Sustained cutaneous vasoconstriction during and following cyrotherapy treatment: Role of oxidative stress and Rho kinase

The Effect of the Timing of Cold Application on Pain and Satisfaction in Patients With Fractures

This experimental study used a repeated-measures design to examine the effect of the timing of cold application on pain and satisfaction in a sample of 60 patients who had fracture surgery. Cold was applied for 20 minutes each hour for four hours to patients assigned to the experimental group. Whereas cold was applied once to those in the control group: for 20 minutes during the first hour after surgery. Results following data analysis from repeated measurements of pain before and after cold application in both groups showed a significant difference between the groups (p < .05). Patients' levels of satisfaction with nursing care practice were higher in the experimental group than in the control group, although not significantly (p > .05). The pain score in the experimental group decreased significantly with each cold application. In the control group, the pretreatment pain score decreased significantly after one cold application, increasing again in 3 hours without cold application. These findings are important for nurses caring for postoperative patients and giving discharge instructions. Our findings suggest repeated cold applications for 20 minutes at hourly intervals may result in better overall pain reduction than a single cold application.

Cryotherapy in Postoperative Shoulder Surgery: A Systematic Review

Cryotherapy, a therapeutic technique involving localized cooling of the body, has gained popularity for postsurgical rehabilitation. It induces a reduction in cellular metabolism, vasoconstriction, and pain relief, making it an attractive option for managing postoperative (PO) shoulder pain. This systematic review aimed to assess the effectiveness of cryotherapy in PO shoulder patients, focusing on pain, range of motion, functionality, and temperature changes. The review included six randomized clinical trials, involving a total of 233 patients who underwent various shoulder surgeries. Cryotherapy was applied using different methods, including Cryo/Cuff, Cryoton®, Polar Care 300, and ice packs. Results indicated that cryotherapy was generally effective in reducing PO shoulder pain. However, one study found no significant difference in pain outcomes between the cryotherapy group and control group. Furthermore, three studies demonstrated a decrease in intra-articular and skin temperatures with cryotherapy application. A risk of bias analysis revealed some concerns in the overall risk of bias for five studies, with one study considered to have a high risk of bias. Although publication bias assessment was not conducted due to the limited number of included studies, it was noted that the studies exhibited heterogeneity in terms of population, intervention methods, and outcome measures. In conclusion, cryotherapy appears to be a promising adjunctive treatment for PO shoulder pain, although the existing evidence has some limitations, including small sample sizes and methodological concerns. More high-quality studies are needed to establish the full extent of cryotherapy's effectiveness in PO shoulder rehabilitation, especially regarding its impact on functionality and range of motion.

Influence of acute beetroot juice supplementation on cold-induced vasodilation and fingertip rewarming

PURPOSE

Vasoactive ingredients in beetroot (BR) such as nitrate are known to induce vasodilation in temperate conditions. This study investigated the effect of BR ingestion on cold induced vasodilation (CIVD) and rewarming of finger skin temperature (T_fing) during and after hand immersion in cold water.

METHODS

Twenty healthy males (mean ± SD; age 22.2 ± 0.7 years, height 172.6 ± 6.0 cm, body mass 61.3 ± 11.7 kg) repeated a hand cold water immersion test twice with prior BR or water beverage ingestion (randomised order). They rested for 2 h in thermoneutral conditions (27 °C, 40% relative humidity) after consuming the beverage, then immersed their non-dominant hand in 8 °C water for 30 min. They then rewarmed their hand in the ambient air for 20 min. Skin temperature at seven body sites, T_fing, finger skin blood flow (SkBF_fing), and blood pressure were measured.

RESULTS

During hand immersion parameters of CIVD (T_fing and SkBF_fing) were not different between BR and water conditions although skin temperature gradient from proximal to distal body sites was significantly smaller with BR (P < 0.05). During rewarming, SkBF_fing and cutaneous vascular conductance were significantly higher with BR than with water (P < 0.05). The rewarming speed in T_fing and SkBF_fing was significantly faster with BR at 15- (BR 1.24 ± 0.22 vs water 1.11 ± 0.26 °C/min) and 20-min rewarming (P < 0.05). Additionally, individuals with slower rewarming speed with water demonstrated accelerated rewarming with BR supplementation.

CONCLUSION

BR accelerated rewarming in T_fing and SkBF_fing after local cold stimulus, whereas, CIVD response during hand cold immersion was not affected by BR ingestion.

