Reductions in Plasma Cystatin C After Initiation of Antiretroviral Therapy Are Associated With Reductions in Inflammation: ACTG A5224s

Comparison of Renal Function Biomarkers of Serum Creatinine and Cystatin C in HIV-Infected People on Dolutegravir-Containing Therapy

Objective(s)

HIV-1-infected Chinese patients who were treated naïve with combination dolutegravir (DTG) and tenofovir disoproxil fumarate (TDF) group, DTG without TDF group, TDF without DTG, as well as patients switched to DTG-containing therapy from other drugs were included.

Design

The dynamics of serum creatinine, cystatin C (CysC) level, eGFR_cr and eGFR_CysC at the baseline, 4 w, 12w, 24w, 36w and 48w for different group of patients were collected and evaluated.

Methods

Changes in serum creatinine, levels, eGFR_cr and eGFR_CysC were analyzed among groups and in different time-points. Intra-group correlation coefficient and Bland–Altman plot were used to compare the results of eGFR_cr and eGFR_CysC.

Results

Thirty-seven treated-naïve HIV-patients in combined DTG and TDF group (group 1), 23 in DTG without TDF patients (group 2) and 47 patients on TDF without DTG group (control group, group 3) along with 31 patients whose ART switch to DTG-containing regimens (group 4) were collected. Serum creatinine was significantly elevated in the group 1 and group 2 instead of group 3 from baseline to 48w. Mean decreased change of eGFR calculated by serum creatinine proved the same conclusion. However, there were no differences in serum cystatin C and eGFR_CysC between baseline and at 48 weeks in DTG-containing groups. Moreover, the proportion of eGFRcr decreased over 30% was significantly higher in DTG-treatment group.

Conclusion

We demonstrated the clinical benefits of CysC for assessing the glomerular filtration rate when evaluating renal function in HIV-1-infected patients treated with whether DTG combined with TDF or not.

Association of Kidney Disease With Abnormal Cardiac Structure and Function Among Ugandans With HIV Infection

BACKGROUND

People with HIV (PWH) are at an increased risk of both heart and kidney disease, but the relationship between kidney disease and cardiac structure and function in this population has not been well studied. In particular, whether the relationship between kidney disease and cardiac structure and function is stronger for PWH compared with uninfected controls is unknown.

METHODS

One hundred PWH on antiretroviral therapy were compared with 100 age-matched and sex-matched controls without HIV in Uganda. Multivariable regression models were used to examine associations between creatinine-based and cystatin C-based estimated glomerular filtration rate (eGFR), albumin-creatinine ratio, and echocardiographic measures of cardiac structure and function.

RESULTS

PWH had lower eGFRcr (β -7.486, 95% confidence interval: -13.868 to -1.104, P = 0.022) and a higher rate of albumin-creatinine ratio ≥30 (odds ratio 2.146, 95% confidence interval: 1.027 to 4.484, P = 0.042) after adjustment for traditional risk factors. eGFR was inversely associated with both left ventricular mass index and diastolic dysfunction in adjusted models but not with systolic function. Albuminuria was associated with more diastolic dysfunction among PWH but not controls (P for interaction = 0.046). The association of HIV with a higher left ventricular mass index (P = 0.005) was not substantially affected by adjusting for eGFRcr.

CONCLUSION

Among Ugandans, eGFR is associated with elevated LV mass and diastolic dysfunction. The association between albuminuria and diastolic dysfunction is particularly strong for PWH.

The Impact of Immunosuppression on Chronic Kidney Disease in People Living With Human Immunodeficiency Virus: The D:A:D Study

BACKGROUND

Relations between different measures of human immunodeficiency virus-related immunosuppression and chronic kidney disease (CKD) remain unknown.

METHODS

Immunosuppression measures included baseline, current, time-lagged and nadir CD4, years and percentage of follow-up (%FU) with CD4 ≤200 cells/μL, and CD4 recovery. CKD was defined as confirmed estimated glomerular filtration rate <60 mL/minute/1.73 m2.

