Parasitic kidney disease: milestones in the evolution of our knowledge

Immune response, oxidative stress, and histological changes of Wistar rats after being administered with Parascaris equorum antigen

Worldwide, particularly in developing nations, helminth infections are the leading causes of livestock illness and mortality. Parascaris (P.) equorum, a parasitic worm from the Ascarididae family, significantly impacts the production, health, and working performance of equines. This study aimed to investigate the impact of intraperitoneal sensitization of P. equorum on the immune system, oxidative stress, and histology in Wistar rats. After acclimatization for 7 days, we divided the rats into five groups, each consisting of six rats. Group I, serving as the control, was administered distilled water, followed by groups II (day 7), III (day 14), IV (day 21), and V (day 33). The rats were euthanized every day mentioned (Days 7-33). On day 0, a dosage of 1ml/100 gm rat (containing 500 μg/ml protein content) emulsified crude antigen extract with an incomplete Freund's adjuvant (1:1 volume), followed by a second dose of the same antigen concentration on day 7. To assess the allergenicity of this nematode, we measured a whole blood profile, serum levels of IFN-γ, IL-5, IL-10, IL-13, and IL-33, total immunoglobulins IgE and IgG, and oxidative stress markers. Also, we examined histological changes in the liver, kidney, and spleen. The results showed that values of total leukocyte count, granulocytes, monocytes, and lymphocytes were significantly (P < 0.05) increased on day 14 post-infection relative to other days of investigation. It was found that the levels of total immunoglobulins (IgE and IgG) and cytokines (INF-γ, IL-5, IL-13, and IL-33) on days 14 and 21 were significantly higher than in the control group. At all periods of the experiment, the injected group exhibited significantly higher concentrations of MDA and NO compared to the control group (P < 0.05). Conversely, GSH and CAT levels (P < 0.05) dropped significantly on days 7, 14, and 21. Different rat tissues showed alterations. Ultimately, this study described the detrimental effects of P. equorum crude antigen administration on the immune system, oxidative states, and histological changes of Wistar rats at various intervals.

Environmental Exposures and Kidney Disease

Accumulating evidence underscores the large role played by the environment in the health of communities and individuals. We review the currently known contribution of environmental exposures and pollutants on kidney disease and its associated morbidity. We review air pollutants, such as particulate matter; water pollutants, such as trace elements, per- and polyfluoroalkyl substances, and pesticides; and extreme weather events and natural disasters. We also discuss gaps in the evidence that presently relies heavily on observational studies and animal models, and propose using recently developed analytic methods to help bridge the gaps. With the expected increase in the intensity and frequency of many environmental exposures in the decades to come, an improved understanding of their potential effect on kidney disease is crucial to mitigate potential morbidity and mortality.

Etiology of Persistent Microalbuminuria in Nigeria (P_MICRO study): protocol and study design

BACKGROUND

Microalbuminuria is an independent risk factor for cardiovascular and kidney disease and a predictor of end organ damage, both in the general population and in persons with HIV (PWH). Microalbuminuria is also an important risk factor for mortality in PWH treated with antiretroviral therapy (ART). In the ongoing Renal Risk Reduction (R3) study in Nigeria, we identified a high prevalence of microalbuminuria confirmed by two measurements 4-8 weeks apart in ART-experienced, virologically suppressed PWH. Although Stage 1 or 2 hypertension and exposure to potentially nephrotoxic antiretroviral medications were common in R3 participants, other traditional risk factors for albuminuria and kidney disease, including diabetes, APOL1 high-risk genotype, and smoking were rare. Co-infection with endemic pathogens may also be significant contributors to albuminuria, but co-infections were not evaluated in the R3 study population.

METHODS

In Aim 1, we will cross-sectionally compare the prevalence of albuminuria and established kidney disease risk factors in a cohort of PWH to age- and sex-matched HIV-negative adults presenting for routine care at the Aminu Kano Teaching Hospital in Kano, Nigeria. We will leverage stored specimens from 2500 R3 participants and enroll an additional 500 PLWH recently initiated on ART (≤ 24 months) and 750 age- and sex-matched HIV-negative adults to determine the contribution of HIV, hypertension, and other comorbid medical conditions to prevalent albuminuria. In Aim 2, we will follow a cohort of 1000 HIV-positive, ART-treated and 500 HIV-negative normoalbuminuric adults for 30 months to evaluate the incidence and predictors of albuminuria.

