TY  - JOUR
A1  - von Websky, Karoline
A1  - Hasan, Ahmed Abdallah Abdalrahman Mohamed
A1  - Reichetzeder, Christoph
A1  - Tsuprykov, Oleg
A1  - Hocher, Berthold
T1  - Impact of vitamin D on pregnancy-related disorders and on offspring outcome
JF  - The Journal of Steroid Biochemistry and Molecular Biology
N2  - Observational studies from all over the world continue to find high prevalence rates of vitamin D insufficiency and deficiency in many populations, including pregnant women. Beyond its classical function as a regulator of calcium and phosphate metabolism, vitamin D elicits numerous effects in the human body. Current evidence highlights a vital role of vitamin D in mammalian gestation. During pregnancy, adaptations in maternal vitamin D metabolism lead to a physiologic increase of vitamin D levels, mainly because of an increased renal production, although other potential sources like the placenta are being discussed. A sufficient supply of mother and child with calcium and vitamin D during pregnancy ensures a healthy bone development of the fetus, whereas lack of either of these nutrients can lead to the development of rickets in the child. Moreover, vitamin D insufficiency during pregnancy has consistently been associated with adverse maternal and neonatal pregnancy outcomes. In multitudinous studies, low maternal vitamin D status was associated with a higher risk for pre-eclampsia, gestational diabetes mellitus and other gestational diseases. Likewise, several negative consequences for the fetus have been reported, including fetal growth restriction, increased risk of preterm birth and a changed susceptibility for later-life diseases. However, study results are diverging and causality has not been proven so far. Meta-analyses on the relationship between maternal vitamin D status and pregnancy outcomes revealed a wide heterogeneity of studied populations and the applied methodology in vitamin D assessment. Until today, clinical guidelines for supplementation cannot be based on high-quality evidence and it is not clear if the required intake for pregnant women differs from non-pregnant women. Long-term safety data of vitamin D supplementation in pregnant women has not been established and overdosing of vitamin D might have unfavorable effects, especially in mothers and newborns with mutations of genes involved in vitamin D metabolism. Reliable data from large observational and interventional randomized control trials are urgently needed as a basis for any detailed and safe recommendations for supplementation in the general population and, most importantly, in pregnant women. This is of utmost importance, as ensuring a sufficient vitamin D-supply of mother and child implies a great potential for the prevention of birth complications and development of diseases.
KW  - Vitamin D deficiency
KW  - Free vitamin D
KW  - Vitamin D binding protein
KW  - Epigenetics
KW  - DNA methylation
KW  - Single nucleotide polymorphism
KW  - Preeclampsia
KW  - Gestational diabetes mellitus
KW  - Small for gestational age
KW  - Long term health
Y1  - 2018
U6  - https://doi.org/10.1016/j.jsbmb.2017.11.008
SN  - 0960-0760
VL  - 180
SP  - 51
EP  - 64
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Tsuprykov, Oleg
A1  - Chen, Xin
A1  - Hocher, Carl-Friedrich
A1  - Skoblo, Roman
A1  - Yin, Lianghong
A1  - Hocher, Berthold
T1  - Why should we measure free 25(OH) vitamin D?
JF  - The Journal of Steroid Biochemistry and Molecular Biology
N2  - Vitamin D, either in its D-2 or D-3 form, is essential for normal human development during intrauterine life, kidney function and bone health. Vitamin D deficiency has also been linked to cancer development and some auto immune diseases. Given this huge impact of vitamin Don human health, it is important for daily clinical practice and clinical research to have reliable tools to judge on the vitamin D status. The major circulating form of vitamin D is 25-hydroxyvitamin D (25(OH)D), although it is not the most active metabolite, the concentrations of total 25-hydroxyvitamin D in the serum are currently routinely used in clinical practice to assess vitamin D status. In the circulation, vitamin D - like other steroid hormones - is bound tightly to a special carrier - vitamin D-binding protein (DBP). Smaller amounts are bound to blood proteins - albumin and lipoproteins. Only very tiny amounts of the total vitamin D are free and potentially biologically active. Currently used vitamin D assays do not distinguish between the three forms of vitamin D - DBP-bound vitamin D, albumin-bound vitamin D and free, biologically active vitamin D. Diseases or conditions that affect the synthesis of DBP or albumin thus have a huge impact on the amount of circulating total vitamin D. DBP and albumin are synthesized in the liver, hence all patients with an impairment of liver function have alterations in their total vitamin D blood concentrations, while free vitamin D levels remain mostly constant. Sex steroids, in particular estrogens, stimulate the synthesis of DBP. This explains why total vitamin D concentrations are higher during pregnancy as compared to nonpregnant women, while the concentrations of free vitamin D remain similar in both groups of women. The vitamin D-DBP as well as vitamin D-albumin complexes are filtered through the glomeruli and re-uptaken by megalin in the proximal tubule. Therefore, all acute and chronic kidney diseases that are characterized by a tubular damage, are associated with a loss of vitamin D-DBP complexes in the urine. Finally, the gene encoding DBP protein is highly polymorphic in different human racial groups. In the current review, we will discuss how liver function, estrogens, kidney function and the genetic background might influence total circulating vitamin D levels and will discuss what vitamin D metabolite is more appropriate to measure under these conditions: free vitamin D or total vitamin D.
