Incidence,risk factors,and adverse outcomes of acute kidney injury in very premature neonates: a single center experience

Background/aim Acute kidney injury (AKI) is a serious morbidity in premature neonates. The aim of this study was to determine the incidence of AKI and to evaluate its impact on morbidity and mortality in very premature infants.Materials and methodsThis retrospective cohort study was conducted in the neonatal intensive care unit (NICU). A total of 410 preterm infants who were born before 32 gestational weeks were screened and 318 were included in this analysis. AKI was defined according to the modified neonatal Kidney Disease: Improving Global Outcomes criteria.ResultsThe incidence of AKI was 32.1% (102/318). Regression analyses revealed that lower gestational age, vasopressor use, and hemodynamically significant patent ductus arteriosus were significantly associated with an increased risk for AKI. After adjustment for potential confounders, those with AKI had a higher risk of death before 36 weeks of corrected gestational age (adjusted hazard ratio: 3.02, 95% confidence interval 1.47– 6.22). Additionally, the AKI group had a higher rate of bronchopulmonary dysplasia (BPD) (46% vs. 24%, p < 0.001) and longer hospital stay with a mean difference of 38 days.ConclusionAKI is common in very premature neonates and associated with higher mortality, longer hospital stay, and BPD. Identification of risk factors and preventive strategies for AKI may improve the outcomes in this vulnerable population.     

Impact of hospital-acquired acute kidney injury on Covid-19 outcomes in patients with and without chronic kidney disease: a multicenter retrospective cohort study

Background/aim Hospital-acquired acute kidney injury (HA-AKI) may commonly develop in Covid-19 patients and is expected to have higher mortality. There is little comparative data investigating the effect of HA-AKI on mortality of chronic kidney disease (CKD) patients and a control group of general population suffering from Covid-19.Materials and methodsHA-AKI development was assessed in a group of stage 3–5 CKD patients and control group without CKD among adult patients hospitalized for Covid-19. The role of AKI development on the outcome (in-hospital mortality and admission to the intensive care unit [ICU]) of patients with and without CKD was compared.Results Among 621 hospitalized patients (age 60 [IQR: 47–73]), women: 44.1%), AKI developed in 32.5% of the patients, as stage 1 in 84.2%, stage 2 in 8.4%, and stage 3 in 7.4%. AKI developed in 48.0 % of CKD patients, whereas it developed in 17.6% of patients without CKD. CKD patients with HA-AKI had the highest mortality rate of 41.1% compared to 14.3% of patients with HA-AKI but no CKD (p < 0.001). However, patients with AKI+non-CKD had similar rates of ICU admission, mechanical ventilation, and death rate to patients with CKD without AKI. Adjusted mortality risks of the AKI+non-CKD group (HR: 9.0, 95% CI: 1.9–44.2) and AKI+CKD group (HR: 7.9, 95% CI: 1.9–33.3) were significantly higher than that of the non-AKI+non-CKD group.ConclusionAKI frequently develops in hospitalized patients due to Covid-19 and is associated with high mortality. HA-AKI has worse outcomes whether it develops in patients with or without CKD, but the worst outcome was seen in AKI+CKD patients.     

Acute kidney injury after trauma: Prevalence, clinical characteristics and RIFLE classification

Background:

Acute kidney injury (AKI) is an uncommon but serious complication after trauma. The objective of this study was to evaluate the prevalence, clinical characteristics and outcome of AKI after trauma.

Patients and Methods:

This was a retrospective study performed from January 2006 to January 2008 in an emergency specialized hospital in Fortaleza city, northeast of Brazil. All patients with AKI admitted in the study period were included. Prevalence of AKI, clinical characteristics and outcome were investigated.