DISCUSSION

The findings from this study will support the development of interventions to prevent or address microalbuminuria in PWH to reduce kidney and cardiovascular morbidity and mortality. Such interventions might include more intensive monitoring and treatment of traditional risk factors, the provision of renin-angiotensin aldosterone system or sodium-glucose cotransporter-2 inhibitors, consideration of changes in ART regimen, and screening and treatment for relevant co-infections.

Time-dependent renal pathologies associated with the liver fluke infection, opisthorchiasis felinea

Fish-borne trematode infections affect the health of more than 18 million people in Russia and Asian countries. Infection of humans and other mammals with the liver fluke Opisthorchis felineus (Rivolta, 1884) is accompanied by gradual development of liver disorders. Although there is indirect evidence that opisthorchiasis may be associated with damage to other organs, direct evidence of the connection between opisthorchiasis felinea and a kidney pathology has not yet been reported. To gain first insights into the possible relation, we investigated time course profiles of blood markers of renal failure as well as renal histological changes during opisthorchiasis from 1 month to 1.5 years postinfection in golden hamsters Mesocricetus auratus. For the first time, we showed that opisthorchiasis felinea leads to the development of glomerulopathy. In particular, O. felineus infection provoked gradual increases in serum creatinine, serum glucose, and urine protein concentrations. Moreover, there was gradual accumulation of renal tubular casts and of the mesangial matrix. Although the mechanisms underlying these renal pathologies remain unclear and require further research, we can conclude that O. felineus infection causes gradual progression of glomerulopathy accompanied by tubulopathy. Thus, overall, these aberrations correlate with the time course of hepatic pathological changes in opisthorchiasis felinea.

Kidney complications of parasitic diseases

Parasitic agents have been known to cause human disease since ancient times and are endemic in tropical and subtropical regions. Complications of parasitic diseases, including kidney involvement, are associated with worse outcomes. Chagas disease, filariasis, leishmaniasis, malaria and schistosomiasis are important parasitic diseases that can damage the kidney. These diseases affect millions of people worldwide, primarily in Africa, Asia and Latin America, and kidney involvement is associated with increased mortality. The most common kidney complications of parasitic diseases are acute kidney injury, glomerulonephritis and tubular dysfunction. The mechanisms that underlie parasitic disease-associated kidney injury include direct parasite damage; immunological phenomena, including immune complex deposition and inflammation; and systemic manifestations such as haemolysis, haemorrhage and rhabdomyolysis. In addition, use of nephrotoxic drugs to treat parasitic infections is associated with acute kidney injury. Early diagnosis of kidney involvement and adequate management is crucial to prevent progression of kidney disease and optimize patient recovery.

Association between Opisthorchis viverrini Infection and Glomerular Disease in Thailand

INTRODUCTION

Opisthorchis viverrini (OV) is a major cause of infection in Southeast Asia. Previous studies in mouse models have shown that OV infection can contribute to immune-complex glomerulonephritis (GN). However, OV infection in human kidney tissue has never been demonstrated. Herein, we evaluated the association of OV infection with biopsy-proven glomerular disease.

METHODS

This study was performed in adult patients who underwent kidney biopsy between July 2016 and February 2017. All kidney tissue samples were processed using the standard techniques for renal pathological diagnoses and immunohistochemistry techniques to detect OV antigen. Pre-implanted donor kidney tissue samples were used as controls. The participants were also assessed for OV infection by serum OV immunoglobulin G antibody (Ab) levels and/or presence of OV eggs in stool.

RESULTS

Forty-three renal tissue samples from glomerular disease patients and 50 from transplant donors were included in the study. Mean age in the GN group was 41.7 ± 15.9 years, estimated glomerular filtration rate (eGFR) was 70.65 ± 36.61 mL/min/1.73 m2, and median proteinuria was 3.17 (1.70-4.95) g/day. Lupus nephritis (LN) was the most common diagnosis (32.6%), followed by IgA nephropathy (23.3%), IgM nephropathy (18.6%), and primary membranous nephropathy (MN; 7%). The OV antigen was observed in kidney tissue from patients with IgA nephropathy, LN, primary MN, focal segmental glomerulosclerosis, and IgM nephropathy. By contrast, no OV antigen was detected in tissue samples from the control group. The presence of OV antigens was observed in glomerular endothelial cells, mesangial cells, tubular cells, and peritubular capillaries. The odds ratio of positive serum OV Ab to predict the presence of OV antigen in kidney tissues was 4.47 (p = 0.057), and there was a negative correlation between levels of serum OV Ab and eGFR (r = -0.31, p = 0.04).

DISCUSSION/CONCLUSION

This is the first study to demonstrate the presence of OV antigen in human kidney tissue, which indicates that OV infection may be associated with biopsy-proven glomerular diseases.

