No abstract

In this study, the two determinants of the rate of osteoclastic bone resorption, cell number and cell activity, were evaluated to characterize the response to two chronic resorptive stimuli, a calcium-deficient diet and a phosphorus-deficient diet, fed to rats for 8 days. The number of osteoclast nuclei was determined directly and the resorptive activity of osteoclasts indirectly from cell size. In our sampling site in the tibial diaphysis, there were marked increases in osteoclast layer width (i.e., cell size) and in the number of osteoclasts and osteoclast nuclei in both test groups. Also, in both test groups the increase in the number of osteoclast nuclei was greater than the increase in osteoclast width, emphasizing the importance of osteoclast stem cell activity in the resorptive response. When the data on the control and test animals were pooled, there was a strong correlation between the width of the osteoclast layer and the number of osteoclast nuclei (r = 0.87, P less than 0.001). Thus, these two resoprtive stimuli produced proportional changes in osteoclast cell number and probably activity, raising the possibility that the resorptive response is sterotyped. These results also suggest the existence of a control mechanism which coupled the proliferative activity of osteoclast stem cells and the resorptive activity of osteoclasts. Despite the fact that the rats were subjected to chronic resorptive stimuli, forming surface and the total number of osteoblasts were also increased. Moreover, in data pooled from control and test rats, there was a strong correlation between the number of osteoclast nuclei and the number of osteoblasts (r = 0.92, P less than 0.001). This implies that chronic resorptive stimuli directly or indirectly stimulate osteogenic stem cells to increase production of osteoblasts as well as osteoclasts. The observed coupling of differentiated cell number probably contributes to the established phenomenon of coupling between the rates of bone accretion and resorption.

Background. Flavin mononucleotide (FMN), released from damaged mitochondrial complex I during hypothermic liver perfusion, has been shown to be predictive of 90-day graft loss. Normothermic machine perfusion (NMP) and normothermic regional perfusion (NRP) are used for organ reconditioning and quality assessment before transplantation. This pilot study aimed to investigate the changes of FMN levels during normothermic reperfusion of kidneys, livers, and lungs and examine whether FMN could serve as a biomarker to predict posttransplant allograft quality. Methods. FMN concentrations, in perfusates collected during NMP of kidneys, abdominal NRP, and ex vivo lung perfusion, were measured using fluorescence spectrometry and correlated to the available perfusion parameters and clinical outcomes. Results. Among 7 transplanted kidneys out of the 11 kidneys that underwent NMP, FMN levels at 60 minutes of NMP were significantly higher in the allografts that developed delayed graft function and primary nonfunction (P = 0.02). Fifteen livers from 23 circulatory death donors that underwent NRP were deemed suitable for transplantation. Their FMN levels at 30 minutes of NRP were significantly lower than those not procured for transplantation (P = 0.004). In contrast, little FMN was released during the 8 lung perfusions. Conclusions. This proof of concept study suggested that FMN in the perfusates of kidney NMP has the potential to predict posttransplant renal function, whereas FMN at 30 minutes of NRP predicts whether a liver would be accepted for transplantation. More work is required to validate the role of FMN as a putative biomarker to facilitate safe and reliable decision-making before embarking on transplantation.

Early removal of ureteric stents following kidney transplantation may reduce the incidence of UTI while it uncertain if there is a higher risk of MUC. BI stents are the optimum method for achieving this benefit.

Ex vivo normothermic perfusion (EVNP) technology is a promising means of organ preservation, assessment, and preconditioning prior to kidney transplantation, which has been pioneered by a single group. We describe the challenges of setting up clinical EVNP programs in 2 new centers, as well as early patient outcomes. Governance, training, and logistical pathways are described. In order to demonstrate safety and proficiency in this new technique, early patient outcomes are also described. Patient outcomes included the incidence of primary nonfunction, delayed graft function, graft and patient survival at 1 year. Contralateral kidneys undergoing static cold storage alone were used as a comparator group. Between March 2016 and July 2017, EVNP was performed on 14 kidneys from 12 donors (11 kidneys in center 1, 3 kidneys in center 2). Of the 14 kidneys that underwent EVNP, 12 organs were implanted into 10 recipients. Two pairs of kidneys were implanted as dual grafts and 1 kidney was implanted simultaneously with a pancreas. The remaining 7 kidneys were transplanted as single allografts. Seven pairs of kidneys were available for paired analysis comparing EVNP versus static cold storage. Graft and patient outcomes were comparable between the 2 preservation techniques. The introduction of a clinical EVNP service requires a careful multimodal approach, drawing on the expertise of specialists in transplantation, hematology, and microbiology. Both new clinical EVNP programs demonstrated proficiency and safety when a structured dissemination process was followed.

