Statins-Their Role in Bone Tissue Metabolism and Local Applications with Different Carriers

Statins, widely prescribed for lipid disorders, primarily target 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase competitively and reversibly, resulting in reduced low-density lipoprotein cholesterol (LDL-C). This mechanism proves effective in lowering the risk of lipid-related diseases such as ischemic cerebrovascular and coronary artery diseases. Beyond their established use, statins are under scrutiny for potential applications in treating bone diseases. The focus of research centers mainly on simvastatin, a lipophilic statin demonstrating efficacy in preventing osteoporosis and aiding in fracture and bone defect healing. Notably, these effects manifest at elevated doses (20 mg/kg/day) of statins, posing challenges for systematic administration due to their limited bone affinity. Current investigations explore intraosseous statin delivery facilitated by specialized carriers. This paper outlines various carrier types, characterizing their structures and underscoring various statins' potential as local treatments for bone diseases.

Applications of Calcium-Based Nanomaterials in Osteoporosis Treatment

With rapidly aging populations worldwide, osteoporosis has become a serious global public health problem. Caused by disordered systemic bone remodeling, osteoporosis manifests as progressive loss of bone mass and microarchitectural deterioration of bone tissue, increasing the risk of fractures and eventually leading to osteoporotic fragility fractures. As fracture risk increases, antiosteoporosis treatments transition from nonpharmacological management to pharmacological intervention, and finally to the treatment of fragility fractures. Calcium-based nanomaterials (CBNMs) have unique advantages in osteoporosis treatment because of several characteristics including similarity to natural bone, excellent biocompatibility, easy preparation and functionalization, low pH-responsive disaggregation, and inherent pro-osteogenic properties. By combining additional ingredients, CBNMs can play multiple roles to construct antiosteoporotic biomaterials with different forms. This review covers recent advances in CBNMs for osteoporosis treatment. For ease of understanding, CBNMs for antiosteoporosis treatment can be classified as locally applied CBNMs, such as implant coatings and filling materials for osteoporotic bone regeneration, and systemically administered CBNMs for antiosteoporosis treatment. Locally applied CBNMs for osteoporotic bone regeneration develop faster than the systemically administered CBNMs, an important consideration given the serious outcomes of fragility fractures. Nevertheless, many innovations in construction strategies and preparation methods have been applied to build systemically administered CBNMs. Furthermore, with increasing interest in delaying osteoporosis progression and avoiding fragility fracture occurrence, research into systemic administration of CBNMs for antiosteoporosis treatment will have more development prospects. Deep understanding of the CBNM preparation process and optimizing CBNM properties will allow for increased application of CBNMs in osteoporosis treatments in the future.

Is There a Role for Preoperative Local Infiltration of Tranexamic Acid in Elective Spine Surgery? A Prospective Randomized Controlled Trial Analyzing the Efficacy of Intravenous, Local Infiltration, and Topical Administration of Tranexamic Acid

STUDY DESIGN

Randomized control trial.

OBJECTIVE

The purpose of the study is to evaluate the safety and efficacy of tranexamic acid in reducing blood loss when administered through various routes in instrumented spine surgeries.

METHODS

A total of 104 patients undergoing instrumented spine surgery were randomly assigned to 4 groups (n = 26 in each group). Groups included (1) ivTXA-intravenous administration of tranexamic acid (TXA) 1 hour prior to surgery, (2) loTXA-local infiltration of TXA bilaterally into the paraspinal musculature prior to incision, (3) tTXA-topical application of TXA just before wound closure, and (4) control group. Outcome measures included intraoperative blood loss, postoperative blood loss, need for blood transfusion, length of hospital stay, and hematological parameters.

RESULTS

All the 3 different modes of TXA administration were found to be effective in reducing blood loss in the treated groups compared with the control group. Intraoperative blood loss was significantly reduced in ivTXA (223.6 ± 40.1 mL, P < .0001) and loTXA (256.07 ± 119 mL, P = .0039) groups when compared with controls (344 ± 88.5 mL).The postoperative blood loss was least in tTXA followed by ivTXA, loTXA, and controls. There was 67% reduction in need for blood transfusion in tTXA group, 55.5% reduction in ivTXA group, and 33% reduction in loTXA group when compared with the control group.

CONCLUSION

In instrumented spine surgery, ivTXA and loTXA were found to be equally effective in reducing the intraoperative blood loss. The tTXA has better postoperative blood conserving effects. This is the first study to detail about safety and efficacy on local infiltration of TXA in spine surgery, which is an effective and safe method for reducing intraoperative blood loss.

