Brian Kwan

Dr. Brian Kwan


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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5 May 2020 in American Journal of Kidney Diseases
Verified
Journal Article
Closed access
BKBrian Kwan
Brian Kwan
TFTobias Fuhrer
Tobias Fuhrer
JZJing Zhang
Jing Zhang
MDManjula Darshi
Manjula Darshi
BEBenjamin Van Espen
Benjamin Van Espen
RTRaymond R. Townsend
Raymond R. Townsend

16 October 2023 in Journal of Clinical Investigation
Verified
Journal Article
Open access
PDF file
Kumar SharmaKumar Sharma
Kumar Sharma
Guanshi ZhangGuanshi Zhang
Guanshi Zhang
JHJens Hansen
Jens Hansen
PBPetter Bjornstad
Petter Bjornstad
HLHak Joo Lee
Hak Joo Lee
RIRavi Iyengar
Ravi Iyengar
Diabetic kidney disease (DKD) can lead to end-stage kidney disease (ESKD) and mortality; however, few mechanistic biomarkers are available for high-risk patients, especially those without macroalbuminuria. Urine from participants with diabetes from the Chronic Renal Insufficiency Cohort (CRIC) study, the Singapore Study of Macro-angiopathy and Micro-vascular Reactivity in Type 2 Diabetes (SMART2D), and the American Indian Study determined whether urine adenine/creatinine ratio (UAdCR) could be a mechanistic biomarker for ESKD. ESKD and mortality were associated with the highest UAdCR tertile in the CRIC study and SMART2D. ESKD was associated with the highest UAdCR tertile in patients without macroalbuminuria in the CRIC study, SMART2D, and the American Indian study. Empagliflozin lowered UAdCR in nonmacroalbuminuric participants. Spatial metabolomics localized adenine to kidney pathology, and single-cell transcriptomics identified ribonucleoprotein biogenesis as a top pathway in proximal tubules of patients without macroalbuminuria, implicating mTOR. Adenine stimulated matrix in tubular cells via mTOR and stimulated mTOR in mouse kidneys. A specific inhibitor of adenine production was found to reduce kidney hypertrophy and kidney injury in diabetic mice. We propose that endogenous adenine may be a causative factor in DKD.

1 August 2020 in The Journal of Clinical Endocrinology & Metabolism
Verified
Journal Article
Open access
PDF file
HSH. Irene Su
H. Irene Su
BKBrian Kwan
Brian Kwan
BWBrian W Whitcomb
Brian W Whitcomb
KSKsenya Shliakhsitsava
Ksenya Shliakhsitsava
ADAndrew C Dietz
Andrew C Dietz
LNLoki Natarajan
Loki Natarajan
Context Many female survivors of adolescent and young adult cancers (AYA survivors) have shortened reproductive lifespans. However, the timing and duration of ovarian function after cancer treatment are largely unknown. Objective To model the trajectory of ovarian function over two decades following cancer treatment and evaluate how trajectories vary by treatment gonadotoxicity and age. Design In a prospective cohort, AYA survivors aged 18-39 at variable times since cancer treatment completion provided dried blood spots (DBS) every 6 months for up to 18 months. Anti-Müllerian hormone (AMH) levels were measured using the Ansh DBS AMH enzyme-linked immunosorbent assay. The mean AMH trajectory was modeled for the entire cohort and separately by treatment gonadotoxicity and age using functional principal components analysis. Results 763 participants, mean (standard deviation) enrollment age 33.3 (4.7) and age at cancer diagnosis 25.9 (5.7) years, contributed 1905 DBS samples. The most common cancers were breast (26.9%), lymphoma (24.8%), and thyroid (18.0%). AMH trajectories differed among survivors by treatment gonadotoxicity (low, moderate, or high) (P < 0.001). Following low or moderately gonadotoxic treatments, AMH levels increased over 2-3 years and plateaued over 10-15 years before declining. In contrast, following highly gonadotoxic treatment, AMH levels were lower overall and declined shortly after peak at 2-3 years. Younger age at treatment was associated with higher trajectories, but a protective effect of younger age was not observed in survivors exposed to highly gonadotoxic treatments (Pinteraction < 0.001). Conclusions In this large AYA survivor cohort, timing and duration of ovarian function strongly depended on treatment gonadotoxicity and age at treatment. The findings provide novel, more precise information to guide reproductive decision-making.

