Acute kidney injury in patients with cirrhosis - practical summary.

Acute kidney injury (AKI) is a relatively common condition in patients with advanced liver disease and which is associated with increased mortality. It mainly affects patients with decompensated cirrhosis, particularly those with advanced portal hypertension and ascites. The dual organ involvement may have different forms. The contributing pathogenetic mechanisms are common and predict a dismal prognosis. Early diagnosis and interventions involving specialists (in particular, hepatologists and nephrologists) are essential to improve outcomes.

Reduction in acute kidney injury stage predicts survival in patients with type-1 hepatorenal syndrome.

BACKGROUND: Hepatorenal syndrome type 1 (HRS-1), a form of acute kidney injury (AKI) in cirrhosis, has a median survival of days to weeks if untreated. The impact of reduction in AKI stage on overall survival in cirrhosis, independent of HRS reversal, is unclear. METHODS: The Randomized, placEbo-controlled, double-blind study to confirm the reVERSal of HRS-1 with terlipressin study assessed terlipressin versus placebo, both with albumin, as treatment for HRS-1 for ≤14 days. Renal dysfunction severity was categorized by AKI stage at enrollment. Baseline patient characteristics were evaluated as predictors of AKI improvement using a multivariate model; the association between AKI stage reduction and 90-day survival was assessed using linear regression. RESULTS: A total of 184 patients (terlipressin: n = 91; placebo: n = 93) with similar numbers in AKI Stages 1-3 (terlipressin/placebo, Stage 1: n = 25/26; Stage 2: n = 35/33; Stage 3: n = 31/34) were included. Predictors of AKI improvement were absence of alcoholic hepatitis, baseline serum creatinine and male gender. Overall survival was not significantly different across AKI stages (range 53-65%). In patients with no AKI worsening, 90-day survival was consistently better when AKI improved independent of HRS reversal, regardless of the initial AKI stage, with patients with Stage 1 at initial diagnosis achieving the greatest clinical benefit. A significant association was observed between AKI reduction and overall 90-day survival (P = 0.0022). CONCLUSIONS: A reduction in AKI stage, independent of HRS reversal, was sufficient to improve overall survival in patients with HRS-1. The goal for HRS-1 treatment should be less stringent than absolute HRS reversal.

Disruption of Renal Arginine Metabolism Promotes Kidney Injury in Hepatorenal Syndrome in Mice.

Tubular dysfunction is an important feature of renal injury in hepatorenal syndrome (HRS) in patients with end-stage liver disease. The pathogenesis of kidney injury in HRS is elusive, and there are no clinically relevant rodent models of HRS. We investigated the renal consequences of bile duct ligation (BDL)-induced hepatic and renal injury in mice in vivo by using biochemical assays, real-time polymerase chain reaction (PCR), Western blot, mass spectrometry, histology, and electron microscopy. BDL resulted in time-dependent hepatic injury and hyperammonemia which were paralleled by tubular dilation and tubulointerstitial nephritis with marked upregulation of lipocalin-2, kidney injury molecule 1 (KIM-1) and osteopontin. Renal injury was associated with dramatically impaired microvascular flow and decreased endothelial nitric oxide synthase (eNOS) activity. Gene expression analyses signified proximal tubular epithelial injury, tissue hypoxia, inflammation, and activation of the fibrotic gene program. Marked changes in renal arginine metabolism (upregulation of arginase-2 and downregulation of argininosuccinate synthase 1), resulted in decreased circulating arginine levels. Arginase-2 knockout mice were partially protected from BDL-induced renal injury and had less impairment in microvascular function. In human-cultured proximal tubular epithelial cells hyperammonemia per se induced upregulation of arginase-2 and markers of tubular cell injury. CONCLUSION: We propose that hyperammonemia may contribute to impaired renal arginine metabolism, leading to decreased eNOS activity, impaired microcirculation, tubular cell death, tubulointerstitial nephritis and fibrosis. Genetic deletion of arginase-2 partially restores microcirculation and thereby alleviates tubular injury. We also demonstrate that BDL in mice is an excellent, clinically relevant model to study the renal consequences of HRS. (Hepatology 2018; 00:000-000).

Urinary cell cycle arrest biomarker [TIMP-2]·[IGFBP7] in patients with hepatorenal syndrome.

