The significant improvement in ovarian PCOS syndrome using hydralazine and alendronate aromatase inhibitor FDA-approved drugs in Wistar rat models

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. The aim of this study was to investigate the therapeutic potential of vitamin C, glutamine, mesalazine, hydralazine, and alendronate as new drug candidates for the treatment of letrozole-induced PCOS in female Wistar rats. PCOS was induced in rats by intramuscular injection of estradiol valerate (2 mg/kg body weight for 28 days). The rats then received normal saline (PCOS group), letrozole (0.5 mg/kg), vitamin C (100 mg/kg), glutamine (1000 mg/kg), mesalazine (200 mg/kg), hydralazine (30 mg/kg), and alendronate (17.5 mg/kg). Serum testosterone, LH, FSH, estradiol and progesterone levels were determined by ELISA method. H&E staining was used for histological analysis in the ovarian tissues. The groups treated with hydralazine and alendronate, show a significant decrease in testosterone, LH hormone, cystic and atretic follicles, and a significant increase in the number of single layer, multilayer, antral, graafian follicles and the volume of corpus luteum as compared to the PCOS group. Hydrolazine and alendronate appear to be effective in restoring folliculogenesis and increasing ovulation in PCOS rat. So that the natural process of ovulation and the improvement of the histology of polycystic ovaries and its shift towards healthy and active ovaries were observed. This finding supports the potential beneficial effect of hydrolazine and alendronate on improving PCOS complication.

Hydralazine loaded nanodroplets combined with ultrasound-targeted microbubble destruction to induce pyroptosis for tumor treatment

Pyroptosis, a novel type of programmed cell death (PCD), which provides a feasible therapeutic option for the treatment of tumors. However, due to the hypermethylation of the promoter, the critical protein Gasdermin E (GSDME) is lacking in the majority of cancer cells, which cannot start the pyroptosis process and leads to dissatisfactory therapeutic effects. Additionally, the quick clearance, systemic side effects, and low concentration at the tumor site of conventional pyroptosis reagents restrict their use in clinical cancer therapy. Here, we described a combination therapy that induces tumor cell pyroptosis via the use of ultrasound-targeted microbubble destruction (UTMD) in combination with DNA demethylation. The combined application of UTMD and hydralazine-loaded nanodroplets (HYD-NDs) can lead to the rapid release of HYD (a demethylation drug), which can cause the up-regulation of GSDME expression, and produce reactive oxygen species (ROS) by UTMD to cleave up-regulated GSDME, thereby inducing pyroptosis. HYD-NDs combined with ultrasound (US) group had the strongest tumor inhibition effect, and the tumor inhibition rate was 87.15% (HYD-NDs group: 51.41 ± 3.61%, NDs + US group: 32.73%±7.72%), indicating that the strategy had a more significant synergistic anti-tumor effect. In addition, as a new drug delivery carrier, HYD-NDs have great biosafety, tumor targeting, and ultrasound imaging performance. According to the results, the combined therapy reasonably regulated the process of tumor cell pyroptosis, which offered a new strategy for optimizing the therapy of GSDME-silenced solid tumors.

Effects of vasodilators on beat-to-beat and every fifteen minutes blood pressure variability induced by noradrenaline infusion in rats

Increased blood pressure variability (BPV) was shown to be associated with cardiovascular morbidities and/or mortalities. There are various types of BPV depending on time intervals of BP measurements, ranging from beat-to-beat to visit-to-visit or year-to-year. We previously found that continuous infusion of noradrenaline (NA) for 14 days increased short-term BPV every 15 min in rats. The aims of this study were to examine (1) whether NA infusion increases very short-term beat-to-beat BPV, (2) the effects of azelnidipine and hydralazine on NA-induced BPV, and (3) whether baroreceptor reflex sensitivity (BRS) is affected by NA or NA plus those vasodilators. Nine-week-old Wistar rats infused subcutaneously with 30 μg/h NA were orally treated with or without 9.7 mg/day azelnidipine or 5.9 mg/day hydralazine over 14 days. BP levels were continuously monitored via abdominal aortic catheter with a telemetry system in an unrestrained condition. Standard deviations (SDs) were used to evaluate beat-to-beat BPV and BPV every 15 min which was obtained by averaging BP levels for 10-s segment at each time point. BRS was determined by a sequence analysis. Continuous NA infusion over 14 days increased average BP, beat-to-beat BPV, and BPV every 15 min, lowering BRS. Comparing the two vasodilators, hydralazine reduced BP elevation by NA; meanwhile, azelnidipine alleviated BPV augmentation, preserving BRS, despite a smaller BP reduction. Thus, NA infusion increased both very short- and short-term BPV concomitantly with impaired BRS, while azelnidipine had an inhibitory effect, possibly independent of BP-lowering, on those types of BPV and impairment of BRS.

Hydralazine combined with conventional therapy improved outcomes in severe systolic dysfunction and mitral regurgitation

AIMS

Patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF) accompanied by significant mitral regurgitation (MR) had poor outcome. Several vasodilator trials showed neutral results. We aimed to investigate the effect of early up-titration of hydralazine combined with conventional treatment in acute HF with severe systolic dysfunction and significant MR.

METHODS AND RESULTS

The study was open-labelled, one-to-one ratio randomized designed. Consecutively hospitalized patients with decompensated HF symptoms, LVEF < 35%, and MR more than moderate severity were enrolled after exclusion. All participants with inadequate preload should have intake promotion with/without fluid supply. Patients receiving evidence-based medications (EBMs) as conventional treatment served as the control. Hydralazine + conventional treatment group received up-titration of hydralazine at Days 1-5 of the index admission combined with EBMs and throughout the course of follow-up. The endpoints included cardiovascular (CV) death and HF rehospitalization. Totally, 408 patients were enrolled (203 in conventional treatment and 205 in hydralazine + conventional treatment). The mean follow-up period was 3.5 years. The mean dose of hydralazine was 191 mg at index admission and 264 mg at study end in hydralazine + conventional treatment group. Both groups did not significantly differ in prescription rates and dosages of EBMs (all P > 0.05) at study end. Side effects did not differ between the two groups. Finally, 51% (104 out of 203 cases) reached endpoints in conventional group and 34.6% (71 out of 205 cases) in hydralazine + conventional treatment group, which had a significant reduction in CV events (hazard ratio 0.613, 95% confidence interval 0.427-0.877, P < 0.001). In-hospital death during the index admission was significantly higher in conventional group (5.4% vs. 0.5%, respectively; P = 0.001).

CONCLUSIONS

When administered without inadequate preload, combining early up-titration of hydralazine with EBMs improves outcome in patients with severe systolic dysfunction and significant MR, and it is safe and well tolerated.

Pharmacogenomics of Preeclampsia therapies: Current evidence and future challenges for clinical implementation

Preeclampsia is a pregnancy-specific disorder, and it is a leading cause of maternal and perinatal morbidity and mortality. The application of pharmacogenetics to antihypertensive agents and dose selection in women with preeclampsia is still in its infancy. No current prescribing guidelines from the clinical pharmacogenetics implementation consortium (CPIC) exist for preeclampsia. Although more studies on pharmacogenomics are underway, there is some evidence for the pharmacogenomics of preeclampsia therapies, considering both the pharmacokinetic (PK) and pharmacodynamic (PD) properties of drugs used in preeclampsia. It has been revealed that the CYP2D6*10 variant is significantly higher in women with preeclampsia who are non-responsive to labetalol compared to those who are in the responsive group. Various genetic variants of PD targets, i.e., NOS3, MMP9, MMP2, TIMP1, TIMP3, VEGF, and NAMPT, have been investigated to assess the responsiveness of antihypertensive therapies in preeclampsia management, and they indicated that certain genetic variants of MMP9, TIMP1, and NAMPT are more frequently observed in those who are non-responsive to anti-hypertensive therapies compared to those who are responsive. Further, gene-gene interactions have revealed that NAMPT, TIMP1, and MMP2 genotypes are associated with an increased risk of preeclampsia, and they are more frequently observed in the non-responsive subgroup of women with preeclampsia. The current evidence is not rigorous enough for clinical implementation; however, an institutional or regional-based retrospective analysis of audited data may help close the knowledge gap during the transitional period from a traditional approach (a "one-size-fits-all" strategy) to the pharmacogenomics of preeclampsia therapies.

Hydralazine represses Fpn ubiquitination to rescue injured neurons via competitive binding to UBA52

A major impedance to neuronal regeneration after peripheral nerve injury (PNI) is the activation of various programmed cell death mechanisms in the dorsal root ganglion. Ferroptosis is a form of programmed cell death distinguished by imbalance in iron and thiol metabolism, leading to lethal lipid peroxidation. However, the molecular mechanisms of ferroptosis in the context of PNI and nerve regeneration remain unclear. Ferroportin (Fpn), the only known mammalian nonheme iron export protein, plays a pivotal part in inhibiting ferroptosis by maintaining intracellular iron homeostasis. Here, we explored in vitro and in vivo the involvement of Fpn in neuronal ferroptosis. We first delineated that reactive oxygen species at the injury site induces neuronal ferroptosis by increasing intracellular iron via accelerated UBA52-driven ubiquitination and degradation of Fpn, and stimulation of lipid peroxidation. Early administration of the potent arterial vasodilator, hydralazine (HYD), decreases the ubiquitination of Fpn after PNI by binding to UBA52, leading to suppression of neuronal cell death and significant acceleration of axon regeneration and motor function recovery. HYD targeting of ferroptosis is a promising strategy for clinical management of PNI.