Results:

Of the 129 patients admitted to the intensive care unit (ICU), 52 had AKI. The mean age was 30.1 ± 19.2 years, and 79.8% were males. The main causes of AKI were sepsis in 27 cases (52%) and hypotension in 18 (34%). Oliguria was observed in 33 cases (63%). Dialysis was required for 19 patients (36.5%). Independent risk factors associated with AKI were abdominal trauma [odds ratio (OR) = 3.66, P = 0.027] and use of furosemide (OR = 4.10, P = 0.026). Patients were classified according to RIFLE criteria as Risk in 12 cases (23%), Injury in 13 (25%), Failure in 24 (46%), Loss in 1 (2%) and End-stage in 2 (4%). Overall in-hospital mortality was 95.3%. The main cause of death was sepsis (24%). Mortality was 100% among patients with AKI.

Conclusions:

AKI is a fatal complication after trauma, which presented with a high mortality in the studied population. A better comprehension of factors associated with death in trauma-associated AKI is important, and more effective measures of prevention and treatment of AKI in this population are urgently needed.     

Clinical profile of acute kidney injury in a pediatric intensive care unit from Southern India: A prospective observational study

Background:

Although the term acute renal failure was replaced by acute kidney injury (AKI) recently, there is a paucity of data on the incidence and profile of AKI in critically ill children from the developing world.

Objectives:

The objective of this study is to determine the incidence, etiology, short term outcome and predictors of fatality in critically ill children admitted to the pediatric intensive care unit (PICU) with AKI, aged 1 month to 13 years.

Materials and Methods:

In this prospective observational study, from June 2010 to March 2011, 215 children admitted to the PICU were screened for AKI, defined according to the AKI Network criteria. The patients with AKI were followed-up until discharge/death. Their clinical and biochemical data were recorded.

Results:

The incidence of AKI among 215 patients screened was 54 (25.1%). The common etiologies were infections, [34 (62.9%)], acute glomerulonephritis (7.6%), snake envenomation (5.7%), hemolytic uremic syndrome (3.8%) and congestive cardiac failures (3.8%). Among infections, pneumonia and septicemia constituted 26.5% each, meningoencephalitis accounted for 23.5%, and dengue, scrub typhus, tuberculosis and malaria constituted 9.3% of children with AKI. 27.8% of patients required dialysis. Overall mortality was 46.3%. On logistic regression analysis, requirement of mechanical ventilation was an independent predictor of fatality in AKI.

Conclusions:

Besides the high incidence of AKI in critically ill-children admitted to the PICU (25.1%), the condition was associated with adverse outcomes, including high mortality (46.3%) and need for dialysis (27.8%). Infections dominated the etiological profile. Requirement of mechanical ventilation predicted an adverse outcome in our patient population.     

肾胺酶及其在急性肾损伤中作用的研究进展

肾胺酶作为近年来新发现的一种黄素蛋白,主要由肾小管近端上皮细胞合成和分泌,在心、肝、骨骼肌等多器官系统均有表达。肾胺酶曾被认为是一种儿茶酚胺类的降解酶,并在心血管疾病的病理生理过程中起到重要作用;而近期研究对肾胺酶的结构、生物学特性及作用有了新的认识,并认为其在急性肾损伤的发生发展中起到了重要作用。本文对主要对肾胺酶的结构、功能及作用等方面进行了综述。     

Acute kidney injury in critically ill children: Risk factors and outcomes

Background:

Acute kidney injury (AKI) is common in patients in the pediatric intensive care unit (PICU) and is associated with poor outcome. We conducted the present study to determine the incidence, risk factors and outcomes of AKI in the PICU.

Materials and Methods:

We collected data retrospectively from case records of children admitted to the PICU during one year. We defined and classified AKI according to modified pRIFLE criteria. We used multivariate logistic regression to determine risk factors of AKI and association of AKI with mortality and morbidity.

Results:

Of the 252 children included in the study, 103 (40.9%) children developed AKI. Of these 103 patients with AKI, 39 (37.9%) patients reached pRIFLE max of Risk, 37 (35.9%) patients reached Injury, and 27 (26.2%) had Failure. Mean Pediatric Risk of Mortality (PRISM III) score at admission was higher in patients with AKI than in controls (P < 0.001).     