Background: Patients with hepatorenal syndrome carry a high short-term mortality. Early diagnosis and treatment are essential for patients' outcome. Nevertheless diagnosis of HRS remains difficult. First-line therapy terlipressin is often associated with severe complications. Biomarkers become more on focus for an early diagnosis. Objective: The aim of this study was to test the diagnostic accuracy of urinary [TIMP-2]·[IGFBP7] for HRS patients and prognostic value for therapy responding patients. Material and methods: NephroCheck® measures urinary concentrations of TIMP-2 and IGFBP-7, both indicating stress of renal cells and associated with induction of cell cycle arrest. 22 HRS patients and 30 patients with normal kidney function were included. [TIMP-2]·[IGFBP7] was measured using NephroCheck®. HRS patients receiving terlipressin were also examined. Results: [TIMP-2]·[IGFBP7] values did not differ significantly (1.3 ± 2.09 vs. 1.03 ± 1.03; p = 0.55). Furthermore, there was no significant difference of [TIMP-2]·[IGFBP7] regarding response of terlipressin (1.32 ± 2.39 vs. 0.81 ± 1.05; p = 0.56). Low [TIMP-2]·[IGFBP7] values were significantly associated with higher mortality (p = 0.01). Conclusions: The results of this study suggest that [TIMP-2]·[IGFBP7] is not suitable for diagnostic of HRS and prediction of therapy response, but there might be evidence for prognostic value of [TIMP-2]·[IGFBP7] in regard to mortality of liver cirrhosis patients.

New Developments in Hepatorenal Syndrome.

Hepatorenal syndrome (HRS) continues to be one of the major complications of decompensated cirrhosis, leading to death in the absence of liver transplantation. Challenges in precisely evaluating renal function in the patient with cirrhosis remain because of the limitations of serum creatinine (Cr) alone in estimating glomerular filtration rate (GFR); current GFR estimating models appear to underestimate renal dysfunction. Newer models incorporating renal biomarkers, such as the Cr-Cystatin C GFR Equation for Cirrhosis appear to estimate measured GFR more accurately. A major change in the diagnostic criteria for HRS based on dynamic serial changes in serum Cr that regard HRS type 1 as a special form of acute kidney injury promises the possibility of earlier identification of renal dysfunction in patients with cirrhosis. The diagnostic criteria of HRS still include the exclusion of other causes of kidney injury. Renal biomarkers have been disappointing in assisting with the differentiation of HRS from prerenal azotemia and other kidney disorders. Serum metabolomic profiling may be a more powerful tool to assess renal dysfunction, although the practical clinical significance of this remains unclear. As a result of the difficulties of assessing renal function in cirrhosis and the varying HRS diagnostic criteria and the rigor with which they are applied, the precise incidence and prevalence of HRS is unknown, but it is likely that HRS occurs more commonly than expected. The pathophysiology of HRS is rooted firmly in the setting of progressive reduction in renal blood flow as a result of portal hypertension and splanchnic vasodilation. Progressive marked renal cortical ischemia in patients with cirrhosis parallels the evolution of diuretic-sensitive ascites to diuretic-refractory ascites and HRS, a recognized continuum of renal dysfunction in cirrhosis. Alterations in nitrous oxide production, both increased and decreased, may play a major role in the pathophysiology of this evolution. The inflammatory cascade, triggered by bacterial translocation and endotoxemia, increasingly recognized as important in the manifestation of acute-on-chronic liver failure, also may play a significant role in the pathophysiology of HRS. The mainstay of treatment remains vasopressor therapy with albumin in an attempt to reverse splanchnic vasodilation and improve renal blood flow. Several meta-analyses have confirmed the value of vasopressors, chiefly terlipressin and noradrenaline, in improving renal function and reversing HRS type 1. Other interventions such as renal replacement therapy, transjugular intrahepatic portosystemic shunt, and artificial liver support systems have a very limited role in improving outcomes in HRS. Liver transplantation remains the definitive treatment for HRS. The frequency of simultaneous liver-kidney transplantation has increased dramatically in the Model for End-stage Liver Disease era, with changes in organ allocation policies. This has resulted in a more urgent need to predict native kidney recovery from HRS after liver transplantation alone, to avoid unnecessary simultaneous liver-kidney transplantation.

Oxidative stress, NOx/l-arginine ratio and glutathione/glutathione S-transferase ratio as predictors of 'sterile inflammation' in patients with alcoholic cirrhosis and hepatorenal syndrome type II.

