Targeted therapy in patients with PIK3CA-related overgrowth syndrome

CLOVES syndrome (congenital lipomatous overgrowth, vascular malformations, epidermal naevi, scoliosis/skeletal and spinal syndrome) is a genetic disorder that results from somatic, mosaic gain-of-function mutations of the PIK3CA gene, and belongs to the spectrum of PIK3CA-related overgrowth syndromes (PROS). This rare condition has no specific treatment and a poor survival rate. Here, we describe a postnatal mouse model of PROS/CLOVES that partially recapitulates the human disease, and demonstrate the efficacy of BYL719, an inhibitor of PIK3CA, in preventing and improving organ dysfunction. On the basis of these results, we used BYL719 to treat nineteen patients with PROS. The drug improved the disease symptoms in all patients. Previously intractable vascular tumours became smaller, congestive heart failure was improved, hemihypertrophy was reduced, and scoliosis was attenuated. The treatment was not associated with any substantial side effects. In conclusion, this study provides the first direct evidence supporting PIK3CA inhibition as a promising therapeutic strategy in patients with PROS.

Persistent expression of neutrophil gelatinase-associated lipocalin and M2 macrophage markers and chronic fibrosis after acute kidney injury

Recent epidemiologic studies revealed a correlation between acute kidney injury (AKI) episodes and the progression to chronic kidney disease (CKD). Although the severity and duration of the initial insult likely predict the development of CKD, information regarding tissue markers predictive of early development of renal fibrosis is limited. We investigated key markers in fibrotic kidney in rats and mice. Seven- to eight-week-old male Sprague-Dawley rats underwent bilateral ischemia-reperfusion injury (IRI). Kidney tissues were collected to determine the markers correlated with the severity of kidney fibrosis. In a separate set, a specific chemokine (C-C motif) receptor 2 (CCR2) inhibitor, RS-102895, was administered to 9-week-old male C57BL/6J mice that underwent unilateral IRI (9.2 mg/kg/day in drinking water for 17 days) to investigate whether blockade of the monocyte chemotactic protein-1 (MCP-1) signaling was sufficient to prevent fibrosis. Among candidate tissue markers, neutrophil gelatinase-associated lipocalin (NGAL) and MCP-1 mRNA expressions were correlated with kidney fibrosis. Studies on macrophage polarity showed that mRNA expression of M2, but not M1 macrophage markers, were correlated with acute-phase serum creatinine and fibrosis. Pharmacological blockade of the MCP-1-CCR2 signaling downregulated CCR2, which was insufficient to improve fibrosis in mouse unilateral IRI model, suggesting that additional, redundant pathways contribute to fibrosis. These findings suggested that tissue NGAL expression and M2 macrophage markers are promising markers that show severity of kidney fibrosis. Mechanistic involvement of these markers in CKD pathogenesis warrant additional investigation.

Ethanol ablation for refractory bile leakage after complex hepatectomy

BACKGROUND

Only a few reports exist on the use of ethanol ablation for posthepatectomy bile leakage. The aim of this study was to assess the value of ethanol ablation in refractory bile leakage.

METHODS

Medical records of consecutive patients who underwent a first hepatobiliary resection with bilioenteric anastomosis between 2007 and 2016 were reviewed retrospectively, with special attention to bile leakage and ethanol ablation therapy. Bile leakage was graded as A/B1/B2 according to the International Study Group of Liver Surgery definition. Absolute ethanol was injected into the target bile duct during fistulography.

RESULTS

Of the 609 study patients, 237 (38·9 per cent) had bile leakage, including grade A in 33, grade B1 in 18 and grade B2 in 186. Left trisectionectomy was more often associated with grade B2 bile leakage than other types of hepatectomy (P < 0·001). Of 186 patients with grade B2 bile leakage, 31 underwent ethanol ablation therapy. Ethanol ablation was started a median of 34 (range 15-122) days after hepatectomy. The median number of treatments was 3 (1-7), and the total amount of ethanol used was 15 (3-71) ml. Complications related to ethanol ablation included transient fever (27 patients) and mild pain (13). Following ethanol ablation, bile leakage resolved in all patients and drains were removed. The median interval between the first ablation and drain removal was 28 (1-154) days.