Hydralazine inhibits neuroinflammation and oxidative stress in APP/PS1 mice via TLR4/NF-κB and Nrf2 pathways

Alzheimer's disease (AD) is a common chronic progressive neurodegenerative disorder, and curative treatment has not been developed. The objective of this study was to investigate the potential effects of hydralazine (Hyd, a hypertension treatment drug) on the development process of AD and its mechanisms. We treated 6-month-old male APP/PS1 mice with Hyd for 5 weeks, measured changes in behavior and pathological status, and analyzed differences in gene expression by RNA sequencing. The results demonstrated that Hyd improved cognitive deficits and decreased amyloid beta protein deposition in the cortex and hippocampus, while RNA sequencing analysis suggested that the regulation of neuroinflammation and energy metabolism might play pivotal roles for Hyd's beneficial effects. Therefore, we further investigated inflammatory response, redox state, and mitochondrial function, as well as the expression of toll-like receptor 4 (TLR4)/nuclear factor Kappa B (NF-κB)-dependent neuroinflammation gene and nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant gene in AD mice. The results showed that Hyd reduced the damage of neuroinflammation and oxidative stress, improved mitochondrial dysfunction, downregulated pro-inflammation gene expression, and upregulated antioxidant gene expression. The results in lipopolysaccharide (LPS)-induced BV2 cell model demonstrated that Hyd suppressed pro-inflammatory response via TLR4/NF-κB signaling pathway. In addition, by silencing the Nrf2 gene expression, it was found that Hyd can reduce LPS-induced reactive oxygen species production by activating the Nrf2 signaling pathway. Therefore, administration of Hyd in the early stage of AD might be beneficial in delaying the pathological development of AD via inhibiting neuroinflammation and oxidative stress.

Xanthine oxidase/NADPH oxidase inhibition by hydralazine attenuates acute kidney injury and prevents the transition of acute kidney injury to chronic kidney disease

AIMS

The enhancement of inflammation and reactive oxygen species leads to the damage of renal tubular cells in acute kidney injury (AKI), and the upregulation of inflammation increases the risk of AKI being converted into chronic kidney disease (CKD). Hydralazine has shown renoprotective effects in multiple kidney diseases and was shown to be a potent xanthine oxidase (XO) inhibitor. This study aimed to investigate the mechanisms of hydralazine in ischemia-reperfusion (I/R)-stimulated renal proximal tubular epithelial cells in vitro and in AKI animals in vivo.

MAIN METHODS

The effects of hydralazine in AKI-to-CKD transition were also evaluated. Human renal proximal tubular epithelial cells were stimulated by I/R conditions in vitro. To generate a mouse model of AKI, a right nephrectomy was performed, followed by left renal pedicle I/R using a small atraumatic clamp.

KEY FINDINGS

In the in vitro part, hydralazine could protect renal proximal tubular epithelial cells against insults from the I/R injury through XO/NADPH oxidase inhibition. In the in vivo part, hydralazine preserved renal function in AKI mice and improved the AKI-to-CKD transition by decreasing renal glomerulosclerosis and fibrosis independently of blood pressure lowering. Furthermore, hydralazine exerted antioxidant, anti-inflammatory, and anti-fibrotic effects both in vitro and in vivo.

SIGNIFICANCE

Hydralazine, as a XO/NADPH oxidase inhibitor, could protect renal proximal tubular epithelial cells from the insults of I/R and prevent kidney damage in AKI and AKI-to-CKD. The above experimental studies strengthen the possibility of repurposing hydralazine as a potential renoprotective agent through its antioxidative mechanisms.

The Effects of Verapamil, Hydralazine, and Doxazosin on Renin, Aldosterone, and the Ratio Thereof

PURPOSE

Hydralazine, doxazosin, and verapamil are currently recommended by the Endocrine Society as acceptable bridging treatment in those in whom full cessation of antihypertensive medication is infeasible during screening for primary aldosteronism (PA). This is under the assumption that they cause minimal to no effect on the aldosterone-to-renin ratio, the most widely used screening test for PA. However, limited evidence is available regarding the effects of these particular drugs on said ratio.

METHODS

In the present study, we retrospectively assessed the changes in aldosterone, renin, and aldosterone-to-renin values in essential hypertensive participants before and after treatment with either hydralazine (n = 26) or doxazosin (n = 20) or verapamil (n = 15). All samples were taken under highly standardized conditions.

RESULTS

Hydralazine resulted in a borderline significant rise in active plasma renin concentration (19 vs 25 mIU/L, p = 0.067) and a significant fall in the aldosterone-to-renin ratio (38 vs 24, p = 0.017). Doxazosin caused declines in both plasma aldosterone concentration (470 vs 330 pmol/L, p = 0.028) and the aldosterone-to-renin ratio (30 vs 20, p = 0.020). With respect to verapamil, we found no statistically significant effect on any of these outcome variables.

CONCLUSION

We conclude that the assumption that these drugs can be used with little consequence to the aldosterone-to-renin cannot be substantiated. While it is possible that they are indeed the best option when full antihypertensive drug cessation is infeasible, the potential effects of these drugs must still be taken into account when interpreting the aldosterone-to-renin ratio.

Cell-type dependent regulation of pluripotency and chromatin remodeling genes by hydralazine

BACKGROUND

The generation of induced pluripotent stem cells has opened the field of study for stem cell research, disease modeling and drug development. However, the epigenetic signatures present in somatic cells make cell reprogramming still an inefficient process. This epigenetic memory constitutes an obstacle in cellular reprogramming. Here, we report the effect of hydralazine (HYD) and valproic acid (VPA), two small molecules with proven epigenetic activity, on the expression of pluripotency genes in adult (aHF) and neonatal (nbHF) human fibroblasts.

METHODS

aHF and nbHF were treated with HYD and/or VPA, and viability and gene expression assays for OCT4, NANOG, c-MYC, KLF4, DNMT1, TET3, ARID1A and ARID2 by quantitative PCR were performed. aHF and nbHF were transfected with episomal plasmid bearing Yamanaka factors (OCT4, SOX2, KLF4 and c-MYC) and exposed to HYD and VPA to determine the reprogramming efficiency. Methylation sensitive restriction enzyme (MSRE) qPCR assays were performed on OCT4 and NANOG promoter regions. Immunofluorescence assays were carried out for pluripotency genes on iPSC derived from aHF and nbHF.

RESULTS

HYD upregulated the expression of OCT4 (2.5-fold) and NANOG (fourfold) genes but not c-Myc or KLF4 in aHF and had no significant effect on the expression of all these genes in nbHF. VPA upregulated the expression of NANOG (twofold) in aHF and c-MYC in nbHF, while it downregulated the expression of NANOG in nbHF. The combination of HYD and VPA canceled the OCT4 and NANOG overexpression induced by HYD in aHF, while it reinforced the effects of VPA on c-Myc expression in nbHF. The HYD-induced overexpression of OCT4 and NANOG in aHDF was not dependent on demethylation of gene promoters, and no changes in the reprogramming efficiency were observed in both cell populations despite the downregulation of epigenetic genes DNMT1, ARID1A, and ARID2 in nbHF.

CONCLUSIONS

Our data provide evidence that HYD regulates the expression of OCT4 and NANOG pluripotency genes as well as ARID1A and ARID2 genes, two members of the SWI/SNF chromatin remodeling complex family, in normal human dermal fibroblasts.

Coordination of hydralazine with Cu2+ at acidic pH promotes its oxidative degradation at neutral pH

Hydralazine (HL), a frequently prescribed oral antihypertensive drug, shows redox interactions with transition metals such as copper that are not fully understood. Copper may be present at high concentrations in the digestive tract and can affect oral drugs. An important parameter for such interactions is pH, which changes from acidic in the gastric juice to neutral pH in intestines. In this study, we examined interactions of HL with Cu²⁺ ions in conditions that mimic pH shift in the digestive tract using UV-Vis, Raman and EPR spectroscopy, cyclic voltammetry and oximetry. In the acidic solution, Cu²⁺ formed a stable mononuclear complex with two bidentate coordinated HL molecules. On the other hand, at neutral pH, Cu²⁺ initiated oxidation and degradation of HL. The degradation was more rapid in the HL-Cu²⁺ system that was initially prepared at acidic pH and then shifted to neutral pH. The formation of the complex at acidic pH increases the availability of Cu²⁺ for redox reactions after the shift to neutral pH at which Cu²⁺ is poorly soluble. These results imply that the change of pH along the digestive tract may promote HL degradation by allowing the formation of the complex at gastric pH which makes Cu²⁺ available for subsequent oxidation of HL at neutral pH.

Comparison of efficacy of intravenous labetalol and intravenous hydralazine for management of pre-eclampsia in pregnant women

Objectives

To compare the efficacy of intravenous Labetalol and intravenous Hydralazine in reduction of blood pressure in patients with severe pre-eclampsia.

