International Journal of Health & Allied Sciences

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 8  |  Issue : 4  |  Page : 236--241

Can N acetyl cysteine - Taurine provide additional reduction in microalbuminuria in type 2 diabetic patients already on optimum doses of Angiotensin converting enzyme inhibitors?


M Premanath1, M Mahesh2, M Suresh Babu2, M Bhanukumar2, D Devananda3,  
1 Senior Consultant, Internal Medicine and Diabetes, JSS Medical College, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
2 Department of Medicine, JSS Medical College, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
3 Asst Professor of Biochemistry, JSS Medical College, JSS Academy of Higher Education and Research, Mysore, Karnataka, India

Correspondence Address:
Dr. M Premanath
Prem Health Care, 671, Nrupatunga Road, M-Block, Kuvempunagar, Mysore - 570 023, Karnataka
India

Abstract

BACKGROUND: Usage of either angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) with or without dual channel calcium blockers (DCCB) is the standard recommendation for prevention of progression of micro to macro albuminuria and diabetic nephropathy (DN); however, these agents have their limitations. Animal studies with taurine and N-acetyl cysteine (NAC) have demonstrated additional reduction of microalbuminuria (MA). OBJECTIVES: To know whether the combination of NAC and taurine would additionally reduce MA and transforming growth factor β (TGF β) expression in T2 diabetics who are already on optimal doses of either ACEI or ARB and/or DCCB, and to know the effect of this combination on glycated hemoglobin (HbA1c), blood pressure (BP), lipid parameters, and estimated glomerular filtration rate (e-GFR). MATERIALS AND METHODS: Eighty diabetics, having MA, who were already on optimum doses of ARB or ACEI and or DCCB were recruited. Fifty were allocated to the test group and 30 were in the control group. All were examined with their height, weight, body mass index, waist circumference, and BP was measured initially and at the end of 3 months. The test group was administered NAC + taurine tablets, one tablet daily for 3 months and placebo was given to the control group. HbA1c, lipid profile, serum creatinine, MA, TGF β and e-GFR were estimated before and on completion of the study. ANOVA and Pearson's correlation were employed for statistical analysis. RESULTS: Forty-one in the test group and 21 in the placebo group completed the study. The test group did show reduction in MA and TGF β. MA reduced from 161.75 ± 120.38 mcg to 138.42 ± 153.60 mcg. TGF β decreased from 15.69 ± 9.16 to 12.68 ± 8.02 and both were not statistically significant. There was no change in serum creatinine and e-GFR. The drug did not have any significant effect on lipids, HbA1c, and BP. CONCLUSIONS: The combination of NAC + taurine provides additional reduction in MA and TGF β in those on ARB or ACEI with or without DCCB. The drug may thus be beneficial to those who have reached maximum reduction of MA with the other molecules. TGF β reduction is also a bonus which may postpone nephropathy. Further studies with larger recruits and increased doses may show statistically significant results.



How to cite this article:
Premanath M, Mahesh M, Babu M S, Bhanukumar M, Devananda D. Can N acetyl cysteine - Taurine provide additional reduction in microalbuminuria in type 2 diabetic patients already on optimum doses of Angiotensin converting enzyme inhibitors?.Int J Health Allied Sci 2019;8:236-241


How to cite this URL:
Premanath M, Mahesh M, Babu M S, Bhanukumar M, Devananda D. Can N acetyl cysteine - Taurine provide additional reduction in microalbuminuria in type 2 diabetic patients already on optimum doses of Angiotensin converting enzyme inhibitors?. Int J Health Allied Sci [serial online] 2019 [cited 2019 Nov 19 ];8:236-241
Available from: http://www.ijhas.in/text.asp?2019/8/4/236/269246


