Artificial Bladder: Filling the Void Alexander Kutikov, MD (talk prepared in 2002, reviewed in 2011) Alexander Kutikov, MD (talk prepared in 2002, reviewed in 2011)

Bladder Regeneration: Overview Introduction Use of GI Segments Approaches to Bladder Replacement Alloplastic Bladders Tissue Engineered Bladders In-Situ Regenerated In-Vitro Regenerated Summary Introduction Use of GI Segments Approaches to Bladder Replacement Alloplastic Bladders Tissue Engineered Bladders In-Situ Regenerated In-Vitro Regenerated Summary

Introduction: Bladder Disease 400 Million Suffer from Bladder Dz  Cancer  Trauma  Infection  Inflammation  Iatrogenic Injuries  Congenital Anomalies Many Require Bladder Replacement 400 Million Suffer from Bladder Dz  Cancer  Trauma  Infection  Inflammation  Iatrogenic Injuries  Congenital Anomalies Many Require Bladder Replacement

Current Treatment Bladder replacement w/ GI segments > 100 year-old method Remains the standard of care Bladder replacement w/ GI segments > 100 year-old method Remains the standard of care

Problems w/ Using Bowel GI Tissue - Designed to Absorb Solutes GU Tissue - Designed to Excrete Solutes GI Tissue - Designed to Absorb Solutes GU Tissue - Designed to Excrete Solutes = =

Compliations of GI Neo- Bladders Altered Electrolyte Metabolism Altered Hepatic Metabolism Abnormal Drug Metabolism Infection Calculus Formation Nutritional Disturbances Growth Retardation Osteomalacia Cancer Altered Electrolyte Metabolism Altered Hepatic Metabolism Abnormal Drug Metabolism Infection Calculus Formation Nutritional Disturbances Growth Retardation Osteomalacia Cancer

Ideal Bladder Substitute Adequate Urine Storage Complete Evacuation of Urine (volitional) Preserve Renal Function Biocompatible Resistant to Urinary Encrustation Resistant to Bacterial Infection Adequate Urine Storage Complete Evacuation of Urine (volitional) Preserve Renal Function Biocompatible Resistant to Urinary Encrustation Resistant to Bacterial Infection Must be superior to GI segments

Approaches to Bladder Substitution Alloplastic Bladders Tissue Engineered Bladders In-Situ Regenerated In-Vitro Generated Alloplastic Bladders Tissue Engineered Bladders In-Situ Regenerated In-Vitro Generated

Alloplastic Organs

Alloplastic Bladder First prosthetic bladder reported in 1960 Box-shaped silicone reservoir attached to anterior abdominal wall Silicone tube brought out onto the skin served as outlet Hydronephrosis due to ureteral prosthetic anastomosis main reason for failure No dog survived more than 1 month First prosthetic bladder reported in 1960 Box-shaped silicone reservoir attached to anterior abdominal wall Silicone tube brought out onto the skin served as outlet Hydronephrosis due to ureteral prosthetic anastomosis main reason for failure No dog survived more than 1 month

Alloplastic Bladder: Mayo Clinic Model Rigid polysulfone shell Distensible silicone shell 8 Fr silicone tubes in ureters Fluid Implanted intraperitoneally No dog survived > 10 wks

Infections w/ abscess formation * Urinary leaks at anastomoses * Mechanical failure of device* Urinary encrustation Formation of constrictive capsule RF 2 o to Hydronephrosis Infections w/ abscess formation * Urinary leaks at anastomoses * Mechanical failure of device* Urinary encrustation Formation of constrictive capsule RF 2 o to Hydronephrosis Alloplastic Bladder: Reasons for Failure * - Applies to Mayo Clinic Model

Alloplastic Bladder: Aachen Model Subcutaneous compressible reservoirs Dacron-covered silicone tubes through renal parenchyma Y-shaped Dacron-reinforced silicone reservoir drains into urethra 7 years to develop

Alloplastic Bladder: Aachen Model Implanted into 5 sheep Functioned effectively in 2 sheep for 18 mo Urinary leakage in 3 animals due to anastamotic or material failure Kidney structure and function preserved in all cases No further publications on use of Aachen Model since 1996 Implanted into 5 sheep Functioned effectively in 2 sheep for 18 mo Urinary leakage in 3 animals due to anastamotic or material failure Kidney structure and function preserved in all cases No further publications on use of Aachen Model since 1996

Alloplastic Bladder: Lessons Learned Minimize anastomoses btwn living tissue and alloplasts  Transrenal-parenchymal insertion of urteral prosthesis offers hope Infection is a major hurdle to overcome  Antibiotic-coated solid materials under investigation Minimize anastomoses btwn living tissue and alloplasts  Transrenal-parenchymal insertion of urteral prosthesis offers hope Infection is a major hurdle to overcome  Antibiotic-coated solid materials under investigation TISSUE ENGINEERING: potential solution to both problems