KW  - 1,25(OH)(2) vitamin D
KW  - Bioavailable vitamin D
KW  - Calculated free 25(OH) vitamin D
KW  - Free 25(OH) vitamin D
KW  - Free vitamin D
KW  - Directly measured free vitamin D
KW  - Genetic polymorphism
KW  - Total 25(OH) vitamin D
KW  - Vitamin D-binding protein
Y1  - 2107
U6  - https://doi.org/10.1016/j.jsbmb.2017.11.014
SN  - 0960-0760
VL  - 180
SP  - 87
EP  - 104
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Tsuprykov, Oleg
A1  - Chaykovska, Lyubov
A1  - Kretschmer, Axel
A1  - Stasch, Johannes-Peter
A1  - Pfab, Thiemo
A1  - Krause-Relle, Katharina
A1  - Reichetzeder, Christoph
A1  - Kalk, Philipp
A1  - Adamski, Jerzy
A1  - Hocher, Berthold
T1  - Endothelin-1 overexpression improves renal function in eNOS knockout mice
JF  - Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry and pharmacology
N2  - Background/Aims: To investigate the renal phenotype under conditions of an activated renal ET-1 system in the status of nitric oxide deficiency, we compared kidney function and morphology in wild-type, ET-1 transgenic (ET+/+), endothelial nitric oxide synthase knockout (eNOS-/-) and ET+/+eNOS-/- mice. Methods: We assessed blood pressure, parameters of renal morphology, plasma cystatin C, urinary protein excretion, expression of genes associated with glomerular filtration barrier and tissue remodeling, and plasma metabolites using metabolomics. Results: eNOS-/- and ET+/+eNOS-/- mice developed hypertension. Osteopontin, albumin and protein excretion were increased in eNOS-/- and restored in ET+/+eNOS-/- animals. All genetically modified mice developed renal interstitial fibrosis and glomerulosclerosis. Genes involved in tissue remodeling (serpinel, TIMP1, Collal, CCL2) were up-regulated in eNOS-/-, but not in ET+/+eNOS-/- mice. Plasma levels of free carnitine and acylcarnitines, amino acids, diacyl phosphatidylcholines, lysophosphatidylcholines and hexoses were descreased in eNOS-/- and were in the normal range in ET+/+eNOS-/- mice. Conclusion: eNOS-/- mice developed renal dysfunction, which was partially rescued by ET-1 overexpression in eNOS-/- mice. The metabolomics results suggest that ET-1 overexpression on top of eNOS knockout is associated with a functional recovery of mitochondria (rescue effect in 13-oxidation of fatty acids) and an increase in antioxidative properties (normalization of monounsaturated fatty acids levels). (C) 2015 The Author(s) Published by S. Karger AG, Basel
KW  - Chronic kidney disease
KW  - Endothelial nitric oxide synthase
KW  - Endothelin
KW  - Mice
KW  - Nitric oxide
Y1  - 2015
U6  - https://doi.org/10.1159/000438516
SN  - 1015-8987
SN  - 1421-9778
VL  - 37
IS  - 4
SP  - 1474
EP  - 1490
PB  - Karger
CY  - Basel
ER  - 
TY  - CHAP
A1  - Tsuprykov, Oleg
A1  - Buse, Claudia
A1  - Skoblo, Roman
A1  - Hocher, Berthold
T1  - Free 25 (OH) vitamin D, but not total 25 (OH) vitamin D, is strongly correlated with gestational age and calcium in normal human pregnancy
T2  - Journal of bone and mineral research
Y1  - 2017
SN  - 0884-0431
SN  - 1523-4681
VL  - 32
SP  - S323
EP  - S323