No Decrease in Infection Rate with the Use of Local Vancomycin Powder After Partial Hip Replacement in Elderly Patients with Comorbidities

Introduction

The goal of this study was to evaluate the effects of local intra-wound vancomycin powder (VP) administration to decrease surgical site infections (SSIs), particularly in elderly patients with comorbidities, after having undergone partial hip replacement in the treatment of intertrochanteric (ITF) or femoral neck fractures (FNF).

Methods

We retrospectively reviewed patients who underwent partial hip replacement in the treatment of ITF or FNF in one year. We divided the patients into two groups. The non vancomycin-treated group received standard systemic prophylaxis only (1 gr cefazolin IV), while the vancomycin-treated group received 1 gr of VP in the surgical wound just before surgical closure in addition to the systemic prophylaxis. We included patients of 64 years or older who also had one or more comorbidities. We compared the post-operative SSI rates between the non vancomycin-treated group and the vancomycin-treated group.

Results

A total of 93 patients were included in the study. We detected post-operative wound infection in six patients (6.4%). The rate of SSI was found to be 5.7% in the vancomycin-treated group and 6.9% in the non vancomycin-treated group respectively, which showed no statistically significant difference (p:0.498). The incidence of SSI was statistically higher in the patients who had a follow-up in the post-operative intensive care unit than the patients who had not any follow-up in the intensive care unit.

Conclusion

Local application of VP in the surgical wound was found to be ineffective in reducing the incidence of SSI after partial hip replacement in elderly patients with comorbidities.

Saponin Micelles Lead to High Mucosal Permeation and In Vivo Efficacy of Solubilized Budesonide

Due to fast nasal mucociliary clearance, only the dissolved drug content can effectively permeate the mucosa and be pharmaceutically active after intranasal application of suspensions. Therefore, the aim of this study was to increase the budesonide concentration in solution of a nasal spray formulation. Budesonide, a highly water-insoluble corticosteroid, was successfully solubilized using a micellar formulation comprising escin, propylene glycol and dexpanthenol in an aqueous buffered environment (“Budesolv”). A formulation based on this micellar system was well-tolerated in the nasal cavity as shown in a good laboratory practice (GLP) local tolerance study in rabbits. Ex vivo permeation studies into porcine nasal mucosa revealed a faster and more efficient absorption. Budesolv with 300 µg/mL solubilized budesonide resulted in a budesonide concentration of 42 µg/g tissue after only 15 min incubation. In comparison, incubation with the marketed product Rhinocort^® aqua 64 (1.28 mg/mL budesonide as suspension) led to 15 µg/g tissue. The in vivo tumor-necrosis-factor (TNF)-α secretion in an acute lung inflammation mouse model was significantly reduced (p < 0.001) following a prophylactic treatment with Budesolv compared to Rhinocort^® aqua 64. Successful treatment 15 min after the challenge was only possible with Budesolv (40% reduction of TNF-α, p = 0.0012) suggesting a faster onset of action. The data reveal that solubilization based on saponin micelles presents an opportunity for the development of products containing hardly soluble substances that result in a faster onset and a better topical treatment effect.

[The effectiveness of local application of vancomycin powder in the prevention of surgical site infections in spine surgery: a meta-analysis]

OBJECTIVE

To perform a meta-analysis of studies examining the effectiveness of the local application of vancomycin powder for the prophylaxis of surgical site infections (SSIs) in spine surgery.

MATERIAL AND METHODS

Retrospective cohort studies and prospective randomized clinical trials were searched for in the Pubmed, EMBASE, Cochrane Library and eLibrary databases published from 2008 to December 2018. For the resulting variables, the odds ratio and 95% confidence interval were calculated using random and fixed effects models. Estimation of the degree of heterogeneity is estimated using the coefficient I². Statistically significant differences were considered differences p<0.05.

RESULTS

The meta-analysis included 28 clinical studies that included the results of the local application of vancomycin powder in 17,469 patients after performing various spinal surgical interventions. Two publications had a prospective, randomized, controlled study design. Topical application of vancomycin powder reduces the incidence of SSIs after spine surgery (p<0.0001). The use of vancomycin powder reduces the incidence of SSIs in patients operated on with stabilizing implants (p=0.004). On the other hand, the topical application of vancomycin powder did not affect the prevalence of SSIs in respondents who were operated on without the use of stabilizing implants (p=0.12) or due to deformities of the spine (p=0.06).

CONCLUSION

Topical application of vancomycin powder is highly effective in preventing the development of SSIs in patients after spinal surgical interventions.

