Genetically Inducing Renal Lymphangiogenesis Attenuates Hypertension in Mice.

BACKGROUND: Hypertension (HTN) is associated with renal pro-inflammatory immune cell infiltration and increased sodium retention. We reported previously that renal lymphatic vessels, which are responsible for trafficking immune cells from the interstitial space to draining lymph nodes, increase in density under hypertensive conditions. We also demonstrated that augmenting renal lymphatic density can prevent HTN in mice. Whether renal lymphangiogenesis can treat HTN in mice is unknown. We hypothesized that genetically inducing renal lymphangiogenesis after the establishment of HTN would attenuate HTN in male and female mice from three different HTN models.

METHODS: Mice with inducible kidney-specific overexpression of VEGF-D (KidVD) experience renal lymphangiogenesis upon doxycycline administration. HTN was induced in KidVD+ and KidVD- mice by subcutaneous release of angiotensin II, administration of the nitric oxide synthase inhibitor L-NAME, or consumption of a 4% salt diet following a L-NAME priming and washout period. After a week of HTN stimuli treatment, doxycycline was introduced. Systolic blood pressure readings were taken weekly. Kidney function was determined from urine and serum measures. Kidneys were processed for RT-qPCR, flow cytometry, and imaging.

RESULTS: Mice that underwent renal-specific lymphangiogenesis had significantly decreased systolic blood pressure and renal pro-inflammatory immune cells. Additionally, renal lymphangiogenesis was associated with a decrease in sodium transporter expression and increased fractional excretion of sodium, indicating improved sodium handling efficiency.

CONCLUSIONS: These findings demonstrate that augmenting renal lymphangiogenesis can treat HTN in male and female mice by improving renal immune cell trafficking and sodium handling.