madman
Super Moderator
Abstract
Mineralized Peyronie’s plaque (MPP) impairs penile function. The association, colocalization, and dynamic interplay between organic and inorganic constituents can provide insights into the biomineralization of Peyronie's plaque. Human MPPs (n = 11) were surgically excised, and the organic and inorganic constituents were spatially mapped using multiple high-resolution imaging techniques. Multiscale image analyses resulted in spatial colocalization of elements within a highly porous material with heterogenous composition, lamellae, and osteocytic lacuna-like features with a morphological resemblance to bone. The lower (520 ±179 mg/cc) and higher (1024 ± 155 mg/cc) mineral density regions were associated with higher (11%) and lower (7%) porosities in MPP. Energy-dispersive X-ray and micro-X-ray fluorescent spectroscopic maps in the higher mineral density regions of MPP revealed higher counts of calcium (Ca) and phosphorus (P), and a Ca/P ratio of 1.48 ± 0.06 similar to bone. More importantly, higher counts of zinc (Zn) were localized at the interface between softer (more organic to inorganic ratio) and harder (less organic to inorganic ratio) tissue regions of MPP and adjacent softer matrix, indicating the involvement of Zn-related proteins and/or pathways in the formation of MPP. In particular, dentin matrix protein-1 (DMP-1) was colocalized in a matrix rich in proteoglycans and collagen that contained osteocytic lacuna-like features. This combined materials science and biochemical with correlative microspectroscopic approach provided insights into the plausible cellular and biochemical pathways that incite mineralization of an existing fibrous Peyronie’s plaque.
Statement of Significance
Aberrant human penile mineralization is known as mineralized Peyronie’s plaque (MPP) and often results in a loss of form and function. This study focuses on investigating the spatial association of matrix proteins and elemental composition of MPP by colocalizing calcium, phosphorus, and trace metal zinc with dentin matrix protein 1 (DMP-1), acidic proteoglycans, and fibrillar collagen along with the cellular components using high-resolution correlative microspectroscopic techniques. Spatial maps provided insights into cellular and biochemical pathways that incite the mineralization of fibrous Peyronie’s plaque in humans.
1. INTRODUCTION
Aberrant human penile mineralization is known as mineralized Peyronie’s plaque (MPP) [1]. The genesis of MPP is reliant on the formation of fibrotic plaque in the tunica albuginea of the penile corpora cavernosum [2, 3]. Fibrillar proteins including collagen, elastin, and fibronectin were identified in the fibrotic plaque of the MPP [4, 5]. MPP commonly forms on the dorsal aspect of the penis and can result in a loss of form and thereby function [6].
The biomineralization process of MPP [1] resembles heterotopic ossification (HO). HO results from fibroblast proliferation stimulated by the repetitive mechanical insult to the tissue followed by microvascular injury and subsequent deposition of fibrin [7, 8]. MPP results from the differentiation of the fibroblasts in the tunica albuginea into myofibroblasts [9]. Myofibroblasts [10], smooth muscle cells [11, 12], and pericytes [13, 14] in blood vessels have been shown to undergo differentiation to osteogenic lineage in vitro. These cells are thought to be the initiators of mineralization of the softer but inflamed matrices. This biochemical pathway is thought to be a biologically controlled biomineralization process culminating in an MPP. Surgical excision of MPP followed by mechanical therapy to restore penile form and function is the current clinical intervention [1]. Inflammation-related processes as well as the cation and anion recruitment including the metal ion Zn2+ are unknown. Various qualitative results focus on the ultrastructure of MPP [15-17]. Limited studies exist on the spatial-temporal localization of the biochemical and cytochemical markers of MPP and the surrounding soft tissue. Additionally, the spatial and chemical association of elements including calcium and phosphorus toward mineralization of collagen fibrils within the fibrotic plaque and the role of the neurovascular bundle in the subsequent formation of MPP following an insult are yet to be understood. As such, some questions to ask include 1) does MPP grow from a mineralized nodule, and 2) does it begin as a fibrotic tissue and mineralize with phenotypic resemblance to bone? This study focuses on investigating the spatial association of matrix proteins and elemental composition of MPP by colocalizing Ca, P, and trace metal Zn with dentin matrix protein 1 (DMP-1), acidic proteoglycans, and fibrillar collagen along with the cellular components using high resolution correlative microspectroscopic techniques. Spatial maps of colocalized organic and inorganic constituents will provide insights into plausible biomineralization pathways of fibrotic Peyronie’s plaque and help guide effective clinical interventions.
*In summary, the correlative microspectroscopic approach on quantitative spatial mapping of MD, elements, and matrix alluded to MPP as HO. Both MPP and HO appear to share mechanobiological pathways, that is, mechanical trauma as a possible cue for soft tissue conversion into hard tissue. Overall, results suggest a systematic well-orchestrated interplay between the metal ion Zn2+ and matrix proteins that incite mineralization of Peyronie’s fibrotic plaque.
5. CONCLUSIONS
Zn, plausibly in the form of trace metal ion Zn2+, was localized at the interface of softer and harder tissues of MPP, indicating the role of Zn-related biochemical pathways in the biomineralization of fibrotic Peyronie’s plaque. Future studies should investigate the phase of mineralized particles, i.e., amorphous or crystalline, in association with the ECM proteins through the use of mechanobiological functional assays. These mechanistic models will reveal the direct influence of shifts in cellular expressions and differentiation. These cellular processes result in a shift in tissue compliance; all of which are necessary to map the biomineralization pathways to mitigate heterotopic mineralization in tissues which otherwise would result in loss of function.
