Renal denervation and CD161a immune ablation prevent cholinergic hypertension and renal sodium retention

Cholinergic receptor activation leads to premature development of hypertension and infiltration of proinflammatory CD161a+/CD68+ M1 macrophages into the renal medulla. Renal inflammation is implicated in renal sodium retention and the development of hypertension. Renal denervation is known to decrease renal inflammation. The objective of this study was to determine the role of CD161a+/CD68+ macrophages and renal sympathetic nerves in cholinergic-hypertension and renal sodium retention. Bilateral renal nerve denervation (RND) and immune ablation of CD161a+ immune cells were performed in young prehypertensive spontaneously hypertensive rat (SHR) followed by infusion of either saline or nicotine (15 mg·kg−1·day−1) for 2 wk. Immune ablation was conducted by injection of unconjugated azide-free antibody targeting rat CD161a+. Blood pressure was monitored by tail cuff plethysmography. Tissues were harvested at the end of infusion. Nicotine induced premature hypertension, renal expression of the sodium-potassium chloride cotransporter (NKCC2), increases in renal sodium retention, and infiltration of CD161a+/CD68+ macrophages into the renal medulla. All of these effects were abrogated by RND and ablation of CD161a+ immune cells. Cholinergic activation of CD161a+ immune cells with nicotine leads to the premature development of hypertension in SHR. The effects of renal sympathetic nerves on chemotaxis of CD161a+ macrophages to the renal medulla, increased renal expression of NKCC2, and renal sodium retention contribute to cholinergic hypertension. The CD161a+ immune cells are necessary and essential for this prohypertensive nicotine-mediated inflammatory response. NEW & NOTEWORTHY This is the first study that describes a novel integrative physiological interaction between the adrenergic, cholinergic, and renal systems in the development of hypertension, describing data for the role of each in a genetic model of essential hypertension. Noteworthy findings include the prevention of nicotine-mediated hypertension following successful immune ablation of CD161a+ immune cells and the necessary role these cells play in the overexpression of the sodium-potassium-chloride cotransporter (NKCC2) in the renal medulla and renal sodium retention. Renal infiltration of these cells is demonstrated to be dependent on the presence of renal adrenergic innervation. These data offer a fertile ground of therapeutic potential for the treatment of hypertension as well as open the door for further investigation into the mechanism involved in inflammation-mediated renal sodium transporter expression. Taken together, these findings suggest immune therapy, renal denervation, and, possibly, other new molecular targets as having a potential role in the development and maintenance of essential hypertension. Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/cd161a-immune-cells-in-cholinergic-hypertension/ .

Immune Ablation Using Cyclophosphamide without Stem Cell Rescue for Intractable Multiple Sclerosis and Its Variants

Background: Multiple sclerosis (MS) is the most common progressively disabling neurologic disease of young adults worldwide. MS is a cytotoxic T Cell mediated disease with autoimmune-driven destruction occurring most actively in the early stages. Immune suppression with high dose steroids, cyclophosphamide (CTX), cladribine, and mitoxantrone has demonstrated benefit in intractable, more progressive or frequently relapsing patients, both on clinical and MRI parameters. In particular, non-ablative doses of CTX appear to stabilize progressive MS for one year or longer and were most effective earlier in the course of the disease. In aggressive MS deletion of cytotoxic T cells through immune ablation may offer a more durable remission than standard immune suppression. Due to aldehyde dehydrogenase mediated resistance of CD34+ cells to CTX, hematopoietic reconstitution without hematopoietic stem cell rescue is possible and could eliminate the need for stem cell mobilization which has been associated with disease flare and potential re-infusion of T-cells. Objective: To assess the safety and efficacy of immunoablation using CTX without hematologic stem cell rescue for intractable relapsing progressive multiple sclerosis failing standard immune modulation or immune suppression. Patients and Methods: Eight patients (median age = 29, range 24–37, men = 2, women = 6) between January 2005 and July 2008 underwent immunoablation with high dose CTX (HD-CTX) at 50 mg per kg per day intravenously for four consecutive days. Adequate hydration and forced diuresis were implemented to prevent hemorrhagic cystitis. G-CSF was started 6 days after the last dose of chemotherapy at 5 mcg/kg per day until the absolute neutrophil count was > 1000 per UL for two consecutive days. Red cell transfusions were administered to maintain hemoglobin of > 8 gm/dl and platelet transfusions were given to patients with < 10 Th/ul or to patients with active bleeding regardless of their platelet count. Clinical, laboratory, and MRI monitoring was scheduled at 3–6 month intervals over 24 months. Results: Eight patients have been treated with HD-CTX since 2005 and six of these patients have been monitored for more than 2 years. Hematologic complications included grade 4 neutropenia in all patients (duration 9–18 days), grade 4 thrombocytopenia in all patients (duration 3–13 days in 5 patients; 3 patients were discharged prior to platelet recovery), and grade 3 anemia in 6 patients (duration 1–9 days). All 8 patients required platelet transfusion (mean = 3.85 units, range 1–13 units) and 7 patients required PRBC transfusion (mean = 1.625 units, range 0–4 units). Non-hematologic grade 3 or 4 complications included grade 3 neutropenic fever in 7 patients, grade 3 hematuria in 2 patients and CTX-induced cardiotoxity with troponin elevation and infective endocarditis in 1 patient. 1 pt had a dystonic reaction to compazine. All patients have demonstrated improvements ranging from halting progression of MS clinically and radiologically to dramatic reductions of neurologic deficits, except in two patients whose disease reprogressed after 20 months of stability. One of these two patients demonstrated only subclinical disease activity on brain MRI without clinical correlates whereas the other experienced two milder clinical exacerbations. The latter has begun therapy with natalizumab, and the same has been recommended for the former. Given the refractory nature of these patients’ MS prior to therapy, the absence of further disease activity has been remarkable. Conclusions: Immunoablation with HD-CTX without stem cell rescue in patients with intractable MS represents a reasonable treatment option. These patients had significant improvements ranging from amelioration to stabilization of the disease course as well as reduction of disabilities. HD-CTX was tolerable with acceptable side effects and full hematologic recovery without the use of stem cell rescue. This is particularly important in patients with MS because of the associated disease flare and potential re-infusion of T-cells with stem cell mobilization. More data is needed and this clinical trial continues to accrue patients.

