Stress Test and Treatment of Chronic Kidney Disease

Abstract

The present invention includes a novel method for treating chronic kidney disease, comprising administering a compound that induces a stress protein response in a patient, and administering a potent antioxidant if the patient's response is below a predefined level. The method also includes a quantitative index for determining the patient's antioxidant reserve capacity.

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 993,446, filed Mar. 23, 2020, which is incorporated herein by reference.

Background Art

[0002] Oxidative stress is a characteristic and mediator of chronic kidney disease (CKD). A decline in antioxidant defense capacity is thought to be part of the cause. However, currently there is no method to predict and evaluate antioxidant defense in humans. Accordingly, there is a need for a method for quantitatively measuring a patient's antioxidant defense and for a treatment method that takes into account the level of the patient's antioxidant response.

Summary of the Invention

Means for Solving the Problems

[0003] (Summary of the Invention) The present invention is a method for treating a patient, comprising: (a) administering to the patient a compound that is a transient oxidative stress inducer; (b) measuring the patient's response to the compound, the response including an elevated level of expression of one or more antioxidant proteins; and (c) administering treatment to the patient if the expression level of one or more antioxidant proteins exceeds a predefined level. In one aspect, the patient may have chronic kidney disease. The compound may be a protoporphyrin such as tin protoporphyrin, and the antioxidant proteins include one or more of HO-1, ferritin, p21, or NQO1. The treatment may include administering an antioxidant such as tetrahydrocurcumin.

[0004] In one aspect, the method is performed such that the expression level of one or more antioxidant proteins is measured prior to step (a) and the expression level of one or more antioxidant proteins measured in step (b) is compared to the expression level measured prior to step (a).

[0005] In another aspect, the present invention relates to a method comprising: (a) administering a compound to a patient, thereby stimulating the production of one or more antioxidant proteins in the patient; (b) obtaining one or more body fluid samples from the patient; and (c) measuring the level of one or more antioxidant proteins produced in the patient. The compound may be a transient oxidative stress inducer including a porphyrin such as tin protoporphyrin or mesoporphyrin. The antioxidant may include one or more of HO-1, ferritin, p21, or NQO1. In another aspect, the production level of one or more antioxidant proteins is measured before step (a), and the expression level of one or more antioxidant proteins measured in step (c) is compared with the expression level measured before step (a). The measured level of antioxidant protein provides a quantitative indicator of the patient's antioxidant reserve capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0006]

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Mode for Carrying Out the Invention

[0007] The inventors have determined that SnPP can function as a pharmaceutical “stress test” for measuring human gene responsiveness and thus antioxidant reserve capacity by increasing stress proteins variably in humans. A stress test can be part of a method for treating chronic kidney disease by administering a potent antioxidant to patients in whom the test indicates a deficiency in antioxidant reserve capacity. The test can also be used to independently evaluate the level of a patient's antioxidant reserve capacity in order to further guide the patient's treatment regimen.

[0008] In one aspect, the present invention includes a method of treating a patient comprising the following steps: (a) administering to the patient a compound that is a transient oxidative stress inducer; (b) measuring the patient's response to the compound, the response including an elevated level of expression of one or more antioxidant proteins; and (c) administering treatment to the patient if the expression level of one or more antioxidant proteins exceeds a predefined level.

[0009] The compound is preferably a protoporphyrin or mesoporphyrin such as tin protoporphyrin. The compound may be a zinc, tin or cobalt protoporphyrin or mesoporphyrin. The compound must be capable of inducing the production of stress proteins in a dose-dependent manner in humans. This makes it possible to quantitatively measure the patient's antioxidant reserve capacity. Examples of antioxidant proteins include one or more of HO-1, ferritin, p21, or NQO1. In one aspect, the present invention measures the patient's baseline levels of these proteins prior to administering the compound. This allows comparison of the increased levels of proteins induced by administration of the compound.

[0010] The specific methods disclosed herein are useful for the treatment of conditions associated with chronic kidney disease. If a patient undergoing treatment for chronic kidney disease lacks antioxidant reserve capacity, the patient may benefit from administration of a potent antioxidant, such as tetrahydrocurcumin (19,20), or an Nrf2 activator, such as bardoxolone methyl.

