Elevated Vascular Sympathetic Neurotransmission and Remodelling Is a Common Feature in a Rat Model of Foetal Programming of Hypertension and SHR

Mice Models for Peripheral Denervation to Enhance Vascular Regeneration

Sympathetic innervation plays a critical role in regulating vascular function, yet its influence on vascular regeneration and reinnervation following ischemic injury remains poorly understood. This study develops and validates murine models of localized sympathetic denervation using 6-hydroxydopamine (6-OHDA) to enable study of the sympathetic nervous system's impact on vascular systems during tissue repair. Two methods of 6-OHDA administration were employed: a single topical application during open surgery and minimally invasive weekly subcutaneous injections. The topical application model achieved temporary denervation lasting 1 week without causing vascular damage, while the subcutaneous injection model provided sustained denervation for up to 4 weeks with minimal inflammation and no significant changes to vascular architecture. To investigate the effects of denervation in an ischemic context, these models were combined with a hindlimb ischemia model. Ischemia induced persistent denervation in both 6-OHDA-treated and control limbs, with limited sympathetic nerve regeneration observed over 4 weeks. Despite persistent denervation, microvascular density and perfusion recovery in ischemic muscles were comparable between denervated and control groups. This suggests that ischemia governs vascular regeneration independently of sympathetic input. These results demonstrate that localized 6-OHDA administration provides a versatile tool for achieving controlled sympathetic denervation in peripheral arteries. These models provide a novel platform for studying vascular regeneration and reinnervation under both normal and ischemic conditions, offering novel insights into the interactions between neural regulation and vascular repair processes. This work lays the foundation for future research into neural-vascular crosstalk and new possibilities for developing regenerative therapies targeting the autonomic regulation of vascular health.

Chronic rose oxide and exercise synergistically modulate cardiovascular and autonomic functions in hypertensive rats

With the alarming rise in cases of arterial hypertension worldwide, there is an urgent need to develop combined therapies to mitigate this scenario. Rose oxide (RO), a monoterpene with anti-inflammatory and hypotensive properties, emerges as an alternative. The present study is the first to evaluate the effect of RO administered chronically and combined with physical exercise (swimming) since both have been reported to have beneficial impacts on hypertension. Male SHR and Wistar rats (aged 12 weeks) received RO for 34 consecutive days (orally; 100 mg/kg). The progression of systolic arterial pressure (SAP) was monitored through tail-cuff plethysmography. Twenty-four hours before the end of the treatment, the animals were anesthetized, and the femoral artery and vein were cannulated to record the pulsatile arterial pressure and to administer drugs, respectively. Hemodynamic and autonomic parameters and baroreflex sensitivity and intrinsic heart rate (IHR) were evaluated. Treatment with RO, administered alone or combined with exercise, reduced SAP and mean arterial pressure in SHR. The swimming protocol did not prevent increases in BP, but when combined with RO, it improved autonomic control, assessed through heart rate variability and parasympathetic tone. IHR was attenuated in SHR, and none of the treatments reversed this response. Therefore, combining RO with physical exercise may enhance their antihypertensive effects, improving autonomic function, reducing oxidative stress and inflammation, providing synergistic cardiovascular benefits, improving metabolic health, promoting a comprehensive lifestyle intervention, and potentially allowing for reduced medication dosages. This multifaceted approach could offer a more effective and sustainable strategy for managing hypertension.

Advances on the Experimental Research in Resistant Hypertension

PURPOSE OF REVIEW

Resistant Hypertension (RH) poses a significant public health challenge, contributing to increased mortality, cardiovascular events and organ damage. Both clinical and experimental research are striving for higher standards in a translational manner to integrate new findings and confirm hypotheses. Considering that many are the aspects of RH that are still under investigation, this review aims to shed light on the advances made in experimental research concerning RH. It seeks to underscore the pivotal role of experimental studies in shaping clinical practices and also explore future perspectives.

RECENT FINDINGS

It is important to emphasize the significance of experimental models, primarily for advancing our understanding: experimental models have greatly contributed to our comprehension of the underlying mechanisms in RH, including factors like sympathetic activation, endothelial dysfunction and structural vessel abnormalities. Secondly, for assessing treatment approaches: animal models have also played a crucial role in evaluating the potential effectiveness of diverse treatment approaches for RH. These encompass both pharmacological options, involving combinations of established drugs or novel pharmaceuticals, and non-pharmacological alternatives, which include surgical procedures like renal denervation, medical devices like baroreceptor stimulators, and lifestyle modifications. The most lacking component in translational research is the fact that there is no well-established animal model that perfectly replicates RH. Consequently, alternative strategies, including the combination of models, must be considered. What remains clear is that the development of animal models closely mimicking RH holds the promise of providing valuable insights into the essential mechanisms and responses necessary to combat or slow the global progression of RH.

Slower Growth during Lactation Rescues Early Cardiovascular and Adipose Tissue Hypertrophy Induced by Fetal Undernutrition in Rats

Low birth weight (LBW) and accelerated growth during lactation are associated with cardiometabolic disease development. LBW offspring from rats exposed to undernutrition during gestation (MUN) develops hypertension. In this rat model, we tested if slower postnatal growth improves early cardiometabolic alterations. MUN dams were fed ad libitum during gestation days 1–10, with 50% of the daily intake during days 11–21 and ad libitum during lactation. Control dams were always fed ad libitum. Pups were maintained with their own mother or cross-fostered. Body weight and length were recorded weekly, and breastmilk was obtained. At weaning, the heart was evaluated by echocardiography, and aorta structure and adipocytes in white perivascular fat were studied by confocal microscopy (size, % beige-adipocytes by Mitotracker staining). Breastmilk protein and fat content were not significantly different between groups. Compared to controls, MUN males significantly accelerated body weight gain during the exclusive lactation period (days 1–14) while females accelerated during the last week; length growth was slower in MUN rats from both sexes. By weaning, MUN males, but not females, showed reduced diastolic function and hypertrophy in the heart, aorta, and adipocytes; the percentage of beige-type adipocytes was smaller in MUN males and females. Fostering MUN offspring on control dams significantly reduced weight gain rate, cardiovascular, and fat hypertrophy, increasing beige-adipocyte proportion. Control offspring nursed by MUN mothers reduced body growth gain, without cardiovascular modifications. In conclusion, slower growth during lactation can rescue early cardiovascular alterations induced by fetal undernutrition. Exclusive lactation was a key period, despite no modifications in breastmilk macronutrients, suggesting the role of bioactive components. Our data support that lactation is a key period to counteract cardiometabolic disease programming in LBW and a potential intervention window for the mother.