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Tsuprykov, Oleg
A1  - Buse, Claudia
A1  - Skoblo, Roman
A1  - Haq, Afrozul
A1  - Hocher, Berthold
T1  - Reference intervals for measured and calculated free 25-hydroxyvitamin D in normal pregnancy
JF  - The Journal of Steroid Biochemistry and Molecular Biology
N2  - The determination of free 25-hydroxyvitamin D (25(OH)D) as compared to the analysis of total 25-hydroxyvitamin D might reflect better the vitamin D status during pregnancy, since vitamin D-binding protein (DBP) concentrations increase throughout pregnancy and the vast majority of 25(OH)D is tightly bound to DBP thus strongly influencing total 25(OH)D. The concentration of the biologically active free 25(OH)D - on the other hand - is much less dependent on the DBP concentrations. The study was conducted in May-June 2016 in 368 Caucasian pregnant healthy women - residents of Northeastern Germany. Free 25(OH)D was either measured directly by commercial ELISA kit or assessed by calculation via total 25(OH)D, DBP, and albumin serum concentrations. Regardless of the detection method, free 25(OH)D lowers in the 3rd trimester comparing to the 1st trimester (by 12% and 21%, p < 0.05 and p < 0.001, for measured and calculated free 25(OH)D, respectively), whereas total 25(OH)D was not decreased in late pregnancy. DBP rises with gestational age. Total 25(OH)D was not correlated with serum calcium (p = 0.251), whereas free 25(OH)D was significantly (p = 0.007 for measured free 25(OH)D and p < 0.001 for calculated free 25(OH)D) positively correlated with calcium. All 25(OH) D isoforms were significantly negatively correlated with bone-specific alkaline phosphatase (BSAP), however the correlation strength was the lowest with total 25(OH)D (rho = -0.108, p = 0.038), whereas both measured and calculated free 25(OH)D revealed better associations with BSAP (rho = -0.203 and rho = -0.211 for measured and calculated free 25(OH)D, respectively, p < 0.001 for both). We established pregnancy trimester specific reference intervals for free measured and calculated 25(OH)D and DBP. Both measured and calculated free 25(OH)D showed better correlations with parameters of the endocrine vitamin D system (calcium and BSAP). Both ways of measuring free 25(OH)D in pregnant women are suitable as novel laboratory parameter for vitamin D status monitoring during human pregnancy and might replace in the future the routine total 25(OH)D assessment.
KW  - Measured free 25-hydroxyvitamin D
KW  - Calculated free 25-hydroxyvitamin D
KW  - Vitamin D-binding protein
KW  - Pregnancy
KW  - Reference intervals
Y1  - 2018
U6  - https://doi.org/10.1016/j.jsbmb.2018.03.005
SN  - 0960-0760
VL  - 181
SP  - 80
EP  - 87
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Tsuprykov, Oleg
A1  - Ando, Ryotaro
A1  - Reichetzeder, Christoph
A1  - von Websky, Karoline
A1  - Antonenko, Viktoriia
A1  - Sharkovska, Yuliya
A1  - Chaykovska, Lyubov
A1  - Rahnenfuehrer, Jan
A1  - Hasan, Ahmed Abdallah Abdalrahman Mohamed
A1  - Tammen, Harald
A1  - Alter, Markus L.