CONCLUSION

Ethanol ablation is safe and effective, and may be a treatment option for refractory bile leakage.

Vascular adhesion protein-1 enhances neutrophil infiltration by generation of hydrogen peroxide in renal ischemia/reperfusion injury

Vascular adhesion protein-1 (VAP-1) is a unique molecule since it acts as an adhesion molecule as well as an ectoenzyme catalyzing oxidative deamination of primary amines and generates hydrogen peroxide in the extracellular space. While VAP-1 is implicated in various inflammatory diseases, its role in acute kidney injury is less characterized. Here we studied VAP-1 expression in the kidney and the effect of its inhibition in a rat model of renal ischemia/reperfusion injury. VAP-1 was predominantly expressed in pericytes, which released enzymatically active enzyme. In vivo, a specific VAP-1 inhibitor, RTU-1096, significantly ameliorated rat renal ischemia/reperfusion injury and decreased neutrophil infiltration measured 12 hours after injury without altering macrophage or T lymphocyte populations. The protective effect of VAP-1 inhibition was lost in neutrophil-depleted rats, suggesting its inhibition ameliorated renal ischemia/reperfusion injury by suppressing neutrophil infiltration. To investigate whether hydrogen peroxide generated by VAP-1 enzyme reaction enhances neutrophil infiltration, we conducted an under-agarose migration assay with purified human neutrophils. Recombinant human VAP-1 significantly induced neutrophil migration, which was almost completely inhibited by RTU-1096 or catalase. Thus, VAP-1 plays a critical role in the pathophysiology of renal ischemia/reperfusion injury by enhancement of neutrophil infiltration generating a local hydrogen peroxide gradient. Hence, VAP-1 inhibition may be a novel therapy in ischemic acute kidney injury.

Identification of rare HIV-1 Group N, HBV AE, and HTLV-3 strains in rural South Cameroon

Surveillance of emerging viral variants is critical to ensuring that blood screening and diagnostic tests detect all infections regardless of strain or geographic location. In this study, we conducted serological and molecular surveillance to monitor the prevalence and diversity of HIV, HBV, and HTLV in South Cameroon. The prevalence of HIV was 8.53%, HBV was 10.45%, and HTLV was 1.04% amongst study participants. Molecular characterization of 555 HIV-1 specimens identified incredible diversity, including 7 subtypes, 12 CRFs, 6 unclassified, 24 Group O and 2 Group N infections. Amongst 401 HBV sequences were found a rare HBV AE recombinant and two emerging sub-genotype A strains. In addition to HTLV-1 and HTLV-2 strains, sequencing confirmed the fifth known HTLV-3 infection to date. Continued HIV/HBV/HTLV surveillance and vigilance for newly emerging strains in South Cameroon will be essential to ensure diagnostic tests and research stay a step ahead of these rapidly evolving viruses.

Effect of AST-120 in Chronic Kidney Disease Treatment: Still a Controversy?

AST-120 (kremezin; Kureha Chemical, Tokyo, Japan) is an oral spherical carbonaceous adsorbent, which was approved for clinical use in Japanese chronic kidney disease (CKD) patients in 1991. It adsorbs indole, the precursor of indoxyl sulfate, in the intestines and prevents indoxyl sulfate production. Indoxyl sulfate, initially identified as a major uremic toxin that causes uremic symptoms, contributes to CKD progression. Since AST-120 decreases serum indoxyl sulfate in a dose-dependent manner, multicenter prospective trials have been conducted in Japan in the 1980s; these trials were mostly in favor of the efficacy of AST-120 in delaying the initiation of dialysis in patients with advanced stage CKD. Many animal studies support the effects of AST-120 on renal outcomes as well as on cardiovascular complications. However, there are yet no reports that unequivocally demonstrate the improvement of hard renal endpoints and/or cardiovascular endpoints. This commentary briefly reviews the major outcomes of the recent clinical trials on AST-120.

