Activation of Human T Cells in Hypertension: Studies of Humanized Mice and Hypertensive Humans

Emerging evidence supports an important role for T cells in the genesis of hypertension. Because this work has predominantly been performed in experimental animals, we sought to determine whether human T cells are activated in hypertension. We used a humanized mouse model in which the murine immune system is replaced by the human immune system. Angiotensin II increased systolic pressure to 162 versus 116 mm Hg for sham-treated animals. Flow cytometry of thoracic lymph nodes, thoracic aorta, and kidney revealed increased infiltration of human leukocytes (CD45(+)) and T lymphocytes (CD3(+) and CD4(+)) in response to angiotensin II infusion. Interestingly, there was also an increase in the memory T cells (CD3(+)/CD45RO(+)) in the aortas and lymph nodes. Prevention of hypertension using hydralazine and hydrochlorothiazide prevented the accumulation of T cells in these tissues. Studies of isolated human T cells and monocytes indicated that angiotensin II had no direct effect on cytokine production by T cells or the ability of dendritic cells to drive T-cell proliferation. We also observed an increase in circulating interleukin-17A producing CD4(+) T cells and both CD4(+) and CD8(+) T cells that produce interferon-γ in hypertensive compared with normotensive humans. Thus, human T cells become activated and invade critical end-organ tissues in response to hypertension in a humanized mouse model. This response likely reflects the hypertensive milieu encountered in vivo and is not a direct effect of the hormone angiotensin II.

Genetic and environmental predictors of chronic kidney disease in patients with type 2 diabetes and diabetic foot ulcer: a pilot study

Chronic kidney disease (CKD) is often observed among patients with type 2 diabetes mellitus (T2DM) and diabetic foot (DF) leading to end stage renal disease. The aim of this pilot study was to determine genetic and environmental factors involved in the etiology of CKD among patients with DF. The following polymorphisms were studied: rs1800469, rs759853, rs1553005, rs1799983, rs1801133, rs3134069, rs2073618, rs8192678, rs6330, rs11466112, rs121917832 in terms of alleles distribution in patients with DF and T2DM, with or without CKD. The study includes 101 patients with T2DM and DF. Studied groups were divided into 39 individuals with CKD (cases) and 62 controls, depending on the presence of kidney failure defined as eGFR < 60ml/min/1.73m(2) and coexistence of microalbuminuria > 30 mg/dl in at least 3 urine samples. Cases and controls were matched according to mean age, gender, mean duration of T2DM, mean duration of insulin therapy, mean duration of DF cholesterol levels and smoking frequencies. The study showed that CKD risk factors were the following variables: creatinine level, body weight, hips circumference, ischemic heart disease, hypertension and diabetic retinopathy. Moreover, the results suggest the protective role of the allele C of rs3134069 polymorphism in CKD development in patients with T2DM and DF in the following allelic variants: [AA] vs. [AC] and [AA] vs. [AC + CC]. The allele C was observed to be less frequent than the allele A in patients with T2DM and DF. None of the other following polymorphisms was observed to be a potential risk factor of CKD in T2DM and DF population: rs6330, rs759853, rs1553005, rs1799983, rs1801133, rs1800469, rs8192678, rs11466112, rs121917832. We concluded that the rs3134069 polymorphism seems to be the most likely protective genetic factor in CKD development in patients with T2DM and DF.