Topical Management of Peristomal Pyoderma Gangrenosum: A Report of 3 Case Studies.

BACKGROUND: Peristomal pyoderma gangrenosum (PPG) presents multiple challenges for healthcare providers. The diagnosis of PPG may be delayed, and it may be mistaken for an irritant dermatitis or an infection. Patients with ostomies secondary to inflammatory bowel disease (IBD) may experience PPG. Issues related to PPG include difficulty maintaining a seal of the ostomy pouching system and preventing contamination of the painful, necrotic ulcerations characteristic of this condition. Treatment focuses on the appropriate assessment of the ulcers, successful pouch application, and proper management of IBD through a collaborative effort of both dermatologists and certified WOC nurses (CWOCN). CASES: We treated 3 patients diagnosed with Crohn's disease (CD) who developed refractory PPG. All 3 were treated with a topical steroid lotion, prednisone, and adalimumab or a combination of these agents. Ostomy products and application were tailored to prevent leakage and protect areas of ulceration. All ulcers were healed within 6 months of our initial consultation. CONCLUSION: We successfully managed 3 patients with CD and PPG with appropriate ostomy care, including revision of the ostomy pouching techniques, topical steroid treatment, and treatment based on assessment of ulcer status by the dermatologist and the WOC nurse.

A novel evaluation method for determining drug-induced hepatotoxicity using 3D bio-printed human liver tissue.

Predicting drug-induced liver injury is important in early stage drug discovery; however, an accurate prediction with existing hepatotoxicity evaluation tools is difficult. Conventional monolayer (2D) cultures have short viabilities and are therefore inappropriate for performing long-term toxicity tests. Conventionally used 200-µm spheroids also have toxicity detection limits. The goal of this study was to develop a humanized liver tissue capable of evaluating long-term toxicity with high sensitivity. Spheroids consisting of co-cultured cryopreserved primary human hepatocytes and human hepatic stellate cells were developed using a 3D bio-printer. The "3D bio-printed liver tissue", of ∼1 mm, was then used for long-term viability assessments (over 25 days) based on ATP, albumin, and urea levels. Hepatotoxicity evaluation was performed by analyzing the expression of genes involved in drug metabolism and transport over a 2-week drug exposure period. The 3D bio-printed liver tissue showed improved viability and enhanced gene expression of enzymes related to drug metabolism and transport, as compared to the controls. Additionally, the 3D bio-printed liver tissue demonstrated a high sensitivity for hepatotoxicity evaluation when combined with pathological evaluation and measurements for ATP production, and secretion of albumin and urea. In conclusion, the 3D bio-printed liver tissue was able to detect the toxicity of compounds that was, otherwise, undetected by 2D culture and conventionally used spheroids. These findings demonstrate a 3D bio-printed liver tissue with increased accuracy of hepatotoxicity prediction in the early stages of drug discovery, as compared to currently available methods.

Scaffold-free 3D bio-printed human liver tissue stably maintains metabolic functions useful for drug discovery.

The liver plays a central role in metabolism. Although many studies have described in vitro liver models for drug discovery, to date, no model has been described that can stably maintain liver function. Here, we used a unique, scaffold-free 3D bio-printing technology to construct a small portion of liver tissue that could stably maintain drug, glucose, and lipid metabolism, in addition to bile acid secretion. This bio-printed normal human liver tissue maintained expression of several kinds of hepatic drug transporters and metabolic enzymes that functioned for several weeks. The bio-printed liver tissue displayed glucose production via cAMP/protein kinase A signaling, which could be suppressed with insulin. Bile acid secretion was also observed from the printed liver tissue, and it accumulated in the culture medium over time. We observed both bile duct and sinusoid-like structures in the bio-printed liver tissue, which suggested that bile acid secretion occurred via a sinusoid-hepatocyte-bile duct route. These results demonstrated that our bio-printed liver tissue was unique, because it exerted diverse liver metabolic functions for several weeks. In future, we expect our bio-printed liver tissue to be applied to developing new models that can be used to improve preclinical predictions of long-term toxicity in humans, generate novel targets for metabolic liver disease, and evaluate biliary excretion in drug development.