Methodology

This comparative study was conducted at the Department of Obstetrics and Gynecology at Ziauddin University Hospital, Karachi from1st June 2019 to 30th June 2020. Total 208 pregnant women having severe pre-eclampsia (systolic pressure ≥160 mmHg and diastolic pressure ≥110mmHg) were included in study. Group A received I/V Labetalol. Group B received I/V Hydralazine. Efficacy of drugs was observed by reduction in blood pressure and the number of doses administered. Data was analysed using SPSS version 26.

Results

Systolic blood pressure reduction in Labetalol group was significantly lower than in hydralazine group (105.5 ±11.3 vs. 115.8 ±17.1, p≤ 0.001). Diastolic blood pressure reduction was also lower in labetalol group than in hydralazine group (p= 0.03). Number of dosage of drugs in Group A (Labetalol) was 3.2 ±1.2 vs. Group B (Hydralazine) was 4.4±1.4, p =0.006).

Conclusion

The results of this study show that Labetalol is more effective as compared to Hydralazine in terms of reducing the systolic and diastolic blood pressure and number of doses (Drugs) for in patients with severe preeclampsia.

Hydralazine plays an immunomodulation role of pro-regeneration in a mouse model of spinal cord injury

Spinal cord injury (SCI) results in severe motor and sensory dysfunction with no effective therapy. Spinal cord debris (sp) from injured spinal cord evokes secondary SCI continuously. We and other researchers have previously clarified that it is mainly bone marrow derived macrophages (BMDMs) infiltrating in the lesion epicenter to clear sp, rather than local microglia. Unfortunately, the pro-inflammatory phenotype of these infiltrating BMDMs is predominant which impairs wound healing. Hydralazine, as a potent vasodilator and scavenger of acrolein, has protective effects in many diseases. Hydralazine is also confirmed to promote motor function and hypersensitivity in SCI rats through scavenging acrolein. However, few studies have explored the effects of hydralazine on immunomodulation, as well as spontaneous pain and emotional response, the important syndromes in clinical patients. It remains unclear whether hydralazine affects infiltrating BMDMs after SCI. In this study, we targeted BMDMs to explore the influence of hydralazine on immune cells in a mouse model of SCI, and also investigated the contribution of polarized BMDMs to hydralazine-induced neurological function recovery after SCI in male mice. The adult male mice underwent T10 spinal cord compression. The results showed that in addition to improving motor function and hypersensitivity, hydralazine relieved SCI-induced spontaneous pain and emotional response, which is a newly discovered function of hydralazine. Hydralazine inhibited the recruitments of pro-inflammatory BMDMs and educated infiltrated BMDMs to a more reparative phenotype involving in multiple biological processes associated with SCI pathology, including immune/inflammation response, neurogenesis, lipid metabolism, oxidative stress, fibrosis formation, and angiogenesis, etc. As an overall effect, hydralazine-treated BMDMs loaden with sp partially rescued neurological function after SCI. It is concluded that hydralazine plays an immunomodulation role of educating pro-inflammatory BMDMs to a more reparative phenotype; and hydralazine-educated BMDMs contribute to hydralazine-induced improvement of neurological function in SCI mice, which provides support for drug and cell treatment options for SCI therapy.

Effects of systemic drugs on the development and progression of age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of severe loss of central vision among people over 50. The pathophysiology of the disease is multifactorial and can be attributed to genetics, aging, inflammation, environmental factors, and lifestyle factors including smoking, diet, obesity, and alcohol consumption. While there is no treatment for dry AMD, the current standard treatment for wet AMD is an intraocular injection of anti-vascular endothelial growth factor-an effective, yet expensive, therapy that requires ongoing treatment. As the aging population continues to grow, and AMD diagnoses continue to rise, new treatments should be explored to reduce vision complications and decrease treatment burdens. Many systemic conditions have progressive pathological changes that may affect AMD, particularly those affecting systemic vasculature like diabetes and cardiovascular status. Consequently, systemic drugs used to treat coexistent systemic diseases may influence some of the pathogenic mechanisms of AMD and lead its progression or delay. In this review we explore the current literature to summarize the findings of the reported effects of antihypertensive, immunosuppressants, cholesterol lowering agents, nonsteroidal anti-inflammatory drugs, dopamine precursors, hypoglycemic agents, and anticoagulants on AMD.

Overlapping Syndromes: Drug-Induced Vasculitis From Hydralazine With Positive Antinuclear Antibodies

Hydralazine is an antihypertensive medication that has been associated with drug-associated autoimmune syndromes like interstitial lung disease, pauci-immune glomerulonephritis, and hypocomplementemia. Hydralazine-induced ANCA-associated vasculitis and hydralazine induced positive antinuclear antibodies are rare. Clinical manifestations range from arthralgia, petechiae, or rash to multiorgan involvement. When presented as pulmonary-renal syndrome, it can be rapidly progressive and fatal. Here, we describe a case of hydralazine-associated vasculitis with rapidly progressive glomerulonephritis and highlight the importance of early diagnosis and prompt treatment.

Effect of the cholinergic system of the lateral periaqueductal gray (lPAG) on blood pressure and heart rate in normal and hydralazine hypotensive rats

Objectives

Due to the presence of the cholinergic system in the lateral periaqueductal gray (lPAG) column, the cardiovascular effects of acetylcholine (ACH) and its receptors in normotensive and hydralazine (HYD) hypotensive rats in this area were evaluated.

Materials and Methods

After anesthesia, the femoral artery was cannulated and systolic blood pressure (SBP), mean arterial pressure (MAP), heart rate (HR), and also electrocardiogram for evaluation of low frequency (LF) and high frequency (HF) bands, important components of heart rate variability (HRV), were recorded. ACH, atropine (Atr, a muscarinic antagonist), and hexamethonium (Hex, an antagonist nicotinic) alone and together microinjected into lPAG, changes (Δ) of cardiovascular responses and normalized (n) LF, HF, and LF/HF ratio were analyzed.

Results

In normotensive rats, ACH decreased SBP and MAP, and enhanced HR while Atr and Hex did had no effects. In co-injection of Atr and Hex with ACH, only ACH+Atr significantly attenuated parameters. In HYD hypotension, ACH had no affect but Atr and Hex significantly improved the hypotensive effect. Co-injection of Atr and Hex with ACH decreased the hypotensive effect but the effect of Atr+ACH was higher. In normotensive rats, ACH decreased nLF, nHF, and nLF/nHF ratio. These parameters in the Atr +ACH group were significantly higher than in ACH group. In HYD hypotension nLF and nLF/nHF ratio increased which was attenuated by ACH. Also, Atr+ACH decreased nLF and nLF/nHF ratio and increased nHF.

Conclusion

The cholinergic system of lPAG mainly via muscarinic receptors has an inhibitory effect on the cardiovascular system. Based on HRV assessment, peripheral cardiovascular effects are mostly mediated by the parasympathetic system.

A Spotlight on Drug-Induced Vasculitis

PURPOSE OF REVIEW

Drug-induced vasculitis (DIV) is a rare form of vasculitis related to the use of various drugs. DIV primarily affects small to medium size vessels, but it can potentially involve vessels of any size. Differentiating between primary systemic vasculitis and DIV can be challenging; however, it is crucial, so that the offending agent can be discontinued promptly.

RECENT FINDINGS

The clinical phenotype of DIV is protean and depends on the size of the affected vessels. It ranges from arthralgias, to an isolated cutaneous rash, to severe single or multi-organ involvement. While withdrawal of the offending drug is the most important step in management, a significant number of patients require immunosuppressive therapy for varying periods of time. DIV can affect any vascular bed size, leading to protean vasculitic syndromes. Increased awareness among general practitioners, specialty, and subspecialty physicians is crucial for early recognition, and withdrawal of drug for better outcomes.

Antioxidation and Nrf2-mediated heme oxygenase-1 activation contribute to renal protective effects of hydralazine in diabetic nephropathy

Reactive oxygen species (ROS) and oxidative stress are associated with the progression of diabetic nephropathy (DN). Hydralazine is an antihypertensive agent and may act as a xanthine oxidase (XO) inhibitor to reduce uric acid levels in a mouse renal injury model. This study aimed to investigate the potential mechanisms of hydralazine in experimental DN. Streptozotocin-induced diabetic mice were fed a high-fat diet to generate DN. Human renal proximal tubular epithelial cells were used in vitro. Nitrendipine and allopurinol which can reduce blood pressure or XO activity levels, were used as two positive controls. Hydralazine downregulated NF-κB/p38 signaling pathways and reduced TNF-α/IL-6 expressions in high glucose-stimulated renal proximal tubular epithelial cells. Hydralazine reduced in vitro ROS production via XO inhibition and nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated heme oxygenase (HO)-1 activation. Furthermore, hydralazine reduced high glucose-induced apoptosis by downregulating PARP/caspase-3 signaling. Hydralazine and allopurinol but not nitrendipine reduced serum uric acid levels and systemic inflammation. Hydralazine and allopurinol treatment improved renal function with decreased urinary albumin-to-creatinine ratios, glomerular hypertrophy, glomerulosclerosis, and fibrosis in the kidney of DN mice. While both hydralazine and allopurinol downregulated XO and NADPH oxidase expression, only hydralazine upregulated Nrf2/HO-1 renal expression, suggesting the additional effects of hydralazine independent of XO/ NADPH oxidase inhibition. In conclusion, hydralazine protected renal proximal tubular epithelial cells against the insults of high glucose and prevented renal damage via XO/NADPH oxidase inhibition and Nrf-2/HO-1 activation, suggesting the comprehensive antioxidation and anti-inflammation mechanisms for the management of DN.