[0011] Another aspect of the invention is a method that enables the measurement of a patient's antioxidant capacity in a dose-dependent manner. This method includes the following steps: (a) administering a compound to the patient, whereby the compound stimulates the production of one or more antioxidant proteins in the patient; (b) obtaining one or more body fluid samples from the patient; and (c) measuring the levels of one or more antioxidant proteins produced in the patient.

[0012] The compound is preferably tin protoporphyrin, or a transient oxidative stress inducer such as other protoporphyrins or mesoporphyrins. Administration of the compound induces stress proteins such as one or more of HO-1, ferritin, p21, or NQO1. The levels of these induced proteins provide a quantitative indicator of the patient's antioxidant reserve capacity. Those patients having a capacity lower than a predefined value are candidates for potent antioxidant therapy.

[0013] As shown in Figure 1, in healthy volunteers, plasma HO-1 levels increased in a dose-dependent manner after SnPP injection. Plasma HO-1 levels were measured on days 1 - 4 after baseline and after injection of 9, 27, or 90 mg of SnPP. A time- and dose-dependent increase was observed (mean values / 95% confidence intervals are shown). In each subject group, a significant increase in HO-1 values over time was observed (ANOVA / repeated measures; all p-values < 0.001, determined by within-group analysis).

[0014] As shown in Figure 2, plasma HO-1 levels increased after SnPP injection in participants with stage 3 CKD (15 - 29 ml / min / 1.73 m2) and stage 4 CKD (30 - 59 ml / min / 1.73 m2). Plasma HO-1 levels were measured at baseline and on days 1 - 4 after injection of 27 mg or 90 mg of SnPP. An increase in HO-1 that was dependent on time and dose was observed in both the CKD3 and CKD4 groups. In all between-group comparisons, P < 0.001; ANOVA, repeated measures. Mean values / 95% confidence intervals are shown.

[0015] As shown in Figure 3, plasma ferritin levels increased in response to SnPP injection. Plasma ferritin levels were measured at baseline and at 24 + 48 hours after injection of 90 mg of SnPP in healthy volunteers and CKD3 / CKD4 participants. CKD participants had significantly higher baseline ferritin levels compared to healthy volunteers (p < 0.005 in between-group comparison). A significant increase in plasma ferritin was shown after SnPP injection in all three groups (p-values by ANOVA, repeated measures, within-group analysis). The increase relative to the baseline value was similar in the CKD group and the healthy volunteer group. Mean / 95% confidence intervals are shown.

[0016] Figure 4 shows the baseline NQO1 levels in healthy volunteers and CKD participants. The combination of the CKD cohort and healthy volunteers had substantially the same plasma NQO1 concentration. However, in CKD patients, the urinary NQO1 / creatinine level was significantly elevated (p < 0.01; unpaired t-test). When the urinary NQO1 / creatinine values were transformed to log base 10, the individual values showed a strong inverse correlation with the corresponding baseline eGFR of each subject (r, -0.85).

[0017] Plasma and urinary NQO1 responses to 90 mg SnPP infusion are shown in Figure 5. Healthy volunteers and CKD participants showed an acute and nearly identical increase in plasma NQO1 after 90 mg SnPP injection. Furthermore, healthy volunteers and combined CKD participants showed a significant and progressive increase in urinary NQO1 / creatinine levels during the 72-hour observation period. Healthy volunteers had lower baseline urinary NQO1 levels than CKD participants, but the slope of the time-dependent increase in SnPP-induced urinary NQO1 was similar in the healthy volunteer and CKD groups. Values are mean / 95% confidence interval; urinary values are after log base 10 transformation; statistics by ANOVA repeated measures, within-group comparison.

