Understanding the Renal Fibrotic Process in Leptospirosis

Leptospirosis kidney disease: Evolution from acute to chronic kidney disease

Leptospirosis is a neglected bacterial disease caused by leptospiral infection that carries a substantial mortality risk in severe cases. Research has shown that acute, chronic, and asymptomatic leptospiral infections are closely linked to acute and chronic kidney disease (CKD) and renal fibrosis. Leptospires affect renal function by infiltrating kidney cells via the renal tubules and interstitium and surviving in the kidney by circumventing the immune system. The most well-known pathogenic molecular mechanism of renal tubular damage caused by leptospiral infection is the direct binding of the bacterial outer membrane protein LipL32 to toll-like receptor-2 expressed in renal tubular epithelial cells (TECs) to induce intracellular inflammatory signaling pathways. These pathways include the production of tumor necrosis factor (TNF)-α and nuclear factor kappa activation, resulting in acute and chronic leptospirosis-related kidney injury. Few studies have investigated the relationship between acute and chronic renal diseases and leptospirosis and further evidence is necessary. In this review, we intend to discuss the roles of acute kidney injury (AKI) to/on CKD in leptospirosis. This study reviews the molecular pathways underlying the pathogenesis of leptospirosis kidney disease, which will assist in concentrating on potential future research directions.

Chronic kidney disease with unknown cause across the global spectrum

PURPOSE OF REVIEW

In the 1990s, a type of chronic kidney disease with unknown cause (CKDu) was identified in Central America and Sri Lanka. Patients lacked hypertension, diabetes, glomerulonephritis, or other usual causes of kidney failure. Affected patients are predominantly male agricultural workers aged 20-60 years, living in economically disadvantaged areas with poor access to medical care. Patients typically present late and progress to end-stage kidney disease within 5 years, resulting in social and economic hardship for families, regions, and countries. This review covers the current state of knowledge for this disease.

RECENT FINDINGS

The prevalence of CKDu is increasing in known endemic regions and across the globe, reaching epidemic proportions. There is primary tubulointerstitial injury with secondary glomerular and vascular sclerosis. No definitive etiologic factors have been identified, and these may vary or overlap in different geographic locations. The leading hypotheses include exposure to agrochemicals, heavy metals and trace elements, and kidney injury from dehydration/heat stress. Infections and lifestyle factors may play a role, but are likely not key. Genetic and epigenetic factors are beginning to be explored.

SUMMARY

CKDu is a leading cause of premature death in young-to-middle-aged adults in endemic regions and has become a public health crisis. Studies are underway to investigate clinical, exposome, and omics factors, and hopefully will provide insights into pathogenetic mechanisms resulting in biomarker discovery, preventive measures, and therapeutics.