In vitro and in vivo testing of a novel local nicardipine delivery system to the brain: a preclinical study

OBJECTIVE

The management of patients with aneurysmal subarachnoid hemorrhage (aSAH) remains a highly demanding challenge in critical care medicine. Despite all efforts, the calcium channel antagonist nimodipine remains the only drug approved for improving outcomes after aSAH. However, in its current form of application, it provides less than optimal efficacy and causes dose-limiting hypotension in a substantial number of patients. Here, the authors tested in vitro the release dynamics of a novel formulation of the calcium channel blocker nicardipine and in vivo local tolerance and tissue reaction using a chronic cranial window model in mice.

METHODS

To characterize the release kinetics in vitro, dissolution experiments were performed using artificial cerebrospinal fluid over a time period of 21 days. The excipients used in this formulation (NicaPlant) for sustained nicardipine release are a mixture of two completely degradable polymers. A chronic cranial window in C57BL/6 mice was prepared, and NicaPlant slices were placed in proximity to the exposed cerebral vasculature. Epifluorescence video microscopy was performed right after implantation and on days 3 and 7 after surgery. Vessel diameter of the arteries and veins, vessel permeability, vessel configuration, and leukocyte-endothelial cell interaction were quantified by computer-assisted analysis. Immunofluorescence staining was performed to analyze inflammatory reactions and neuronal alterations.

RESULTS

In vitro the nicardipine release profile showed an almost linear curve with about 80% release at day 15 and full release at day 21. In vivo epifluorescence video microscopy showed a significantly higher arterial vessel diameter in the NicaPlant group due to vessel dilatation (21.6 ± 2.6 µm vs 17.8 ± 1.5 µm in controls, p < 0.01) confirming vasoactivity of the implant, whereas the venous diameter was not affected. Vessel dilatation did not have any influence on the vessel permeability measured by contrast extravasation of the fluorescent dye in epifluorescence microscopy. Further, an increased leukocyte-endothelial cell interaction due to the implant could not be detected. Histological analysis did not show any microglial activation or accumulation. No structural neuronal changes were observed.

CONCLUSIONS

NicaPlant provides continuous in vitro release of nicardipine over a 3-week observation period. In vivo testing confirmed vasoactivity and lack of toxicity. The local application of this novel nicardipine delivery system to the subarachnoid space is a promising tool to improve patient outcomes while avoiding systemic side effects.

Characterization of New TRPM8 Modulators in Pain Perception

BACKGROUND

Transient Receptor Potential Melastatin-8 (TRPM8) is a non-selective cation channel activated by cold temperature and by cooling agents. Several studies have proved that this channel is involved in pain perception. Although some studies indicate that TRPM8 inhibition is necessary to reduce acute and chronic pain, it is also reported that TRPM8 activation produces analgesia. These conflicting results could be explained by extracellular Ca²⁺-dependent desensitization that is induced by an excessive activation. Likely, this effect is due to phosphatidylinositol 4,5-bisphosphate (PIP2) depletion that leads to modification of TRPM8 channel activity, shifting voltage dependence towards more positive potentials. This phenomenon needs further evaluation and confirmation that would allow us to understand better the role of this channel and to develop new therapeutic strategies for controlling pain.

EXPERIMENTAL APPROACH

To understand the role of TRPM8 in pain perception, we tested two specific TRPM8-modulating compounds, an antagonist (IGM-18) and an agonist (IGM-5), in either acute or chronic animal pain models using male Sprague-Dawley rats or CD1 mice, after systemic or topical routes of administration.

RESULTS

IGM-18 and IGM-5 were fully characterized in vivo. The wet-dog shake test and the body temperature measurements highlighted the antagonist activity of IGM-18 on TRPM8 channels. Moreover, IGM-18 exerted an analgesic effect on formalin-induced orofacial pain and chronic constriction injury-induced neuropathic pain, demonstrating the involvement of TRPM8 channels in these two pain models. Finally, the results were consistent with TRPM8 downregulation by agonist IGM-5, due to its excessive activation.

CONCLUSIONS

TRPM8 channels are strongly involved in pain modulation, and their selective antagonist is able to reduce both acute and chronic pain.

[Local administration of vancomycin powder in posterior lumbar fusion surgery]

AIM

To evaluate an efficacy of local administration of vancomycin powder in posterior lumbar fusion surgery for prevention of local infection.

MATERIAL AND METHODS

The study included 214 patients. All patients were divided into 2 groups: I group (control) and II (experimental). Patients of the first group underwent conventional antibiotic prophylaxis of wound infections, in group II traditional antibiotic prophylaxis was supplemented by local administration of vancomycin powder 1 g prior to wound closure.