Quantifiable Contrast-Enhanced Ultrasound Explores the Role of Protection, Rest, Ice (Cryotherapy), Compression and Elevation (PRICE) Therapy on Microvascular Blood Flow

The aim of this randomized controlled laboratory study was to evaluate the role of standardized protection, rest, ice (cryotherapy), compression and elevation (PRICE) therapy on microvascular blood flow in human skeletal muscle. Quantifiable contrast-enhanced ultrasound was used to analyze intramuscular tissue perfusion (ITP) of the rectus femoris (RF) and vastus intermedius (VI) muscles in 20 healthy athletes who were randomly assigned to PRICE or control groups. Baseline perfusion measurements (resting conditions, T₀) were compared with cycling exercise (T₁), intervention (PRICE or control, T₂) and follow-up at 60 min post-intervention (T₃). The 20 min PRICE intervention included rest, cryotherapy (3°C), compression (35 mm Hg) and elevation. After intervention, PRICE demonstrated a decrease of ITP in VI (-47%, p = 0.01) and RF (-50%, p = 0.037) muscles. At T_3, an ongoing decreased ITP for the RF (p = 0.003) and no significant changes for the VI were observed. In contrast, the control group showed an increased ITP at T₂ and no significant differences at T₃. PRICE applied after exercise led to a down-regulation of ITP, and the termination of PRICE does not appear to be associated with a reactive hyperemia for at least 60 min after treatment.

Preliminary study on the effect of sex on skin cooling response during whole body cryostimulation (-110 °C): Modeling and prediction of exposure durations

In order to determine the required duration of whole-body exposure to extreme cold (-110 °C) in males and females for achieving the same cold-induced response, a mathematical model of skin cooling kinetics was developed. This modeling is derived from the implementation of a new experimental cryotherapy protocol to obtain continuous skin temperature maps over time. Each 3-min whole-body cryostimulation session was divided into six incremental sessions of 30 s carried out over six consecutive days. Seventeen young, healthy subjects (8 males aged 22.6 ±3.0 years and 9 females aged 23.7 ±4.7 years) agreed to participate in this study. The smallest sex-related difference in temperature was found in the trunk area (2.93 °C after 3 min) while the greatest temperature drop was found in the lower limbs (5.92 °C after 3 min). The largest temperature variation was observed between the trunk and the lower limbs, and peaked at 2.67 °C in males and 6.99 °C in females. For both sexes, skin cooling kinetics showed a strong transient exponential type decrease followed by linear regression behavior. It appeared that for achieving the same cold-induced response, the required duration of cryostimulation is longer for males. For example, a trunk skin cooling of -12 °C could be achieved in 125s for females vs 170s for males (+36% longer); for the lower limbs, the same skin cooling magnitude could be reached after 87s for females vs 140s for males (+62% longer).

From Nanowarming to Thermoregulation: New Multiscale Applications of Bioheat Transfer

This review explores bioheat transfer applications at multiple scales from nanoparticle (NP) heating to whole-body thermoregulation. For instance, iron oxide nanoparticles are being used for nanowarming, which uniformly and quickly rewarms 50-80-mL (≤5-cm-diameter) vitrified systems by coupling with radio-frequency (RF) fields where standard convective warming fails. A modification of this approach can also be used to successfully rewarm cryopreserved fish embryos (∼0.8 mm diameter) by heating previously injected gold nanoparticles with millisecond pulsed laser irradiation where standard convective warming fails. Finally, laser-induced heating of gold nanoparticles can improve the sensitivity of lateral flow assays (LFAs) so that they are competitive with laboratory tests such as the enzyme-linked immunosorbent assay. This approach addresses the main weakness of LFAs, which are otherwise the cheapest, easiest, and fastest to use point-of-care diagnostic tests in the world. Body core temperature manipulation has now become possible through selective thermal stimulation (STS) approaches. For instance, simple and safe heating of selected areas of the skin surface can open arteriovenous anastomosis flow in glabrous skin when it is not already established, thereby creating a convenient and effective pathway to induce heat flow between the body core and environment. This has led to new applications of STS to increase or decrease core temperatures in humans and animals to assist in surgery (perioperative warming), to aid ischemic stress recovery (cooling), and even to enhance the quality of sleep. Together, these multiscale applications of nanoparticle heating and thermoregulation point to dramatic opportunities for translation and impact in these prophylactic, preservative, diagnostic, and therapeutic applications of bioheat transfer.

