E.M.D.V. Ekanayake’s research while affiliated with University of North Dakota and other places

Background Chronic kidney disease of uncertain etiology (CKDu) is an emergent health concern, particularly in tropical farming communities in several global hotspots, including Sri Lanka. This particular nephropathy is characterized by a progressive decline in kidney function in the absence of conventional chronic kidney disease (CKD) risk factors such as diabetes mellitus, hypertension, and other identifiable kidney disorders. As it is almost asymptomatic at early stages, CKDu is mostly diagnosed at late stages with significant kidney damage. Hence, the identification of disease susceptibility and vulnerable communities at the earliest possible instances is highly important for the management of the disease. Objective We aimed to compare kidney health across three different farming communities in Sri Lanka to identify CKDu susceptibilities. Methods A cross-sectional study was performed with three selected farming communities: paddy farmers (PF; N = 581), sugarcane farmers (SF; N = 550), and vegetable farmers (VF; N = 244) in comparison with an age-matched control group of nonfarming (NF; N = 225) individuals. A medical examination was performed to investigate health status and medical history, whereas a urinalysis was performed to determine creatinine and albumin contents. Estimated glomerular filtration rate (eGFR) and urinary albumin-creatinine ratio (ACR) were used for assessment of kidney function. CKDu susceptibility was determined based on eGFR, and urinary ACR adhering to the clinical practice guidelines in Sri Lanka. Results The median (interquartile range [IQR]) eGFR levels of PF (85 mL/min/1.73 m ² [72-97]) and SF (93 mL/min/1.73 m ² [73-112]) were significantly lower than that of the NF group (103 mL/min/1.73 m ² [87-125]) ( P < .0001), whereas eGFR of VF (100 mL/min/1.73 m ² [80-111]) was not significantly different compared with NF. The median (IQR) urinary ACR levels of the study groups, PF, SF, VF, and NF, were 0.59 (0.26-1.45), 0.46 (0.28-0.88), 0.45 (0.34-0.90), and 0.44 (0.34-1.02) mg/mmol, respectively. However, urinary ACR did not differ significantly across the study groups ( P > .05). The prevalence of CKDu within PF (13.60%), SF (12.54%), and VF (6.67%) communities was significantly higher ( P < .05) compared with the NF (2.67%). Of the total CKD cases, CKDu susceptible cases represented 73%, 69%, 50%, and 25% in PF, SF, VF, and NF, respectively, indicating a high risk of CKDu susceptibility among farming communities. Moreover, a noteworthy association of CKDu was observed with agrochemical exposure (odds ratio [OR] = 3.11, 95% confidence interval [CI] = 1.36-7.09). Concerning the farming practices, sugarcane farming showed the highest association with CKDu prevalence (OR = 3.40, 95% CI = 1.49-7.78). Conclusions Compared with the nonfarming group, a significant risk of CKDu was observed in the three farming communities, particularly among paddy and sugarcane farmers. Longitudinal epidemiological studies to identify vulnerable farming communities and associated risk factors are critically needed to develop effective management strategies against CKDu within farming communities.

Pediatric renal injury is an emerging health concern in communities affected by chronic kidney disease of uncertain etiology (CKDu). Early detection of susceptibilities through highly sensitive and specific biomarkers can lead to effective therapeutic and preventive interventions against renal diseases. Here, we aimed to investigate the utility of kidney injury molecule (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) in early detection of renal abnormalities in selected pediatric communities in Sri Lanka. The study areas were stratified as CKDu endemic, emerging, and non-endemic based on the prevalence of CKDu, and a total of 804 school students (10–18 years of age) participated in the study. The median (IQR) urinary KIM-1 levels of the participants were 0.193 (0.026–0.338), 0.082 (0.001–0.220) and 0.040 (0.003–0.242) ng/mgCr for CKDu endemic, emerging and non-endemic regions respectively. Participants from CKDu endemic regions reported elevated (p < 0.0001) urinary KIM-1 expression compared to those from the other regions. The median (IQR) NGAL levels in participants from CKDu endemic (2.969; 1.833–5.641), emerging (3.374; 1.766–6.103), and non-endemic (3.345; 1.742–5.128 ng/mgCr) regions showed no significant difference. Also, urinary albumin-creatinine ratio (UACR) showed no significant differences across gender or residency. The prevalence of albuminuria was 1–2% in the locations irrespective of CKDu burden. Albuminuric participants reported higher (p < 0.05) urinary KIM-1 levels in comparison to normoalbuminuric participants. Significantly elevated urinary KIM-1 expression in a pediatric population from CKDu affected regions, especially in the presence of albuminuria, may indicate low-grade early renal damage supporting the utility of KIM-1 as a quantifiable biomarker.