Pathomechanisms in the Kidneys in Selected Protozoan Parasitic Infections

Leishmaniasis, malaria, toxoplasmosis, and acanthamoebiasis are protozoan parasitic infections. They remain important contributors to the development of kidney disease, which is associated with increased patients' morbidity and mortality. Kidney injury mechanisms are not fully understood in protozoan parasitic diseases, bringing major difficulties to specific therapeutic interventions. The aim of this review is to present the biochemical and molecular mechanisms in kidneys infected with Leishmania spp., Plasmodium spp., Toxoplasma gondii, and Acanthamoeba spp. We present available mechanisms of an immune response, oxidative stress, apoptosis process, hypoxia, biomarkers of renal injury in the serum or urine, and the histopathological changes of kidneys infected with the selected parasites. Pathomechanisms of Leishmania spp. and Plasmodium spp. infections have been deeply investigated, while Toxoplasma gondii and Acanthamoeba spp. infections in the kidneys are not well known yet. Deeper knowledge of kidney involvement in leishmaniasis and malaria by presenting their mechanisms provides insight into how to create novel and effective treatments. Additionally, the presented work shows gaps in the pathophysiology of renal toxoplasmosis and acanthamoebiasis, which need further research.

Infection-Induced Kidney Diseases

Infection induced kidney diseases are of concern for clinicians because timely detection and treatment of infections may cure or limit the extent of injury inflicted by microorganisms causing the infections. Infections can cause kidney injury by either direct invasion, or indirectly by immune mediated mechanisms, which manifest as post-infectious glomerulonephritis, or infection-related glomerulonephritis. Clinical manifestations may be acute or chronic depending on the microorganisms, endemic/epidemic nature and source of infection. All microbials virus, bacteria, mycobacteria, fungus, and protozoa have been implicated in kidney diseases either causing direct kidney injuries or immune-mediated injuries. Infection control practices in large parts of world is limited by poverty, social behavior, high population density, deforestation, inadequate access to safe drinking water, and poor health care facilities. Although, antimicrobials and vaccinations have successfully eradicated and cured many infectious diseases; however injudicious antimicrobial use and emergence of resistant organisms complicated the disease severity like secondary renal amyloidosis with chronic persistent infection. Re-emergence of various infections has been a recent pattern in developed world leading to uncertain diagnostic challenges, and association with kidney diseases.

Tropical Diseases Nephropathy - An Underemphasized Comorbidity

The tropical areas are a home to a number of diseases because of the hot & humid climate, and lack of health care facilities. Tropical Nephropathies are a major health problem and a matter of great concern. The main causes of kidney injury in tropics are due to bacterial, viral or parasitic infections like malaria, dengue, leptospirosis, scrub typhus, acute gastroenteritis, tuberculosis, leprosy and toxic envenomations like snake bite. Renal injury associated with tropical infections has a wide spectrum of presentations ranging from acute kidney injury to chronic kidney disease. Renal involvement in infectious diseases by one or other mechanism is a definite cause of increased morbidity and mortality. Proper understanding of these diseases, early diagnosis, patient education and improved health care facilities will lead to a better outcome and improved survival. This article reviews the various tropical infections causing kidney injury including pathophysiology and line of management.

Preliminary study on tubuloglomerular dysfunction and evidence of renal inflammation in patients with visceral leishmaniasis

Visceral leishmaniasis (VL) is a re-emerging zoonosis of worldwide distribution. Monocyte chemotactic protein-1 (MCP-1) and malondialdehyde (MDA) are inflammation biomarkers that have never been investigated in VL. The aim of this study is to investigate the association between renal abnormalities and inflammation biomarkers in VL. This study is a preliminary prospective study with 16 VL adult patients evaluated before treatment compared with a group of 13 healthy volunteers and 5 VL patients evaluated after treatment. Urinary concentration and acidification tests were performed. MCP-1 and MDA were quantified in urine. Urinary concentration deficit was found in all VL patients before (100%) and four VL patients after (80%) treatment. Urinary acidification deficit was found in nine cases before (56.2%) and two cases after (40%) treatment. Urinary MCP-1 (374 ± 359 versus 42 ± 29 pg/mg creatinine, P = 0.002) as well as urinary MDA (5.4 ± 2.6 versus 2.0 ± 0.8 μmol/mL) showed significant differences between VL patients and controls. These data show that VL patients present urinary concentration and acidification deficit, which can persist even after specific treatment. Urinary MCP-1 and MDA are elevated in patients with VL, which suggests renal inflammation and incipient renal damage.