RESULTS

There were 12 cases of wound infection in group I and 5 cases in group II. There were significant differences in overall incidence of wound infection and wound infections caused by S. aureus (p=0.035; p=0.044, respectively). Significant risk factors of local infection were determined in group II: obesity, diabetes mellitus, arterial hypertension, coronary artery disease, length of hospital-stay and previous lumbosacral spinal surgery. Multivariate analysis revealed following risk factors of wound infection: diabetes mellitus, arterial hypertension, coronary artery disease, the number of involved spinal segments and previous lumbosacral spinal surgery.

CONCLUSION

Local application of vancomycin powder in posterior lumbar fusion surgery significantly reduces the incidence of wound infection.

Cade oil poisoning: about a case

Throughout Morocco, cade oil is used in folk medicine for many purposes, in particular for atopic dermatosis. It is also used as a wormer. Cade oil poisoning of newborns and infants thus often has an iatrogenic origin, resulting especially from the ingestion of a significant amount or from a prolonged and extensive cutaneous application. Thus, this oil, used for therapeutic purposes, is responsible for a non-negligible number of cases of poisoning, some fatal. We report a case of poisoning after cutaneous application of cade oil in a 2-month-old infant. The outcome was fatal. This report calls attention to the real possibility of this event and emphasizes the interest of preventing it by promoting information to families in Morocco.

A randomized controlled clinical trial of topical insulin-like growth factor-1 therapy for sudden deafness refractory to systemic corticosteroid treatment

BACKGROUND

To date, no therapeutic option has been established for sudden deafness refractory to systemic corticosteroids. This study aimed to examine the efficacy and safety of topical insulin-like growth factor-1 (IGF-1) therapy in comparison to intratympanic corticosteroid therapy.

METHODS

We randomly assigned patients with sudden deafness refractory to systemic corticosteroids to receive either gelatin hydrogels impregnated with IGF-1 in the middle ear (62 patients) or four intratympanic injections with dexamethasone (Dex; 58 patients). The primary outcome was the proportion of patients showing hearing improvement (10 decibels or greater in pure-tone average hearing thresholds) 8 weeks after treatment. The secondary outcomes included the change in pure-tone average hearing thresholds over time and the incidence of adverse events.

RESULTS

In the IGF-1 group, 66.7% (95% confidence interval [CI], 52.9-78.6%) of the patients showed hearing improvement compared to 53.6% (95% CI, 39.7-67.0%) of the patients in the Dex group (P = 0.109). The difference in changes in pure-tone average hearing thresholds over time between the two treatments was statistically significant (P = 0.003). No serious adverse events were observed in either treatment group. Tympanic membrane perforation did not persist in any patient in the IGF-1 group, but did persist in 15.5% (95% CI, 7.3-27.4%) of the patients in the Dex group (P = 0.001).

CONCLUSIONS

The positive effect of topical IGF-1 application on hearing levels and its favorable safety profile suggest utility for topical IGF-1 therapy in patients with sudden deafness.

TRIAL REGISTRATION

UMIN Clinical Trials Registry Number UMIN000004366, October 30th, 2010.

Assessment of the effect of local application of amifostine on acute radiation-induced oral mucositis in guinea pigs

The aim of present study was to assess the radioprotective effects of the local application of amifostine to treat acute buccal mucositis in guinea pigs. A total of 32 guinea pigs were randomized into four groups: (Group A) topically administered 50 mg of amifostine plus radiotherapy (RT); (Group B) 100 mg amifostine plus RT; (Group C) normal saline plus RT; and (Group D) normal saline plus sham RT. The opportunity for administration was 15 min before irradiation. When administered, the cotton pieces that had been soaked with 0.5 ml amifostine solution or saline were applied gently on the buccal mucosa of each guinea pig for 30 min. The animals in Groups A, B and C were irradiated individually with a single dose of 30 Gy to the bilateral buccal mucosa. Eight days after irradiation, the animals were scored macroscopically; they were then euthanized, and the buccal mucosal tissues were processed for hematoxylin-eosin staining and ICAM-1 immunohistochemical analysis. In Groups A and B, the mean macroscopic scores were 2.9 ± 0.6 and 2.4 ± 1.1, respectively. There was no significant difference between the two groups (P > 0.05). However, when they were separately compared with Group C (4.4 ± 0.7), a noticeable difference was obtained (P < 0.05). No mucositis was observed in Group D. Comparisons of the expression of ICAM-1 were in agreement with the macroscopic data. Histologically, superficial erosion, exudate and ulcer formation were all observed in the RT groups; only the severity and extent were different. The microscopic observations in the amifostine-treated groups were better than in Group C. The results demonstrated that topical administration of amifostine to the oral mucosa is effective treatment of acute radiation-induced mucositis.