Continuous intake of alcohol leads to liver cirrhosis because of imbalance of oxidative stress/antioxidative defense and chronic 'sterile inflammation'. Hepatorenal syndrome (HRS) is the most severe complication of liver cirrhosis. The aim of our study was to assess: (1) the oxidative stress/antioxidative defense markers such as malondialdehyde (MDA), oxidative glutathione (GSH) and glutathione S-transferase (GST), (2) inflammation [C-reactive protein (CRP)], and (3) nitrate/nitrite levels (NOx) and its substrate L-arginine level. The study enrolled three groups: a group with cirrhosis and HRS (48 patients), a group with cirrhosis without HRS (32 patients), and a control group (40 healthy blood donors). All the patients with cirrhosis and HRS had type II HRS. MDA concentration was significantly higher in the groups with cirrhosis with and without HRS. Significant positive correlation was documented between the MDA level and de Ritis coefficient (AST/ALT), a marker of liver damage severity; between MDA and inflammation (CRP); between MDA and NOx concentration in the groups with cirrhosis with and without HRS. The correlation between MDA and creatinine level was significant in the group with HRS. The levels of GSH and GST were significantly lower in the groups with cirrhosis with and without HRS. The results of the study revealed that an increase in MDA and NOx concentration, along with decreased values of antioxidative defense and L-arginine, may indicate that liver damage can have an influence on progression to renal failure.

Nephrotoxicity of Natural Products.

BACKGROUND: The manufacture and sale of natural products constitute a multi-billion dollar industry. Nearly a third of the American population admit to using some form of complementary or alternative medicine, with many using them in addition to prescription medications. Most patients fail to inform their healthcare providers of their natural product use and physicians rarely inquire. Annually, thousands of natural product-induced adverse events are reported to Poison Control Centers nationwide. Natural product manufacturers are not responsible for proving safety and efficacy, as the FDA does not regulate them. However, concerns exist surrounding the safety of natural products. SUMMARY: This review provides details on natural products that have been associated with renal dysfunction. We have focused on products that have been associated with direct renal injury, immune-mediated nephrotoxicity, nephrolithiasis, rhabdomyolysis with acute renal injury, hepatorenal syndrome, and common adulterants or contaminants that are associated with renal dysfunction. KEY MESSAGES: The potential for natural products to cause renal dysfunction is justifiable. It is imperative that natural product use be monitored closely in all patients. Healthcare practitioners must play an active role in identifying patients using natural products and provide appropriate patient education.

Ultrastructure of hepatorenal cell populations in patients with HCV and HBV infection markers. Hepatorenal associations.

Hepatorenal cell populations were studied in patients with HCV and HBV infection markers and renal dysfunction. Pronounced mosaicism of ultrastructural changes in hepatocytes was associated with polymorphic cytopathic effects caused by RNA-genome hepatitis C virus and DNA-genome hepatitis B virus. The destructive component of the tubular compartment predominated in renal biopsy specimens from patients, with subsequent degeneration of the tubular epithelium associated with progressive interstitial fi brosis. Immunohistochemical studies detected HCV NS3Ag and HBcAg structural marker in the tubular epitheliocytes. An appreciable part of the structural and functional changes in the liver in patients with HCV and HBV infections was caused by the therapeutic complex, including programmed hemoperfusion.

Bile cast nephropathy is a common pathologic finding for kidney injury associated with severe liver dysfunction.

Cholemic nephrosis represents a spectrum of renal injury from proximal tubulopathy to intrarenal bile cast formation found in patients with severe liver dysfunction. However, the contribution of this diagnosis has been largely forgotten in the modern literature. To more precisely define this, we conducted a clinicopathologic study of 44 subjects (41 autopsies and 3 renal biopsies) from jaundiced patients at the University of Chicago. Of these, 24 patients had bile casts with involvement of distal nephron segments in 18 mild cases and extension to proximal tubules for 6 severe cases. Eleven of 13 patients with hepatorenal syndrome and all 10 with cirrhosis (due to alcoholism) had tubular bile casts. These casts significantly correlated with higher serum total and direct bilirubin levels, and a trend toward higher serum creatinine, AST, and ALT levels. Bile casts may contribute to the kidney injury of severely jaundiced patients by direct bile and bilirubin toxicity, and tubular obstruction. Both mechanisms are analogous to the injury by myeloma or myoglobin casts. Accounting for the presence of renal bile casts provides a more complete representation of the renal injury that can occur in this unique clinical setting. Thus, bile cast nephropathy is an appropriate term for the severe form of injury observed in the spectrum of cholemic nephrosis. Additional studies are needed to establish the significance of this parameter for patient management in different clinical settings.

