Background and objective: The involvement of immune factors in a given disease is suggested by evidence that a disease can be prevented by immunosuppression and can be transferred by lymphoid cells. Because the first type of experimental result was achieved in Lyon hypertensive (LH) rats, the present study was undertaken to determine whether hypertension can be transferred to normotensive recipients. As a control, the blood pressure effects of lymphoid cell grafts from renovascular hypertensive donors were also determined.
Design and methods: Splenocytes and lymph node cells from LH and Lyon low-blood pressure (LL) rats with two-kidney Goldblatt hypertension were respectively injected into LH x Lyon normotensive (LN) F1 hybrids and LL rats aged 7, 8, 9 and 10 weeks. Blood pressure was measured by plethysmography from age 6 to 13 weeks and an intra-arterial recording was performed in 14-week-old conscious rats.
Results: Lymphoid cell injections from LL rat donors with two-kidney hypertension did not modify the blood pressure of LL rat recipients. In contrast, lymphoid cell grafts from LH rat donors induced a significant increase in blood pressure in F1 recipients compared with control F1 rats after the first injection. As confirmed by intra-arterial recording, this blood pressure effect lasted until age 14 weeks (145 +/- 1 versus 137 +/- 1 mmHg in grafted and ungrafted F1, respectively). It was not related to alterations in the acute role of the renin-angiotensin and sympathetic nervous systems and was not associated with increased pressor responses to the vasoconstrictor drugs tested.
Conclusion: The present study demonstrates that genetic hypertension can be partially transferred by lymphoid cells in F1 recipients. The effect seems to be specific to genetic hypertension because lymphoid cells from renovascular hypertensive donors failed to transfer this secondary form of hypertension. The present results support the hypothesis that cellular immune reactions contribute to the pathogenesis of hypertension and LH rats.