Going Micro in Leptospirosis Kidney Disease

Uncovering latent infections in kidneys: A novel molecular approach for differential Leptospira detection

Leptospirosis, a re-emerging zoonotic disease caused by Leptospira spp., poses significant global health and veterinary challenges. Long-term colonization of renal tubules by Leptospira in asymptomatic hosts highlights the need for sensitive detection methods. This study evaluates the chronic or latent Leptospira infections in kidneys using a novel molecular approach to examine individual immune responses differences. Digital PCR strategies employing newly developed primer-probe sets targeting the flagellar fliG gene were used to assess the presence of trace Leptospira in infected murine kidneys and urine samples from laboratory-confirmed leptospirosis patients. RNA-based digital PCR detected leptospires in 58 % (targeting lipl32) and 83 % (targeting fliG) of infected kidneys, demonstrating that the digital PCR strategy targeting the fliG gene offers superior sensitivity. Notably, the newly developed fliG-targeting assay detected as low as 20 fg of Leptospira DNA, offering ten-fold greater sensitivity than traditional qPCR for trace detection. This allows for differential detection of Leptospira species and facilitates monitoring of extremely low bacterial loads with greater sensitivity than conventional methods. We also observed regenerating renal tubules with mitosis and elevated cytokine expression in kidneys with transcriptionally active Leptospira during chronic infection. This approach aids in identifying latent infections and offers insights into individual variations. Our research provides a powerful molecular tool for epidemiological studies and public health surveillance, contributing valuable insights into the prevalence and transmission dynamics of this pervasive zoonotic disease.

Potassium Homeostasis

Potassium homeostasis is essential for maintaining the normal resting membrane potential of excitable cells. Yet daily dietary potassium typically far exceeds total extracellular potassium, thus the body has elegant strategies to shift potassium into cells promptly after a meal and then the kidneys efficiently excrete potassium. Potassium excretion depends on adequate kidney perfusion and filtration, sodium delivery to the distal nephron and aldosterone action on the distal nephron. Both hypokalemia and hyperkalemia have been associated with an increase in mortality. In this piece, we share 5 challenging cases to explore normal potassium homeostasis and disorders that can lead to derangements in potassium balance or excretion.

Pathological and molecular study of kidneys in apparently healthy cattle and sheep with special reference to Leptospira species in central and northern Jordan

Background and Aim

Renal pathological conditions can cause significant economic losses for livestock owners. This study investigated and described the gross pathology and histopathology of lesions found in the kidneys of sheep and cattle, with particular attention to the presence of Leptospira spp.

Materials and Methods

Three hundred and sixty kidneys from apparently healthy sheep and cattle (208 and 152, respectively) were collected from slaughterhouses in Jordan for gross and histopathological examinations, multiplex polymerase chain reaction (PCR) analysis, and gene sequencing of Leptospira spp.

Results

Histopathological analysis of the samples revealed the following conditions: interstitial nephritis (4.44%), glomerulonephritis (4.16%), acute tubular necrosis (17.22%), and renal congestion (4.72%). In addition, in 26.9% of the samples, hyaline material was observed in the interstitium of the cortex and medulla. The PCR results revealed that 83 (23.1%) of the 360 samples were positive for Leptospira spp. 16S rRNA, 42/152 (28%) of cattle, and 41/208 (20%) of sheep. Four samples (two sheep and two cattle) were sequenced and deposited in GenBank with accession numbers from OL701310 to OL701313. Basic Local Alignment Search Tool search and nucleotide similarities between OL701311 and OL701313 resulted in the highest similarities with different Leptospira borgpetersenii strains, whereas OL701310 showed the highest nucleotide similarity (99.2%) with the Leptospira interrogans strain. Similarly, phylogenetic analysis revealed that OL701311 to OL701313 clustered together with different serovars of L. borgpetersenii, whereas OL701310 clustered with the L. interrogans clade.

Conclusion

This is the first study to reveal a close association between pathogenic Leptospira spp. and kidney disorders in Jordanian cattle and sheep. These findings may help expand the current understanding of the causes and mechanisms of renal disease in cattle and sheep and contribute to developing more effective prevention and treatment programs.

Human leptospirosis: In search for a better vaccine

Leptospirosis is a neglected disease caused by bacteria of the genus Leptospira and is more prevalent in tropical and subtropical countries. This pathogen infects humans and other animals, responsible for the most widespread zoonosis in the world, estimated to be responsible for 60 000 deaths and 1 million cases per year. To date, commercial vaccines against human leptospirosis are available only in some countries such as Japan, China, Cuba and France. These vaccines prepared with inactivated Leptospira (bacterins) induce a short-term and serovar-specific immune response, with strong adverse side effects. To circumvent these limitations, several research groups are investigating new experimental vaccines in order to ensure that they are safe, efficient, and protect against several pathogenic Leptospira serovars, inducing sterilizing immunity. Most of these protocols use attenuated cultures, preparations after LPS removal, recombinant proteins or DNA from pathogenic Leptospira spp. The aim of this review was to highlight several promising vaccine candidates, considering their immunogenicity, presence in different pathogenic Leptospira serovars, their role in virulence or immune evasion and other factors.

Neglected and Emerging Infections of The Kidney

Individuals, societies, and the environment are affected by neglected and emerging diseases. These diseases result in a variety of severe outcomes, including permanent disabilities, chronic diseases such as chronic kidney disease, and even mortality. Consequences include high health care expenditures, loss of means of support, social stigma, and social exclusion. The burden of these diseases is exacerbated in low- and middle-income countries owing to poverty, inadequate fundamental infrastructure, and the absence of health and social protection systems. The World Health Organization is committed to promoting the following public health strategies to prevent and control neglected tropical diseases: preventive chemotherapy; intensive case management; vector control; provision of safe drinkable water, sanitation, and hygiene; and veterinary public health. In addition, it promotes a One Health strategy, which is a collaborative, multisectoral, and interdisciplinary approach to achieving the greatest health outcomes by recognizing the interdependence of human beings, animals, plants, and their shared environment. This article provides knowledge and strategies for the prevention and treatment of neglected and emerging diseases, with a particular concentration on kidney diseases, as part of a comprehensive approach to One Health.

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.