RESULTS

Of 33 791 persons, 2226 developed CKD. Univariably, all immunosuppression measures predicted CKD. Multivariably, the strongest predictor was %FU CD4 ≤200 cells/μL (0 vs >25%; incidence rate ratio [IRR], 0.77 [95% confidence interval [CI], .68-.88]), with highest effect in those at low D:A:D CKD risk (IRR, 0.45 [95% CI, .24-.80]) vs 0.80 [95% CI, .70-.93]).

CONCLUSIONS

Longer immunosuppression duration most strongly predicts CKD and affects persons at low CKD risk more.

Natural cystatin C fragments inhibit GPR15-mediated HIV and SIV infection without interfering with GPR15L signaling

GPR15 is a G protein-coupled receptor (GPCR) proposed to play a role in mucosal immunity that also serves as a major entry cofactor for HIV-2 and simian immunodeficiency virus (SIV). To discover novel endogenous GPR15 ligands, we screened a hemofiltrate (HF)-derived peptide library for inhibitors of GPR15-mediated SIV infection. Our approach identified a C-terminal fragment of cystatin C (CysC95-146) that specifically inhibits GPR15-dependent HIV-1, HIV-2, and SIV infection. In contrast, GPR15L, the chemokine ligand of GPR15, failed to inhibit virus infection. We found that cystatin C fragments preventing GPR15-mediated viral entry do not interfere with GPR15L signaling and are generated by proteases activated at sites of inflammation. The antiretroviral activity of CysC95-146 was confirmed in primary CD4+ T cells and is conserved in simian hosts of SIV infection. Thus, we identified a potent endogenous inhibitor of GPR15-mediated HIV and SIV infection that does not interfere with the physiological function of this GPCR.

Cross-Sectional and Longitudinal Performance of Creatinine- and Cystatin C-Based Estimating Equations Relative to Exogenously Measured Glomerular Filtration Rate in HIV-Positive and HIV-Negative Persons

BACKGROUND

Reliable estimates of glomerular filtration rate (GFR) are important in the clinical management of HIV-positive patients. Data on the performance of widely used estimating equations (eGFR) relative to exogenously measured GFR are sparse in this population.

METHODS

We evaluated cross-sectional and longitudinal accuracy and bias of eGFR, based on creatinine and cystatin C, relative to disappearance of infused iohexol from plasma (iGFR) in a cohort of participants followed annually for up to 7 years.

RESULTS

A total of 222 HIV-positive and 139 HIV-negative participants contributed 1240 visits with valid iGFR and eGFR measures. Estimated GFR based on both creatinine and cystatin C performed the best. Estimated GFR based on creatinine alone overestimated iGFR by 9 mL·min·1.73 m on average and was significantly less accurate in HIV-positive than HIV-negative individuals. The performance of equations based on either creatinine alone or cystatin C alone were significantly affected by participant factors (eg, non-suppressed HIV RNA, nadir CD4 count, hepatitis C virus coinfection). The average iGFR slope was -4% per year in HIV-positive participants. In both HIV-positive and HIV-negative participants, eGFR slope measures were generally unbiased but inaccurate, with only 60%-74% of observations falling within ±5% points of iGFR slope.

CONCLUSIONS

Both creatinine and cystatin C have limitations as GFR indices in HIV-positive individuals. Estimated GFR based on both creatinine and cystatin C performed best in our study and may be preferred in HIV-positive persons with kidney disease or comorbidities that place them at high risk for kidney disease.

Do Combination Antiretroviral Therapy Regimens for HIV Infection Feature Diverse T-Cell Phenotypes and Inflammatory Profiles?

