted microspheres to the distant organs. In summary, PLGA microspheres were injectable and able to induce a new hybrid tissue formation without initial volume decrease or particle migration. These preliminary results suggest that this material may be a potentially useful bulking agent for urological injection therapies.