Recent advances in understanding of chronic kidney disease

Chronic kidney disease (CKD) is defined as any condition that causes reduced kidney function over a period of time. Fibrosis, tubular atrophy and interstitial inflammation are the hallmark of pathological features in CKD. Regardless of initial insult, CKD has some common pathways leading CKD to end-stage kidney disease, including hypoxia in the tubulointerstitium and proteinuria. Recent advances in genome editing technologies and stem cell research give great insights to understand the pathogenesis of CKD, including identifications of the origins of renal myofibroblasts and tubular epithelial cells upon injury. Environmental factors such as hypoxia, oxidative stress, and epigenetic factors in relation to CKD are also discussed.

Changes in standing body sway of pregnant women after long-term bed rest

Pregnant women tend to fall and increased body postural instability, namely body sway, may be one of the causative factors. We had a clinical impression that pregnant women after long-term bed rest tend to fall. We hypothesised that such women may show increased body sway, which we attempted to determine. Pregnant women (n = 161) were divided into three groups: (i) women with preterm labour after 2-week bed rest, (ii) those after 4-week bed rest, and (iii) those without bed rest or preterm labour. Body sway was analysed using stabilometry, that is, computed analysis of movement of the centre of gravity. The 3 groups fundamentally showed the same stabilometric measurements. Women with oedema showed greater medial-lateral sway than those without it. Factors other than oedema yielded no differences in stabilometric parameters. Long-term bed rest fundamentally did not increase body sway to the extent that stabilometry could reveal it. It may be prudent to consider that pregnant women with oedema tend to fall.

Liver regeneration following experimental major hepatectomy with choledochojejunostomy

BACKGROUND

Surgical treatment for perihilar cholangiocarcinoma frequently involves hepatectomy and extrahepatic bile duct resection with a choledochojejunostomy (CJ). Cholangitis owing to bilioenteric anastomosis is a common complication. The impact of CJ or regurgitating cholangitis on the liver regeneration process after major hepatectomy is unknown.

METHODS

Rats underwent 70 per cent hepatectomy (Hx group) or hepatectomy with CJ (Hx + CJ group). The intrahepatic inflammatory response, hepatic regeneration rate, and expression of regeneration-associated genes in the liver and blood were compared between these two groups.

RESULTS

Levels of hepatobiliary markers in the blood were significantly higher 4 and 7 days after operation in the Hx + CJ group than the Hx group. Intrahepatic expression of inflammation-associated genes, such as interleukin 6 and tumour necrosis factor α, was also significantly higher in the Hx + CJ group on days 4 and 7. A progressive periportal inflammatory response was identified in the Hx + CJ group by histological examination. The hepatic regeneration rate was significantly lower in the Hx + CJ group than in the Hx group on day 2 (mean(s.d.) 14·2(6·3) versus 21·4(2·6) per cent; P = 0·013) and day 4 (32·4(5·3) versus 41·3(4·4) per cent; P = 0·004). Gene expression levels of hepatic regeneration-promoting factors such as hepatocyte growth factor were significantly lower in the Hx + CJ group than the Hx group on day 1.

CONCLUSION

CJ perturbs early liver regeneration after hepatectomy. An excessive inflammatory response in the liver and suppression of liver regeneration-associated factors may play a role. Surgical relevance Patients with perihilar cholangiocarcinoma may need major hepatectomy with extrahepatic bile duct resection and choledochojejunostomy. This carries a substantial risk of postoperative complications including liver failure. A rat model of partial hepatectomy with choledochojejunostomy was established. The molecular mechanisms underlying liver regeneration, and perturbation of this process by duodenobiliary reflux via the choledochojejunostomy, are described. The results give insight into the pathophysiological events following major hepatectomy with extrahepatic bile duct resection and choledochojejunostomy. This may help to develop a treatment strategy to reduce postoperative liver failure.

Inflammation and hypoxia linked to renal injury by CCAAT/enhancer-binding protein δ

