Increased (Pro)renin Receptor Expression in the Hypertensive Human Brain

Figure 1. Mapping and identification of the paraventricular nucleus of the hypothalamus (PVN) in the human brain. Representative images showing the identified PVN region in a human brain section. (A) Schematic atlas showing the mapped location of the PVN. (B,C) Representative images showing hematoxylin and eosin (H&E) staining (B) and immunohistochemical detection of the (pro)renin receptor (PRR; C) in the identified PVN region of the human brain. Fx, fornics; Ot, optic tract.

Figure 2. Mapping and identification of the rostral ventrolateral medulla (RVLM) in the human brain. Representative images showing the identified RVLM region in a human brain section. (A) Schematic atlas showing the mapped location of the PVN. (B,C) Representative images showing H&E staining and immunohistochemical detection of the PRR in the identified RVLM region of the human brain. (D) Immunohistochemical staining with an anti-tyrosine hydroxylase (TH) antibody identifying catecholaminergic neurons in the RVLM. Io, inferior olive.

Figure 3. Expression of the PRR in PVN neurons of the human brain. (A) PVN brain tissues were immunolabeled for the PRR (red) and the neuronal marker HuC/HuD (green). (B) PVN brain tissues were immunolabeled for the PRR (red) and the astrocyte marker GFAP (green). (C) Sections processed without primary antibody but with Alexa 488 (green) or Alexa 594 (red) secondary antibody were used as negative controls. ab, antibody; 1°, primary; and 2°, secondary.

Figure 4. Expression of the PRR in RVLM neurons of the human brain. (A) RVLM brain tissues were immunolabeled for the PRR (red) and the neuronal marker HuC/HuD (green). (B) RVLM brain tissues were immunolabeled for the PRR (red) and the astrocyte marker glial fibrillary acidic protein (GFAP; green). (C) Sections processed without primary antibody but with Alexa 488 (green) or Alexa 594 (red) secondary antibody were used as negative controls. ab, antibody; 1°, primary; and 2°, secondary.

Figure 5. Increased PRR immunoreactivity in the PVN of the hypertensive human brain. (A,B) Representative images of PVN tissues from a normotensive (NTN) human brain and a hypertensive (HTN) human brain immunolabeled for the PRR. (C) Representative image of PVN tissue immunolabeled with rabbit pre-immune serum. (D) Significant difference in the relative intensity of PRR immunoreactivity in NTN and HTN groups in the PVN. (E) The relative intensity of PRR immunoreactivity in NTN and HTN groups in lateral PVN region. (F) The background relative intensity for NTN, HTN groups, and the negative control. (N = 7) and NTN (N = 4) subjects; * p < 0.05 vs. NTN by two-tailed, unpaired Student’s t-test.

Figure 6. Increased PRR immunoreactivity in the RVLM of the hypertensive human brain. (A,B) Representative images of RVLM tissues from the NTN and HTN human brain immunolabeled for the PRR. (C) Representative image of RVLM tissue immunolabeled with rabbit pre-immune serum. (D) Significant increase in the relative intensity of PRR immunoreactivity in NTN and HTN groups in the RVLM. (E) The relative intensity of PRR immunoreactivity in NTN and HTN groups in lateral RVLM region. (F) The background relative intensity for NTN, HTN groups, and the negative control. (N = 5) and NTN (N = 4) subjects; * p < 0.05 vs. NTN by two-tailed, unpaired Student’s t-test.

Figure 7. PRR immunoreactivity is positively correlated with sBP in the PVN of the human brain. A least-square correlation post analysis was used to calculate the correlation between the relative intensity of PRR immunoreactivity and systolic BP (sBP; A), diastolic BP (dBP; B), body mass index (BMI; C), and age (D). N = 11.

Figure 8. PRR immunoreactivity is not significantly correlated with sBP in the RVLM of the human brain. A least-square correlation post analysis was used to calculate the correlation between the relative intensity of PRR immunoreactivity and sBP (A), dBP (B), BMI (C), and age (D). N = 9.