title: Renal Morphology, Clinical Findings, and Progression Rate in Mesoamerican Nephropathy.
abstract: BACKGROUND
  Mesoamerican nephropathy (MeN) is a chronic kidney disease affecting rural inhabitants in Central America. We have previously described the renal morphology in 8 patients from El Salvador. To confirm the renal pathology, we have studied kidney biopsies from patients with MeN in Nicaragua. Follow-up urine and blood samples from both biopsy studies were collected to investigate the natural history.
  
  
  METHODS
  Case series.
  
  
  METHODS
  In the kidney biopsy study, 19 male sugarcane workers in Nicaragua with suspected MeN were investigated with questionnaires, kidney biopsies, and blood and urine analysis. Inclusion criteria were age 20 to 65 years and plasma creatinine level of 1.13 to 2.49mg/dL or estimated glomerular filtration rate (eGFR) of 30 to 80mL/min/1.73m2. Exclusion criteria were proteinuria with protein excretion > 3g/24 h, uncontrolled hypertension, diabetes mellitus, or other known kidney disease. In the follow up-study, blood and urine from the kidney biopsy study in Nicaragua (n=18) and our previous biopsy study of MeN cases in El Salvador (n=7) were collected 1 to 1.5 and 2 to 2.5 years after biopsy, respectively.
  
  
  RESULTS
  Renal morphology, clinical, and biochemical characteristics, change in eGFR per year.
  
  
  METHODS
  eGFR was calculated using the CKD-EPI creatinine (eGFRcr), cystatin C (eGFRcys), and creatinine-cystatin C (eGFRcr-cys) equations.
  
  
  RESULTS
  In the kidney biopsy study, participants had a mean eGFRcrof 57 (range, 33-96) mL/min/1.73m2. 47% had low plasma sodium and 21% had low plasma potassium levels. 16 kidney biopsies were representative and showed glomerulosclerosis (mean, 38%), glomerular hypertrophy, and signs of chronic glomerular ischemia. Mild to moderate tubulointerstitial damage and mostly mild vascular changes were seen. In the follow up-study, median duration of follow-up was 13 (range, 13-27) months. Mean change in eGFRcrwas -4.4±8.4 (range, -27.7 to 10.2) mL/min/1.73m2per year. Most patients had stopped working with sugarcane cultivation.
  
  
  CONCLUSIONS
  3 biopsy specimens had 4 or fewer glomeruli.
  
  
  CONCLUSIONS
  This study confirms the renal morphology of MeN: chronic glomerular and tubulointerstitial damage with glomerulosclerosis and chronic glomerular ischemia. Follow-up data show that eGFRs, on average, deteriorated.
authors.affiliation: Division of Renal Medicine, Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Julia
authors.initials: J
authors.lastname: Wijkström
authors.affiliation: Research Center on Health, Work and Environment, National Autonomous University of Nicaragua at León, León, Nicaragua; Department of Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Marvin
authors.initials: M
authors.lastname: González-Quiroz
authors.affiliation: Department of Pediatrics, National Autonomous University of Nicaragua at León, León, Nicaragua.
authors.forename: Mario
authors.initials: M
authors.lastname: Hernandez
authors.affiliation: Servicio de Nefrología, Hospital Nacional Rosales, San Salvador, El Salvador.
authors.forename: Zulma
authors.initials: Z
authors.lastname: Trujillo
authors.affiliation: Division of CRC, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Kjell
authors.initials: K
authors.lastname: Hultenby
authors.affiliation: Clinical Pathology and Cytology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Anneli
authors.initials: A
authors.lastname: Ring
authors.affiliation: Clinical Pathology and Cytology, Karolinska University Hospital, Stockholm, Sweden; Drug Safety and Metabolism, AstraZeneca, Mölndal, Stockholm, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Söderberg
authors.affiliation: Research Center on Health, Work and Environment, National Autonomous University of Nicaragua at León, León, Nicaragua.
authors.forename: Aurora
authors.initials: A
authors.lastname: Aragón
authors.affiliation: Division of Renal Medicine, Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Carl-Gustaf
authors.initials: CG
authors.lastname: Elinder
authors.affiliation: Division of Renal Medicine, Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden; Clinical Pathology and Cytology, Karolinska University Hospital, Stockholm, Sweden. Electronic address: annika.wernerson@ki.se.
authors.forename: Annika
authors.initials: A
authors.lastname: Wernerson
mesh_terms: D058186:Acute Kidney Injury; D000328:Adult; D002489:Central America / Q000453:epidemiology; D003404:Creatinine / Q000378:metabolism; D055316:Cystatin C / Q000378:metabolism; D018450:Disease Progression; D004544:El Salvador; D019353:Endemic Diseases; D000067565:Farmers; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006358:Hot Temperature; D006801:Humans; D006984:Hypertrophy; D007008:Hypokalemia / Q000453:epidemiology / Q000378:metabolism; D007010:Hyponatremia / Q000453:epidemiology / Q000378:metabolism; D020896:Hypovolemia; D061705:Image-Guided Biopsy; D007511:Ischemia; D007668:Kidney / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D007678:Kidney Glomerulus / Q000098:blood supply / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009527:Nicaragua / Q000453:epidemiology; D016273:Occupational Exposure; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D012424:Rural Population; D031786:Saccharum; D012598:Sclerosis; D014463:Ultrasonography; D014883:Water-Electrolyte Imbalance; D055815:Young Adult
chemical_list: D055316:Cystatin C; D003404:Creatinine
keywords: CKD of unknown etiology (CKDu); Central America; El Salvador; Mesoamerican nephropathy (MeN); Nicaragua; chronic kidney disease (CKD); dehydration; disease progression; endemic nephropathy; environmental exposure; heat stress; kidney biopsy; renal morphology; renal pathology; sugarcane