Emerging renal biomarkers (e.g., kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL)) are thought to be highly sensitive in diagnosing renal injury. However, global data on reference intervals for emerging biomarkers in younger populations are lacking. Here, we aimed to determine reference intervals for KIM-1 and NGAL across a pediatric population in Sri Lanka; a country significantly impacted by the emergence of chronic kidney disease of unexplained etiology (CKDu). Urine samples were collected from children (10–18 years) with no prior record of renal diseases from the dry climatic zone of Sri Lanka (N = 909). Urinary KIM-1 and NGAL concentrations were determined using the enzyme-linked immunosorbent assay (ELISA) and adjusted to urinary creatinine. Biomarker levels were stratified by age and gender, and reference intervals derived with quantile regression (2.5th, 50th, and 97.5th quantiles) were expressed at 95% CI. The range of median reference intervals for urinary KIM-1 and NGAL in children were 0.081–0.426 ng/mg Cr, 2.966–4.850 ng/mg Cr for males, and 0.0780–0.5076 ng/mg Cr, 2.0850–3.4960 ng/mg Cr for females, respectively. Renal biomarkers showed weak correlations with age, gender, ACR, and BMI. Our findings provide reference intervals to facilitate screening to detect early renal damage, especially in rural communities that are impacted by CKDu.

Extensive use of herbicides is common among rural agricultural workers in Sri Lanka. Recent studies have postulated their role in the development of chronic kidney disease of unknown etiology (CKDu). Paraquat and glyphosate are leading herbicides used by sugarcane farmers (SF), hence occupational exposure is inevitable. This study examined the expression of urinary paraquat, glyphosate and biomarkers among residential SF in CKDu emerging regions, Warunagama (WA) and Rahathangama (RH), in the Uva Province with non-endemic Matara (MA) in the Southern Province of Sri Lanka. Urinary glyphosate, Paraquat, Kidney injury molecule -1 (KIM-I), Neutrophil gelatinase-associated lipocalin (NGAL) andβ2-microglobulin (B2M) were determined using enzyme-linked immunosorbent assays (ELISA). Urinary creatinine, microalbumin, serum creatinine (SCr), serum cystatin C, estimated glomerular filtration rate (eGFR), and albumin creatinine ratio (ACR) were also assessed. Generally, herbicide residues and kidney injury biomarkers were higher in SF compared to the non-endemic MA. Creatinine-adjusted urinary glyphosate and paraquat levels were significantly higher in WA compared to MA. ACR in RH (median 14.9; IQR 5.4–393.1 mg/g) and WA (23.7; 11.5–64.6) was significantly higher than MA (4.3; 2.2–6.7). This study reports 39 individuals with impaired kidney function among SF in Sri Lanka for the first time. Urinary NGAL levels were significantly higher in both WA (median 2.14; IQR 1.28–6.15 ng/mg Cr) and RH (3.09; 1.15–9.09) compared to MA (1.28; 0.56–2.81). However, urinary KIM-I levels in RH (3.2; 1.29–106.1 ng/g Cr) and WA (3.6; 1.94–115.1) were not significantly higher in MA (1.74; 0.76–116.9). Urinary NGAL (r = 0.493), eGFR (r = −0.147) and ACR (r = 0.171) significantly correlated with urinary glyphosate, but not with urinary paraquat levels. Urinary KIM-1 levels did not correlate with either urinary glyphosate or paraquat, while urinary B2M and serum cystatin C levels showed significant correlation with urinary glyphosate levels. The current study reports higher urinary herbicide levels among sugarcane farmers in WA and RH, and that is potentially linked to the subsequent decline in kidney function, as indicated by ACR, eGFR, and NGAL. We posit that these indicators may serve as markers to detect renal injury among herbicide-exposed SF in Rural Sri Lanka.

