Utility and Costs During the Initial Year of 3D Printing in an Academic Hospital.

OBJECTIVE: There is a paucity of utility and cost data regarding the launch of 3D printing in a hospital. The objective of this project is to benchmark utility and costs for radiology-based in-hospital 3D printing of anatomic models in a single, adult academic hospital. METHODS: All consecutive patients for whom 3D printed anatomic models were requested during the first year of operation were included. All 3D printing activities were documented by the 3D printing faculty and referring specialists. For patients who underwent a procedure informed by 3D printing, clinical utility was determined by the specialist who requested the model. A new metric for utility termed Anatomic Model Utility Points with range 0 (lowest utility) to 500 (highest utility) was derived from the specialist answers to Likert statements. Costs expressed in United States dollars were tallied from all 3D printing human resources and overhead. Total costs, focused costs, and outsourced costs were estimated. The specialist estimated the procedure room time saved from the 3D printed model. The time saved was converted to dollars using hospital procedure room costs. RESULTS: The 78 patients referred for 3D printed anatomic models included 11 clinical indications. For the 68 patients who had a procedure, the anatomic model utility points had an overall mean (SD) of 312 (57) per patient (range, 200-450 points). The total operation cost was $213,450. The total cost, focused costs, and outsourced costs were $2,737, $2,180, and $2,467 per model, respectively. Estimated procedure time saved had a mean (SD) of 29.9 (12.1) min (range, 0-60 min). The hospital procedure room cost per minute was $97 (theoretical $2,900 per patient saved with model). DISCUSSION: Utility and cost benchmarks for anatomic models 3D printed in a hospital can inform health care budgets. Realizing pecuniary benefit from the procedure time saved requires future research.

Long noncoding RNA Hoxb3os is dysregulated in autosomal dominant polycystic kidney disease and regulates mTOR signaling.

Autosomal dominant polycystic kidney disease (ADPKD) is a debilitating disease that is characterized by the accumulation of numerous fluid-filled cysts in the kidney. ADPKD is primarily caused by mutations in two genes, PKD1 and PKD2 Long noncoding RNAs (lncRNA), defined by a length >200 nucleotides and absence of a long ORF, have recently emerged as epigenetic regulators of development and disease; however, their involvement in PKD has not been explored previously. Here, we performed deep RNA-Seq to identify lncRNAs that are dysregulated in two orthologous mouse models of ADPKD (kidney-specific Pkd1 and Pkd2 mutant mice). We identified a kidney-specific, evolutionarily conserved lncRNA called Hoxb3os that was down-regulated in cystic kidneys from Pkd1 and Pkd2 mutant mice. The human ortholog HOXB3-AS1 was down-regulated in cystic kidneys from ADPKD patients. Hoxb3os was highly expressed in renal tubules in adult WT mice, whereas its expression was lost in the cyst epithelium of mutant mice. To investigate the function of Hoxb3os, we utilized CRISPR/Cas9 to knock out its expression in mIMCD3 cells. Deletion of Hoxb3os resulted in increased phosphorylation of mTOR and its downstream targets, including p70 S6 kinase, ribosomal protein S6, and the translation repressor 4E-BP1. Consistent with activation of mTORC1 signaling, Hoxb3os mutant cells displayed increased mitochondrial respiration. The Hoxb3os mutant phenotype was partially rescued upon re-expression of Hoxb3os in knockout cells. These findings identify Hoxb3os as a novel lncRNA that is down-regulated in ADPKD and regulates mTOR signaling and mitochondrial respiration.

Transcription factor HNF1ß regulates expression of the calcium-sensing receptor in the thick ascending limb of the kidney.

Mutations in hepatocyte nuclear factor 1ß (HNF1ß) cause autosomal dominant tubulointerstitial kidney disease (ADTKD-HNF1ß), and patients tend to develop renal cysts, maturity-onset diabetes of the young (MODY), and suffer from electrolyte disturbances, including hypomagnesemia, hypokalemia, and hypocalciuria. Previous HNF1ß research focused on the renal distal convoluted tubule (DCT) to elucidate the ADTKD-HNF1ß electrolyte phenotype, although 70% of Mg2+ is reabsorbed in the thick ascending limb of Henle's loop (TAL). An important regulator of Mg2+ reabsorption in the TAL is the calcium-sensing receptor (CaSR). This study used several methods to elucidate the role of HNF1ß in electrolyte reabsorption in the TAL. HNF1ß ChIP-seq data revealed a conserved HNF1ß binding site in the second intron of the CaSR gene. Luciferase-promoter assays displayed a 5.8-fold increase in CaSR expression when HNF1ß was present. Expression of the HNF1ß p.Lys156Glu mutant, which prevents DNA binding, abolished CaSR expression. Hnf1ß knockdown in an immortalized mouse kidney TAL cell line (MKTAL) reduced expression of the CaSR and Cldn14 (claudin 14) by 56% and 48%, respectively, while Cldn10b expression was upregulated 5.0-fold. These results were confirmed in a kidney-specific HNF1ß knockout mouse, which exhibited downregulation of the Casr by 81%. Cldn19 and Cldn10b expression levels were also decreased by 37% and 83%, respectively, whereas Cldn3 was upregulated by 4.6-fold. In conclusion, HNF1ß is a transcriptional activator of the CaSR. Consequently, patients with HNF1ß mutations may have reduced CaSR activity in the kidney, which could explain cyst progression and hyperabsorption of Ca2+ and Mg2+ in the TAL resulting in hypocalciuria.

Hepatocyte Nuclear Factor-1ß Regulates Urinary Concentration and Response to Hypertonicity.

The transcription factor hepatocyte nuclear factor-1ß (HNF-1ß) is essential for normal kidney development and function. Inactivation of HNF-1ß in mouse kidney tubules leads to early-onset cyst formation and postnatal lethality. Here, we used Pkhd1/Cre mice to delete HNF-1ß specifically in renal collecting ducts (CDs). CD-specific HNF-1ß mutant mice survived long term and developed slowly progressive cystic kidney disease, renal fibrosis, and hydronephrosis. Compared with wild-type littermates, HNF-1ß mutant mice exhibited polyuria and polydipsia. Before the development of significant renal structural abnormalities, mutant mice exhibited low urine osmolality at baseline and after water restriction and administration of desmopressin. However, mutant and wild-type mice had similar plasma vasopressin and solute excretion levels. HNF-1ß mutant kidneys showed increased expression of aquaporin-2 mRNA but mislocalized expression of aquaporin-2 protein in the cytoplasm of CD cells. Mutant kidneys also had decreased expression of the UT-A urea transporter and collectrin, which is involved in apical membrane vesicle trafficking. Treatment of HNF-1ß mutant mIMCD3 cells with hypertonic NaCl inhibited the induction of osmoregulated genes, including Nr1h4, which encodes the transcription factor FXR that is required for maximal urinary concentration. Chromatin immunoprecipitation and sequencing experiments revealed HNF-1ß binding to the Nr1h4 promoter in wild-type kidneys, and immunoblot analysis revealed downregulated expression of FXR in HNF-1ß mutant kidneys. These findings reveal a novel role of HNF-1ß in osmoregulation and identify multiple mechanisms, whereby mutations of HNF-1ß produce defects in urinary concentration.