Targeted delivery of acrolein scavenger hydralazine in spinal cord injury using folate-linker-drug conjugation

Oxidative stress has been shown to play a critical pathogenic role in functional loss after spinal cord injury (SCI). As a direct result of oxidative stress, lipid peroxidation-derived aldehydes have emerged as key culprits that sustain secondary injury and contribute significantly to pathological outcomes. Acrolein, a neurotoxin, has been shown to be elevated in SCI and can result in post-SCI neurological deficits. Reducing acrolein has therefore emerged as a novel and effective therapeutic strategy in SCI. Previous studies have revealed that hydralazine, an FDA approved blood pressure lowering medication, when administered after SCI shows strong acrolein scavenging capabilities and significantly improves cellular and behavioral outcomes. However, while effective at scavenging acrolein, hydralazine's blood pressure lowering activity can have a detrimental impact on neurotrauma patients. Here, our goal was to preserve the acrolein scavenging capability while mitigating the effect of hydralazine on blood pressure. We accomplished this using a folate-targeted delivery system to deploy hydralazine to the folate receptor positive inflammatory site of the cord injury. Using a model of rat SCI, we found that this system is effective for targeting the injury site, and that folate targeted hydralazine can scavenge acrolein without significantly impacting blood pressure.

Hydralazine protects the heart against acute ischaemia/reperfusion injury by inhibiting Drp1-mediated mitochondrial fission

AIMS

Genetic and pharmacological inhibition of mitochondrial fission induced by acute myocardial ischaemia/reperfusion injury (IRI) has been shown to reduce myocardial infarct size. The clinically used anti-hypertensive and heart failure medication, hydralazine, is known to have anti-oxidant and anti-apoptotic effects. Here, we investigated whether hydralazine confers acute cardioprotection by inhibiting Drp1-mediated mitochondrial fission.

METHODS AND RESULTS

Pre-treatment with hydralazine was shown to inhibit both mitochondrial fission and mitochondrial membrane depolarisation induced by oxidative stress in HeLa cells. In mouse embryonic fibroblasts (MEFs), pre-treatment with hydralazine attenuated mitochondrial fission and cell death induced by oxidative stress, but this effect was absent in MEFs deficient in the mitochondrial fission protein, Drp1. Molecular docking and surface plasmon resonance studies demonstrated binding of hydralazine to the GTPase domain of the mitochondrial fission protein, Drp1 (KD 8.6±1.0 µM), and inhibition of Drp1 GTPase activity in a dose-dependent manner. In isolated adult murine cardiomyocytes subjected to simulated IRI, hydralazine inhibited mitochondrial fission, preserved mitochondrial fusion events, and reduced cardiomyocyte death (hydralazine 24.7±2.5% vs. control 34.1±1.5%, P=0.0012). In ex vivo perfused murine hearts subjected to acute IRI, pre-treatment with hydralazine reduced myocardial infarct size (as % left ventricle: hydralazine 29.6±6.5% vs. vehicle control 54.1±4.9%, P=0.0083), and in the murine heart subjected to in vivo IRI, the administration of hydralazine at reperfusion, decreased myocardial infarct size (as % area-at-risk: hydralazine 28.9±3.0% vs. vehicle control 58.2±3.8%, P<0.001).

CONCLUSION

We show that, in addition to its antioxidant and anti-apoptotic effects, hydralazine, confers acute cardioprotection by inhibiting IRI-induced mitochondrial fission, raising the possibility of repurposing hydralazine as a novel cardioprotective therapy for improving post-infarction outcomes.

Hydralazine attenuates renal inflammation in diabetic rats with ischemia/reperfusion acute kidney injury

Acute kidney injury (AKI) is one of the major complications with increased oxidative stress and inflammation in diabetic patients. Hyperglycemia stimulates the formation of advanced glycation end products (AGEs). However, hyperglycemia directly triggers the interaction between AGEs and transmembrane AGEs receptors (RAGE), which enhances oxidative stress and increases the production of inflammatory substances. Therefore, diabetes plays a pivotal role in kidney injury. Hydralazine, a vasodilator and antihypertensive drug, was found to have the ability to reduce ROS, oxidative stress, and inflammation. We applied Hydralazine co-culture with AGEs in rat mesangial cells (RMC) and to renal ischemia/reperfusion(I/R) injury models in streptozotocin-induced diabetic rats. Hydralazine significantly decreased AGEs-induced RAGE, iNOS, and COX-2 expressions in RMC. Compared to the diabetic with AKI group, hydralazine decreased inflammation-related protein, and JAK2, STAT3 signaling in rat kidney tissue. Our studies indicate that Hydralazine has the potential to become a beneficial drug in the treatment of diabetic acute kidney injury.

Case Study 11: Considerations for Enzyme Mapping Experiments-Interaction Between the Aldehyde Oxidase Inhibitor Hydralazine and Glutathione

Often it may be convenient and efficient to address multiple research questions with a single experiment. In many instances, however, the best approach is to design the experiment to address one question at a time. The design of enzyme mapping experiments is discussed in this chapter, focusing on considerations pertinent to the study of aldehyde oxidase (AO) vs. cytochrome P450 metabolism. Specifically, a case is presented in which reduced glutathione (GSH) was included in an experiment with human liver S9 fraction to trap reactive metabolites generated from cytochrome P450-mediated metabolism of lapatinib and its O-dealkylated metabolite, M1 (question 1). The AO inhibitor hydralazine was included in this experiment to investigate the involvement of AO-mediated metabolism of M1 (question 2). The presence of GSH was found to interfere with the inhibitory activity of hydralazine. Consideration of the time-dependent nature of hydralazine inhibitory activity toward AO when designing this experiment could have predicted the potential for GSH to interfere with hydralazine. This case underscores the importance of clearly identifying the research question, tailoring the experimental protocol to answer that question, and then meticulously considering how the experimental conditions could influence the results, particularly if attempting to address multiple questions with a single experiment.

Vericiguat, organic nitrates, and heart failure in African Americans

African Americans (AA) have a higher prevalence of heart failure (HF) when compared with White Americans (3% vs 2%), respectively and HF comes on at an earlier age and is more severe in AA. The A-HEFT trial with the combination of hydralazine and isosorbide dinitrate (ISDNHYD) for self-described AA with NYHA class III-IV heart failure with reduced ejection fraction (HFrEF) showed reduction in mortality and HF hospitalizations with a class I level of evidence A recommendation in the ACC/AHA guidelines. Vericiguat is an oral soluble guanylate cyclase stimulator that enhances the cyclic guanosine monophosphate (GMP) pathway. A randomized, double-blind, placebo-controlled trial in patients with higher risk HFrEF in which AA were underrepresented found that vericiguat reduced the composite primary outcome of cardiovascular death or first HF hospitalization. In the new era of guideline directed medical therapies of quadruple therapy - hydralazine and isosorbide dinitrate should be preferred over vericiguat in AA with HFrEF.

Efficacy of nifedipine versus hydralazine in the management of severe hypertension in pregnancy: A randomised controlled trial

Background

Despite the availability of effective antihypertensive drugs, the quality of evidence regarding the best antihypertensive agent for the treatment of hypertensive emergencies in pregnancy is still poor.

Aim

The aim of this study was to compare the efficacy and side effects of oral nifedipine and intravenous hydralazine for control of blood pressure (BP) in severe hypertension in pregnancy.

Materials and Methods

An open-label, parallel, randomised, controlled trial of 78 pregnant women (≥28 weeks' gestation) with severe hypertension was conducted. Severe hypertension was defined as systolic BP of 160 mmHg or above and/or diastolic BP of 110 mmHg or above. They were randomly (1:1 ratio) administered oral nifedipine 20 mg or intravenous hydralazine 10 mg every 30 min up to 5 doses or until the target BP of 140-150 mmHg systolic and 90-100 mmHg diastolic was achieved. Intravenous labetalol was given if the primary treatment failed. The primary outcome measure was the number of doses needed to achieve targeted BP. The secondary outcome measures were the time needed to achieve desired BP, maternal adverse effects and perinatal outcome.

Results

The sociodemographic characteristics did not differ between the two study groups. The average number of dosages (nifedipine; 1.4 ± 0.6 vs. hydralazine; 1.7 ± 0.5, P = 0.008) needed to control the BP was lower in the nifedipine arm. Time (min) taken to control the BP was similar between the groups (hydralazine; 43.7 ± 19.7 vs. nifedipine; 51.2 ± 18.9, P = 0.113). Adverse maternal and perinatal effects did not differ in the study groups.