Intrawound application of vancomycin reduces wound infection after open release of post-traumatic stiff elbows: a retrospective comparative study

BACKGROUND

With the improvements in wound healing through the use of intravenous prophylactic antibiotics and technical refinements, postoperative elbow infections have become less common but still occur in certain elective elbow surgeries. The objective of this study was to evaluate the safety and efficacy of prophylactic application of vancomycin into the operative site to reduce the incidence of infection after the open release of post-traumatic stiff elbows.

METHODS

A retrospective review of 272 such patients during a 4-year period was performed. In the control group (93 patients), simple prophylaxis with standard intravenous antibiotics was performed; in the vancomycin group (179 patients), vancomycin powder was applied directly into the wound before closure along with standard intravenous prophylaxis.

RESULTS

After a follow-up of at least 6 months, the control group was found to have 6 infections (6.45%; confidence interval: 2.40%-13.52%) compared with none (0%; confidence interval: 0-2%.04%) in the vancomycin group, which was a statistically significant difference (P = .0027). No adverse effects were documented from the direct use of the vancomycin powder.

CONCLUSIONS

The local application of vancomycin powder may be a promising means of preventing postoperative elbow infections after elbow release in patients with post-traumatic elbow stiffness.

Levels of sirolimus in saliva and blood following mouthwash application

OBJECTIVES

Sirolimus (rapamycin) is a mammalian target of rapamycin (mTOR) inhibitor with antiproliferative activity. Its systemic administration is currently evaluated for the management of squamous cell carcinoma and various oral disorders. Topical oral application can enhance availability, efficacy and improve safety and compliance. Our objective was to evaluate the release profile and the safety of a sirolimus mouthwash.

SUBJECTS AND METHODS

A sirolimus mouthwash (0.05 mg ml(-1) ) was applied to ten healthy male volunteers. Saliva and blood samples were taken after rinsing. Mass spectrometry and chemiluminescent microparticle immunoassay were used to determine saliva and blood levels of sirolimus. A topical oral release profile measurement and safety evaluation were performed.

RESULTS

After rinsing with the mouthwash, a classic immediate release profile was noted in the oral cavity. Extremely high initial sirolimus levels rapidly declined over a 4-hour period. Systemic exposure was limited, with a maximum level significantly lower than therapeutic doses, and safety was confirmed.

CONCLUSIONS

A single rinse with sirolimus mouthwash leads to high transient levels of the drug in the saliva. Although levels were variable, a therapeutic concentration was achieved topically along with minimal systemic absorption. These results broaden the potential clinical use of oral topical rapalogs.

Interleukin-2 in cancer treatment: disappointing or (still) promising? A review

The central question to discuss in this review is whether the results of interleukin-2 (IL-2) treatment are still disappointing or again promising. Although in the (recent) past application of high doses of systemically applied rIL-2 has led to some success, the overall results are not as one had hoped. Considering these poor results it seems clear that the application of high systemic doses rIL-2 was not a good choice. IL-2 has been used more or less as a chemotherapeutic compound in the highest tolerable dose. This has led to a great number of unwanted toxic side-effects. In addition, these doses mainly stimulated nonspecific lymphokine-activated killer activity through low-affinity IL-2 receptors, which does not lead to systemic immunity. On the other hand, several groups have shown that application of intratumoral low doses of IL-2 can be highly effective against cancer and without toxic side-effects. Significant tumor loads constituting up to 6% of the total body weight of a mouse were eradicated after treatment with low-dose rIL-2 given locally. Furthermore local treatment can lead to eradication of a tumor at a distant site. This type of therapy is effective in many systems namely against different tumor types in mice, hepatocellular carcinoma in guinea-pigs and vulval papilloma and carcinoma and ocular carcinoma in cattle. Low-dose IL-2 is very effective in experimental animals if it is given relatively late after inoculation of the tumor cells. In other words, it seems necessary that some sort of immune reaction has started or is developing before low doses of rIL-2 effectively stimulate it. In fact there is strong evidence that T lymphocytes, both CD4+ and CD8+ cells, are directly involved in the process leading to induction of specific immunity. In our opinion rIL-2 therapy should therefore aim at the stimulation of such (originally weak) specific immune reaction. Under these conditions also systemic immunity can be induced. In conclusion, application of rIL-2 as a modality for cancer treatment is still promising. High priority should be given to a further delineation of the mechanisms involved after local application. The method of giving IL-2 systemically in the highest tolerable dose should be abandoned. Specific stimulation of the immune system by low-dose rIL-2 is a much more promising option.