Level of Cutaneous Blood Flow Depression During Cryotherapy Depends on Applied Temperature: Criteria for Protocol Design

Cryotherapy is commonly used for the management of soft tissue injury. The dose effect of the applied cooling temperature has not been quantified previously. Six subjects were exposed during five different experiments to local skin temperatures of 16.6 °C, 19.8 °C, 24.7 °C, 27.3 °C, and 37.2 °C for 1 h of active heat transfer followed by 2 h of passive environmental interaction. Skin blood perfusion and temperature were measured continuously at treatment and control sites. All treatments resulted in significant changes in cutaneous vascular conductance (CVC, skin perfusion/mean arterial pressure) compared to baseline values. The drop in CVC for cooling to both 19.8 °C and 16.6 °C was significantly larger than for 27.3 °C (P < 0.05 and P < 0.0005, respectively). The depression of CVC for cooling to 16.6 °C was significantly larger than at 24.7 °C (P < 0.05). Active warming at 37.2 °C produced more than a twofold increase in CVC (P < 0.05). A simulation model was developed to describe the coupled effects of exposure time and temperature on skin perfusion. The model was applied to define an equivalent cooling dose defined by exposure time and temperature that produced equivalent changes in skin perfusion. The model was verified with data from 22 independent cryotherapy experiments. The equivalent doses were applied to develop a nomogram to identify therapeutic time and temperature combinations that would produce a targeted vascular response. The nomogram may be applied to design cryotherapy protocols that will yield a desired vascular response history that may combine the benefits of tissue temperature reduction while diminishing the risk of collateral ischemic injury.

From Nanowarming to Thermoregulation: New Multiscale Applications of Bioheat Transfer

This review explores bioheat transfer applications at multiple scales from nanoparticle (NP) heating to whole-body thermoregulation. For instance, iron oxide nanoparticles are being used for nanowarming, which uniformly and quickly rewarms 50-80-mL (≤5-cm-diameter) vitrified systems by coupling with radio-frequency (RF) fields where standard convective warming fails. A modification of this approach can also be used to successfully rewarm cryopreserved fish embryos (∼0.8 mm diameter) by heating previously injected gold nanoparticles with millisecond pulsed laser irradiation where standard convective warming fails. Finally, laser-induced heating of gold nanoparticles can improve the sensitivity of lateral flow assays (LFAs) so that they are competitive with laboratory tests such as the enzyme-linked immunosorbent assay. This approach addresses the main weakness of LFAs, which are otherwise the cheapest, easiest, and fastest to use point-of-care diagnostic tests in the world. Body core temperature manipulation has now become possible through selective thermal stimulation (STS) approaches. For instance, simple and safe heating of selected areas of the skin surface can open arteriovenous anastomosis flow in glabrous skin when it is not already established, thereby creating a convenient and effective pathway to induce heat flow between the body core and environment. This has led to new applications of STS to increase or decrease core temperatures in humans and animals to assist in surgery (perioperative warming), to aid ischemic stress recovery (cooling), and even to enhance the quality of sleep. Together, these multiscale applications of nanoparticle heating and thermoregulation point to dramatic opportunities for translation and impact in these prophylactic, preservative, diagnostic, and therapeutic applications of bioheat transfer.

Pronounced and sustained cutaneous vasoconstriction during and following cyrotherapy treatment: Role of neurotransmitters released from sympathetic nerves

Cryotherapy is a therapeutic technique using ice or cold water applied to the skin to manage soft tissue trauma and injury. While beneficial, there are some potentially detrimental side effects, such as pronounced vasoconstriction and tissue ischemia that are sustained for hours post-treatment. This study tested the hypothesis that this vasoconstriction is mediated by 1) activation of post-synaptic α-adrenergic receptors and/or 2) activation of post-synaptic neuropeptide Y1 (NPY Y1) receptors. 8 subjects were fitted with a commercially available cryotherapy unit with a water perfused bladder on the lateral portion of the right calf. Participants were instrumented with four intradermal microdialysis probes beneath the bladder. The following conditions were applied at the four treatment sites: 1) control (Ringer solution), 2) combined post-synaptic β-adrenergic receptors and neuropeptide (NPY) Y₁ receptors blockade (P+B site), 3) combined post-synaptic α-adrenergic receptor, β-adrenergic receptor, and NPY Y₁ receptor blockade (Y+P+B site), and 4) blockade of pre-synaptic release of all neurotransmitters from the sympathetic nerves (BT site). Following thermoneutral baseline data collection, 1°C water was perfused through the bladder for 30min, followed by passive rewarming for 60min. Skin temperature (T_skin) fell from ~34°C to ~18.5°C during active cooling across all sites and there was no difference between sites (P>0.05 vs. control for each site). During passive rewarming T_skin rose to a similar degree in all sites (P>0.05 relative to the end of cooling). In the first 20min of cooling %CVC was reduced at all sites however, this response was blunted in the BT and the Y+P+B sites (P>0.05 for all comparisons). By the end of cooling the degree of vasoconstriction was similar between sites with the exception that the reduction in %CVC in the Y+B+P site was less relative to the reduction in the control site. %CVC was unchanged in any of the sites during passive rewarming such that each remained similar to values obtained at the end of active cooling. These findings indicate that the initial vasoconstriction (i.e. within the 1st 20min) that occurs during cryotherapy induced local cooling is achieved via activation of post-synaptic α-adrenergic receptors; whereas nonadrenergic mechanisms predominate as the duration of cooling continues. The sustained vasoconstriction that occurs following cessation of the cooling stimulus does not appear to be related to activation of post-synaptic α-adrenergic receptors or NPY Y1 receptor.