Conclusion

Oral nifedipine and intravenous hydralazine showed comparable efficacy in the BP control in the severe hypertensive disorders of pregnancy without significant difference in adverse maternal and perinatal outcomes. However, further studies are required to explore the role of these drugs in BP control during hypertensive emergencies in pregnancy.

ClinicalTrials.gov

(Identification number: NCT04435210).

Reduction of fatty liver in rats by nicotinamide via the regeneration of the methionine cycle and the inhibition of aldehyde oxidase

Nonalcoholic fatty liver disease, which has been rapidly increasing in the world in recent years, is roughly classified into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis. This study was based on our previous reports that stated that the combination treatment of N1-methylnicotinamide (MNA) and hydralazine (HYD) improves fatty liver in NAFL model rats. This finding was attributed to the MNA metabolism inhibition by HYD, which is a strong inhibitor of aldehyde oxidase (AO); this results in an increase in hepatic MNA and improved fatty liver. We hypothesized that orally administered nicotinamide (NAM), which is the precursor of MNA and is a form of niacin, would be efficiently metabolized by nicotinamide N-methyltransferase in the presence of exogenous S-adenosylmethionine (SAM) in NAFL rats. To address this issue, NAFL model rats were orally administered with NAM, SAM, and/or HYD. As a result, liver triglyceride (TG) and lipid droplet levels were barely altered by the administration of NAM, SAM, NAM+SAM, or NAM+HYD. By contrast, the triple combination of NAM+SAM+HYD significantly reduced hepatic TG and lipid droplet levels and significantly increased hepatic MNA levels. These findings indicated that the combination of exogenous SAM with AO inhibitors, such as HYD, has beneficial effects for improving fatty liver with NAM.

Hydralazine-Induced ANCA Associated Vasculitis (AAV) Presenting with Pulmonary-Renal Syndrome (PRS): A Case Report with Literature Review

Hydralazine, an arterial vasodilator, is a widely used medication for the management of hypertension and heart failure, especially for patients who cannot tolerate the use of ACEIs or ARBs. It is generally well-tolerated and has a safe profile in pregnancy. However, hydralazine can induce immune-mediated side effects, such as hydralazine-induced lupus and less commonly hydralazine- induced ANCA vasculitis. The latter most commonly affects the kidneys with or without other organ involvement. There are several cases reported in the literature of hydralazine-induced ANCA associated vasculitis (AAV) that have pulmonary manifestations, also known as hydralazine- induced pulmonary-renal syndrome (PRS), a condition with a high risk of mortality. We are reporting a case of Hydralazine-induced ANCA associated glomerulonephritis with severe diffuse alveolar hemorrhage (DAH). In addition, we will review the current literature and discuss the importance of prompt diagnosis and early management to decrease mortality and morbidity associated with this serious condition.

Nitrates in combination with hydralazine in cardiorenal syndrome: a randomized controlled proof-of-concept study

AIMS

Cardiorenal syndrome (CRS) is a common problem of great morbidity and mortality. Hydralazine-isosorbide dinitrate (H-ISDN) may be used in renal failure and may improve exercise capacity in heart failure (HF). Our proof-of-concept study aimed to evaluate early evidence of efficacy, safety, and feasibility of H-ISDN compared with standard of care in CRS.

METHODS AND RESULTS

This multi-centre, single-blind, randomized trial in Singapore enrolled CRS patients, defined as chronic HF with concomitant renal failure [estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m² ]. The primary outcome was 6 min walk test (6MWT) distance measured at 6 months. Secondary outcomes included study feasibility; efficacy outcomes which included renal, cardiac, and endothelial functions, health-related quality of life using Short Form-36, clinical outcomes; and adverse events. Forty-four patients [71 ± 10 years; 75% male; median (inter-quartile range) N-terminal prohormone brain natriuretic peptide 1346 (481-2272) pg/mL] with CRS (left ventricular ejection fraction 42 ± 12% and eGFR 46 ± 15 ml/min/1.73 m² ) were randomized into two equal groups. Of these, 39 (89%) had hypertension, 27 (61%) had diabetes mellitus, and 17 (39%) had atrial fibrillation. Six (27%) discontinued H-ISDN owing to intolerance and poor compliance. There was a trend towards improved 6MWT distance with H-ISDN compared with standard of care at 6 months (mean difference 27 m; 95% CI, -12 to 66), with little differences in secondary efficacy outcomes. Giddiness and hypotension occurred more frequently with H-ISDN, but HF hospitalizations and mortality were less.

CONCLUSIONS

Our pilot study does not support the addition of H-ISDN on top of standard medical therapy to improve exercise capacity in patients with CRS.

Genotype-Guided Hydralazine Therapy

BACKGROUND

Despite its approval in 1953, hydralazine hydrochloride continues to be used in the management of resistant hypertension, a condition frequently managed by nephrologists and other clinicians. Hydralazine hydrochloride undergoes metabolism by the N-acetyltransferase 2 (NAT2) enzyme. NAT2 is highly polymorphic as approximately 50% of the general population are slow acetylators. In this review, we first evaluate the link between NAT2 genotype and phenotype. We then assess the evidence available for genotype-guided therapy of hydralazine, specifically addressing associations of NAT2 acetylator status with hydralazine pharmacokinetics, antihypertensive efficacy, and toxicity.

SUMMARY

There is a critical need to use hydralazine in some patients with resistant hypertension. Available evidence supports a significant link between genotype and NAT2 enzyme activity as 29 studies were identified with an overall concordance between genotype and phenotype of 92%. The literature also supports an association between acetylator status and hydralazine concentration, as fourteen of fifteen identified studies revealed significant relationships with a consistent direction of effect. Although fewer studies are available to directly link acetylator status with hydralazine antihypertensive efficacy, the evidence from this smaller set of studies is significant in 7 of 9 studies identified. Finally, 5 studies were identified which support the association of acetylator status with hydralazine-induced lupus. Clinicians should maintain vigilance when prescribing maximum doses of hydralazine. Key Messages: NAT2 slow acetylator status predicts increased hydralazine levels, which may lead to increased efficacy and adverse effects. Caution should be exercised in slow acetylators with total daily hydralazine doses of 200 mg or more. Fast acetylators are at risk for inefficacy at lower doses of hydralazine. With appropriate guidance on the usage of NAT2 genotype, clinicians can adopt a personalized approach to hydralazine dosing and prescription, enabling more efficient and safe treatment of resistant hypertension.

Low-dose hydralazine improves endotoxin-induced coagulopathy and multiple organ dysfunction via its anti-inflammatory and anti-oxidative/nitrosative properties

Coagulopathy is the major cause of organ injury as well as a strong predictor of mortality in septic patients. Systemic inflammatory response and redox imbalance are regarded as the major causes of sepsis-induced coagulopathy. There is growing evidence that a vasodilator hydralazine has beneficial effects on heart failure, hypertension, and ischemia/reperfusion injury via its antioxidant and anti-inflammatory properties. However, the effects of hydralazine on sepsis have not been examined. Therefore, we evaluated the effects of low-dose hydralazine on coagulopathy and multiple organ dysfunction in septic rats induced by endotoxin. Sepsis-induced coagulopathy was established by intravenous injection of rats with lipopolysaccharide (LPS). The changes of blood pressure, heart rate, blood glucose, hemostatic variables, prothrombin time, organ function indices, interleukin-6 (IL-6) concentration, and nitric oxide (NO) level were assessed during the experimental period. In addition, the aortas, lungs, livers, and kidneys were dissected to analyze superoxide levels and protein expressions. LPS induced (i) coagulopathy, multiple organ dysfunction, and circulatory failure successfully, and (ii) excessive superoxide, NO, and IL-6 production, accompanied by the overexpression of iNOS and Wnt5a in animals. Treatment of LPS-induced septic rats with low-dose hydralazine not only improved coagulopathy but also ameliorated multiple organ dysfunction. These could be due to attenuation of the overproduction of superoxide, NO, and IL-6, which were attributed to reduction of the overexpression of iNOS and Wnt5a. Thus, these findings indicate that low-dose hydralazine could be a potential therapy for sepsis-induced coagulopathy and multiple organ dysfunction via its anti-inflammatory and anti-oxidative/nitrosative properties.

Hydralazine-induced antineutrophil cytoplasmic antibody-associated vasculitis with pulmonary-renal syndrome: a case report

Background

Hydralazine is a common vasodilator which has been used for the treatment of hypertension and heart failure. Hydralazine can induce antineutrophil cytoplasmic antibody-associated vasculitis due to its auto-immunogenic capability and one of the very rare presentations is pulmonary–renal syndrome.

Case presentation

We report a case of a 64-year-old African American woman, who presented to our emergency room with shortness of breath, orthopnea, paroxysmal nocturnal dyspnea, leg swelling, fatigue, loss of appetite, cough with clear sputum, and lightheadedness. On admission, she developed acute hypoxic respiratory failure requiring intubation and acute renal failure requiring hemodialysis. A serologic workup was positive for antineutrophil cytoplasmic antibody, antinuclear antibody, anti-histone, anti-cardiolipin IgM, and anti-double-stranded DNA antibodies. A renal biopsy was done due to persistent deterioration in kidney function and demonstrated classic crescentic (pauci-immune) glomerulonephritis. Hydralazine was empirically discontinued early in the admission and she was started on corticosteroids and cyclophosphamide following biopsy results. She was clinically stable but remained dependent on hemodialysis after discharge.