Full Text



 Introduction



Diabetic nephropathy (DN) is the leading cause of chronic kidney disease (CKD) and affects nearly 40% of type 1 and type 2 diabetics. It is defined by the increase in urinary albumin excretion (UAE) and serum creatinine.[1],[2] UAE can be measured, by 24 h collection of urine which is cumbersome or in a spot sample by measuring albumin/creatinine ratio. UAE rate (UAER) of 30–300 mg/24 h or 30–299 mcg/mg of creatinine, is considered as micro albuminuria and beyond 300 mg/24 h or 300 mcg/mg of creatinine as macroalbuminuria.[3] Subjects with a urinary albumin–creatinine ratio of 30–300 had 9.2 times higher incidence of overt nephropathy[4] and CKD ranges 0.79%–1.4% in the population.[5]

Hyperglycemia, hypertension and genetic predisposition are the main risk factors for DN and hyperlipedemia, smoking, and dietary protein also play a part.[1] Hyperglycemia causes DN through a variety of mechanisms including the induction of oxidative stress and acceleration of the glycation reaction.[6],[7],[8] Chronic induction of pro sclerotic cytokine, transforming growth factor β (TGF β) has been implicated in the pathogenesis of DN.[9] Angiotensin II (A II) is known to stimulate TGF β and increased levels may predict the course of DN.[10]

UAER is associated with increased ambulatory blood pressure (BP).[11] Arterial BP rather than glycated hemoglobin (HBA1c) concentration, seem to be the main predictor of progression of MA to clinical albuminuria[12] and renin angiotensin system blockade with angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) confer additional benefits on renal function, independent of BP reduction and may be related to decrease in intra glomerular pressure and passage of protein in to the proximal tubule.[1]

Taurine and NAC have shown to reduce micro albuminuria due to their various actions on A II and as antioxidants, especially in animals.[6],[13],[14]

In the present scenario, to prevent the progression of micro albuminuria to macro albuminuria and DN, the options available, are to use either ACEI or ARB and or dual channel calcium blocker (DCCB) (Cilnidepine). These drugs have proved their worth by reducing MA and have prevented the progression to DN but have their limitations. Animal experiments with taurine and NAC have been very encouraging in reducing MA, but studies on human beings are sparse.

In this study, we evaluated the combination of NAC and Taurine in T2 diabetics with micro albuminuria, who were already on therapy with optimum doses of either ACEI or ARB and/or Cilnidipine to know the additional reduction in MA if any, and whether there would be a decrease in TGF β expression signifying prevention of progression of micro albuminuria to DN.

Objectives of the study

Primary objective

To ascertain whether the combination of NAC and Taurine would reduce microalbuminuria (MA) and TGF β expression in T2 diabetics who are already on optimum doses of either ACEI or ARB and/or Cilnidipine.

Secondary objective

To know the effect of this combination on HbA1c, BP, lipid parameters and estimated glomerular filtration rate (e-GFR).

Study design

Inclusion criteria

T2 diabetics, aged more than 18 years, who have microalbuminuria and were already on therapy with optimum doses of either ACEI or ARB and/or Cilnidipine.

Exclusion criteria

T1 diabetics, poorly controlled T2 diabetics, diabetics having uncontrolled hypertension, CKD with low GFR, co-morbid conditions like congestive cardiac failure (CCF), acutely ill, having tuberculosis, HIV, any infections in the individuals, were excluded.

 Material and Methods



Eighty T2 diabetics, fulfilling the inclusion criteria were recruited 20 by each of the four clinicians from their private clinics. 50 were used as test cases and 30 as controls. This study was carried out over a 4 months period between May and October of 2015.

