Mesoamerican nephropathy: A not so unknown chronic kidney disease

Genetic Factors Related to the Development or Progression of Mesoamerican Endemic Nephropathy

Over the past two decades, Mesoamerican endemic nephropathy (MeN) has become a major public health problem in certain regions of Mexico and Central American countries. The etiology of this disease is multifactorial, and important environmental factors have been described, such as chronic heat stress, recurrent episodes of dehydration, infections, and exposure to toxins of chemical and biological origin. Genetic and epigenetic factors have been proposed to play significant roles in MeN. Recent studies have analyzed the role of these factors in MeN. In some cases, these factors appear to be associated with accelerated deterioration of established kidney disease due to preexisting endothelial dysfunction and tubulopathy. In other cases, they appear to be associated with early kidney damage, even before occupational exposure, suggesting that they may play a relevant role in the genesis of the disease. Other factors appear to act as risk reducers for developing MeN in areas with a high prevalence of the disease. Therefore, this disease has a rather complex multifactorial etiology, with possible polygenic contributions, possible epigenetic phenomena, and multiple environmental factors.

Chronic Kidney Disease of Unknown Etiology: A Global Health Threat in Rural Agricultural Communities-Prevalence, Suspected Causes, Mechanisms, and Prevention Strategies

Chronic Kidney Disease of Unknown Etiology (CKDu) is a worldwide hidden health threat that is associated with progressive loss of kidney functions without showing any initial symptoms until reaching end-stage renal failure, eventually leading to death. It is a growing health problem in Asia, Central America, Africa, and the Middle East, with identified hotspots. CKDu disease mainly affects young men in rural farming communities, while its etiology is not related to hypertension, kidney stones, diabetes, or other known causes. The main suspected causal factors are heat-stress, dehydration, exposure to agrochemicals, heavy metals and use of hard water, infections, mycotoxins, nephrotoxic agents, altitude, and genetic factors. This review gives an overview of CKDu and sheds light on its medical history, geographic distribution, and worldwide prevalence. It also summarizes the suspected causal factors, their proposed mechanisms of action, as well as the main methods used in the CKDu prior detection and surveillance. In addition, mitigation measures to reduce the burden of CKDu are also discussed. Further investigation utilizing more robust study designs would provide a better understanding of the risk factors linked to CKDu and their comparison between affected regions.

Mobilisation of jerboa kidney gene networks during dehydration and opportunistic rehydration

Desert animals have evolved systems that enable them to thrive under dry conditions. Focusing on the kidney, we have investigated the transcriptomic adaptations that enable a desert rodent, the Lesser Egyptian Jerboa (Jaculus jaculus), to withstand water deprivation and opportunistic rehydration. Analysis of the whole kidney transcriptome showed many differentially expressed genes in the Jerboa kidney, 6.4% of genes following dehydration and an even greater number (36.2%) following rehydration compared to control. Genes correlated with the rehydration condition included many ribosomal protein coding genes suggesting a concerted effort to accelerate protein synthesis when water is made available. We identify an increase in TGF-beta signaling antagonists in dehydration (e.g., GREM2). We also describe expression of multiple aquaporin and solute carrier transporters mapped to specific nephron segments. The desert adapted renal transcriptome presented here is a valuable resource to expand our understanding of osmoregulation beyond that derived from model organisms.

Chronic Kidney Disease of Non-traditional Etiology in a Young Man From Central America: Geography, Poverty, and Uncertain Pathophysiology Create a Formidable Medical Challenge

A man in his early 20s with kidney biopsy-confirmed focal segmental glomerulosclerosis (FSGS) was admitted with one month of nausea and vomiting, intermittent episodes of confusion, shortness of breath, and dysuria. He reported that many people from his native village in Central America, where he harvested sugarcane as a child, have died from kidney disease, including his father and cousin. He believed the source of disease to be agrochemicals found in the village's water supply. Although FSGS would be a rare manifestation, the patient's risk factors strongly suggested chronic kidney disease of unknown etiology (CKDu) - also known as Mesoamerican nephropathy (MeN) - a phenomenon he had never previously heard of. He took lisinopril for the last six years to manage his kidney disease. Due to uremic symptoms and abnormal electrolytes, he was initiated on hemodialysis.