Background Ileus is common after elective colorectal surgery, and is associated with increased adverse events and prolonged hospital stay. The aim was to assess the role of non‐steroidal anti‐inflammatory drugs (NSAIDs) for reducing ileus after surgery. Methods A prospective multicentre cohort study was delivered by an international, student‐ and trainee‐led collaborative group. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The primary outcome was time to gastrointestinal recovery, measured using a composite measure of bowel function and tolerance to oral intake. The impact of NSAIDs was explored using Cox regression analyses, including the results of a centre‐specific survey of compliance to enhanced recovery principles. Secondary safety outcomes included anastomotic leak rate and acute kidney injury. Results A total of 4164 patients were included, with a median age of 68 (i.q.r. 57–75) years (54·9 per cent men). Some 1153 (27·7 per cent) received NSAIDs on postoperative days 1–3, of whom 1061 (92·0 per cent) received non‐selective cyclo‐oxygenase inhibitors. After adjustment for baseline differences, the mean time to gastrointestinal recovery did not differ significantly between patients who received NSAIDs and those who did not (4·6 versus 4·8 days; hazard ratio 1·04, 95 per cent c.i. 0·96 to 1·12; P = 0·360). There were no significant differences in anastomotic leak rate (5·4 versus 4·6 per cent; P = 0·349) or acute kidney injury (14·3 versus 13·8 per cent; P = 0·666) between the groups. Significantly fewer patients receiving NSAIDs required strong opioid analgesia (35·3 versus 56·7 per cent; P < 0·001). Conclusion NSAIDs did not reduce the time for gastrointestinal recovery after colorectal surgery, but they were safe and associated with reduced postoperative opioid requirement.

Background There remains a lack of consensus on the optimal storage method for deceased donor kidneys. This meta‐analysis compares storage with hypothermic machine perfusion (HMP) vs traditional static cold storage (SCS). Methods The Cochrane Kidney and Transplant Specialised Register was searched to identify (quasi‐) randomized controlled trials (RCTs) to include in our meta‐analysis. PRISMA guidelines were used to perform and write this review. Results There is high‐certainty evidence that HMP reduces the risk of delayed graft function (DGF) when compared to SCS (2138 participants from 14 studies, RR = 0.77; 0.67‐0.90, P = .0006). This benefit is significant in both donation following circulatory death (DCD; 772 patients from seven studies, RR = 0.75; 0.64‐0.87, P = .0002) and donation following brainstem death (DBD) grafts (971 patients from four studies, RR = 0.78; 0.65‐0.93, P = .006). The number of perfusions required to prevent one episode of DGF was 7.26 and 13.60 in DCD and DBD grafts, respectively. There is strong evidence that HMP also improves graft survival in both DBD and DCD grafts, at both 1 and 3 years. Economic analyses suggest HMP is cost‐saving at 1 year compared with SCS. Conclusion Hypothermic machine perfusion is superior to SCS in deceased donor renal transplantation. Direct comparisons with normothermic machine perfusion in RCTs are essential to identify optimal preservation methods in kidney transplantation.

Background. MicroRNAs (miRNAs) are short noncoding RNAs which each cause repression of many target genes. Previous work has demonstrated that therapeutic blockade of single miRNAs is possible. miR-24-3p and miR-145-5p are reported to have a detrimental role in ischemia-reperfusion injury. As the action of miRNAs is inhibitory, we hypothesized that dual blockade of both miRNAs could synergistically upregulate shared target genes. Methods. Quantification of miRNA expression in donated kidneys was performed using polymerase chain reaction (PCR) panels. Ischemia-reperfusion injury was modeled in vitro by placing human umbilical vein endothelial cells into a hypoxic incubator (1% O2) for 24 hours, with reoxygenation for 6 hours. RNA expression was quantified with reverse transcription quantitative polymerase chain reaction and protein expression assessed with Western blot. Antisense oligonucleotides were used to inhibit miRNAs. Results. miR-24-3p and miR-145-5p were highly expressed in human kidneys following extended cold ischemia. In vitro, hypoxia caused significant upregulation of miR-24-3p (P ≤ 0.001) and miR-145-5p (P ≤ 0.001) and significant downregulation in messenger RNA of shared targets superoxide dismutase 2 (P ≤ 0.001) and heme oxygenase 1 (P ≤ 0.001). These changes were mirrored at the protein level. Dual inhibition of both miR-24-3p and miR-145-5p caused significant upregulation of superoxide dismutase 2 and heme oxygenase 1 protein following hypoxia-reoxygenation; fold change of 3.17 (P ≤ 0.05) and 6.97 (P ≤ 0.05) respectively. Dual inhibition resulted in reduced cellular reactive oxygen species production compared with negative control (P ≤ 0.05) and single blockade of miR-24-3p (P ≤ 0.01) or miR-145-5p (P ≤ 0.05). Conclusions. Dual blockade of 2 miRNAs can act synergistically to increase the expression of shared gene targets. Dual blockade of miR-24-3p and miR-145-5p represents a novel therapeutic option worthy of further research.