Conclusion

Hydralazine-induced antineutrophil cytoplasmic antibody-associated vasculitis with pulmonary–renal syndrome is a rare occurrence. In the setting of hydralazine use, multiple positive antigens, and multisystem involvement, clinicians should consider this rare condition requiring prompt cessation of offending drug, early evaluation with biopsy, and contemplate empiric immunosuppressive therapy while biopsy confirmation is pending.

The flipside of hydralazine in pregnancy: A systematic review and meta-analysis

The present systematic review and meta-analysis investigated the effects of hydralazine compared with other antihypertensive drugs in maternal, perinatal and neonatal outcomes of pregnant women with hypertensive disorders. Twenty studies with 1283 participants were included. Of them, 626 received hydralazine and 657 other antihypertensive treatments, such as labetalol, nifedipine, ketanserin, diazoxide, urapidil, isradipine and epoprostenol. Women receiving hydralazine had higher heart rate (WMD: 13.4, 95%CI: 0.1 to 26.8 beats/min), increased number of adverse effects (RR: 1.21, 95%CI: 1.01 to 1.45) and gave birth to neonates of lower birthweight (WMD: 13.4, 95%CI: 0.1 to 26.8 beats/min) compared with other antihypertensive treatments at the end of follow-up. When studies, which used antihypertensive agents that are no longer indicated for hypertension in pregnancy, were excluded in the sensitivity analyses, hydralazine found not to have a statistically significant difference compared with labetalol and nifedipine regarding the reduction of maternal blood pressure (WMD: 1.72, 95%CI: -1.47 to 4.9 mmHg for systolic, WMD: 0.26, 95%CI: -1.75 to 2.28 mmHg for diastolic), maternal heart rate (WMD: 13.56, 95%CI: -5.62 to 32.74 beats/min), low birthweight (WMD: -88.62, 95%CI: -243.24 to 66 beats/min) and adverse events (RR: 1.19, 95%CI: 0.99 to 1.43). Hydralazine seems not to be inferior compared to labetalol and nifedipine for safety and efficacy.

Severe hydralazine-induced lupus presenting as systemic lupus erythematosus

Despite its long history of untoward side effects of a systemic autoimmune disease, drug-induced lupus can be difficult to recognize because of the disconnect between chronic drug usage and onset of symptoms. In this case, the patient was treated with hydralazine for two years when symptoms were initially reported, but a diagnosis of hydralazine-induced lupus was not considered for another half year. Despite treatment with steroidal and nonsteroidal anti-inflammatory medications during this period, rheumatologic symptoms and signs continued to deteriorate, consistent with the diagnosis of systemic lupus erythematosus. Not until the patient voluntarily discontinued hydralazine did symptoms begin to improve, fully resolving over the subsequent 6-12 months largely in the absence of anti-inflammatory medication. This patient demonstrates that failure to recognize a drug-induced disease etiology can result in substantial worsening of rheumatologic symptoms over the subsequent six months, ultimately satisfying criteria for systemic lupus erythematosus. While symptoms and signs largely normalized, some laboratory abnormalities and occasional arthralgia remained two years after discontinuing hydralazine, suggesting smoldering inflammatory disease.

Cardioprotection of hydralazine against myocardial ischemia/reperfusion injury in rats

This study aimed to investigate whether hydralazine could reduce cardiac ischemia/reperfusion (I/R) injury in rats. Anesthetized male Sprague-Dawley rats underwent myocardial I/R injury. Saline, hydralazine (HYD, 10-30 mg/kg) was administered intraperitoneally 10 min before reperfusion. After 30 min of ischemia and 24 h of reperfusion, the myocardial infarct size was determined using TTC staining. Heart function and oxidative stress were determined through biochemical assay and DHE staining. HE staining was used for histopathological evaluation. Additionally, the cardiomyocytes apoptosis and protein expression of PI3K-Akt-eNOS pathway marker were detected by TUNEL and Western blotting. The serum levels of malonaldehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) and reactive oxygen species were significantly elevated in cardiac I/R group, but the superoxide dismutase (SOD) level was suppressed. However, intraperitoneal pretreatment with hydralazine at a dose of 10-30 mg/kg before cardiac I/R significantly limited the increase in CK-MB, LDH, oxidative stress, inflammatory factors, histological damage and apoptosis in the hearts. In addition, hydralazine also increased p-PI3K, p-AKT, p-eNOS expression and decreased Cleaved Caspase-3, Cleaved Caspase-9 expression in the hearts. Our results suggest that the cardioprotective effect of hydralazine against I/R injury might be a cooperation of the inhibition of oxidative stress, inflammatory response, apoptosis with the motivation of eNOS phosphorylation via activating the PI3K/AKT signal pathway.

Hydralazine improves ischemia-induced neovasculogenesis via xanthine-oxidase inhibition in chronic renal insufficiency

Oxidative stress is related to the progression of renal diseases and modulation of oxidative stress can lead to a reduction in vascular events in patients with chronic renal insufficiency (CRI). Indoxyl sulfate (IS) and xanthine oxidase (XO) are related to impaired neovasculogenesis in CRI. Hydralazine is suggested for blood pressure control in CRI. This study aimed to investigate whether hydralazine could improve ischemia-induced neovasculogenesis in CRI animals by reducing reactive oxygen species (ROS) levels. Mice underwent subtotal nephrectomy or sham surgery. Nitrendipine, probenecid, and allopurinol were used to reduce blood pressure, uric acid (UA), and XO activity levels, respectively, for comparison. Blood pressure, XO activity and UA levels that were increased after subtotal nephrectomy were reduced by hydralazine treatment. Allopurinol decreased blood XO activity and UA levels. Only hydralazine and allopurinol increased the number of circulating endothelial progenitor cells (EPCs) and improved neovasculogenesis in CRI mice. IS activated XO mRNA and ROS and inhibited the functions of EPCs and endothelial cells, which could be reversed by hydralazine. However, no additional beneficial effects were observed when XO was inhibited with both hydralazine and siRNA. In conclusion, hydralazine, as a potential XO inhibitor, not only reduced blood pressure and UA levels but also increased the number of circulating EPCs and improved neovasculogenesis in CRI animals. Hydralazine directly inhibited IS-induced ROS and XO activation in EPCs and endothelial cells, and restored their functions in vitro. Future studies should evaluate whether hydralazine could provide additional vascular protection in patients with CRI.

Alleviation of mechanical stress-induced allodynia by improving blood flow in chronic constriction injury mice

Reduced blood flow in the skin is observed in patients with neuropathic pain and in animal models. The aim of the present study was to elucidate the relationship between reduced skin blood flow and neuropathic pain in mice with a chronic constriction injury (CCI). Noradrenaline-induced contraction was enhanced in isolated plantar arteries ipsilateral to the CCI surgery compared to the contralateral arteries. Ten μM hydralazine, a peripheral vasodilator, at improved the enhanced contractile response in the ipsilateral arteries. The plantar blood flow in vivo was lower on the ipsilateral side of the CCI mice than on the contralateral side, and a 50% paw withdrawal threshold, as measured using the von Frey filament test, was lower on the former than on the latter side. An intraperitoneal injection (i.p.) of hydralazine (1 mg/kg) or phentolamine (5 mg/kg) improved blood flow in the skin and hyperalgesia in the ipsilateral plantar. In adrenalectomized CCI mice, plantar blood flow in the skin on the ipsilateral side was increased compared to in sham-operated mice, which was accompanied by alleviation of hyperalgesia. Moreover, the enhanced contractile response to noradrenaline was also observed in the ipsilateral plantar arteries isolated from the adrenalectomized CCI mice. Either hydralazine (1 mg/kg, i.p.) or an adrenalectomy barely affected mean arterial pressure in the CCI mice, whereas phentolamine (5 mg/kg, i.p.) lowered it. These results suggest that reduced blood flow in the skin contributes to neuropathic pain and that improving that blood flow with peripheral vasodilators, such as hydralazine, can alleviate it.

Nicardipine Reduces Blood Pressure Variability After Spontaneous Intracerebral Hemorrhage

BACKGROUND

Blood pressure variability (BPV) is an independent predictor for early hematoma expansion, neurologic deterioration, and mortality. There are no studies on the effect of intravenous (IV) antihypertensive drugs on BPV. We sought to determine whether patients have more BPV with certain antihypertensive agents, in particular the effect of IV nicardipine.

METHODS

We conducted a single-center, retrospective chart review of individuals diagnosed with spontaneous intracerebral hemorrhage (ICH) receiving labetalol, hydralazine, and/or nicardipine within 24 h of hospital admission to assess the primary endpoint of BPV, defined as the standard deviation of systolic BP, with labetalol and/or hydralazine compared to nicardipine ± labetalol and/or hydralazine. Repeated measures linear regression was performed to compare BPV over 24 h between regimens, and Cox proportional hazards regression was used to compare the time to goal SBP between regimens.