Immune Ablation Using High-Dose Cyclophosphamide without Stem Cell Rescue for Intractable Multiple Sclerosis.

Background: Immune ablation with autologous stem cell transplant has been studied in small phase I/II trials with modest success. However, the administration of granulocyte colony-stimulating factor (G-CSF) has led to disease flare in a number of patients. Immunoablative dosing of cyclophosphamide (CTX) without stem cell rescue has been beneficial in a variety of autoimmune disorders, including CIDP, lupus, and myasthenia gravis, as well as inducing durable complete responses in patients with severe aplastic anemia. Therefore, we attempted this method in patients with intractable MS. Methods: Patients were hospitalized; treatment was initiated with CTX at 50 mg/kg/day for four consecutive days. Patients were supported with adequate hydration and forced diuresis to prevent hemorrhagic cystitis. G-CSF was started 6 days after the completion of chemotherapy at 5 mcg/kg/day until the absolute neutrophil count (ANC) >1000 per UL for 2 consecutive days. Patients received supportive transfusions to maintain a hemoglobin of >8gm/dL and platelet count of >10 thousand/UL. Antibiotic therapy was administered per institutional guidelines for febrile neutropenia. Results: Four of planned 10 patients with definite MS, median age 26 (range 23–37), have been treated since February, 2005. All had progressive neurologic decline refractory to standard therapy and also to moderate-dose intermittent pulse IV CTX (1 gm/m2 total dose per cycle) with concurrent IV glucocorticoids. They had received a median of 6.5 (range 3–8) prior cycles, to a total median dose 15,600 (range 10,000–20,000) mg of CTX. The median duration of hospitalization was 19.5 (range 16–21) days. Hematologic toxicity was of short duration, and all patients became neutropenic on day 9. Median duration of neutropenia was 11 (range 7–15) days, with grade IV neutropenia lasting a median of 10.5 (range 6–12) days. Two of 4 patients developed grade III anemia requiring packed red blood cell transfusions; no patient developed grade IV anemia. All patients required supportive transfusions with platelets for grade IV thrombocytopenia, lasting a median of 4.5 (range 2–8) days. Treatment was well tolerated, without serious non-hematologic adverse events. The most common side effect was nausea, mild in 2 patients and moderate in 1 patient. 2 patients experienced diarrhea. 1 patient developed hematuria requiring cystoscopy and bladder irrigation. Three of 4 patients received IV antibiotics for neutropenic fevers; no sources of infection were identified. One patient developed reactivation of oral herpetic lesions despite prophylactic acyclovir. One patient had self-limited mild stomatitis. All patients experienced improvement of neurologic functions, two were clinically dramatic; 3 patients also had dramatic improvement of MRI findings. Conclusion: This is the first report of immune ablation in recalcitrant MS using high dose cyclophosphamide without stem cell rescue. Despite multiple previous CTX doses, all 4 patients responded clinically to high dose therapy, and treatment was remarkably well tolerated with short duration of hematologic toxicity. No disease relapses occurred during chemotherapy or administration of G-CSF. Further follow-up and additional patients are required to evaluate long-term efficacy and late toxicities.