Ethical approval for the study was obtained from the institutional ethical committee. Informed consent was obtained from all the participants. Subjects were clinically examined and their height (cm), weight (kg), body mass index, and waist circumference (WC) (cm) were recorded. The duration of diabetes and the medications they were on was documented. Sitting BP with a standard sphygmomanometer was recorded after a 5 min rest and average of three readings was taken. The same parameters were re checked at the completion of the study. Those individuals who had a microalbuminuria creatinine ratio (MACR) of &362;100 mcg/mg of creatinine were taken for the test group and those with MACR <100 mcg/mg of creatinine were taken as controls. Each participant in the test pool was provided with 1 month sample of the drug called Lupinac which is a combination of 150 mg of N-acetyl cysteine (NAC) and 500 mg of Taurine. One tablet per day, in the morning after breakfast was advised. They were asked to report every month for the next 3 months for the medication. No changes were made in the medications; patients were already taking. At each visit (total of 4 visits) Weight and BP were recorded and were given medication for further 1 month. The procedure was the same for the subjects in the control group except that they were given the placebo. Both the test group as well as the control group were blinded and were not aware whether they were receiving placebo or the study drug.

Investigations

HbA1c (HPLCD10 BIORAD), MACR (immunoturbidometry), serum cholesterol (CHO-POD), serum triglycerides (TG) (GPO-POD), high-density lipoprotein (HDL) (3rd generation direct assay), low-density lipoprotein (LDL) (3rd generation direct assay), and serum creatinine (enzymatic method) were estimated in a National Acredition Board for Laboratories (NABL)-accredited laboratory both at the beginning of the study and at the completion of the study period of 3 months.

The serum samples were separated and stored at the appropriate temperature (−20 C) in the laboratory until all the recruitment was over, as well as at the end of the study when the investigations were repeated. These samples were analyzed for TGF β by a competitive enzyme-linked immunosorbent assay, according to manufacturer's instructions (sandwich enzyme immune assay) at the Center of Excellence in Molecular Biology and Regenerative Medicine, Department of Biochemistry JSS Medical College, Mysore. e-GFR was calculated using Cockcroft-Gault equation. The value was multiplied by a factor of 0.85 in women subjects.

Statistical methods

To find out the pre post difference between the selected variables in control and study groups, repeated measure ANOVA was employed. To find whether the decrease in MACR leads decrease/increase among selected variables, Pearson's product moment correlation technique was used. Descriptive statistics like mean, standard deviation, and 95% confidence interval were also employed. P <0.05 was taken as statistically significant.

 Results



Of the total 80 individuals, data pertaining to 62 individuals (41 in the study group and 21 in the control group) were available for analysis as there were 18 dropouts. 36 (87.2%) individuals in the study group and 19 (90.4%) in the control group were in the age group of 46–75 years [Table 1]. The age of the individuals in the study group (58.65 ± 10.19 years) and that in the control group (58.23 ± 8.65) were well matched [Table 2]. The gender ratio of male to female, 53.7%:46.3% in the study group was equally matched with that of 52.4%:47.6% in the control group [Table 3].{Table 1}{Table 2}{Table 3}

ARB was the drug of choice as 92.7% of subjects in the study group and 76.2% in the control group were on it and 7.3% in the study group and 23.8% in the control group were on ACEI [Table 4] and [Table 5] In addition to this, 36.6% in the study group and 14.3% in control group were also on DCCB [Table 6].{Table 4}{Table 5}{Table 6}

There was no change in the serum creatinine in the study group before and after the consumption of NAC with Taurine, but it got reduced from 1.63 to 1.52 in the control group (P = 0.078). MACR was reduced from 161.75 mcg to 138.42 mcg in the study group, whereas negligible change was seen (65.46 vs. 63.49) in the control group (P = 0.409). e-GFR showed almost no change in the study group (73.62 vs. 75.18) but increased from 76.14 to 84.42 in the control group (P = 0.126). TGFβ decreased from 15.69 to 12.68 in the study group but no change was seen in the control group (P = 0.149); none of the changes were statistically significant [Table 7].{Table 7}