RESULTS

Of the 1330 patients screened, 272 were included in our analysis; those included had a mean age of 69 years with 87.9% of Caucasian race. A total of 164 patients received IV bolus antihypertensives alone (labetalol, hydralazine or both), and 108 patients received IV nicardipine with or without additional IV boluses (labetalol, hydralazine, or both). Those who had IV nicardipine had significantly less BPV (p = 0.04) and was more likely to attain an SBP goal < 140 mmHg (p < 0.01).

CONCLUSION

Our study suggests patients with ICH who do not receive a nicardipine-based antihypertensive regimen have more BPV, which has been associated with poor clinical outcomes. Prospective, randomized, controlled trials are needed to determine the impact of specific antihypertensive regimens on clinical outcomes.

Electrocardiographic Changes Following Acute Hydralazine Overdose

Hydralazine is an FDA-approved antihypertensive agent which has been utilized for years either alone or in combination with other medications especially the beta-blockers. Hydralazine works as a direct-acting vasodilator, thereby exerting a decrease in vascular resistance and increase in intravascular volume. When overdosed, hydralazine applies its toxic effects by extending its pharmacological action, which produces hypotension, syncope, tachycardia, and nausea. However, studies and case reports of acute hydralazine toxicity and its effects on electrocardiographic changes are rare, and most of the medical literature have only highlighted its immunological side effects. In this report, we are presenting a case of acute hydralazine overdose in a young woman who ended up in CCU due to remarkably abnormal electrocardiogram and unstable hemodynamics followed by myocardial infarction.

Hydralazine protects against renal ischemia-reperfusion injury in rats

In this study, we investigated whether hydralazine could reduce renal ischemia and reperfusion (I/R) injury in rats. Renal I/R was induced by a 70-min occlusion of the bilateral renal arteries and a 24-h reperfusion, which was confirmed by the increased the mortality, the levels of blood urea nitrogen (BUN), blood creatinine (Cr), renal tissue NO and the visible histological damage of the kidneys. Apoptosis was evaluated by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL) staining. Furthermore, the serum levels of malonaldehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were significantly elevated in renal I/R group, while the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) levels were suppressed. However, intragastric pretreatment with hydralazine at doses of 7.5-30 mg/kg before renal I/R significantly limited the increase in mortality, BUN, Cr, oxidative stress, inflammatory factors, histological damage and apoptosis in the kidneys. In addition, hydralazine also increased p-AKT, Bcl-2 expression and decreased iNOS, Bax, cleaved caspase-3 expression in the kidneys. In conclusion, hydralazine reduced renal I/R injury probably via inhibiting NO production by iNOS/NO pathway, inhibiting oxidative stress, inflammatory response and apoptosis by a mitochondrial-dependent pathway.

Carbonyl scavengers as pharmacotherapies in degenerative disease: Hydralazine repurposing and challenges in clinical translation

During cellular metabolism, spontaneous oxidative damage to unsaturated lipids generates many electrophilic carbonyl compounds that readily attack cell macromolecules, forming adducts that are potential drivers of tissue dysfunction. Since such damage is heightened in many degenerative conditions, researchers have assessed the efficacy of nucleophilic carbonyl-trapping drugs in animal models of such disorders, anticipating that they will protect tissues by intercepting toxic lipid-derived electrophiles (LDEs) within cells. This Commentary explores recent animal evidence for carbonyl scavenger efficacy in two disparate yet significant conditions known to involve LDE production, namely spinal cord injury (SCI) and alcoholic liver disease (ALD). Primary emphasis is placed on studies that utilised hydralazine, a clinically-approved "broad-spectrum" scavenger known to trap multiple LDEs. In addition to reviewing recent studies of hydralazine efficacy in animal SCI and ALD models, the Commentary reviews new insights concerning novel lifespan- and healthspan-extending properties of hydralazine obtained during studies in model invertebrate organisms, since the mechanisms involved seem of likely benefit during the treatment of degenerative disease. Finally, noting that human translation of the histoprotective properties of hydralazine have been limited, the final section of the Commentary will address two obstacles that hamper clinical translation of LDE-trapping therapies while also suggesting potential strategies for overcoming these problems.

Differential effect of angiotensin II and blood pressure on hippocampal inflammation in mice

Background

Angiotensin II (Ang II), a peptide hormone involved in the development of hypertension, causes systemic and cerebral inflammation, affecting brain regions important for blood pressure control. The cause-and-effect relationship between hypertension and inflammation is two-way, but the role of blood pressure in the induction of cerebral inflammation is less clear. The vulnerability of specific brain regions, particularly those important for memory, is also of interest.

Methods

We used molecular biology approaches, immunohistochemistry, and electron microscopy to examine the interdependence between the hypertensive and pro-inflammatory effects of Ang II. We examined the effect of blood pressure by administering a subpressive (200 ng/kg/min) or a pressive Ang II dose (1000 or 1900 ng/kg/min) with and without hydralazine (150 mg/L) for 1 week and used phenylephrine to increase blood pressure independently of the renin-angiotensin system.

Results

Ang II increased ionized calcium-binding adaptor molecule 1 (Iba-1) levels (marker of microgliosis) in the whole brain and in the hippocampus in a dose-dependent manner. Pressive Ang II induced specific changes in microglial morphology, indicating differences in functional phenotype. An increase in hippocampal glial fibrillary acidic protein (GFAP) was seen in mice receiving pressive Ang II, while no induction of cerebral gliosis was observed after 7 days of subpressive Ang II infusion. Although phenylephrine led to increased astrogliosis, it did not affect Iba-1 expression. Pressive Ang II stimulated TNF-α production in the hippocampus, and daily treatment with hydralazine prevented this increase. Hydralazine also reduced GFAP and Iba-1 levels. With longer perfusion (14 days), subpressive Ang II led to some but not all the inflammatory changes detected with the pressive doses, mainly an increase in CD68 and Iba-1 but not of GFAP or TNF-α.

Conclusions

Blood pressure and Ang II differentially contribute to hippocampal inflammation in mice. Control of blood pressure and Ang II levels should prevent or reduce brain inflammation and therefore brain dysfunctions associated with hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1090-z) contains supplementary material, which is available to authorized users.

Outcomes of hydralazine induced renal vasculitis

Objective

Hydralazine has been implicated as an etiologic agent for lupus-like syndrome and vasculitis. Hydralazine-induced vasculitis frequently affects the kidney, but the long-term renal outcomes in these patients have not yet been studied.

Methods

Patients who had a diagnosis of ANCA-associated vasculitis (AAV) and were on hydralazine at the time of AAV diagnosis were included in this retrospective cohort study. Clinical and laboratory data were obtained from the review of medical records.

Results

Seven patients met the criteria for hydralazine-induced AAV. Five patients (71%) were African-American and four (57%) were female. The median age was 69 years at the time of diagnosis. All patients had renal involvement with two of them showing lung involvement as well. All patients had positive MPO antibody and one patient had positive PR3 antibody. ANA was positive in all patients, and three of seven patients had positive anti-histone antibody. All of them were treated with immunosuppression and withdrawal of hydralazine. Three patients reached end-stage renal disease. The median follow-up time was 13 months.

Conclusion

Renal involvement in hydralazine-induced AAV was universal and can be associated with a poor renal outcome despite immunosuppressive therapy.

Comparison of Efficacy and Safety of Intravenous Labetalol Versus Hydralazine for Management of Severe Hypertension in Pregnancy

Background

There is no consensus about the better intravenous drug between Hydralazine and Labetalol to control hypertension in cases of severe hypertension in pregnancy. Both drugs have their own advantages and disadvantages.

Methods

This is a prospective randomized controlled trial comparing the efficacy and safety of intravenous Labetalol versus Hydralazine for management of severe hypertension in pregnancy. A total of 152 eligible subjects were randomised in two groups consisting 76 subjects each by envelope method. Both the groups were comparable with respect to systolic, diastolic and mean arterial blood pressure at admission. One group received Labetalol and the other Hydralazine. The number of drug doses, the time taken to achieve target blood pressure and side-effects were noted.

Results

With a single dose, Labetalol (81.5%) was able to achieve target blood pressure in a significantly higher number of cases as compared to Hydralazine (69.5%). Labetalol could help in achieving the target blood pressure faster than Hydralazine. The incidence of maternal adverse effects was comparable between the groups. Fetal outcome was comparable in both groups.

Conclusion

Hydralazine and Labetalol both were found to be equally efficacious in reducing blood pressure in cases of severe hypertension in pregnancy. Labetalol achieved the target blood pressure faster than Hydralazine. The adverse effects of both the drugs were comparable.

Left ventricular hypertrophy does not prevent heart failure in experimental hypertension

BACKGROUND

Left ventricular hypertrophy (LVH) secondary to hypertension has been accepted to prevent heart failure (HF) while paradoxically increasing cardiovascular morbi-mortality.

OBJECTIVES

To evaluate whether antihypertensive treatment inhibits LVH, restores beta-adrenergic response and affects myocardial oxidative metabolism.