TNFα-induced IP3R1 expression through TNFR1/PC-PLC/PKCα and TNFR2 signalling pathways in human mesangial cell.

BACKGROUND: Little information is available regarding the mechanisms involved in cytokine-induced type 1 inositol 1,4,5-trisphosphate receptor (IP(3)R1) expression in human mesangial cells (HMCs) in the occurrence of hepatorenal syndrome (HRS). Over-expression of IP(3)R1 would enhance both IP(3)-binding activity and sensitivity. We hypothesize that it is possible that increased IP(3)R1, induced by TNFα, would lead to increased IP(3) sensitivity in response to a variety of vasoconstrictors, and promote HMC contraction and thus lead to reduced GFP, promoting HRS occurrence and development. METHODS: Quantitative real-time polymerase chain reaction and immunoblot assay were used to examine the effects of TNFα on IP(3)R1 mRNA and protein expression. Several inhibitors of kinases, depletion PKC, over-expression of dominant-negative mutant of PKC and non-radioactive PKC assay were used to examine the mechanism of signal transduction of TNFα-regulated IP(3)R1 in HMCs. RESULTS: TNFα increased IP(3)R1 mRNA and protein expression in HMCs, an effect that was blocked by prolonged incubated chronic PMA, D609, safingol and also by transfection with domain-negative PKCα construct. TNFα activated and promoted autophosphorylation of the PKCα. In addition, both anti-TNFR1 and anti-TNFR2 antibodies blocked TNFα-induced IP(3)R1 protein expression, while only anti-TNFR1 antibodies but not anti-TNFR2 antibodies attenuated TNFα-induced PKCα activity. CONCLUSIONS: TNFα increased the expression of IP(3)R1, and this was mediated, at least in part, through the TNFR1/PC-PLC/PKCα and TNFR2 signalling pathways in HMCs.

[Correction of protein-energy metabolism in hepatorenal failure in surgical patients].

Infringements of a protein-energetic metabolism in hepatorenal complications are an actual problem in urgent surgery. 358 patients with a acute surgical pathology of intestines were analyzed, in 27.4% of patients infringements of functions of a liver and kidneys were revealed, necessity for normalization of the protein-energetic metabolism was noted in 47-70% of cases. As a result the scheme for protein-energetic metabolism correction was specified in depending of a kind of intestinal impassability and a degree of severity of surgical disease. The early correction of a protein-energetic metabolism in complex with the extracorporeal support methods of a detoxication has provided the expressed positive clinical effect.

Terlipressin and albumin combination treatment in patients with hepatorenal syndrome type 2.

Background: Hepatorenal syndrome (HRS) is associated with a poor prognosis. In HRS type 1, loss of renal function is rapidly progressive, while HRS type 2 is characterised by chronic ascites and more moderately elevated renal parameters. While treatment with terlipressin/albumin is well established in type 1, its effectiveness in chronic HRS is less clear. Objective: The aim of this study was to evaluate the effectiveness of terlipressin/albumin treatment in patients with HRS type 2. Methods: All patients with a first episode of HRS between April 2013 and February 2016 were included in this observational study. Relevant clinical and laboratory parameters were recorded and patients were followed. Results: A total of 106 patients with HRS were included. With terlipressin therapy reversal of HRS types 1 and 2 was achieved in 48% and 46% of patients (p = 0.84) with relapse rates of 8% vs 50% (p = 0.001). Overall survival (OS) and survival free of liver transplantation (LTx) were similar in HRS types 1 and 2 (p = 0.69; p = 0.64). In multivariate analysis response to treatment was independently associated with better OS in HRS type 2, in addition to established risk factors such as lower Model for End-Stage Liver Disease score, absence of hepatic encephalopathy and eligibility for LTx. Conclusion: A terlipressin treatment course seems to be justified in selected patients with HRS type 2, especially in countries and settings with long transplant waiting lists. In addition treatment response might also help to identify HRS type 2 patients with a more favourable outcome.

Superinfective Hepatitis E Virus Infection Aggravates Hepatocytes Injury in Chronic Hepatitis B.