23 February 2022 in American Journal of Nephrology
Verified
Journal Article
Open access
PDF file
JZJing Zhang
Jing Zhang
TFTobias Fuhrer
Tobias Fuhrer
HYHongping Ye
Hongping Ye
BKBrian Kwan
Brian Kwan
DMDaniel Montemayor
Daniel Montemayor
LNLoki Natarajan
Loki Natarajan
Introduction: Metabolomics could offer novel prognostic biomarkers and elucidate mechanisms of diabetic kidney disease (DKD) progression. Via metabolomic analysis of urine samples from 995 CRIC participants with diabetes and state-of-the-art statistical modeling, we aimed to identify metabolites prognostic to DKD progression. Methods: Urine samples (N = 995) were assayed for relative metabolite abundance by untargeted flow-injection mass spectrometry, and stringent statistical criteria were used to eliminate noisy compounds, resulting in 698 annotated metabolite ions. Utilizing the 698 metabolites’ ion abundance along with clinical data (demographics, blood pressure, HbA1c, eGFR, and albuminuria), we developed univariate and multivariate models for the eGFR slope using penalized (lasso) and random forest models. Final models were tested on time-to-ESKD (end-stage kidney disease) via cross-validated C-statistics. We also conducted pathway enrichment analysis and a targeted analysis of a subset of metabolites. Results: Six eGFR slope models selected 9–30 variables. In the adjusted ESKD model with highest C-statistic, valine (or betaine) and 3-(4-methyl-3-pentenyl)thiophene were associated (p < 0.05) with 44% and 65% higher hazard of ESKD per doubling of metabolite abundance, respectively. Also, 13 (of 15) prognostic amino acids, including valine and betaine, were confirmed in the targeted analysis. Enrichment analysis revealed pathways implicated in kidney and cardiometabolic disease. Conclusions: Using the diverse CRIC sample, a high-throughput untargeted assay, followed by targeted analysis, and rigorous statistical analysis to reduce false discovery, we identified several novel metabolites implicated in DKD progression. If replicated in independent cohorts, our findings could inform risk stratification and treatment strategies for patients with DKD.

29 October 2019 in European Journal of Psychotraumatology
Verified
Journal Article
Open access
DADean T. Acheson
Dean T. Acheson
BKBrian Kwan
Brian Kwan
AMAdam X. Maihofer
Adam X. Maihofer
VRVictoria B. Risbrough
Victoria B. Risbrough
CNCaroline M. Nievergelt
Caroline M. Nievergelt
DBDewleen G. Baker
Dewleen G. Baker
Background: Insomnia is common in service members and associated with many mental and physical health problems. Recently, longitudinal data have been used to assess the impact of disturbed sleep on mental health outcomes. These studies have consistently shown relationships between sleep disturbance and development of mental illness. Objective: The present study examined the longitudinal relationship between sleep disturbance and PTSD symptomatology in a cohort of Marines and Navy Corpsmen deployed to Iraq and Afghanistan (n = 2,404) assessed prior to deployment, as well as at −3 and 6 months post-deployment. Additionally, we aimed to investigate the extent to which these relationships are moderated by combat-stress severity, and to what extent these findings are replicated in a second, separate cohort of Marines and Navy corpsmen (n = 938) assessed with identical measures prior to deployment and within 3 months of return. Method: The present study employed latent variable path models to examine the relationships between pre-deployment sleep disturbance and post-deployment re-experiencing symptoms. Initial cross-lagged path models were conducted on discovery and replication samples to validate the hypothesized predictive relationships. Follow up moderation path models were then conducted to include the effect of combat-stress severity on these relationships. Results: Initial cross-lagged models supported a significant relationship between pre-deployment sleep disturbance and future re-experiencing PTSD symptoms at all time points. Initial moderation models showed a small moderator effect of combat-stress severity, though the main predictive relationship between pre-deployment sleep disturbance and PTSD symptoms remained significant. The moderator effect was not significant in the replication sample. Conclusions: The results of this study support pre-deployment sleep disturbance as a risk factor for development of post-deployment PTSD symptoms. Interventions aimed at normalizing sleep may be important in preventive measures for PTSD. • This study examined the predictive relationships between sleep disturbance and PTSD symptoms in military personnel.• Results demonstrated that sleep disturbance prior to combat deployment is related to the development of PTSD symptoms following return home.• These results suggest that addressing sleep disturbance prior to deployment may be important in preventing development of PTSD in military service members.

30 September 2021 in Metabolites
Verified
Journal Article
Open access
PDF file
RSRintaro Saito
Rintaro Saito
Akiyoshi HirayamaAkiyoshi Hirayama
Akiyoshi Hirayama
AAArisa Akiba
Arisa Akiba
YKYushi Kamei
Yushi Kamei
YKYuyu Kato
Yuyu Kato
SMShoichi Maruyama
Shoichi Maruyama
Acute kidney injury (AKI) is defined as a rapid decline in kidney function. The associated syndromes may lead to increased morbidity and mortality, but its early detection remains difficult. Using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS), we analyzed the urinary metabolomic profile of patients admitted to the intensive care unit (ICU) after invasive surgery. Urine samples were collected at six time points: before surgery, at ICU admission and 6, 12, 24 and 48 h after. First, urine samples from 61 initial patients (non-AKI: 23, mild AKI: 24, severe AKI: 14) were measured, followed by the measurement of urine samples from 60 additional patients (non-AKI: 40, mild AKI: 20). Glycine and ethanolamine were decreased in patients with AKI compared with non-AKI patients at 6–24 h in the two groups. The linear statistical model constructed at each time point by machine learning achieved the best performance at 24 h (median AUC, area under the curve: 89%, cross-validated) for the 1st group. When cross-validated between the two groups, the AUC showed the best value of 70% at 12 h. These results identified metabolites and time points that show patterns specific to subjects who develop AKI, paving the way for the development of better biomarkers.