Mutations in uromodulin are responsible for autosomal-dominant kidney diseases characterized by defective urine concentrating ability, hyperuricemia, gout, tubulointerstitial fibrosis, renal cysts, and chronic kidney disease.
These studies quantitatively show that the autosomal-dominant gene mutations responsible for UMOD-associated kidney disease cause a profound reduction of THP excretion.
In addition, approximately two-thirds of the known mutations lead to a cysteine amino acid change in uromodulin, and all such variants have been shown to cause UMOD-associated kidney disease.
These results suggest that the UMOD variant may influence the adaptation of the kidney to age-related risk factors of kidney disease such as hypertension and diabetes.
Autosomal dominant medullary cystic kidney disease type 2 (MCKD2) is a tubulo-in terstitial nephropathy that causes renal salt wasting, hyperuricemia, gout, and end-stage renal failure in the fifth decade of life.
These polymorphisms affect uromodulin concentration in the urine, and lower genetically determined urinary uromodulin concentrations seem to protect against renal disease.
A total of 646 individuals, 208 with T2DM without evidence of kidney disease (DM), 221 with DN and 217 healthy controls (HC) were genotyped for UMOD variant rs4293393T>C by restriction fragment length polymorphism.
Blockade of the renin-angiotensin system (RAS) with angiotensin-converting enzyme inhibitors and/or angiotensin II type 1 receptor blockers is the most effective treatment to achieve these purposes in non-diabetic and diabetic proteinuric renal diseases.
However, rats with chronic progressive nephropathy showed augmented renal content of angiotensinogen protein (13.5 +/- 3.5 versus 2.2 +/- 0.4 pixels in control rats; P < 0.05), enhanced expression of cathepsin D-a renin-like enzyme-in cortical collecting tubules (103.5 +/- 27.0 versus 66.2 +/- 3.6 cells/mm2 in controls; P < 0.01), and increased expression of AT1 receptor in interstitium (54.7 +/- 7.8 versus 1.3 +/- 0.4 cells/mm2 in controls; P < 0.001).
Our results suggest that in aged animals, as compared with Hap-II, the TG mice with Hap-I overexpress hAT1R gene due to the stronger transcriptional activity, thus resulting in an increase in their BP and associated renal disorders.
Recently, the angiotensinogen (AGT) gene, M235T, and angiotensin II type 1 receptor (ATR) gene, A1166C, polymorphisms have been associated with the susceptibility to develop hypertension and renal disease.
No single nucleotide polymorphisms in the ACE2 or AGTR1 genes were significantly associated with nephropathy when analysed either by genotype or allele frequencies.
In all the three cohorts, a significantly higher frequency of T allele and TT genotypes of ACACβ and C allele and CC genotypes of AGTR1 were found in patients with DN as compared to patients without nephropathy.
In order to replicate these findings we performed PCR-based genotyping for the A1166-->C DNA polymorphism and the CA repeat at the 3' end of the angiotensin II (type 1) receptor gene employing validated groups of type 1 diabetic patients with (cases, n = 95) and without (controls, n = 97) nephropathy.
Although the expression of renin and angiotensin-converting enzyme in experimental and human renal disease has been well characterized, no information is available regarding human angiotensin type 1 (AT1) receptor expression.