Chronic kidney disease of unknown etiology (CKDu) is an emerging global concern affecting several agricultural communities in the Americas and South Asia. Environmental contaminants such as heavy metals (e.g., Cd, As, Pb, and V) and organic pesticides (e.g., glyphosate) in the drinking water have been hypothesized to play a role in childhood onset and progression of this disease. However, a comprehensive analysis of chemical contaminants in the drinking water and effects of these compounds and their mixtures on kidney development and function remains unknown. Here, we conducted targeted and non-targeted chemical analyses of sediment and drinking water in CKDu affected regions in Sri Lanka, one of the most affected countries. Using zebrafish Danio rerio, a toxicology and kidney disease model, we then examined kidney developmental effects of exposure to (i) environmentally derived samples from CKDu endemic and non-endemic regions and (ii) Cd, As, V, Pb, and glyphosate as individual compounds and in mixtures. We found that drinking water is contaminated with various organic chemicals including nephrotoxic compounds as well as heavy metals, but at levels considered safe for drinking. Histological studies and gene expression analyses examining markers of kidney development (pax2a) and kidney injury (kim1) showed novel metal and glyphosate-metal mixture specific effects on kidney development. Mitochondrial dysfunction is directly linked to kidney failure, and examination of mixture specific mitochondrial toxicity showed altered mitochondrial function following treatment with environmental samples from endemic regions. Collectively, we show that metals in drinking water, even at safe levels, can impede kidney development at an early age, potentiating increased susceptibility to other agrochemicals such as glyphosate. Drinking water contaminant effects on mitochondria can further contribute to progression of kidney dysfunction and our mitochondrial assay may help identify regions at risk of CKDu.

Recent development projects taken place all over Sri Lanka seem to cause massive decline in available habitats, habitat fragmentation and edges. Habitat fragmentation and formation of edges threaten survival and reproduction of avifauna. However this has notbeen widely studied in Sri Lanka. Therefore, the objectives of the present study were to reveal the bird-plant associations in selected fragmented habitats to collect baseline data. Present study has selected edges located at the premises of University of Ruhuna (UP), Matara (5°56'N 80°34'E) and Kirala Kele sanctuary (KK), Matara (5°58' N 80°32' E) and Baruthakanda (BK) a secondary dry zone bush land (6°13'N 81°04' E) situated inHambantota. Birds, vegetationand bird – plant associations at the study sites were surveyed along transects and establishedplots (250 m × 25 m) from April- October 2016. Data were analyzed using diversity indices andsites were compared for bird density and plant density using non parametric statistics (Kruskal Wallis Test). Total number of bird species recorded at UP, KK and BK sites were 51,60 and 59 respectively. Shannon –Wiener diversity was 4.30, 4.25 and 3.63 respectively.Highest mean bird density per unit area was 2101 was observed at BK.. Bird and plant densities were significantly different among study sites. (Kruskal Wallis test value – 6.489, P =0.039). As for the observations in this study, birds used plants mainly for feeding in UP, for nesting and roosting in KK and for resting and nesting in BK indicating the site specificity ofthe bird-plant associations. As for the comparison with the reference sites, edge specific bird species at UP i.e. Blue – faced Malkoha, Stork – Billed Kingfisher, Yellow – rumped Flycatcher and BK i.e. Bright Green Warbler, Cinereous Tit, Dusky Warbler were recorded.

Habitat fragmentation and losses are common within past decade in Sri Lanka mostly in Hambantota area, in Southern province due to several development projects. These habitat losses might affect regional flora and fauna including avifauna. Present study focused on Baruthakanda, a secondary dry zone bush land (06013’34”N 81004’35”E) situated in Sooriyawewa Divisional Secretariat, Hambanthota District (annual temperature and precipitation; 27.2 0 C / 1.80 F, 87.1mm per month) where new commercial-scale solar power stations and highways are being constructed. The species richness and total abundance of avifauna were studied for two separate sites {non-fragmented reference site (060 13’ 08”N 81005’11”E, area: 0.505 km2) and a fragmented site, (06014’04”N 81004’48”E, area: 0.161 km2)} in Baruthakanda. Bird counts were taken weekly intervals at selected points from 6.30 to 8.30 a.m. for six weeks. There were 22 (Shannon Wiener index; 2.662) and 44 (Shannon Wiener index; 3.445) bird species recorded at fragmented site and reference site respectively. Most abundant species recorded at reference site were Common Iora, Rose-ringed Parakeet, Plain Prinia and Spotted Dove while Yellow-wattled Lapwing, Red-vented Bulbul, Asian Palm Swift and Jerdon’s Bushlark were observed abundantly in the fragmented site. A rare endemic species, Ceylon Wood Shrike were observed at both sites. In 2014 authors observed a different composition of avifauna (27 species) in the fragmented site just before disturbed. These data indicates that fragmentation might affect the composition and abundance of bird species. Authors suggest further studies on biodiversity and strict conservation priorities in these areas. Key words: Baruthakanda, Hambantota, Habitat fragmentation, Avifauna