A1  - Klein, Thomas
A1  - Ueda, Seiji
A1  - Yamagishi, Sho-ichi
A1  - Okuda, Seiya
A1  - Hocher, Berthold
T1  - The dipeptidyl peptidase inhibitor linagliptin and the angiotensin II receptor blocker telmisartan show renal benefit by different pathways in rats with 5/6 nephrectomy
JF  - Kidney international : official journal of the International Society of Nephrology
N2  - Dipeptidyl peptidase (DPP)-4 inhibitors delay chronic kidney disease (CKD) progression in experimental diabetic nephropathy in a glucose-independent manner. Here we compared the effects of the DPP-4 inhibitor linagliptin versus telmisartan in preventing CKD progression in non-diabetic rats with 5/6 nephrectomy. Animals were allocated to 1 of 4 groups: sham operated plus placebo; 5/6 nephrectomy plus placebo; 5/6 nephrectomy plus linagliptin; and 5/6 nephrectomy plus telmisartan. Interstitial fibrosis was significantly decreased by 48% with linagliptin but a non-significant 24% with telmisartan versus placebo. The urine albumin-to-creatinine ratio was significantly decreased by 66% with linagliptin and 92% with telmisartan versus placebo. Blood pressure was significantly lowered by telmisartan, but it was not affected by linagliptin. As shown by mass spectrometry, the number of altered peptide signals for linagliptin in plasma was 552 and 320 in the kidney. For telmisartan, there were 108 peptide changes in plasma and 363 in the kidney versus placebo. Linagliptin up-regulated peptides derived from collagen type I, apolipoprotein C1, and heterogeneous nuclear ribonucleoproteins A2/B1, a potential downstream target of atrial natriuretic peptide, whereas telmisartan up-regulated angiotensin II. A second study was conducted to confirm these findings in 5/6 nephrectomy wild-type and genetically deficient DPP-4 rats treated with linagliptin or placebo. Linagliptin therapy in wild-type rats was as effective as DPP-4 genetic deficiency in terms of albuminuria reduction. Thus, linagliptin showed comparable efficacy to telmisartan in preventing CKD progression in non-diabetic rats with 5/6 nephrectomy. However, the underlying pathways seem to be different. Copyright (C) 2016, International Society of Nephrology. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
KW  - albuminuria
KW  - angiotensin receptor blockers
KW  - chronic kidney disease
KW  - DPP-4 inhibition
KW  - proteinuria
KW  - proteomic analysis
Y1  - 2016
U6  - https://doi.org/10.1016/j.kint.2016.01.016
SN  - 0085-2538
SN  - 1523-1755
VL  - 89
SP  - 1049
EP  - 1061
PB  - Nature Publ. Group
CY  - New York
ER  - 
TY  - JOUR
A1  - Sharkovska, Yuliya
A1  - Reichetzeder, Christoph
A1  - Alter, Markus L.
A1  - Tsuprykov, Oleg
A1  - Bachmann, Sebastian
A1  - Secher, Thomas
A1  - Klein, Thomas
A1  - Hocher, Berthold
T1  - Blood pressure and glucose independent renoprotective effects of dipeptidyl peptidase-4 inhibition in a mouse model of type-2 diabetic nephropathy
JF  - Journal of hypertension
N2  - Background: Despite the beneficial effects of type 4 dipeptidyl peptidase (DPP-4) inhibitors on glucose levels, its effects on diabetic nephropathy remain unclear.
 Method: This study examined the long-term renoprotective effects of DPP-4 inhibitor linagliptin in db/db mice, a model of type 2 diabetes.
 Results were compared with the known beneficial effects of renin-angiotensin system blockade by enalapril. Ten-week-old male diabetic db/db mice were treated for 3 months with either vehicle (n = 10), 3 mg linagliptin/kg per day (n = 8), or 20 mg enalapril/kg per day (n = 10). Heterozygous db/m mice treated with vehicle served as healthy controls (n = 8). Results: Neither linagliptin nor enalapril had significant effects on the parameters of glucose metabolism or blood pressure in diabetic db/db mice. However, linagliptin treatment reduced albuminuria and attenuated kidney injury. In addition, expression of podocyte marker podocalyxin was normalized. We also analysed DPP-4 expression by immunofluorescence in human kidney biopsies and detected upregulation of DPP-4 in the glomeruli of patients with diabetic nephropathy, suggesting that our findings might be of relevance for human kidney disease as well.
 Conclusion: Treatment with DPP-4 inhibitor linagliptin delays the progression of diabetic nephropathy damage in a glucose-independent and blood-pressure-independent manner. The observed effects may be because of the attenuation of podocyte injury and inhibition of myofibroblast transformation.
KW  - diabetic nephropathy
KW  - DPP-4 inhibitors
KW  - linagliptin
Y1  - 2014
U6  - https://doi.org/10.1097/HJH.0000000000000328
SN  - 0263-6352
SN  - 1473-5598
VL  - 32
IS  - 11
SP  - 2211
EP  - 2223
PB  - Lippincott Williams & Wilkins
CY  - Philadelphia
ER  - 
TY  - CHAP
A1  - Sharkovska, Y.