Acute kidney injury and electrolyte disorders in COVID-19

Acute kidney injury (AKI) and electrolyte disorders are important complications of hospitalized coronavirus disease 2019 (COVID-19) patients. AKI is thought to occur due to multiple pathophysiological mechanisms, such as multiple organ dysfunction (mainly cardiac and respiratory), direct viral entry in the renal tubules, and cytokine release syndrome. AKI is present in approximately one in every ten hospitalized COVID-19 patients. The incidence rates of AKI increase in patients who are admitted to the intensive care unit (ICU), with levels higher than 50%. Additionally, renal replacement therapy (RRT) is used in 7% of all AKI cases, but in nearly 20% of patients admitted to an ICU. COVID-19 patients with AKI are considered moderate-to-severe cases and are managed with multiple interdisciplinary conducts. AKI acts as a risk factor for mortality in severe acute respiratory syndrome coronavirus 2 infection, especially when RRT is needed. Electrolyte disorders are also common manifestations in hospitalized COVID-19 patients, mainly hyponatremia, hypokalemia, and hypocalcemia. Hyponatremia occurs due to a combination of syndrome of inappropriate secretion of antidiuretic hormone and gastrointestinal fluid loss from vomiting and diarrhea. When it comes to hypokalemia, its mechanism is not fully understood but may derive from hyperaldosteronism due to renin angiotensin aldosterone system overstimulation and gastrointestinal fluid loss as well. The clinical features of hypokalemia in COVID-19 are similar to those in other conditions. Hypocalcemia is the most common electrolyte disorder in COVID-19 and seems to occur because of vitamin D deficiency and parathyroid imbalance. It is also highly associated with longer hospital and ICU stay.     

Acute kidney injury in symptomatic primary Epstein-Barr virus infectious mononucleosis: Systematic review

Background and objectivesTextbooks and reviews do not mention the association of symptomatic primary Epstein-Barr virus infectious mononucleosis with acute kidney injury in subjects without immunodeficiency or autoimmunity.Study designStimulated by our experience with two cases, we performed a review of the literature.ResultsThe literature documents 38 cases (26 male and 12 female individuals ranging in age from 0.3 to 51, median 18 years) of symptomatic primary Epstein-Barr virus infectious mononucleosis complicated by acute kidney injury: 27 acute interstitial nephritides, 1 jaundice-associated nephropathy, 7 myositides and 3 hemolytic uremic syndromes. Acute kidney injury requiring renal replacement therapy was observed in 18 (47%) cases. Acute kidney injury did not resolve in one patient with acute interstitial nephritis. Two patients died because of systemic complications. The remaining 35 cases fully recovered.ConclusionsIn individuals with acute symptomatic Epstein-Barr virus infectious mononucleosis, a relevant kidney injury is rare but the outcome potentially fatal. It results from interstitial nephritis, myositis-associated acute kidney injury, hemolytic uremic syndrome or jaundice-associated nephropathy.     

Iron,ferroptosis, and new insights for prevention in acute kidney injury

Acute kidney injury (AKI) is a very common condition with high morbidity and mortality, which can be seen in 5–7% of all hospitalized patients and in up to 57% of all intensive care unit admissions. Despite recent advances in clinical care, the prevalence of AKI has been shown to increase with virtually no change in mortality. AKI is a complex syndrome occurring in a variety of clinical settings. Early detection is crucial to prevent irreversible loss of renal function. The pathogenesis of AKI is highly multifactorial and complex, including vasoconstriction, reactive oxygen species formation, cell death, abnormal immune modulators and growth factors. Emerging evidence from both human and animal studies suggests that dysregulation of iron metabolism may play a potentially important role in AKI. Therefore, targeting the iron homeostasis may provide a new therapeutic intervention for AKI. New therapeutic strategies including iron chelation therapy, targeting iron metabolism related proteins and direct inhibitors of ferroptosis are imperative to improve the outcomes of patients. Taking into consideration the complexity of AKI, one intervention may not be enough for therapeutic success. Future preclinical studies in animal disease models followed by well-designed clinical trials should be conducted to extend findings from animal AKI models to humans.     