As far as weight, WC, HbA1c, systolic BP (SBP), diastolic BP (DBP), total cholesterol, and LDL cholesterol, no changes were seen both in the study group as well as the control group. Only TG decreased from 194.36 to 167.95 in the study group (P = 0.517) and HDL cholesterol decreased from 44.95 to 40.85 in the control group (P = 0.269). None were statistically significant [Table 7]. MACR was correlated with all the parameters. It did not correlate with serum creatinine, (P = 0.529) e-GFR (P = 0.574) or TGF β (P = 0.908) which were the core findings of this study. It correlated with WC (P = 0.041), DBP (P = 0.005), and HDL (P = 0.038) [Table 8].{Table 8}

 Discussion



MA is considered as a marker of gross endothelial dysfunction (ED) throughout the body. MA is apparently associated with universal sieving of albumin and in the term of trans capillary escape rate of albumin, it may reflect universal sieving.[11] MA is not only a risk factor for DN but also an independent risk factor for cardio vascular mortality in T1 diabetes mellitus (DM), T2 DM and apparently healthy people.[15],[16],[17],[18],[19] In fact a study states that MA, ED and chronic inflammation are inter related.[19] Any degree of MA, is a risk factor for cardiovascular (CV) events in individuals with or without DM.[16],[17] ARB and ACEI have been known to reduce MA by preventing the action of A II which is known to stimulate pro-sclerotic TGFβ.[10] They also reduce MA by reducing intraglomerular BP. DCCB also has the property of reducing MA by its action akin to ARB. There are limitations, in the form of side effects in using any of these drugs. The BP also get lowered as they are anti-hypertensive drugs and it cannot be lowered too much which will have its own adverse effects. The reduction in MA, become static once the limit of using these drugs are reached.

The combination of NAC and Taurine, which is available in the market as a food supplement, has a claim that it could reduce MA as well. Hence we wanted to know whether this combination will have any additional reduction of MA over and above what has been achieved by giving ARB or ACEI and or DCCB. This was the primary objective of this study. How would this combination would achieve reduction in MA was the next question that has to be answered.

Taurine is a conditionally essential amino acid that is found in the tissues of many animal species. It has been shown to attenuate the action of A-II on calcium transport and protein synthesis and A-II signaling. A-II generates reactive oxygen species and produce inflammation, which is reduced by taurine[13] Taurine has anti glycation and antioxidant properties and might be useful in the management of diabetic complications.[14] It has also shown to attenuate hyperglycemia induced apoptosis in human tubular cells by acting as an endogenous antioxidant and may exert a beneficial effect in preventing tubule interstitial injury in DN.[6],[19] Taurine has also shown to reduce mesangial extra cellular matrix formation and TGF β expression in the renal glomerulus.[6],[20]

NAC is the acetylated precursor of L-Cysteine and reduced glutathione. The biological activity of NAC is attributed to the sulfhydroxyl group, while its acetyl substitute amino group affords protection against oxidative and metabolic processes.[15] NAC has shown to attenuate the high glucose induced apoptosis in renal tubule cells[21] Oxidative stress markers such as 8 hydroxy deoxyguanosine and nitro tyrosine have been demonstrated to accumulate in the renal tissue of human beings.[6],[7],[8]

We observed that there was a decrease in MACR in those who took the combined pill of NAC and Taurine (161.75 ± 120.38 vs. 138.42 ± 153.60). The controls showed no change. There was an increase in e-GFR in the control group and the study group did not show much change. There was a decrease in TGFβ in the study group (15.69 ± 9.16 vs. 12.68 ± 8.02) which was not seen in controls. None of these values were statistically significant. Just because these values were not significant statistically may not reduce their importance. Smaller number of individuals and smaller dosage might have been the reasons for this result. A smaller study than ours from Chennai on 41 individuals showed statistically significant decrease in MACR (85 ± 59 vs. 45 ± 25) and TGFβ (18.3 ± 12.4 vs. 13.2 ± 9.9).[22] Has ethnicity or genetic factors have any role? it is difficult to say. In fact, their study also showed increase in e-GFR in the controls like in ours without an explanation.