Tubulointerstitial hypoxia plays a critical role in the pathogenesis of kidney injury, and hypoxia-inducible factor (HIF)-1 is a master regulator of cellular adaptation to hypoxia. Aside from oxygen molecules, factors that modify HIF-1 expression and functional operation remain obscure. Therefore, we sought to identify novel HIF-1-regulating genes in kidney. A short-hairpin RNA library consisting of 150 hypoxia-inducible genes was derived from a microarray analysis of the rat renal artery stenosis model screened for the effect on HIF-1 response. We report that CCAAT/enhancer-binding protein δ (CEBPD), a transcription factor and inflammatory response gene, is a novel HIF-1 regulator in kidney. CEBPD was induced in the nuclei of tubular epithelial cells in both acute and chronic hypoxic kidneys. In turn, CEBPD induction augmented HIF-1α expression and its transcriptional activity. Mechanistically, CEBPD directly bound to the HIF-1α promoter and enhanced its transcription. Notably, CEBPD was rapidly induced by inflammatory cytokines, such as IL-1β in a nuclear factor-κB-dependent manner, which not only increased HIF-1α expression during hypoxia, but was also indispensable for the non-hypoxic induction of HIF-1α. Thus our study provides novel insight into HIF-1 regulation in tubular epithelial cells and offers a potential hypoxia and inflammation link relevant in both acute and chronic kidney diseases.

Anti-inflammatory role of DPP-4 inhibitors in a nondiabetic model of glomerular injury

Dipeptidyl peptidase (DPP)-4 is an enzyme that cleaves and inactivates incretin hormones capable of stimulating insulin secretion from pancreatic β-cells. DPP-4 inhibitors are now widely used for the treatment of type 2 diabetes. Experimental studies have suggested a renoprotective role of DPP-4 inhibitors in various models of diabetic kidney disease, which may be independent of lowering blood glucose levels. In the present study, we examined the effect of DPP-4 inhibitors in the rat Thy-1 glomerulonephritis model, a nondiabetic glomerular injury model. Rats were injected with OX-7 (1.2 mg/kg iv) and treated with the DPP-4 inhibitor alogliptin (20 mg·kg(-1)·day(-1)) or vehicle for 7 days orally by gavage. Alogliptin significantly reduced the number of CD68-positive inflammatory macrophages in the kidney, which was associated with a nonsignificant tendency to ameliorate glomerular injury and reduce proteinuria. Another DPP-4 inhibitor, anagliptin (300 mg·kg(-1)·day(-1) mixed with food) and a glucagon-like peptide-1 receptor agonist, exendin-4 (10 mg/kg sc), similarly reduced CD68-positive macrophage infiltration to the kidney. Furthermore, ex vivo transmigration assays using peritoneal macrophages revealed that exendin-4, but not alogliptin, dose dependently reduced monocyte chemotactic protein-1-stimulated macrophage infiltration. These data suggest that DPP-4 inhibitors reduced macrophage infiltration directly via glucagon-like peptide-1-dependent signaling in the rat Thy-1 nephritis model and indicate that the control of inflammation by DPP-4 inhibitors is useful for the treatment of nondiabetic kidney disease models.

Role of uremic toxins in erythropoiesis-stimulating agent resistance in chronic kidney disease and dialysis patients

Patients with advanced chronic kidney disease are exposed to uremic toxins. In addition to causing uremic symptoms, uremic toxins accelerate the progression of renal failure. Indoxyl sulfate (IS) increases oxygen consumption in tubules, aggravating hypoxia of the kidney, and progression of the kidney disease. IS also induces endoplasmic reticulum stress and thereby contributes the progression of cellular damages in tubular epithelial cells. Hypoxia-inducible factor (HIF) is a master transcriptional regulator of adaptive responses against hypoxia and regulates expression of erythropoietin (EPO). IS suppresses EPO expression via HIF-dependent and HIF-independent manner. IS impedes the recruitment of transcriptional coactivators to HIF via upregulation of Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 through a mechanism of posttranscriptional messenger RNA stabilization. Furthermore, IS induces activating transcription factor 4 via endoplasmic reticulum stress, decreasing EPO expression. Although erythropoiesis-stimulating agent (ESA) resistance is generally defined as lack of responses to exogenous ESA administration, suppression of endogenous production of EPO under uremic conditions may aggravate ESA resistance. Uremia is associated with increased formation of advanced glycation end products (AGE). Studies of transgenic rats overexpressing glyoxalse 1 (GLO1), which detoxifies precursors of advanced glycation end products, demonstrated that glycative stress causes renal senescence and vascular endothelial dysfunction. Glycative stress also suppresses HIF activation making the kidney susceptible to hypoxia as a final common pathway to end-stage kidney disease.