Evaluating the risk of hyperkalaemia and acute kidney injury with cotrimoxazole: a retrospective observational study

ObjectivesIncreasing antimicrobial resistance has renewed interest in older, less used antimicrobials. Cotrimoxazole shows promise; however, hyperkalaemia and acute kidney injury (AKI) are potential complications. Identifying risk factors for and quantification of these events is required for safe use. This study aimed to evaluate predictors of cotrimoxazole-associated AKI and hyperkalaemia in a clinical setting.MethodsPatients prescribed cotrimoxazole were identified using electronic healthcare records over 3 years (1 April 2016 to 31 March 2019). Individual risk factors were recognized. Serum creatinine and potassium trends were analysed over the subsequent 21 days. AKI and patients with hyperkalaemia were classified using Kidney Disease Improving Global Outcomes (KDIGO) and laboratory criteria. Univariate and multiple logistic regression analyses were performed.ResultsAmong 214 patients prescribed cotrimoxazole, 42 (19.6%, 95% confidence interval (CI) 14.6–25.7) met AKI criteria and 33 (15.4%, 95% CI 11.0–21.1) developed hyperkalaemia. Low baseline estimated glomerular filtration rate (<60 mL/min/1.73 m², odds ratio (OR) 7.78, 95% CI 3.57–16.13, p < 0.0001) and cardiac disorders (OR 2.40, 95% CI 1.17–4.82, p 0.011) predicted AKI, while low baseline estimated glomerular filtration rate (<60 mL/min/1.73 m², OR 6.80, 95% CI 3.09–15.06, p < 0.0001) and higher baseline serum potassium (p 0.001) predicted hyperkalaemia. Low-dose cotrimoxazole (<1920 mg/d) was associated with lower AKI and hyperkalaemia risk (p 0.007 and 0.019 respectively). Early (within the first 2–4 days of therapy) serum creatinine changes predicted AKI (OR 3.65, 95% CI 1.73–7.41, p 0.001), and early serum potassium changes predicted hyperkalaemia (>0.6 mmol/L, OR 2.47, 95% CI 1.14–5.27, p 0.0236).ConclusionsCotrimoxazole-associated AKI and hyperkalaemia is frequent and dose dependent. Renal function, serum potassium and preexisting cardiac disorders should be evaluated before prescribing cotrimoxazole. Serum creatinine and potassium monitoring within first 2 to 4 days of treatment to identify susceptible patients is recommended, and the lowest effective dose ought to be prescribed.     

Acceptance and utilization of HIV testing among the youth: a cross-sectional study in Techiman,Ghana

BackgroundIn Ghana, efforts including ‘Know Your Status’ campaign have been made to increase awareness and improve the uptake of HIV screening.ObjectiveThis study examined the acceptance and utilization of the HIV/AIDS ‘Know Your Status’ campaign and determine dthe differences in HIV testing by demographic characteristics among the youth in Techiman, Ghana.MethodThis study was a cross-sectional study conducted among the youth aged 15–24 years. A structured questionnaire was used to collect data from 200 purposively selected respondents.ResultsThe mean age of the respondents was 19.6±2.72 years. There was a universal awareness (100%) of HIV/AIDs, and were knowledgeable about the mode of transmission, symptoms and the prevention of HIV. A high proportion of the respondents (n=161, 80.5%) had heard about the ‘Know Your Status’ (KYS) campaign. Less than half of respondents (n=91, 45.5%) had tested for HIV, and only 16.5% (n=15/91) of respondents tested through the KYS campaign. Testing for HIV was associated with age (p<0.001) and marital status (p<0.001).ConclusionThe youth should therefore be targeted in the awareness and the ‘Know Your Status campaigns’, and in an effortsto promote screening for HIV.     