In a double blind trial of 1 year, Taurine failed to improve kidney complications associated with T2 DM.[13] Another study showed NAC had no additional benefit when combined with ARB. Animal experiments have shown Taurine to be beneficial because of its antiglycation and antioxidant properties.[6],[14] It has also been found that Taurine reduces the expression of extracellular matrix proteins in the kidneys of animals.[6],[9],[20] Whether it has the same action in human beings is a question that cannot be answered easily. Taurine has been found to prevent apoptosis induced by hyperglycemia in human tubule renal cells.[21] Despite reduction in MA and TGF β in the study subjects, MA did not correlate with e-GFR, serum creatinine, and TGF β in our study.

The secondary objective of the present study was to know the effect of this combination on HbA1c, BP and lipid profile. There results revealed no change in HbA1c. Both SBP and DBP were neither elevated nor decreased. However, only TG showed a reduction in the test group (194.36 ± 259.25 vs. 167.95 ± 117.27) and HDL was reduced in the control group (44.95 ± 11.8 vs. 40.85 ± 7.41). None were statistically significant. This is in contrast to the Chennai study which showed statistically significant reduction of DBP.[22]

The reasons for these changes in the lipids are difficult to explain. Perhaps the ant oxidant and antiglycation effect of the combination has a role. But this is speculative.

This study has shown that the combination of NAC and Taurine does reduce MA. This was in addition to the reduction that was already achieved using ARB or ACEI and/or DCCB, which probably would help the patients. There was a reduction of TGF β also and this might help in retarding the progression of the disease.

This study has its limitations. We had used only one tablet of the combination in this study Perhaps a higher dose would have produced increased reduction of MA. The small study size compounded by dropouts may have been be a factor for some of the results not achieving statistical significance.

 Conclusions



Our study has clearly shown that the combination of NAC and Taurine does reduce MA, even though not of statistical significance in this study for reasons cited earlier. This drug combination also leads to reduction in levels of TGF β which lead to retardation in the progression of nephropathy in diabetic patients. This study also revealed that this combination had no effect on HbA1c, BP, e-GFR, serum creatinine and lipids. Larger studies, employing higher doses of this combination are needed to confirm these beneficial effects.

Acknowledgment

We are indebted to the Research Society for Study of Diabetes in India (RSSDI- National) for the awarding us the research grant to conduct this study. Our sincere thanks are due to Dr. Lancy D Souza, PhD, Associate Professor of Psychology, University of Mysore, for his help in statistical analysis. We are grateful to local representative of LUPIN laboratories for supplying the study drug NAC and Taurine (Lupinac) tablets as well as Placebo for this study without any commercial or other preconditions. We wish to place on record sincere thanks to all the participants for their cooperation.

Financial support and sponsorship

RSSDI National.

Conflicts of interest

There are no conflicts of interest.