Mineralized Peyronie’s plaque (MPP) impairs penile function. The association, colocalization, and dynamic interplay between organic and inorganic constituents can provide insights into the biomineralization of Peyronie's plaque. Human MPPs (n = 11) were surgically excised, and the organic and inorganic constituents were spatially mapped using multiple high-resolution imaging techniques. Multiscale image analyses resulted in spatial colocalization of elements within a highly porous material with heterogenous composition, lamellae, and osteocytic lacuna-like features with a morphological resemblance to bone. The lower (520 ±179 mg/cc) and higher (1024 ± 155 mg/cc) mineral density regions were associated with higher (11%) and lower (7%) porosities in MPP. Energy-dispersive X-ray and micro-X-ray fluorescent spectroscopic maps in the higher mineral density regions of MPP revealed higher counts of calcium (Ca) and phosphorus (P), and a Ca/P ratio of 1.48 ± 0.06 similar to bone. More importantly, higher counts of zinc (Zn) were localized at the interface between softer (more organic to inorganic ratio) and harder (less organic to inorganic ratio) tissue regions of MPP and adjacent softer matrix, indicating the involvement of Zn-related proteins and/or pathways in the formation of MPP. In particular, dentin matrix protein-1 (DMP-1) was colocalized in a matrix rich in proteoglycans and collagen that contained osteocytic lacuna-like features. This combined materials science and biochemical with correlative microspectroscopic approach provided insights into the plausible cellular and biochemical pathways that incite mineralization of an existing fibrous Peyronie’s plaque.
Statement of Significance
Aberrant human penile mineralization is known as mineralized Peyronie’s plaque (MPP) and often results in a loss of form and function. This study focuses on investigating the spatial association of matrix proteins and elemental composition of MPP by colocalizing calcium, phosphorus, and trace metal zinc with dentin matrix protein 1 (DMP-1), acidic proteoglycans, and fibrillar collagen along with the cellular components using high-resolution correlative microspectroscopic techniques. Spatial maps provided insights into cellular and biochemical pathways that incite the mineralization of fibrous Peyronie’s plaque in humans.
1. INTRODUCTION
Aberrant human penile mineralization is known as mineralized Peyronie’s plaque (MPP) [1]. The genesis of MPP is reliant on the formation of fibrotic plaque in the tunica albuginea of the penile corpora cavernosum [2, 3]. Fibrillar proteins including collagen, elastin, and fibronectin were identified in the fibrotic plaque of the MPP [4, 5]. MPP commonly forms on the dorsal aspect of the penis and can result in a loss of form and thereby function [6].
The biomineralization process of MPP [1] resembles heterotopic ossification (HO). HO results from fibroblast proliferation stimulated by the repetitive mechanical insult to the tissue followed by microvascular injury and subsequent deposition of fibrin [7, 8]. MPP results from the differentiation of the fibroblasts in the tunica albuginea into myofibroblasts [9]. Myofibroblasts [10], smooth muscle cells [11, 12], and pericytes [13, 14] in blood vessels have been shown to undergo differentiation to osteogenic lineage in vitro. These cells are thought to be the initiators of mineralization of the softer but inflamed matrices. This biochemical pathway is thought to be a biologically controlled biomineralization process culminating in an MPP. Surgical excision of MPP followed by mechanical therapy to restore penile form and function is the current clinical intervention [1]. Inflammation-related processes as well as the cation and anion recruitment including the metal ion Zn2+ are unknown. Various qualitative results focus on the ultrastructure of MPP [15-17]. Limited studies exist on the spatial-temporal localization of the biochemical and cytochemical markers of MPP and the surrounding soft tissue. Additionally, the spatial and chemical association of elements including calcium and phosphorus toward mineralization of collagen fibrils within the fibrotic plaque and the role of the neurovascular bundle in the subsequent formation of MPP following an insult are yet to be understood. As such, some questions to ask include 1) does MPP grow from a mineralized nodule, and 2) does it begin as a fibrotic tissue and mineralize with phenotypic resemblance to bone? This study focuses on investigating the spatial association of matrix proteins and elemental composition of MPP by colocalizing Ca, P, and trace metal Zn with dentin matrix protein 1 (DMP-1), acidic proteoglycans, and fibrillar collagen along with the cellular components using high resolution correlative microspectroscopic techniques. Spatial maps of colocalized organic and inorganic constituents will provide insights into plausible biomineralization pathways of fibrotic Peyronie’s plaque and help guide effective clinical interventions.
*In summary, the correlative microspectroscopic approach on quantitative spatial mapping of MD, elements, and matrix alluded to MPP as HO. Both MPP and HO appear to share mechanobiological pathways, that is, mechanical trauma as a possible cue for soft tissue conversion into hard tissue. Overall, results suggest a systematic well-orchestrated interplay between the metal ion Zn2+ and matrix proteins that incite mineralization of Peyronie’s fibrotic plaque.
5. CONCLUSIONS
Zn, plausibly in the form of trace metal ion Zn2+, was localized at the interface of softer and harder tissues of MPP, indicating the role of Zn-related biochemical pathways in the biomineralization of fibrotic Peyronie’s plaque. Future studies should investigate the phase of mineralized particles, i.e., amorphous or crystalline, in association with the ECM proteins through the use of mechanobiological functional assays. These mechanistic models will reveal the direct influence of shifts in cellular expressions and differentiation. These cellular processes result in a shift in tissue compliance; all of which are necessary to map the biomineralization pathways to mitigate heterotopic mineralization in tissues which otherwise would result in loss of function.