Characteristics,risk factors and outcomes of community-acquired acute kidney injury in the elderly: a prospective tertiary hospital study,Egypt

BackgroundAcute Kidney Injury (AKI) is a public health problem. Elderly present a greater predisposition to the development of AKI, either due to kidney senility, or due to high prevalence of comorbidities and polypharmacy. Considering the scarcity of studies on AKI in the elderly particularly in developing countries, this study emphasizes on the pattern and outcome of AKI in the Egyptian elderly.ObjectiveTo analyze the demographics, risk factors and outcomes of Acute Kidney Injury (AKI) in the Egyptian elderly.MethodsA total of 199 patients were included over one year and were divided into two groups; group I (79 elderly patients) and group II (120 non-elderly patients). The two groups were compared regarding demographics, risk factors and major outcomes including patient and renal survival.ResultsElderly patients showed a higher prevalence of Diabetes Mellitus and chronic kidney disease (p=0.004 and 0.005 respectively). Pre-renal causes of AKI principally dehydration represented the major risk factor (p=0.003). Sepsis and hypertension predicted mortality in the elderly (p=0.001 and 0.035 respectively).ConclusionIn our locality; the elderly is highly vulnerable to AKI. Pre-renal causes principally dehydration represent the main triggers of AKI. Sepsis and hypertension contribute to mortality in this population. Preventive strategies are crucial not only in the hospital but also at home.     

烧伤休克期小儿急性肾损伤的防治

目的 探讨烧伤休克期补液对小儿急性肾损伤（AKI）的影响及联合检测血清肌酐（SCr）、胱抑素C（CysC）、尿微球蛋白及尿酶的临床应用.方法 回顾性分析2010年6月至2013年6月濮阳市油田总医院烧伤整形科收治的严重烧伤患儿116例的病例资料,随机分为传统组（采用传统方案治疗）和改进组（采用改进后方案治疗）进行补液治疗,其中传统组59例,改进组57例.有休克症状的经液体复苏达休克治疗终点指标.烧伤早期1、3、5 d进行SCr、血尿素氮（BUN）、CysC、肾小球滤过率（GFR）及尿a1微球蛋白（a1-MG）、β2微球蛋白（β2-MG）、N-乙酰-B-D-氨基葡萄糖苷酶（NAG）检测,同时依据急性肾损伤网络（AKIN）关于AKI的分级诊断标准（基于RIFLE）评估,所获数据进行样本率、样本均数比较,采用u检验.分析两组液体治疗对AKI的影响程度.结果 补液治疗第1个24 h实际补液总量占公式计算量：59例传统组患儿（108.5±9.3）%,57例改进组患儿（141.7±28.2）%.第2个24 h实际补液总量占公式计算量：59例传统组患儿（104.6±10.3）%, 15例休克期度过不平稳.57例改进组患儿（103.8±9.4）%,7例休克期度过不平稳.发生急性肾损伤：传统组17例（28.8%）,改进组7例（12.3%）,AKI发生率比较差异具有统计学意义（aP＜0.05）.传统组与改进组液体治疗后CysC第1、3天比较差异具有高度统计学意义（P＜0.01）.a1-MG、β2-MG、NAG第1、3、5天比较差异均具有高度统计学意义（P＜0.01）.结论 小儿严重烧伤后及时、快速、充分的液体治疗,尽快纠正休克,可以降低AKI的发生率.动态检测CysC、尿微球蛋白及尿酶准确评估AKI,监测肾小球、肾小管功能,能安全实施个体化补液及综合治疗.     

Acute kidney injury applying pRifle scale in Children of Hospital Universitario del Valle in Cali,Colombia: clinical features,management and evolution

Objective:

To know the epidemiology of Acute Kidney Injury (AKI) in the pediatric population at Hospital Universitario del Valle (HUV), a tertiary University Hospital in Cali, Colombia.