Immune abnormalities featuring HIV infection persist despite the use of effective combination antiretroviral therapy (cART) and may be linked to the development of noninfectious comorbidities. The aim of the present narrative, nonsystematic literature review is to understand whether cART regimens account for qualitative differences in immune reconstitution. Many studies have reported differences in T-cell homeostasis, inflammation, coagulation, and microbial translocation parameters across cART classes and in the course of triple vs dual regimens, yet such evidence is conflicting and not consistent. Possible reasons for discrepant results in the literature are the paucity of randomized controlled clinical trials, the relatively short follow-up of observational studies, the lack of clinical validation of the numerous inflammatory biomarkers utilized, and the absence of research on the effects of cART in tissues. We are currently thus unable to establish if cART classes and regimens are truly accountable for the differences observed in immune/inflammation parameters in different clinical settings. Questions still remain as to whether an early introduction of cART, specifically in the acute stage of disease, or newer drugs and novel dual drug regimens are able to significantly impact the quality of immune reconstitution and the risk of disease progression in HIV-infected subjects.

Plasma Cystatin C Associates With HIV-Associated Neurocognitive Disorder but Is a Poor Diagnostic Marker in Antiretroviral Therapy-Treated Individuals

OBJECTIVE

To examine associations between plasma cystatin C and neurocognitive impairment (NCI) and its performance as a diagnostic marker before and during initial antiretroviral therapy (ART).

METHODS

Multivariable logistic regression and generalized estimating equations examined associations with NCI, determined by neuropsychological measurements, in participants of a 48-week randomized clinical trial of initial ART. Receiver operator characteristic curves examined diagnostic models of NCI.

RESULTS

Cystatin C was associated with NCI before ART [odds ratio (OR) 3.4 (95% CI: 1.2 to 9.4) for each 2-fold increase in baseline levels] and during 48 weeks of ART, in models that excluded baseline measurements [OR 3.0 (1.2 to 7.8) for each 2-fold increase in time-updated levels]. The strength of association increased with more severe impairment using HIV-associated neurocognitive disorder criteria [OR 2.2 (0.8 to 6.0) with asymptomatic NCI and OR 4.0 (1.5 to 11.0) with mild neurocognitive disorder or HIV-associated dementia vs. no impairment, for each 2-fold increase in time-updated levels] or by global development score [OR 2.6 (1.1 to 6.3) with mild impairment and OR 4.6 (1.1 to 18.9) with moderate or severe impairment vs. no impairment]. Cystatin C performed poorly as a diagnostic marker for NCI, however, with an area under the receiver operator characteristic curve of 0.58 at baseline and 0.54 at week 48.

CONCLUSIONS

Higher plasma cystatin C levels were significantly associated with NCI, but these levels did not seem to be useful as a diagnostic marker for this condition.

Change in Renal Function among HIV-Infected Koreans Receiving Tenofovir Disoproxil Fumarate-Backbone Antiretroviral Therapy: A 3-Year Follow-Up Study

PURPOSE

Tenofovir disoproxil fumarate (TDF) is commonly prescribed as a fixed-dose, co-formulated antiretroviral drug for HIV-1 infection. The major concern of long-term TDF use is renal dysfunction. However, little is known about the long-term patterns of changes in renal function in HIV-infected Koreans receiving TDF.

MATERIALS AND METHODS

We prospectively followed 50 HIV-infected Koreans, performing laboratory tests every 3 months during the first year and every 6 months for the next 2 years. Urine N-acetyl-β-D-glucosaminidase (NAG) and plasma cystatin-C were measured using samples collected in the first year. Data on renal function were retrospectively collected on HIV-infected patients receiving first-line TDF (n=40) and in antiretroviral therapy (ART)-naïve patients (n=24) for 3 years. Renal function was evaluated as estimated glomerular filtration rate (eGFR) from serum creatinine [Modification of Diet in Renal Disease (MDRD)] and cystatin-C.