A1  - Alter, Markus L.
A1  - Reichetzeder, Christoph
A1  - Tsuprykov, Oleg
A1  - Klein, T.
A1  - Hocher, Berthold
T1  - DPP-4 inhibition with linagliptin delays the progression of diabetic nephropathy in db/db mice
T2  - Diabetologia : journal of the European Association for the Study of Diabetes (EASD)
Y1  - 2012
SN  - 0012-186X
SN  - 1432-0428
VL  - 55
IS  - 5
SP  - S20
EP  - S20
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Reichetzeder, Christoph
A1  - von Websky, Karoline
A1  - Tsuprykov, Oleg
A1  - Samarin, Azadeh Mohagheghi
A1  - Falke, Luise Gabriele
A1  - Putra, Sulistyo Emantoko Dwi
A1  - Hasan, Ahmed Abdallah Abdalrahman Mohamed
A1  - Antonenko, Viktoriia
A1  - Curato, Caterina
A1  - Rippmann, Joerg
A1  - Klein, Thomas
A1  - Hocher, Berthold
T1  - Head-to-head comparison of structurally unrelated dipeptidyl peptidase 4 inhibitors in the setting of renal ischemia reperfusion injury
JF  - British journal of pharmacology : journal of The British Pharmacological Society
N2  - BACKGROUND AND PURPOSE Results regarding protective effects of dipeptidyl peptidase 4 (DPP4) inhibitors in renal ischaemia-reperfusion injury (IRI) are conflicting. Here we have compared structurally unrelated DPP4 inhibitors in a model of renal IRI. EXPERIMENTAL APPROACH IRI was induced in uninephrectomizedmale rats by renal artery clamping for 30 min. The shamgroup was uninephrectomized but not subjected to IRI. DPP4 inhibitors or vehicle were given p. o. once daily on three consecutive days prior to IRI: linagliptin (1.5 mg.kg(-1).day(-1)), vildagliptin (8mg.kg(-1).day(-1)) and sitagliptin (30 mg.kg(-1).day(-1)). An additional group received sitagliptin until study end (before IRI: 30 mg.kg(-1).day(-1); after IRI: 15mg.kg(-1).day(-1)). KEY RESULTS Plasma-active glucagon-like peptide type 1 (GLP(-1)) increased threefold to fourfold in all DPP4 inhibitor groups 24 h after IRI. Plasma cystatin C, a marker of GFR, peaked 48 h after IRI. Compared with the placebo group, DPP4 inhibition did not reduce increased plasma cystatin C levels. DPP4 inhibitors ameliorated histopathologically assessed tubular damage with varying degrees of drug-specific efficacies. Renal osteopontin expression was uniformly reduced by all DPP4 inhibitors. IRI-related increased renal cytokine expression was not decreased by DPP4 inhibition. Renal DPP4 activity at study end was significantly inhibited in the linagliptin group, but only numerically reduced in the prolonged/dose-adjusted sitagliptin group. Active GLP(-1) plasma levels at study end were increased only in the prolonged/dose-adjusted sitagliptin treatment group. CONCLUSIONS AND IMPLICATIONS In rats with renal IRI, DPP4 inhibition did not alter plasma cystatin C, a marker of glomerular function, but may protect against tubular damage.
Y1  - 2017
U6  - https://doi.org/10.1111/bph.13822
SN  - 0007-1188
SN  - 1476-5381
VL  - 174
SP  - 2273
EP  - 2286
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - CHAP
A1  - Reichetzeder, Christoph
A1  - von Websky, Karoline
A1  - Tsuprykov, Oleg
A1  - Antonenko, V.
A1  - Samarin, Azin Mohagheghi
A1  - Hocher, Berthold
T1  - Effects of DPP-4 inhibition on glomerular and tubular function in a rat model of ischaemia-reperfusion injury
T2  - Diabetologia : journal of the European Association for the Study of Diabetes (EASD)
Y1  - 2015
SN  - 0012-186X
SN  - 1432-0428
VL  - 58
SP  - S34
EP  - S35
PB  - Springer
CY  - New York
ER  -