Methods:

We obtained a series of cases through daily surveillance for a seven-month period (June 1 to December 31, 2009) in patients older than 30 days and under 18 years at HUV. We excluded patients with previous diagnosis of chronic renal failure. The new pRIFLE scale was used to define AKI.

Results:

27 patients were detected, with mean age of 36 months. Incidence of AKI was 0.38% from pediatric admissions and 6.2% from the pediatric intensive care unit (pICU) admissions. The pRIFLE scale at study entrance was: Risk: 2 patients, Injury: 8, Failure: 17. Etiology of AKI was: pre-renal in 89%, primary renal disease in 3.7%, and post-renal in 7.4%. There was an association of AKI with sepsis in 66.7% and 48.2% progressed to septic shock. Six patients required renal replacement therapy, all required peritoneal dialysis. The AKI was multi-factorial in 59.3% and associated with systemic multi-organ failure in 59.3%. At study entry, 63% patients were in pICU. The average hospital stay was 21.3 ± 9.2 days. Six children died, 16 resolved AKI, and nine were left with renal sequelae.

Conclusions:

We recommended pRIFLE scale for early diagnosis of AKI in all pediatric services. Education in pRIFLE scale, prevention of AKI, and early management of sepsis and hypovolemia is recommended.     

胱抑素C评价早中期慢性肾脏病患者肾功能损害的临床价值

目的探讨血清胱抑素C（CysC）评价早中期慢性肾脏病（CKD）患者肾功能损害的临床价值。方法以2008年1月至2010年12月深圳市第六人民医院肾内科住院治疗的221例CKD1～3期患者为观察对象,测定CysC、血肌酐（SCr）、血尿素氮（BUN）、血尿酸（BUA）及血白蛋白（Alb）,与MDRD公式计算的肾小球滤过率（GFR）进行比较。结果 CKD1～3期患者CysC随着GFR的下降而升高,各组间比较差异有统计学意义（P〈0.05）;血清CysC水平与SCr、BUN及BUA水平呈明显正相关（r=0.650,P=0.000;r=0.631,P=0.000;r=0.309,P=0.000）,与GFR水平呈明显负相关（r=-0.717,P=0.000）。CKD2期患者CysC异常检出率为32.8%,SCr为0;CKD3期患者CysC异常检出率为73.0%,SCr为58.4%,CKD3期患者CysC、SCr的异常检出率差异有统计学意义（P〈0.05）。CysC评估GFR的接受者操作特征曲线下面积（AUCROC）为0.853,敏感性为0.780,特异性为0.817;SCr的AUCROC为0.924,敏感性为0.793,特异性为0.958;联合CysC和SCr后,AUCROC上升至0.940,敏感性为0.853,特异性为0.950。结论 CysC是评估早中期CKD患者肾功能损害的敏感指标,联合应用CysC和SCr可提高对早中期慢性肾功能不全患者的诊断效能。     

Aliskiren attenuates oxidative stress and improves tubular status in non-diabetic patients with chronic kidney disease-Placebo controlled,randomized, cross-over study

PurposePharmacological inhibition of the renin-angiotensin-aldosteron system (RAAS) may have a beneficial impact on proteinuria and chronic kidney diseases (CKD) progression. Despite recent progress by means of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB), there is still no optimal therapy which can stop progression of the nephropathy. Recently introduced aliskiren is the first orally bioavailable direct renin inhibitor approved for the treatment of hypertension. The purpose was to evaluate the extent of oxidative stress and tubular injury after the direct renin inhibitor, aliskiren compared with placebo and perindopril in patients with non-diabetic chronic kidney disease (NDCKD).Material/methodsA randomized, double-blind, cross-over trial was performed in 14 patients receiving 300 mg aliskiren, 10 mg perindopril and placebo in random order. The end point was a change in the urinary excretion of N-acetyl-β-D-glucosaminidase (NAG) and α1-microglobulin (α1m) and 15-F_2α-isoprostane.ResultsAliskiren reduced excretion of 15-F_2α-isoprostane (p = 0.03) and α1m (p = 0.01) as compared to placebo. There were no differences between aliskiren and perindopril in this regard. NAG urine excretion did not change after aliskiren and perindopril.ConclusionsAliskiren attenuates oxidative stress and may improve functional status of tubules in patients with NDCKD.     