References

1Gross JL, de Azevedo MJ, Silveiro SP, Canani LH, Caramori ML, Zelmanovitz T. Diabetic nephropathy: Diagnosis, prevention, and treatment. Diabetes Care 2005;28:164-76.
2Murussi M, Baglio P, Gross JL, Silveiro SP. Risk factors for microalbuminuria and macroalbuminuria in type 2 diabetic patients: A 9-year follow-up study. Diabetes Care 2002;25:1101-3.
3Narva AS, Bilous RW. Laboratory assessment of diabetic kidney disease. Diabetes Spectr 2015;28:162-6.
4Nelson RG, Knowler WC, Pettitt DJ, Saad MF, Charles MA, Bennett PH. Assessment of risk of overt nephropathy in diabetic patients from albumin excretion in untimed urine specimens. Arch Intern Med 1991;151:1761-5.
5Rajapurkar M, Dabhi M. Burden of disease – Prevalence and incidence of renal disease in India. Clin Nephrol 2010;74 Suppl 1:S9-12.
6Higo S, Miyata S, Jiang QY, Kitazawa R, Kitazawa S, Kasuga M, et al. Taurine administration after appearance of proteinuria retards progression of diabetic nephropathy in rats. Kobe J Med Sci 2008;54:E35-45.
7Tanji N, Markowitz GS, Fu C, Kislinger T, Taguchi A, Pischetsrieder M, et al. Expression of advanced glycation end products and their cellular receptor RAGE in diabetic nephropathy and nondiabetic renal disease. J Am Soc Nephrol 2000;11:1656-66.
8Vasavada N, Agarwal R. Role of oxidative stress in diabetic nephropathy. Adv Chronic Kidney Dis 2005;12:146-54.
9Ceol M, Gambaro G, Sauer U, Baggio B, Anglani F, Forino M, et al. Glycosaminoglycan therapy prevents TGF-beta1 overexpression and pathologic changes in renal tissue of long-term diabetic rats. J Am Soc Nephrol 2000;11:2324-36.
10Sharma K, Eltayeb BO, McGowan TA, Dunn SR, Alzahabi B, Rohde R, et al. Captopril-induced reduction of serum levels of transforming growth factor-beta1 correlates with long-term renoprotection in insulin-dependent diabetic patients. Am J Kidney Dis 1999;34:818-23.
11Leitão CB, Canani LH, Polson PB, Molon MP, Pinotti AF, Gross JL. Urinary albumin excretion rate is associated with increased ambulatory blood pressure in normoalbuminuric type 2 diabetic patients. Diabetes Care 2005;28:1724-9.
12Intensive therapy and progression to clinical albuminuria in patients with insulin dependent diabetes mellitus and microalbuminuria. Microalbuminuria Collaborative Study Group, United Kingdom. BMJ 1995;311:973-7.
13Nandhini AT, Thirunavukkarasu V, Anuradha CV. Taurine prevents collagen abnormalities in high fructose-fed rats. Indian J Med Res 2005;122:171-7.
14Hua T. Effects of Taurine on advanced glycosylation end products and expression of TGF β in renal cortex of streptozotocin induced diabetic rats. Chin J Endocrinol Metab 2000.
15Feldt-Rasmussen B. Microalbuminuria, endothelial dysfunction and cardio vascular risk. Diabetes Metab 2000;26 Suppl 4:64.
16Dinneen SF, Gerstein HC. The association of microalbuminuria and mortality in non-insulin-dependent diabetes mellitus. A systematic overview of the literature. Arch Intern Med 1997;157:1413-8.
17Gerstein HC, Mann JF, Yi Q, Zinman B, Dinneen SF, Hoogwerf B. Albuminuria and risk of cardiovascular events, death, and heart failure in diabetic and nondiabetic individuals. JAMA 2001;286:421-6.
18Stehouwer CD, Gall MA, Twisk JW, Knudsen E, Emeis JJ, Parving HH. NIncreased urinary albumin excretion, endothelial dysfunction, and chronic low-grade inflammation in type 2 diabetes: Progressive, interrelated, and independently associated with risk of death. Diabetes 2002;51:1157-65.
19Franconi F, Di Leo MA, Bennardini F, Ghirlanda G. Is taurine beneficial in reducing risk factors for diabetes mellitus? Neurochem Res 2004;29:143-50.
20Rasi Hashemi S, Noshad H, Tabrizi A, Mobasseri M, Tayebi Khosroshahi H, Heydarnejad M, et al. Angiotensin receptor blocker and N-acetyl cysteine for reduction of proteinuria in patients with type 2 diabetes mellitus. Iran J Kidney Dis 2012;6:39-43.
21Verzola D, Bertolotto MB, Villaggio B, Ottonello L, Dallegri F, Frumento G, et al. Taurine prevents apoptosis induced by high ambient glucose in human tubule renal cells. J Investig Med 2002;50:443-51.
22Viswanathan V, Nair MB, Tilak P. Effect of taurine and acetylcysteine in attenuating microalbuminuria in type 2 diabetes. Indian J Nephrol 2008;18:85.