Indoxyl sulfate potentiates endothelial dysfunction via reciprocal role for reactive oxygen species and RhoA/ROCK signaling in 5/6 nephrectomized rats

Accumulative indoxyl sulfate (IS) retained in chronic kidney disease (CKD) can potentiate vascular endothelial dysfunction, and herein, we aim at elucidating the underlying mechanisms from the perspective of possible association between reactive oxygen species (ROS) and RhoA/ROCK pathway. IS-treated nephrectomized rats are administered with antioxidants including NADPH oxidase inhibitor apocynin, SOD analog tempol, and mitochondrion-targeted SOD mimetic mito-TEMPO to scavenge ROS, or ROCK inhibitor fasudil to obstruct RhoA/ROCK pathway. First, we find in response to IS stimulation, antioxidants treatments suppress increased aortic ROCK activity and expression levels. Additionally, ROCK blockade prevent IS-induced increased NADPH oxidase expression (mainly p22phox and p47phox), mitochondrial and intracellular ROS (superoxide and hydrogen peroxide) generation, and decreased Cu/Zn-SOD expression in thoracic aortas. Apocynin, mito-TEMPO, and tempol also reverse these markers of oxidative stress. These results suggest that IS induces excessive ROS production and ROCK activation involving a circuitous relationship in which ROS activate ROCK and ROCK promotes ROS overproduction. Finally, ROS and ROCK depletion attenuate IS-induced decrease in nitric oxide (NO) production and eNOS expression levels, and alleviate impaired vasomotor responses including increased vasocontraction to phenylephrine and decreased vasorelaxation to acetylcholine, thereby preventing cardiovascular complications accompanied by CKD. Taken together, excessive ROS derived from NADPH oxidase and mitochondria coordinate with RhoA/ROCK activation in a form of positive reciprocal relationship to induce endothelial dysfunction through disturbing endothelium-dependent NO signaling upon IS stimulation in CKD status.

Intradermal administration of endothelin-1 attenuates endothelium-dependent and -independent cutaneous vasodilation via Rho kinase in young adults

We recently showed that intradermal administration of endothelin-1 diminished endothelium-dependent and -independent cutaneous vasodilation. We evaluated the hypothesis that Rho kinase may be a mediator of this response. We also sought to evaluate if endothelin-1 increases sweating. In 12 adults (25 ± 6 yr), we measured cutaneous vascular conductance (CVC) and sweating during 1) endothelium-dependent vasodilation induced via administration of incremental doses of methacholine (0.25, 5, 100, and 2,000 mM each for 25 min) and 2) endothelium-independent vasodilation induced via administration of 50 mM sodium nitroprusside (20-25 min). Responses were evaluated at four skin sites treated with either 1) lactated Ringer solution (Control), 2) 400 nM endothelin-1, 3) 3 mM HA-1077 (Rho kinase inhibitor), or 4) endothelin-1+HA-1077. Pharmacological agents were intradermally administered via microdialysis. Relative to the Control site, endothelin-1 attenuated endothelium-dependent vasodilation (CVC at 2,000 mM methacholine, 80 ± 10 vs. 56 ± 15%max, P < 0.01); however, this response was not detected when the Rho kinase inhibitor was simultaneously administered (CVC at 2,000 mM methacholine for Rho kinase inhibitor vs. endothelin-1 + Rho kinase inhibitor sites: 73 ± 9 vs. 72 ± 11%max, P > 0.05). Endothelium-independent vasodilation was attenuated by endothelin-1 compared with the Control site (CVC, 92 ± 13 vs. 70 ± 14%max, P < 0.01). However, in the presence of Rho kinase inhibition, endothelin-1 did not affect endothelium-independent vasodilation (CVC at Rho kinase inhibitor vs. endothelin-1+Rho kinase inhibitor sites: 81 ± 9 vs. 86 ± 10%max, P > 0.05). There was no between-site difference in sweating throughout (P > 0.05). We show that in young adults, Rho kinase is an important mediator of the endothelin-1-mediated attenuation of endothelium-dependent and -independent cutaneous vasodilation, and that endothelin-1 does not increase sweating.