Hepatitis E virus (HEV) infection is a major cause of morbidity in endemic areas. Its consequences among chronic hepatitis B (CHB) patients have been under-reported. The aim of this study was to assess the impact of superinfective HEV infection (acute and past) on virological and clinical features of patients with CHB infection. Clinical, biochemical, virological and immunological data of 153 CHB patients including 98 with hepatitis B virus (HBV) monoinfection and 55 with HBV-HEV superinfection with both HEV and HBV infection was retrospectively investigated and analyzed in this study conducted in Wuhan, China. An overall anti-HEV IgG seroprevalence was found to be 35.9% in CHB patients. HBV-HEV superinfection patients showed significantly higher rate of complications (ascites, hepato-renal syndrome & encephalopathy) (all with P=0.04), cirrhosis (P<0.001) and acute-on-chronic liver failure (P<0.001) than HBV monoinfection patients. They also displayed elevated ALTs (P<0.001) and total serum bilirubin (P<0.001) with diminished albumin (P<0.001) and HBV viral load (P<0.001). Cytokines assay revealed increased expression of IL-6 (P=0.02), IL-10 (P=0.009) and TNF-α (P=0.003) in HBV-HEV superinfection patients compared to HBV monoinfection patients. Our study demonstrated that HEV superinfection in CHB patients was associated with progressive clinical manifestation, which is likely due to the enhanced expression of cytokines related with hepatocytes necrosis. HEV was also associated with repressed HBV replication, but the underlying mechanism requires further investigation.

Noradrenaline versus terlipressin in the management of type 1 hepatorenal syndrome: A randomized controlled study.

BACKGROUND: Hepatorenal syndrome (HRS) occurs in decompensated liver disease and carries high mortality. Vasoconstrictors are the drug of choice. Terlipressin is widely used and is expensive. In this study, we compared noradrenaline and terlipressin in the management of type 1 HRS. METHODS: Sixty consecutive patients with type 1 HRS were managed with noradrenaline (Group A, n = 30) or terlipressin (Group B, n = 30) with albumin in a randomized controlled trial at a tertiary center. RESULTS: Reversal of type 1 HRS was achieved in 16 (53%) patients in group A and 17 (57%) in group B. There was statistically insignificant difference between the two groups in decreasing serum creatinine and increasing urine output (p > 0.05). On univariate analysis, Child-Turcotte-Pugh (CTP) score, serum sodium, serum urea, serum albumin, prothrombin time, International normalized ratio (INR), serum alanine aminotransferase (ALT), ascitic fluid protein, and history of bleeding were associated with response to treatment (noradrenaline/terlipressin). However, on multivariate analysis, only baseline CTP score, serum urea, serum albumin, and prothrombin time were independent predictors of response. All patients who responded were discharged alive with no mortality within 30 days. CONCLUSIONS: There is no difference in outcome of patients with type 1 HRS treated with noradrenaline or terlipressin. Thus, noradrenaline, which is cheaper, can be used instead of terlipressin (Clinical Trials Registry-India [CTRI] No. CTRI/2011/09/002032).

[Acute Kidney Injury and Hepatorenal Syndrome].

Acute kidney injury (AKI) is common in patients with liver cirrhosis, occurring in 13-20% of patients hospitalized with decompensated cirrhosis, and is significantly associated with the prognosis. The development and progression of AKI is an independent predictive factor for mortality in these patients. If AKI develops, the renal function declines progressively even if AKI is improved later, the patients have a poorer prognosis compared to those who have not developed AKI. In addition, in patients without appropriate treatment or no improvement with the initial treatment, AKI often progress to hepatorenal syndrome (HRS), which is associated with significant morbidity and mortality. Therefore, early detection and appropriate management for the development of AKI is very important in these patients. Recently, there have been significant revisions in the diagnostic criteria and treatment of AKI and HRS; this manuscript reviews these changes.

High expression of type I inositol 1,4,5-trisphosphate receptor in the kidney of rats with hepatorenal syndrome.