Use of living cells to restore, maintain, or enhance tissues or organs Use of living cells to restore, maintain, or enhance tissues or organs Tissue Engineering: Definition

Tissue Engineering: Principles 1. Implantation of freshly isolated or cultured cells 2. In Situ tissue regeneration 3. Implantation of tissues assembled in vitro from cells and scaffolds 1. Implantation of freshly isolated or cultured cells 2. In Situ tissue regeneration 3. Implantation of tissues assembled in vitro from cells and scaffolds Strategies for Treatment of Diseased/Injured Tissue: Strategies for Treatment of Diseased/Injured Tissue:

Tissue Engineering: Principles 1. Implantation of freshly isolated or cultured cells 2. In Situ tissue regeneration 3. Implantation of tissues assembled in vitro from cells and scaffolds 1. Implantation of freshly isolated or cultured cells 2. In Situ tissue regeneration 3. Implantation of tissues assembled in vitro from cells and scaffolds Strategies for Treatment of Diseased/Injured Tissue: Strategies for Treatment of Diseased/Injured Tissue:

Tissue Engineering: In Situ Regeneration

Numerous Materials Have been Tried as Matrices Most Successful: Small bowel submucosa Acellular submucola of porcine small bowel Bladder Acellular Matrix Grafts (BAMG) Acellular collagen and elastin produced by stripping stromal and epithelial cells from bladder wall Numerous Materials Have been Tried as Matrices Most Successful: Small bowel submucosa Acellular submucola of porcine small bowel Bladder Acellular Matrix Grafts (BAMG) Acellular collagen and elastin produced by stripping stromal and epithelial cells from bladder wall

Tissue Engineering: In Situ Regeneration 7 mo post Distended Normal Bladder S/p hemicystectomy of dome BAMG grafted bladder

Tissue Engineering: In Situ Regeneration B/f SurgeryS/p Surgery7 mo s/p Surgery

Tissue Engineering: In Situ Regeneration Histology a/f 4 months

Tissue Engineering: In Situ Regeneration Bladder wall structurally and functionally nearly identical to native bladder No significant rejection of graft seen Bladder wall structurally and functionally nearly identical to native bladder No significant rejection of graft seen Similar results obtained with SIS and BAMG grafts Human trials with BAMG and SIS being attempted

Tissue Engineering: Principles 1. Implantation of freshly isolated or cultured cells 2. In Situ tissue regeneration 3. Implantation of tissues assembled in vitro 1. Implantation of freshly isolated or cultured cells 2. In Situ tissue regeneration 3. Implantation of tissues assembled in vitro Strategies for Treatment of Diseased/Injured Tissue: Strategies for Treatment of Diseased/Injured Tissue:

Tissue Engineering: In Vitro Assembly

SMOOTH MUSCLE UROTHELIUM

Tissue Engineering: In Vitro Assembly Potential for genetic/phenotypic screeing of harvested cells allows selection against transformed phenotypes Potential for genetic/phenotypic screeing of harvested cells allows selection against transformed phenotypes

Tissue Engineering: In Vitro Assembly Potential for genetic/phenotypic screening of harvested cells allows selection against transformed phenotypes Cells could also be genetically modified to acquire desired properties (e.g. antimicrobial, growth factors, etc.) Potential for genetic/phenotypic screening of harvested cells allows selection against transformed phenotypes Cells could also be genetically modified to acquire desired properties (e.g. antimicrobial, growth factors, etc.)

Tissue Engineering: In Vitro Assembly Bx to implant of graft = 5 weeks

Tissue Engineering: In Vitro Assembly

Native bladder wall Native bladder wall Tissue-engineered Neo-bladder Tissue-engineered Neo-bladder

Tissue Engineering: In Vitro Assembly Function of Tissue Engineered Neo-Bladder: Mean bladder capacity was 95% of precystecomy volume Mean compliance was no different than preoperative values Function of Tissue Engineered Neo-Bladder: Mean bladder capacity was 95% of precystecomy volume Mean compliance was no different than preoperative values

Summary GI Segments: employed as neobladders >100 years; it’s time for change. Alloplastic Neobladders: little hope w/ current materials. Tissue Engineering: hold much hope, but remains experimental. Human studies humbling to date. GI Segments: employed as neobladders >100 years; it’s time for change. Alloplastic Neobladders: little hope w/ current materials. Tissue Engineering: hold much hope, but remains experimental. Human studies humbling to date.