Acute Kidney Injury in Pediatric Patients Receiving Allogeneic Hematopoietic Cell Transplantation: Incidence,Risk Factors,and Outcomes

Acute kidney injury (AKI) is a common adverse event after hematopoietic cell transplantation (HCT). AKI is associated with early death or chronic kidney disease among transplant survivors. However, large-scale pediatric studies based on standardized criteria are lacking. We performed a retrospective analysis of 1057 pediatric patients who received allogeneic HCT to evaluate the incidence and risk factors of AKI according to AKI Network criteria within the first 100 days of HCT. We also determined the effect of AKI on patient survival. The 100-day cumulative incidences of all stages of AKI, stage 3 AKI, and AKI requiring renal replacement therapy (RRT) were 68.2%?±?1.4%, 25.0%?±?1.3%, and 7.6%?±?.8%, respectively. Overall survival at 1 year was not different between patients without AKI and those with stage 1 or 2 AKI (66.1% versus 73.4% versus 63.9%, respectively) but was significantly different between patients without AKI and patients with stage 3 AKI with or without RRT requirement (66.1% versus 47.3% versus 7.5%, respectively; P?<?.001). Age, year of transplantation, donor type, sinusoidal obstruction syndrome (SOS), and acute graft-versus-host disease (GVHD) were independent risk factors for stages 1 through 3 AKI. Age, donor, conditioning regimen, number of HCTs, SOS, and acute GVHD were independent risk factors for AKI requiring RRT. Our study revealed that AKI was a prevalent adverse event, and severe stage 3 AKI, which was associated with reduced survival, was common after pediatric allogeneic HCT. All patients receiving allogeneic HCT, especially those with multiple risk factors, require careful renal monitoring according to standardized criteria to minimize nephrotoxic insults.     

Glomerulocystic kidney disease in a Belgian Malinois dog: an ultrastructural, immunohistochemical, and lectin-binding study

Renal cysts in the cortex of a juvenile Belgian Malinois dog with acute renal failure were studied by means of light, scanning and transmission electron microscopy, immunohistochemistry for intermediate filaments, and binding for wheat germ agglutinin (WGA), peanut agglutinin (PNA), and Maclura pomifera agglutinin (MPA) lectins to determine the morphological and histochemical features of the epithelial cells of these cysts. The cysts were renal corpuscles with expanded urinary space. Glomerular tufts were small with poorly developed capillary loops and increased mesangial matrix. Continuity with the proximal tubule was evident in some cystic glomeruli. Two cell types lined Bowman's capsule. One was squamous with a central cilium and microvilli. The other had morphological and histochemical features of immature podocytes (parietal podocytes). These cells were round and protruded into the urinary space; they had thick cytoplasmic projections that resembled foot processes of podocytes, microvilli, and filtration slits. The parietal podocytes expressed vimentin and cytokeratins and had affinity for WGA as do normal immature podocytes. These features suggest that the parietal podocytes are derived by metaplasia of the parietal cells. The basement membrane of Bowman's capsule was irregularly thickened and showed multifocal glycosylation changes with lectin histochemistry (WGA, PNA, MPA) in areas adjacent to the parietal podocytes. Histologic and ultrastructural findings in this dog are consistent with glomerulocystic kidney disease. This is the second report of canine glomerulocystic kidney disease. Features are similar to those of the human counterpart, but it is unclear whether genetic defects cause the disease in the dog. The presence of parietal podocytes in all cysts suggests that abnormal differentiation may play an important role in the pathogenesis of this type of polycystic kidney disease.