RESULTS

The eGFR (cystatin-C) showed significant changes from 0 to 48 wks (p=0.002), with the lowest levels at 24 wks (84.3±18.8 mL/min vs. 90.3±22.5 mL/min, p=0.021 by post hoc test). Urine NAG levels did not differ at 0, 12, 24, and 48 wks, although eGFR (MDRD) significantly decreased from 0 (98.7±18.9 mL/min/1.73 m²) to 144 wks (89.0±14.7 mL/min/1.73 m²) (p=0.010). The first-line TDF group had significantly lower eGFR (MDRD) than the ART-naïve group at 144 wks (89.7 mL/min/1.73 m² vs. 98.4 mL/min/1.73 m², p=0.036). Thirteen (26%) participants experienced a decrease in renal impairment of 10 mL/min/1.73 m² in eGFR (MDRD) at 144 wks.

CONCLUSION

These data suggest that clinically meaningful renal injury can develop in HIV-infected Koreans receiving long-term TDF.

Cystatin C Falsely Underestimated GFR in a Critically Ill Patient with a New Diagnosis of AIDS

Cystatin C has been suggested to be a more accurate glomerular filtration rate (GFR) surrogate than creatinine in patients with acquired immunodeficiency syndrome (AIDS) because it is unaffected by skeletal muscle mass and dietary influences. However, little is known about the utility of this marker for monitoring medications in the critically ill. We describe the case of a 64-year-old female with opportunistic infections associated with a new diagnosis of AIDS. During her course, she experienced neurologic, cardiac, and respiratory failure; yet her renal function remained preserved as indicated by an eGFR ≥ 120 mL/min and a urine output > 1 mL/kg/hr without diuresis. The patient was treated with nephrotoxic agents; therefore cystatin C was assessed to determine if cachexia was resulting in a falsely low serum creatinine. Cystatin C measured 1.50 mg/L which corresponded to an eGFR of 36 mL/min. Given the >60 mL/min discrepancy, serial 8-hour urine samples were collected and a GFR > 120 mL/min was confirmed. It is unclear why cystatin C was falsely elevated, but we hypothesize that it relates to the proinflammatory state with AIDS, opportunistic infections, and corticosteroids. More research is needed before routine use of cystatin C in this setting can be recommended.

A two-week regimen of high-dose integrase inhibitors does not cause nephrotoxicity in mice

BACKGROUND

The integrase inhibitors, raltegravir and dolutegravir, are nucleoside reverse transcriptase inhibitor-sparing agents which may be used as part of first-line antiretroviral therapy for HIV. These drugs inhibit creatinine secretion through organic cation transporters, thus elevating serum creatinine without affecting glomerular filtration. We sought to determine whether subtle signs of nephrotoxicity could be observed in mice administered a two-week regimen of high-dose integrase inhibitors.

METHODS

C57BL/6 mice were fed standard water (CTRL, n = 6), raltegravir-containing water (40 mg/kg/day, n = 6), or dolutegravir-containing water (2.7 mg/kg/day, n = 6) for two weeks and sacrificed. Endpoints were assessed including urine microalbumin, kidney injury molecule-1 renal tissue gene expression, renal histopathology, serum creatinine, and blood urea nitrogen.

RESULTS

The results are NOT consistent with a direct nephrotoxic effect of the integrase inhibitors in mice. Serum creatinine was significantly elevated in raltegravir and dolutegravir mice (p < 0.05) compared to control (raltegravir = 0.25 mg/dl, dolutegravir = 0.30 mg/dl versus CTRL = 0.17 mg/dl). Blood urea nitrogen, cystatin C, and urine microalbumin were unchanged. Kidney injury molecule-1 tissue expression in raltegravir and dolutegravir groups was nonsignificantly elevated compared to control (1.2-fold compared to control). Renal histopathology by periodic acid-Schiff staining failed to reveal glomerular or tubular renal injury in any group.

CONCLUSION

These studies are consistent with integrase inhibitors competitively inhibiting creatinine secretion. While no evidence of direct nephrotoxicity was observed after two weeks of high-dose drug administration, additional studies may be performed to understand whether these drugs lead to chronic nephropathy.