[0018] Baseline and plasma p21 concentrations after SnPP injection are shown in Figure 6. As reflected by the large standard deviation (SD: numbers in parentheses shown at the bottom of the graph), p21 values varied significantly among participants. (HV = healthy volunteers, BL = baseline). However, despite this variability, healthy volunteers and CKD participants showed an increase in plasma p21 at 12 and 24 hours after SnPP injection (combined CKD participants, p < 0.01, healthy volunteers, p < 0.01; ANOVA, repeated measures, between-group comparison). The fold increase relative to baseline values was significantly higher in the healthy volunteer group compared to the CKD group (mean 2.65 vs. 0.51, respectively, p < 0.001, see text).

[0019]

Table 1

[0020] Legend for Table 1. Demographics and baseline clinical data for three study cohorts. Mean values and standard deviations (numbers in parentheses) are shown. CKD3, 15 - 29 ml / min / 1.73 m 2 ; CKD4, 30 - 59 ml / min / 1.73 m 2 ). For the three classes of drugs, the percentage of participants taking them within each group is shown. BP, blood pressure; BUN, blood urea nitrogen.

[0021]

Table 2

[0022] Legend of Table 2. eGFR is shown as ml / min / 1.73m 2 CKD3 = eGFR is 30 - 59 ml / min / m 2 CKD4 = eGFR is 5 - 29 ml / min / m 2 Values are shown as mean ± 1SD. There was no significant change in eGFR from baseline in response to the highest test dose of tin protoporphyrin (90 mg).

[0023]

Table 3

[0024] Legend of Table 3. Urinary biomarker values with urinary creatinine (Cr) as a factor. HV = healthy volunteer, CKD3 = CKD stage 3 (eGFR 30 - 59 ml / min / 1.73m 2 )、CKD4 = CKD stage 4 (eGFR 15 - 29 ml / min / 1.73m 2 ). eGFR was evaluated at baseline and on days 1 - 4 after SnPP injection. No significant change over time was observed for any of the analytes (see p - values). KIM - 1 = kidney injury molecule 1, NGAL = neutrophil gelatinase - associated lipocalin, NAG = n acetyl glucosaminidase. All values = mean ± 1SD. p - values are shown for changes over time.

[0025] The baseline and peak plasma values of the proteins tested to show the degree of responsiveness to the highest test dose of SnPP (90 mg) are shown in Figure 7. Baseline and maximum (peak) plasma antioxidant protein concentrations generated using the highest test dose of SnPP (90 mg) are shown. CKD = combination of CKD3 and CKD4 groups. The data show the ability of SnPP to upregulate HO-1, ferritin, NQO1 and p21 gene / protein expression. The values shown are the mean and 95% confidence intervals. For changes in values over time, and statistics by ANOVA for repeated measures, see the drawings. All peak values are significantly higher than the baseline values, but the CKD group has a significantly blunted response of p21 compared to the healthy volunteer group (see text). The timing of peak values was 4 days, 12 hours, 12 hours, and 4 hours for HO-1, ferritin, p21, and NQO1, respectively.

[0026] Other embodiments and uses of the invention will be apparent to those skilled in the art upon consideration of the detailed description and practice of the invention disclosed herein. All references cited herein, including all U.S. and foreign patents and patent applications, are hereby incorporated by reference in their entirety and specifically. The specification and examples are intended to be illustrative only, and the true scope and spirit of the invention are indicated by the following claims.

Claims

Measuring the expression of antioxidant proteins in a patient administered with a transient oxidative stress inducer, wherein the transient oxidative stress inducer is a metal protoporphyrin or a metal mesoporphyrin, said measuring, and Determining the expression level of one or more antioxidant proteins, wherein the antioxidant protein includes any one or more of HO-1, ferritin, or NQO1, and when the expression level of one or more antioxidant proteins exceeds a predetermined level, it indicates that the patient requires treatment, said determining A method comprising the steps of.

2. The method according to claim 1, wherein the patient suffers from chronic kidney disease.

3. The method according to claim 1, wherein the metal protoporphyrin is tin, cobalt, or zinc protoporphyrin.

4. The method according to claim 1, wherein the dose of the transient oxidative stress inducer is 9 mg or more.

5. The method according to claim 1, wherein the treatment comprises using a powerful antioxidant.

6. The method according to claim 1, wherein the treatment comprises administering tetrahydrocurcumin.

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