AIM: To detect the expression of type I inositol 1,4,5-trisphosphate receptor (IP3RI) in the kidney of rats with hepatorenal syndrome (HRS). METHODS: One hundred and twenty-five Sprague-Dawley rats were randomly divided into four groups to receive an intravenous injection of D-galactosamine (D-GalN) plus lipopolysaccharide (LPS; group G/L, n = 50), D-GalN alone (group G, n = 25), LPS alone (group L, n = 25), and normal saline (group NS, n = 25), respectively. At 3, 6, 9, 12, and 24 h after injection, blood, liver, and kidney samples were collected. Hematoxylin-eosin staining of liver tissue was performed to assess hepatocyte necrosis. Electron microscopy was used to observe ultrastructural changes in the kidney. Western blot analysis and real-time PCR were performed to detect the expression of IP3RI protein and mRNA in the kidney, respectively. RESULTS: Hepatocyte necrosis was aggravated gradually, which was most significant at 12 h after treatment with D-galactosamine/lipopolysaccharide, and was characterized by massive hepatocyte necrosis. At the same time, serum levels of biochemical indicators including liver and kidney function indexes were all significantly changed. The structure of the renal glomerulus and tubules was normal at all time points. Western blot analysis indicated that IP3RI protein expression began to rise at 3 h (P < 0.05) and peaked at 12 h (P < 0.01). Real-time PCR demonstrated that IP3RI mRNA expression began to rise at 3 h (P < 0.05) and peaked at 9 h (P < 0.01). CONCLUSION: IP3RI protein expression is increased in the kidney of HRS rats, and may be regulated at the transcriptional level.

Type I inositol 1, 4, 5-triphosphate receptors increase in kidney of mice with fulminant hepatic failure.

AIM: To delineate the mechanisms of renal vasocon-striction in hepatorenal syndrome (HRS), we investigated the expression of type I inositol 1, 4, 5-triphosphate receptors (IP3RI) of kidney in mice with fulminant hepatic failure (FHF). METHODS: FHF was induced by lipopolysaccharide (LPS) in D-galactosamine (GalN) sensitized BALB/c mice. There were 20 mice in normal saline (NS)-treated group, 20 mice in LPS-treated group, 20 mice in GalN-treated group, and 60 mice in GalN/LPS-treated group (FHF group). Liver and kidney tissues were obtained at 2, 6, and 9 h after administration. The liver and kidney specimens were stained with hematoxylin-eosin for studying morphological changes under light microscope. The expression of IP3RI in kidney tissue was tested by immunohistochemistry, Western blot and reverse transcription (RT)-PCR. RESULTS: Kidney tissues were morphologically normal at all time points in all groups. IP3RI proteins were found localized in the plasma region of glomerular mesangial cells (GMC) and vascular smooth muscle cells (VSMC) in kidney by immunohistochemical staining. In kidney of mice with FHF at 6 h and 9 h IP3RI staining was up-regulated. Results from Western blot demonstrated consistent and significant increment of IP3RI expression in mice with FHF at 6 h and 9 h (t=3.16, P<0.05; t=5.43, P<0.01). Furthermore, we evaluated IP3RI mRNA expression by RT-PCR and observed marked up-regulation of IP3RI mRNA in FHF samples at 2 h, 6 h and 9 h compared to controls (t=2.97, P<0.05; t=4.42, P<0.01; t=3.81, P<0.01). CONCLUSION: The expression of IP3RI protein increased in GMC and renal VSMC of mice with FHF, possibly caused by up-regulation of IP3RI mRNA.

An ovine hepatorenal fibrocystic model of a Meckel-like syndrome associated with dysmorphic primary cilia and TMEM67 mutations.

Meckel syndrome (MKS) is an inherited autosomal recessive hepatorenal fibrocystic syndrome, caused by mutations in TMEM67, characterized by occipital encephalocoele, renal cysts, hepatic fibrosis, and polydactyly. Here we describe an ovine model of MKS, with kidney and liver abnormalities, without polydactyly or occipital encephalocoele. Homozygous missense p.(Ile681Asn; Ile687Ser) mutations identified in ovine TMEM67 were pathogenic in zebrafish phenotype rescue assays. Meckelin protein was expressed in affected and unaffected kidney epithelial cells by immunoblotting, and in primary cilia of lamb kidney cyst epithelial cells by immunofluorescence. In contrast to primary cilia of relatively consistent length and morphology in unaffected kidney cells, those of affected cyst-lining cells displayed a range of short and extremely long cilia, as well as abnormal morphologies, such as bulbous regions along the axoneme. Putative cilia fragments were also consistently located within the cyst luminal contents. The abnormal ciliary phenotype was further confirmed in cultured interstitial fibroblasts from affected kidneys. These primary cilia dysmorphologies and length control defects were significantly greater in affected cells compared to unaffected controls. In conclusion, we describe abnormalities involving primary cilia length and morphology in the first reported example of a large animal model of MKS, in which we have identified TMEM67 mutations.