METHODS

Ninety spontaneously hypertensive rats (SHR) were distributed into groups and treated (mg/kg, p.o.) with: losartan 30 (L), hydralazine 11 (H), rosuvastatin 10 (R), carvedilol 20 (C). Hypertension control group comprised 18 normotensive rats (Wistar-Kyoto, WKY). Following euthanasia at 16months, contractility was measured in 50% of rats (Langendorff system) before and after isoproterenol (Iso) 10^-9M, 10^-7M and 10^-5M stimulation. Left ventricular weight (LVW) was measured in the remaining hearts, and normalized by BW. Expression of thioredoxin 1 (Trx-1), peroxyredoxin 2 (Prx-2), glutaredoxin 3 (Grx-3), caspase-3 and brain natriuretic peptide (BNP) was determined.

RESULTS

Systolic blood pressure (mmHg): 154±3 (L), 137±1 (H), 190±3 (R)*, 206±3 (SHR)*, 183±1 (C)**, and 141±1 (WKY) (*p<0.05 vs. L, H, WKY, **p<0.05 vs. L, H, WKY, SHR). LVW/BW was higher in SHR and R (p<0.05). Groups SHR, R and C evidenced baseline contractile depression. Response to Iso 10^-5M was similar in WKY and L. Expression of Trx-1, Prx-2 and Grx-3 increased in C, H, R and L (p<0.01).

CONCLUSIONS

Present findings argue against the traditional idea and support that LVH might not be required to prevent HF. Increased expression of thioredoxins by antihypertensive treatment might be involved in protection from HF.

Comparison of Hydralazine and Labetalol to lower severe hypertension in pregnancy

OBJECTIVE

To compare the intravenous Labetalol versus intravenous hydralazine in patients having severe Pregnancy induced hypertension (PIH) and pre eclampsia (PE) in pregnancy.

METHODS

Seventy eight women admitted in the Department of Gynecology and Obstetrics, Civil Hospital Karachi, having severe PIH/PE and fulfilling the inclusion criteria were included in the study. Random selection of patients was performed using sealed opaqe envelop for administration of either intravenous noted (IV) Labetalol or Hydrallazine. The mean fall in the MAP in each group was noted. This data was analyzed by applying SPSS version 13. The study was conducted from November 2012 to April 2013.

RESULTS

The mean (±SD) age of the labetalol group was 27.46 (±5.28) years while that in the hydralazine group was 26.28 (±5.17) years. The mean fall in MAP observed in the labetalol group was 29.10 ± 7.21 mmHg and that in the hydralazine group was 25.05 ± 10.15 mmHg which was statistically significant with the p value being 0.046.

CONCLUSION

Intra Venous labetalol lowered MAP more than hydralazine, when administered to pregnant females with severe Pregnancy induced hypertension and pre eclampsia in pregnancy.

Efficacy of hydralazine and valproate in cutaneous T-cell lymphoma, a phase II study

OBJECTIVES

To evaluate the activity and safety of hydralazine and valproate (Transkrip) in cutaneous T-cell lymphoma (CTCL).

METHODS

Previously untreated and progressive/refractory CTCL patients received hydralazine at 83 mg or 182 mg/day for slow and rapid acetylators respectively plus magnesium valproate at a total dose of 30 mg/Kg t.i.d daily in continuous 28-day cycles in this phase II study. The primary objective was overall response rate (ORR) measured by the modified severity weighted assessment tool (m-SWAT), secondary end-points were time to response (TTR), time to progression (TTP), duration of response (DOR), progression-free survival (PFS), overall survival (OS) and safety.

RESULTS

Fourteen patients were enrolled (7 untreated and 7 pretreated). ORR was 71% with 50% complete and 21% partial. Two had stable disease and two progressed. At a median follow-up of 36 months (5-52), median TTR was 2 months (1-4); median DOR was 28 months (5-45); median PFS 36 and not reached for OS. There were no differences in median TTR, DOR, and PFS between treated and pretreated patients. Pruritus relieve was complete in 13 out of 14 patients. No grade 3 or 4 toxicities were observed.

CONCLUSION

The combination of hydralazine and valproate is safe, very well tolerated and effective in CTCL.

Combination of Hydralazine and Isosorbide-Dinitrate in the Treatment of Patients with Heart Failure with Reduced Ejection Fraction

The use of direct acting vasodilators (the combination of hydralazine and isosorbide dinitrate -Hy+ISDN-) in heart failure with reduced ejection fraction (HFrEF) is supported by evidence, but rarely used.However, treatment with Hy+ISDN is guideline-recommended for HFrEF patients who cannot receive either angiotensin-converting enzyme inhibitors or angiotensin receptor blockers due to intolerance or contraindication, and in self-identified African-American HFrEF patients who are symptomatic despite optimal neurohumoral therapy.The Hy+ISDN combination has arterial and venous vasodilating properties. It can decrease preload and afterload, decrease left ventricular end-diastolic diameter and the volume of mitral regurgitation, reduce left atrial and left ventricular wall tension, decrease pulmonary artery pressure and pulmonary arterial wedge pressure, increase stroke volume, and improve left ventricular ejection fraction, as well as induce left ventricular reverse remodelling. Furthermore, Hy+ISDN combination has antioxidant property, it affects endothelial dysfunction beneficially and improves NO bioavailability. Because of these benefits, this combination can improve the signs and symptoms of heart failure, exercise capacity and quality of life, and, most importantly, reduce morbidity and mortality in well-defined subgroups of HFrEF patients.Accordingly, this therapeutic option can in many cases play an essential role in the treatment of HFrEF.

Adsorptive Behavior and Voltammetric Determination of Hydralazine Hydrochloride at A Glassy Carbon Electrode Modified with Multiwalled Carbon Nanotubes

An electroanalytical method has been introduced for highly sensitive determination of hydralazine hydrochloride (Hy-HCl) based on its oxidation at a glassy carbon electrode modified with multiwalled carbon nanotubes (MWCNT/GCE). Studies showed that the electrochemical oxidation of Hy-HCl was accompanied by adsorption and highly sensitive responses could be achieved by adsorptive stripping voltammetry. The electrooxidation of Hy-HCl at MWCNT/GCE occurred at ~32 mV which was lower than that observed at bare GCE (~52 mV). The optimum working conditions for determination of the drug using differential-pulse adsorptive stripping voltammetry (DPAdSV) were established. The method exhibited linear responses to Hy-HCl in the concentration range 10-220 nM with a detection limit of 2.7 nM. The proposed method was successfully applied to the determination of this compound in pharmaceutical dosage forms.

Hydralazine-Induced ANCA Vasculitis in the Setting of Acute Clostridium Difficile Infection

We report a rare case of Hydralazine-induced ANCA associated glomerulonephritis with alveolar hemorrhage in the setting of acute Clostridium Difficile Infection. A 71-year-old Caucasian woman with hypertension, who was being treated with hydralazine 25 mg twice a day for six years, presented to the hospital with diarrhea, nausea, vomiting and anemia. She had acute kidney injury and urinalysis showed proteinuria, dysmorphic RBCs, and rare RBC cast. She was found to have Clostridium difficile colitis which was successfully treated. She became hypoxemic; CT scan findings showed bilateral pulmonary infiltrates. Broncho-alveolar lavage was consistent with pulmonary hemorrhage. Kidney biopsy revealed focal segmental necrotizing and diffuse crescentic glomerulonephritis, pauci-immune type (ANCA-associated). Hydralazine was discontinued and the patient was treated with corticosteroids, intravenous cyclophosphamide and plasmapheresis. To our knowledge, hydralazine-associated low complement in the setting of C-diff infection has not been previously reported. This is considered a potentially life-threatening condition requiring immediate discontinuation of the offending medication and expedited lifesaving measures. [Full article available at http://rimed.org/rimedicaljournal-2016-11.asp].

A retrospective review of safety using a nursing driven protocol for autonomic dysreflexia in patients with spinal cord injuries

OBJECTIVE/BACKGROUND

Autonomic dysreflexia is a potentially life-threatening condition which afflicts a significant proportion of individuals with spinal cord injuries (SCI). To date, the safety and efficacy of several commonly used interventions for this condition have not been studied.

DESIGN

A retrospective chart review of the safety of a previously implemented nursing driven inpatient autonomic dysreflexia protocol.

METHODS

Seventy-eight male patients with SCI who experienced autonomic dysreflexia while inpatient at our Veterans Affairs SCI unit over a 3-1/2-year period were included. The safety of a nursing driven protocol utilizing conservative measures, nitroglycerin paste, and oral hydralazine was evaluated.

OUTCOME MEASURES

Occurrence of adverse events and relative hypotensive events during all episodes treated with the protocol, and efficacy of attaining target blood pressure for all episodes with protocol adherence and for initial episode experienced by each patient.

RESULTS

Four hundred forty-five episodes of autonomic dysreflexia were recorded in the study period, with 92% adherence to the protocol. When the protocol was followed, target blood pressure was achieved for 97.6% of all episodes. Twenty-three total adverse events occurred (5.2% of all episodes). All adverse events were due to hypotension and only 0.9% required interventions beyond clinical monitoring. Of each patient's initial autonomic dysreflexia episode, 97.3% resolved using the protocol without need for further escalation of care.

CONCLUSION

This inpatient nursing driven-protocol for treating autonomic dysreflexia utilizing conservative measures, nitroglycerin paste and oral hydralazine achieved target blood pressure with a high success rate and a low incidence of adverse events.